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A highly sensitive photonic crystal fiber temperature sensor based on Sagnac interferometer with full liquid filling is proposed. All of the air holes in the PCF are filled with temperature-sensitive liquid, the structure is analyzed theoretically and numerically using the finite element method. Since the sensitivity is related to the group birefringent grating, the size of the sensitivity can be reflected by comparing the absolute value of the group birefringent grating. The structure is optimized by modifying the diameter of d0, d1 and d2 of the air holes for the photonic crystal fiber. In the process of numerical calculation, the best parameters are selected by comparing the absolute value of the group birefringent grating near the special wavelength to obtain higher sensitivity. The average sensitivity of 35.14 nm/°C and − 27.71 nm/°C are obtained at 27–32 °C in a parametrically optimized structure and R2 are 0.98455 and 0.9779. The RI sensitivity is also studied as RI changes from 1.404 to 1.409, the average sensitivity are − 53,714 nm/RIU and − 47,714.29 nm/RIU. [ABSTRACT FROM AUTHOR]

A questionnaire survey on dermal symptoms and home environment was performed in eight Chinese cities (40 279 participants). Data on city level temperature, precipitation, PM10, NO2, and gross domestic product (GDP) per capita were collected. In total, 2.2% had eczema, 2.4% facial erythema (FE) and 2.6% seborrheic dermatitis symptoms (SD). Higher temperature was associated with eczema (OR = 1.09). Higher GDP per capita was related to less SD. Higher PM10 was related to SD. Suburban living was protective for eczema (OR = 0.77) (vs. urban). Living in old buildings (built before 1991) was related to eczema (OR = 1.42). Living near heavily trafficked roads was related to FE (OR = 1.33) and SD (OR = 1.35). Having new furniture was related to all symptoms (OR = 1.26–1.47). Burning mosquito coils (OR = 1.37–1.57) and incense (OR = 1.33–1.37) were associated with eczema, FE, or SD. Presence of cockroaches and rats/mice was associated with FE or SD (OR = 1.31–1.40). Using air conditioner, daily cleaning and frequently exposing bedding to sunshine were protective (OR = 0.60–0.83). In conclusion, higher temperature, higher PM10, urban living, living near heavily trafficked roads, old buildings, new furniture, burning mosquito coils and incense, and presence of cockroaches/rats/mice increased the risk of eczema, FE, or SD. Higher GDP, air conditioner, daily cleaning, and exposing bedding to sunshine were protective. [ABSTRACT FROM AUTHOR]

PETTENKOFER GOLD MEDAL The recipient of the 2020 Pettenkofer Gold Medal is Prof. Tunga Salthammer from Fraunhofer WKI. On behalf of the Academy of Fellows of ISIAQ, we wholeheartedly congratulate the 2020 Award Recipients and the 2020 New Academy Members 2020. The 2020 nomination committee (chaired by Prof. Jørn Toftum from the Technical University of Denmark) reviews the nominees and usually suggests a slate of <10 persons who are then officially elected by all Academy members during formal voting. In 2005, the IAIAS merged with ISIAQ and became the Academy of Fellows of ISIAQ (the Academy). [Extracted from the article]

Abstract: Die Rolle von Chemikalien in Innenraumumgebungen ist seit langem Gegenstand der Forschung. Die meisten der potenziellen Zielsubstanzen sind leichtflüchtige, flüchtige und schwerflüchtige organische Verbindungen (VVOCs, VOCs und SVOCs). In Abhängigkeit von ihren physikalischen Eigenschaften und Stoffübergangsbedingungen verteilen sie sich in oder zwischen der Gasphase, der Partikelphase, dem Hausstaub, Oberflächenfilmen, der Kleidung und anderen Textilien sowie Haut und Haaren der Bewohner. Demzufolge müssen Inhalation, Ingestion und dermale Aufnahme als relevante Wege für die Expositions‐Charakterisierung im Wohnbereich berücksichtigt werden. Die Exposition mit VVOCs, VOCs und SVOCs kann durch Messung ihrer Konzentrationen in den jeweiligen Innenraumkompartimenten oder durch Bestimmung der Zielverbindungen und/oder ihrer Metaboliten im Urin oder Blut erfasst werden. Die verschiedenen Expositionswege erfordern oft die Kombination eines komplexen und interdisziplinären theoretischen Hintergrunds mit experimentellen Methoden. Demzufolge bedarf es einer engen Kommunikation und Zusammenarbeit zwischen Chemikern und Expositionsforschern, um ein besseres Verständnis der Humanexposition mit chemischen Substanzen in verschiedenen Innenraumumgebungen zu erlangen. Eingebettet in den toxikologischen Kontext ist dies die Grundlage für die Erfassung von Gesundheitsrisiken und die Bestimmung von Kontrollstrategien oder ‐ansätzen zur Begrenzung solcher Risiken. [ABSTRACT FROM AUTHOR]

Abstract: There is an ongoing probing of the role of chemicals in the indoor environment. The majority of potential target substances are so‐called very volatile, volatile, and semi‐volatile organic compounds (VVOCs, VOCs, and SVOCs). Depending on their physical properties and the mass transfer conditions, they are distributed in or between the gas phase, particle phase, settled house dust, surface films, clothing, and other fabrics as well as the exposed skin and hair of the occupants themselves. Therefore, inhalation, ingestion, and dermal uptake all must be considered as relevant pathways for exposure assessment in human habitats. Exposure to VVOCs, VOCs, and SVOCs can be estimated by measuring their concentrations in relevant indoor compartments or by determining the amounts of the target compounds and/or their metabolites in urine and blood. Assessing the various routes of exposure often requires a combination of sophisticated and interdisciplinary theoretical background and experimental techniques. Consequently, close communication and collaboration between chemical and exposure scientists are needed to achieve a better understanding of human exposure to chemical substances in various indoor environments. Embedded in the toxicological context, this is the basis for assessing the corresponding health risks and for determining control strategies or approaches to limit such risks. [ABSTRACT FROM AUTHOR]

ABSTRACT: The phenomenon of “shear‐induced crystallization” is commonly observed for crystalline polymers. Herein, we demonstrate that this concept can be applied to promote the self‐assembly of the conductive nanowires (NWs) in dilute solution. It is found that, by a simple rotation‐assisted method, higher yield of poly(3‐butylthiophene) (P3BT) NWs in anisole solvent was obtained than the case under static condition. While the length as well as the crystal modification of the NWs is not changed. The structural analysis suggests that the P3BT NWs take the crystal modification of form I′ rather than the conventional form I, independent of the sampling condition. This conclusion is further confirmed by investigating the phase transition behavior of the NWs using synchrotron radiation wide‐angle X‐ray diffraction technique. Unexpectedly, the active layer in field‐effect transistor (FET) device fabricated by well‐shaped pure NWs network formed under the rotation field shows the comparable carrier mobility with that fabricated by the ambiguous NWs network obtained under the static condition, which implies that the amorphous part plays an important role in affecting the electrical property. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018, 56, 1027–1034 [ABSTRACT FROM AUTHOR]

Inhaled semivolatile organic compounds (SVOCs) are simultaneously present in gas and particle phases. Particles desorb a fraction of their SVOCs moving through the human respiratory tract (RT). Quantifying such desorption is challenging but important since gas- and particle-phase SVOCs deposit in different locations in the RT, encountering different cell populations with varying health consequences. This paper presents a mass transfer model to quantify this desorption process in the head, tracheobronchial, and alveolar regions of the RT. The desorption of SVOCs from inhaled particles can be gauged using the ratio of particle residence time to the time required to achieve particle/gas equilibrium. Results indicate that the larger this ratio is, the more likely particles desorb the SVOCs they carry. For particles smaller than 0.5 ?m diameter and SVOCs with a particle/gas partition coefficient (unitless) of 1010, accounting for desorption reduces the estimated particle-phase SVOC concentrations in the alveolar region by more than 35%; the reduction is almost 700% for 0.05 ?m diameter particles. In hypothetical scenarios representing common indoor and outdoor situations, neglecting desorption significantly overestimates the concentration of ultrafine particle associated SVOCs in the alveolar region. This model is a preliminary step toward more nuanced estimates of exposure to inhaled SVOCs. [ABSTRACT FROM AUTHOR]

As a metastable phase, poly (3-butylthiophene) (P3BT) form II is generally obtained by solvent vapor treatment in rigorous conditions and it is easily transformed to more commonly observed form I with heating. In the present study, by low temperature aging in carbon disulfide (CS 2 ) solution, a simple and feasible method was proposed to prepare neat P3BT form II. Thus prepared crystal exhibits the distinct bundle morphology composed of single-crystal-like nanofibers. With such sample, the transitional mechanism from form II to form I modification is further investigated by in situ WAXD combined with FTIR spectroscopy. It is found that form II transfers to form I via a quasi-ordered smectic phase rather than a direct solid-to-solid transition. This study could be helpful for controlling the crystal structure and morphology in P3BT thin film, which is closely related to its performance in electronic devices. [ABSTRACT FROM AUTHOR]

Six phthalates – dimethyl phthalate (DMP), diethyl phthalate (DEP), di(isobutyl) phthalate (DiBP), di(n-butyl) phthalate (DnBP), butyl benzyl phthalate (BBzP) and di(2-ethylhexyl) phthalate (DEHP) – in indoor gas-phase and dust samples were measured in thirty residential apartments for the first time in Chongqing, China. Monte-Carlo simulation was used to estimate preschool children's exposure via inhalation, non-dietary ingestion and dermal absorption based on gas-phase and dust concentrations. Risk assessment was evaluated by comparing the modeled exposure doses with child-specific benchmarks specified in California's Proposition 65. The detection frequency for all the targeted phthalates was more than 80% except for BBzP. DMP was the most predominant compound in the gas-phase (median = 0.91 μg/m 3 and 0.82 μg/m 3 in living rooms and bedrooms, respectively), and DEHP was the most predominant compound in the dust samples (median = 1543 μg/g and 1450 μg/g in living rooms and bedrooms, respectively). Correlation analysis suggests that indoor DiBP and DnBP might come from the same emission sources. The simulations showed that the median DEHP daily intake was 3.18–4.28 μg/day/kg-bw in all age groups, suggesting that it was the greatest of the targeted phthalates. The risk assessment indicated that the exposure doses of DnBP and DEHP exceeded the child-specific benchmarks in more than 90% of preschool children in Chongqing. Therefore, from a children's health perspective, efforts should focus on controlling indoor phthalate concentrations and exposures. [ABSTRACT FROM AUTHOR]

[Display omitted] • Early life exposure to traffic pollutant nitrogen dioxide (NO 2) plays a key role in childhood asthma. • Pre- or post-natal exposure to increased temperature and extreme hot day elevates asthma risk. • Co-exposure to both high temperatures and air pollution significantly increases risk of asthma. • Boys and younger children are more susceptible to postnatal heat-particle interaction on asthma. • Our study suggests a hypothesis of "fetal origin of asthma" via temperature-pollution interaction. Although mounting evidence has associated air pollution and environmental temperature with children's health problems, it is unclear whether there is an interaction between these factors on childhood asthma. To explore the effects of temperature-pollution interactions during pre- and post-natal periods on asthma among pre-schoolers. A retrospective cohort study of 39,782 pre-schoolers was performed during 2010–2012, in seven cities in China. Exposure to three temperature indicators (TI) and three critical ambient air pollutants, including particulate matter with aerodynamic diameter ≤ 10 μm (PM 10), sulfur dioxide (SO 2) and nitrogen dioxide (NO 2) as proxies of industrial and vehicular air pollution, was estimated by an inverse distance weighted (IDW) method. Two-level logistical regression analysis was used to examine the association between both pre- and post-natal exposure and childhood asthma in terms of odds ratio (OR) and 95 % confidence interval (CI). Asthma prevalence in pre-schoolers at age of 3–6 years (6.9 %) was significantly associated with traffic-related air pollutant (NO 2) exposure, with ORs (95 % CI) of 1.17 (1.06, 1.28), 1.19 (1.05–1.34) and 1.16 (1.03–1.31) for an IQR increase in NO 2 exposure during lifetime, pregnancy, and entire postnatal period respectively. Furthermore, childhood asthma was positively associated with exposure to increased temperature during lifetime, pregnancy, and entire postnatal period with ORs (95 % CI) = 1.89 (1.66, 2.16), 1.47 (1.34, 1.61), and 1.15 (1.11, 1.18) respectively, while was negatively associated with decreased temperatures. Childhood asthma was positively related with exposure to extreme heat days (EHD) during postnatal period particularly in first year of life respectively with ORs (95 % CI) = 1.23 (1.04, 1.46) and 1.26 (1.07, 1.47), but was not related with extreme cold days (ECD) exposure. A combination of high air pollutant levels and high temperatures significantly increased the risk of asthma during both pre- and post-natal periods. Strikingly, we found a significantly positive interaction of temperature and PM 10 or SO 2 on asthma risk among boys and younger children. Prenatal and postnatal exposure to ambient air pollution and high temperatures are independently and jointly associated with asthma risk in early childhood. [ABSTRACT FROM AUTHOR]

The hypothesis that extracellular polymeric substances (EPS) affect the formation of biofilms for subsequent enhanced biodegradation of polycyclic aromatic hydrocarbons was tested. Controlled formation of biofilms on humin particles and biodegradation of phenanthrene and pyrene were performed with bacteria and EPS-extracted bacteria of Micrococcus sp. PHE9 and Mycobacterium sp. NJS-P. Bacteria without EPS extraction developed biofilms on humin, in contrast the EPS-extracted bacteria could not attach to humin particles. In the subsequent biodegradation of phenanthrene and pyrene, the biodegradation rates by biofilms were significantly higher than those of EPS-extracted bacteria. Although, both the biofilms and EPS-extracted bacteria showed increases in EPS contents, only the EPS contents in biofilms displayed significant correlations with the biodegradation efficiencies of phenanthrene and pyrene. It is proposed that the bacterial-produced EPS was a key factor to mediate bacterial attachment to other surfaces and develop biofilms, thereby increasing the bioavailability of poorly soluble PAH for enhanced biodegradation. [ABSTRACT FROM AUTHOR]

Tillage was the key factor affecting soil quality, and plowing, rotary tillage and subsoiling etc. were the important links of tillage pattern. Years of plowing, trying to make the soil crushing and creating a good growth environment were the essence of traditional farming in China. But excessive tillage caused the damage to the vegetation, made the soil lose protection, caused soil erosion, dust wreaking havoc and fertility decline in the end. However, long-term no tillage was also inconducive to the sustainable high yield of crops. In order to solve this problem, through comprehensive consideration, the advantages of different tillage patterns were took and combined reasonably. Then a rotational period of mechanical and ecological tillage pattern was established in wheat/corn double-cropping system and compared with the patterns of years of plowing and years of no tillage. The mechanical and ecological tillage pattern was set as Treatment W, the years of plowing pattern was Treatment F, and the years of no tillage pattern was Treatment N. The rotational period was set to be 5 years. For Treatment W, different agricultural machines were combined suitably for moderate tillage on soil in the 5 years. In the first year, the soil was ploughed with the splintery straw mulch on the soil after harvesting corn, and no tillage the next year; in the third and the fourth year subsoil interleaved, and in the last year no tillage as well. For Treatment F the soil was ploughed every year after harvesting corn and no tillage for Treatment N. In order to study the effects of different patterns on soil and yield, the soils of 0-10, >10-20, >20-30 cm layer were collected and tested for soil organic content, moisture content and bulk density, and yields of wheat and corn were recorded as well every year in the period for all treatments. Then the results were compared. The comparison results showed as follows: in the period of five-year test, Treatment W effectively improved soil organic content at all 3 layers, and the largest improvement was 0.2% at 0-10 cm soil layer; Treatment N also significantly improved soil organic content at 0-10 cm soil layer at the first 3 years, but reduced at the last 2 years; however, soil organic content was reduced for Treatment F at 0-10 cm layer, yet that at >20-30 cm soil layer was significantly improved at the first 3 years, and then reduced at the last 2 years. The soil moisture contents from the highest to the lowest were Treatment W, Treatment N and Treatment F, and the difference between Treatment W and the two other treatments was more significant (P<0.05) with the increasing of the year. At 0-10 cm soil layer, the soil bulk densities of Treatment W and N were significantly lower than Treatment F at 5% level. The yields of Treatment W and N were significantly higher than Treatment F, and the order from the highest to the lowest was Treatment W, Treatment N and Treatment F; the difference was most significant in 2014, wheat yields of Treatment W was 30.8% higher than Treatment F and 22.5% than Treatment N, and yields of corn was 28.4% higher than Treatment F and 20.9% than Treatment N. [ABSTRACT FROM AUTHOR]

Background: Intracranial extraventricular ependymoma (IEE) is an ependymoma located in the brain parenchyma outside the ventricles. IEE has overlapping clinical and imaging characteristics with glioblastoma multiforme (GBM) but different treatment strategy and prognosis. Therefore, an accurate preoperative diagnosis is necessary for optimizing therapy for IEE. Methods: A retrospective multicenter cohort of IEE and GBM was identified. MR imaging characteristics assessed with the Visually Accessible Rembrandt Images (VASARI) feature set and clinicopathological findings were recorded. Independent predictors for IEE were identified using multivariate logistic regression, which was used to construct a diagnostic score for differentiating IEE from GBM. Results: Compared to GBM, IEE tended to occur in younger patients. Multivariate logistic regression analysis identified seven independent predictors for IEE. Among them, 3 predictors including tumor necrosis rate (F7), age, and tumor‐enhancing margin thickness (F11), demonstrated higher diagnostic performance with an Area Under Curve (AUC) of more than 70% in distinguishing IEE from GBM. The AUC was 0.85, 0.78, and 0.70, with sensitivity of 92.98%, 72.81%, and 96.49%, and specificity of 65.50%, 73.64%, and 43.41%, for F7, age, and F11, respectively. Conclusion: We identified specific MR imaging features such as tumor necrosis and thickness of enhancing tumor margins that could help to differentiate IEE from GBM. Our study results should be helpful to assist in diagnosis and clinical management of this rare brain tumor. [ABSTRACT FROM AUTHOR]

Semi-volatile organic compounds (SVOCs) partition between the gas phase and airborne particles. The size distribution of particle-associated SVOCs impacts their fate in outdoor and indoor environments, as well as human exposure to these compounds and subsequent health risks. Allen et al. (1996) previously proposed that the rate of mass transfer can impact polycyclic aromatic hydrocarbon (PAH) partitioning among different sized particles, especially for time scales relevant to urban aerosols. The present study quantitatively builds on this idea, presenting a model that incorporates dynamic SVOC/particle interaction and applying this model to typical outdoor and indoor scenarios. The model indicates that the impact of mass transfer limitations on the size distribution of a particle-associated SVOC can be evaluated by the ratio of the time to achieve gas–particle equilibrium relative to the residence time of particles. The higher this ratio, the greater the influence of mass transfer limitations on the size distribution of particle-associated SVOCs. The influence of such constraints is largest on the fraction of particle-associated SVOCs in the coarse mode (> 2 μm). Predictions from the model have been found to be in reasonable agreement with size distributions measured for PAHs at roadside and suburban locations in Japan. The model also quantitatively explains shifts in the size distributions of particle associated SVOCs compared to those for particle mass, and the manner in which these shifts vary with temperature and an SVOC's molecular weight. [ABSTRACT FROM AUTHOR]

Abstract: Time-resolved infrared spectroscopy has been used to study the melt crystallization behavior of poly(3-octylthiophenes) (P3OT), which is a typical conductive polymer among the family of poly(3-alkylthiophenes) (P3ATs). It is found that, during the isothermal crystallization process at high temperature, the alkyl side chains of P3OT always keep in disordered state, whereas the ordering packing of conjugated backbone takes place. In order to reveal the structural changes and the crystallization kinetics corresponding to the main-chain ordering process, two spectral regions that associated with π–π stacking and the effective conjugation length of P3OT have been analyzed in detail. The characteristic IR bands of crystalline and amorphous phase are identified in each spectral region. Moreover, a simple spectral method has been proposed to calculate the evolution of crystallinity during the isothermal crystallization process of P3OT. Of particular note, the distinct one-dimensional growth kinetic of P3OT crystal has been revealed by Avrami analysis. [Copyright &y& Elsevier]

Asthma, rhinitis and eczema (allergic or non-allergic) have increased throughout the world during the last decades, especially among children. Changes in the indoor environment are suspected to be important causes. China has experienced a dramatic change in indoor environmental exposures during the past two decades. However, such changes and their associations with children’s asthma and other health aspects have not been thoroughly studied. China, Children, Homes, Health (CCHH), Phase I, was a cross-sectional questionnaire survey of 48219 children 1–8 years old in 10 Chinese cities during 2010–2012. The questionnaire includes the International Study of Asthma and Allergies in Childhood (ISAAC) core health questions and additional questions regarding housing, life habits and outdoor environment. In health analyses, children aged 3–6 years old were included. The prevalences of doctor diagnosed asthma varied from 1.7% to 9.8% (mean 6.8%), a large increase from 0.91% in 1999 and 1.50% in 2000. The prevalence of wheeze, rhinitis and atopic eczema (last 12 months) varied from 13.9% to 23.7%, 24.0% to 50.8% and 4.8% to 15.8%, respectively. Taiyuan had the lowest prevalences of all illnesses and Shanghai the highest, except for wheezewhere the highest value was for Urumqi. We found (1) no obvious association between disease prevalences and ambient PM 10 concentrations and (2) higher prevalences of disease in humid climates with hot summers and cold winters, but with no centrally heated buildings. Associations between the diseases and economic status as indexed by Gross Domestic Product (GDP) requires further study. [ABSTRACT FROM AUTHOR]

Highlights: [•] An approach of determining the ideal thermal conductivity distribution versus temperatures of external wall is put forward. [•] Ideal thermal conductivity of external wall approaches the square wave function. [•] The developed approach can also be used in the multilayer walls. [ABSTRACT FROM AUTHOR]

Abstract: The objective of the study was to test the hypothesis that easily available polycyclic aromatic hydrocarbons (PAHs) can stimulate the biodegradation of poorly available PAHs. Therefore, the biodegradation of poorly available PAHs was carried out, with easily available ones as the growth substrate using two phenanthrene-degrading bacteria, Micrococcus sp. PHE3 and Sphingobium sp. PHE9, in a two-liquid phase system (TLPs). Firstly, although anthracene, fluoranthene and pyrene could not be consumed by the monoculture as the sole carbon and energy sources, all of them could be biodegraded when naphthalene (NAP) or phenanthrene (PHE) served as the growth substrate, demonstrating that the spiking of easily available PAHs enhanced biodegradation of poorly available ones. However, fluoranthene could not be biodegraded by Micrococcus sp. PHE9 with PHE as the growth substrate, or by Sphingobium sp. PHE3 using NAP and PHE as the growth substrates, indicating that the growth substrate affected the bacterial utilization of poorly available PAHs. Furthermore, a metabolite, 1,2-dihydroxynaphthalene, was identified when NAP served as the growth substrate. In contrast, no metabolite was detected when PHE was used as the growth substrate. These results exhibited significant implications for the bioremediation of PAHs-contaminated soils. [Copyright &y& Elsevier]

Volatile organic compounds (VOCs) emitted from furniture are recognized as a main cause of bad indoor air quality. In European countries and the U.S., labeling systems for furniture have been established with good effect to address this issue. However, there are problems with these labeling systems. For example, too many VOCs were targeted, and the testing time was too long (7-28 d). Aiming at solving these problems, solutions are put forward to establish furniture VOCs emissions labeling system in China and some practices are introduced in this paper. They are: some furniture popular in the market were tested and main VOCs emitted from these furniture were identified; furniture loading factors in residential homes were surveyed, and reference bedroom and reference living room were established according to the survey results to make emission rate thresholds of furniture; C-history method was developed and applied to testing furniture which could shorten the testing time to 3 d; a reference toluene sample for assessing the precision of the test results of chamber system was prepared. These works are technically helpful for establishing furniture VOCs labeling system in China. [ABSTRACT FROM AUTHOR]

This paper puts forward an approach to determine the optimal mode of doping adsorbents into the wood-based panels for control of their formaldehyde emission. Based on the optimization conclusion, a novel design method for low-emitting wood-based panels by daubing adsorbent layer on the panel's surface is proposed. The formaldehyde emission results from the prepared laboratory specimens indicate the feasibility of the proposed method. This study provides a meaningful guidance on designing low-emitting wood-based panels. [ABSTRACT FROM AUTHOR]

Abstract: It was found that there were unwanted by-products in the photocatalytic oxidation (PCO) of indoor ppb-level toluene, a typical volatile organic compound (VOC) in indoor air. However, up to now the control mechanism of the generation of the products has not been clear. In this study we address the problem: a titania-coated glass-plate reactor was applied to study the by-products and decomposition rate; the by-products generated under a series of water vapor concentrations were instantaneously identified by proton transfer reaction-mass spectrometer (PTR-MS); the results indicate that water vapor has a significant effect not only on the photocatalytic decomposition rate of toluene, but also on its by-products generation; the competitive adsorption mechanism between water vapor, toluene and its by-products was analyzed. By-products may make the typical Langmuir–Hinshelwood model unfeasible in real application. A health risk assessment of the by-products was also introduced. The results show that the maximum decomposition efficiency does not always lead to minimal by-products and lowest health risk. What it does show is that when evaluating the performance of photocatalytic air purification, health risks posed by the by-products should be the primary concern rather than the decomposition efficiency. [Copyright &y& Elsevier]

Abstract: The objective of the study was to test the hypothesis that the attachment of polycyclic aromatic hydrocarbons (PAHs)-degrading bacteria can promote desorption of PAHs from humin, thereby increasing their bioavailability. Biodegradation of humin-bound phenanthrene (PHE) – a model compound for PAHs – was investigated using two PHE-degrading bacteria, Sphingobium sp. PHE3 and Micrococcus sp. PHE9, respectively. Sorption data of PHE to humin fitted well into the modified Freundlich equation. Further, a new sorption band appeared at 1262cm−1, demonstrating intermolecular interactions between PHE and humin. Interestingly, approximately 65.3% of humin-bound PHE was degraded by both strains, although only about 17.8% of PHE could be desorbed from humin by Tenax extraction. Furthermore, both strains grew well in mineral medium and also attached to humin surfaces for substrate uptake. It is proposed that the attached bacteria could possibly consume PHE on the humin via interactions between bacterial surfaces and humin, thereby overcoming the low PHE bioavailability and resulting in enhanced degradation. [Copyright &y& Elsevier]

Abstract: With a home-made heating cell, the structural evolutions of PLLA ultrathin film during the heating and cooling process were investigated in real time by grazing angle IR reflection absorption spectroscopy (IRRAS). It is found that the phase transition behaviors, including the crystallization, melting and even the glass transition of PLLA ultrathin film, can be clearly revealed by detailed analysis on the temperature-dependent IR spectra collected with IRRAS technique. The quantitative analysis shows that temperature-dependent intensity changes calculated by vibrational modes associated with the Ce:glyph name="sbnd" />Oare suitable to reflect the subtle glass transition of PLLA ultrathin film. The qualitative spectral analysis on the Ce vibrational modes suggest that the 10/7 helical chain of PLLA formed during the heating process (i.e. cold crystallization) is preferably flat on the Au substrate, whereas it is perpendicular to substrate during the cooling process (i.e. melt crystallization). Our studies show that temperature dependent IRRAS technique is not only valid to study the glass transition but also the confined crystallization behavior of PLLA ultrathin film deposited on a substrate, which is hard to test by the conventional DSC technique. Besides, it can provide more structural information to understand the various phase transition behaviors of polymer ultrathin films on a molecular level. [Copyright &y& Elsevier]

The volatile organic compounds (VOC) emitted from indoor decorating and refurbishing materials and furniture is recognized as one of the main causes of bad indoor air quality, which has resulted in serious economic losses. In European countries and the U.S., labeling systems for indoor decorating and refurbishing materials and furniture were established to address this issue with good effect. This paper is a review of these existing labeling systems. The basic principle of the labeling systems is introduced. The technical, policy and operational parts of the labeling systems are then discussed. The research concentrates on target pollutants, their threshold values and the testing methods employed. Some problems were uncovered in these labeling systems: too many VOCs were targeted; the method to determine the threshold values was not very rigorous; the testing time was too long (7-28 d). Some China's special features in developing such system are stated. Therefore, as the world's largest national producer and consumer of wood based panels and furniture, China should learn from foreign experience of establishing labeling systems as much as it can. However China should not simply copy the foreign approaches but develop its own scientific labeling system for indoor decorating and refurbishing materials and furniture. [ABSTRACT FROM AUTHOR]

Abstract: The bulk and thin film crystallization behaviors of PLLA/CNTs nanocomposites were investigated by in situ transmittance IR and reflection absorption IR spectroscopy, respectively. The results show that CNTs can enhance both the cold and melt crystallization rates of bulk PLLA, which is consistent with the common observation in the literature. However, it is interesting to find that the crystallization rate of PLLA thin film is suppressed by the addition of CNTs. Moreover, it is found that the existence of CNTs could not alter the preferred orientation of PLLA helical chain in the thin film. The different crystallization kinetics of PLLA induced by the addition of CNTs in bulk and thin film were explained by the confined crystallization behavior of polymer thin film. [Copyright &y& Elsevier]

Abstract: Environmental chambers are widely used to test formaldehyde and other volatile organic compound (VOC) emissions from indoor materials and furniture. However, there is a lack of a proven method to assess the precision of the test results of the chamber system. In this paper, we describe a new standard reference, LIFE (liquid-inner tube diffusion-film-emission), to address this problem. This reference has the following salient features: (1) Constant emission rate, with less than 3.0% change with an ambient airflow speed (>0.014 m/s) at furniture emission range (0.1–1.0 mg/m3 in a 30 m3 chamber with air change rate of 1/h) under standard chamber test conditions as specified by ISO 16000-9 (23 °C, 50% RH); (2) Long duration of emissions, on the order of 1000 h; (3) Easy to store, apply and maintain. The design principle and criteria of the LIFE reference are presented. An analytical model and dimensionless analysis were applied to optimize the factors influencing the emission rate, and experiments were conducted to validate the analytical results. In addition, the equivalent emission parameters of the reference, i.e., the initial emittable concentration, the diffusion coefficient and the partition coefficient, were determined through a three-parameter optimizing regression. This can then be used to check the reliability of a chamber method for testing these three parameters. The developed standard reference should prove useful for calibrating chamber systems for indoor material/furniture VOC emissions tests. [Copyright &y& Elsevier]

Abstract: Air cleaning techniques have been applied worldwide with the goal of improving indoor air quality. The effectiveness of applying these techniques varies widely, and pollutant removal efficiency is usually determined in controlled laboratory environments which may not be realized in practice. Some air cleaners are largely ineffective, and some produce harmful by-products. To summarize what is known regarding the effectiveness of fan-driven air cleaning technologies, a state-of-the-art review of the scientific literature was undertaken by a multidisciplinary panel of experts from Europe, North America, and Asia with expertise in air cleaning, aerosol science, medicine, chemistry and ventilation. The effects on health were not examined. Over 26,000 articles were identified in major literature databases; 400 were selected as being relevant based on their titles and abstracts by the first two authors, who further reduced the number of articles to 160 based on the full texts. These articles were reviewed by the panel using predefined inclusion criteria during their first meeting. Additions were also made by the panel. Of these, 133 articles were finally selected for detailed review. Each article was assessed independently by two members of the panel and then judged by the entire panel during a consensus meeting. During this process 59 articles were deemed conclusive and their results were used for final reporting at their second meeting. The conclusions are that: (1) None of the reviewed technologies was able to effectively remove all indoor pollutants and many were found to generate undesirable by-products during operation. (2) Particle filtration and sorption of gaseous pollutants were among the most effective air cleaning technologies, but there is insufficient information regarding long-term performance and proper maintenance. (3) The existing data make it difficult to extract information such as Clean Air Delivery Rate (CADR), which represents a common benchmark for comparing the performance of different air cleaning technologies. (4) To compare and select suitable indoor air cleaning devices, a labeling system accounting for characteristics such as CADR, energy consumption, volume, harmful by-products, and life span is necessary. For that purpose, a standard test room and condition should be built and studied. (5) Although there is evidence that some air cleaning technologies improve indoor air quality, further research is needed before any of them can be confidently recommended for use in indoor environments. [Copyright &y& Elsevier]

Abstract: Humin, the main component of soil organic matter, greatly influences the nonlinear sorption and desorption hysteresis of polycyclic aromatic hydrocarbons (PAHs) in soil. However, little is known about the bioavailability of PAHs bound to humin. In the present study, a phenanthrene (PHE)-degrading bacterial strain – PHE9 – was isolated and identified as the genus Micrococcus. It was used to investigate the degradation of humin-bound PHE and PHE not bound to humin (non-humin PHE) in liquid mineral medium (MM) and in a two-liquid-phase system (TLPs). The results showed that in MM, about 66.84% of humin-bound PHE was degraded after 49 days, whereas almost all the non-humin PHE was degraded after 27 days. Compared to MM, the TLPs showed a much better efficacy in the removal of PHE, especially for humin-bound PHE: more than 97.28% of non-humin PHE was degraded in 11 days and over 85.62% of humin-bound PHE was degraded in 32 days. It could be concluded that most of humin-bound PHE could be degraded in the MM although humin decreased the bioavailability of PHE, whereas the application of TLPs could enhance the biodegradation of humin-bound PHE. [Copyright &y& Elsevier]

A general mass transfer based model was developed for analyzing volatile organic compound (VOC) emissions from dry multi-layer building materials with two emission surfaces. This model adds to an earlier multi-layer model by considering chemical reactions within the materials. Consequently, it can be used to analyze the effect of these chemical reactions on removing VOCs, and for characterizing secondary VOC emissions from the building material. The model was validated with literature data and our experimental results. Some typical secondary emissions were analyzed using this model, and obviously differed from the primary emissions. The model is a useful tool for predicting, analyzing and "designing" the VOC emission characteristics, including secondary emissions, of building materials. [ABSTRACT FROM AUTHOR]

Abstract: We investigate stationary oscillation for high-order Hopfield neural networks with time delays and impulses. In a recent paper [J. Zhang, Z. J. Gui, Existence and stability of periodic solutions of high-order Hopfield neural networks with impulses and delays, Journal of Computational and Applied Mathematics 224 (2008) 602–613], the authors claim that they obtain a criterion of existence, uniqueness, and global exponential stability of periodic solution (i.e. stationary oscillation) for high-order Hopfield neural networks with time delays and impulses. In this paper, we point out that the main result of the recent paper is unture, and present a new sufficient condition of stationary oscillation for the neural networks. A numerical example is given to illustrate the effectiveness of the obtained result. [Copyright &y& Elsevier]

Abstract: 12 hybrid photocatalysts consisting of titania (TiO2) and an adsorbent such as mordenite were investigated for the photocatalytic decomposition of toluene, a major indoor contaminant in indoor air. The highest decomposition rate was obtained with the use of mordenite and silicon dioxide (SiO2) as additives to TiO2. The photocatalytic activities of hybrid photocatalysts in decomposing toluene are 1.33 times as high as pure P25 at the net weight loading of 0.49mg/cm2 under the test condition. Scanning electron microscopy (SEM) images confirmed that the hybrid photocatalyst films were very porously distributed; TiO2 was adsorbed on the surface of mordenite and SiO2, increasing the reaction area of TiO2. The unimolecular Langmuir–Hishelwood model and mass-transfer-based (MTB) method were used to evaluate the reaction coefficients and adsorption equilibrium coefficients of hybrid photocatalysts. It is evidenced that the reaction areas of two hybrid photocatalysts were 1.52 and 1.64 times larger than that of P25, respectively, which is the major reason to make the high removal efficiency of toluene. [Copyright &y& Elsevier]

Abstract: The generation of harmful by-products during photocatalytic oxidation (PCO) of volatile organic compounds (VOCs) is a bottleneck problem for the application of PCO technology in indoor environment. Toluene is a typical VOC found in indoor air. In this work, the by-products at ppb level were studied during PCO decomposition of toluene in a plate-type reactor and identified using PTR-MS (proton transfer reaction-mass spectrometry) and GC–MS (gas chromatography–mass spectroscopy). The results indicated that benzaldehyde, methanol, acetaldehyde, acetone/propionaldehyde, formic acid/ethanol and acetic acid were the main by-products in the gas phase. By adjusting the concentration of water vapor, some compounds adsorbed on the TiO2 surface were ascertained, which resulted in the deactivation of TiO2. They were benzoic acid, benzene, acrylaldehyde, butyraldehyde and pentanal. Some of these by-products have not been reported in the literature. Possible photocatalytic oxidation pathways of toluene were proposed. A health-related index (HRI) was introduced to assess the risk level to human health of these ppb-level by-products. It concludes that although some undesired by-products (even carcinogenic) are generated during PCO decomposition of toluene, it seems that these by-products do not have negative effects to human health because of their low concentrations. [Copyright &y& Elsevier]

Abstract: Volatile organic compounds (VOCs) are prevalent components of indoor air pollution. Among the approaches to remove VOCs from indoor air, photocatalytic oxidation (PCO) is regarded as a promising method. This paper is a review of the status of research on PCO purification of VOCs in indoor air. The review and discussion concentrate on the preparation and coating of various photocatalytic catalysts; different kinetic experiments and models; novel methods for measuring kinetic parameters; reaction pathways; intermediates generated by PCO; and an overview of various PCO reactors and their models described in the literature. Some recommendations are made for future work to evaluate the performance of photocatalytic catalysts, to reduce the generation of harmful intermediates and to design new PCO reactors with integrated UV source and reaction surface. [Copyright &y& Elsevier]

A correlation between partition coefficients, K, of dry building material and liquid molar volume of volatile organic compounds (VOCs) in it, v l, is presented. Experiment for determining the partition coefficients of the target VOCs including benzene, toluene, ethylbenzene for two kinds of building materials was conducted by a method developed by us. The experimental data verified the correlation. Also the correlation was supported well by the experimental data in the literature. It is found that the correlation can predict the partition coefficients of VOCs with similar structure in the same building material. [Copyright &y& Elsevier]

Abstract: For the materials with constant thermophysical properties, the thermal performance of wallboards (or floor, ceiling) can be described by decrement factor f and time lag φ. However, the phase change material (PCM) may charge large heat during the melting process and discharge large heat during the freezing process, which takes place at some certain temperature or a narrow temperature range. The behavior deviates a lot from the material with constant thermal physical properties. Therefore, it is not reasonable to analyze the thermal performance of PCM wallboard by using the decrement factor f and time lag φ. How to simply and effectively analyze the thermal performance of a PCM wallboard is an important problem. In order to analyze and evaluate the energy-efficient effects of the PCM wallboard and floor, two new parameters, i.e., modifying factor of the inner surface heat flux ‘α’ and ratio of the thermal storage ‘b’, are put forward. They can describe the thermal performance of PCM external and internal walls, respectively. The analysis and simulation methods are both applied to investigate the effects of different PCM thermophysical properties (heat of fusion H m, melting temperature T m and thermal conductivity k) on the thermal performance of PCM wallboard for the residential buildings. The results show that the PCM external wall can save more energy by increasing H m, decreasing k and selecting proper T m (α <1); that the PCM internal wall can save more energy by increasing H m and selecting appropriate T m, k. The most energy-efficient approach of applying PCM in a solar house is to apply it in its internal wall. [Copyright &y& Elsevier]

Through the observation of the pore structure and mercury intruding porosimetry (MIP) experiments of some typical porous building materials, we found that the diffusion coefficient of the material can be expressed by that of a representative elementary volume (REV) in which the pore structure can be simplified as a connection in series of macro and meso pores. Based upon that, a macro–meso two-scale model for predicting the diffusion coefficient of porous building materials is proposed. In contrast to the traditional porous mass transfer model for determining the diffusion coefficient described in the literature [Blondeau, P., Tiffonnet, A.L., Damian, A., Amiri, O., Molina, J.L., 2003. Assessment of contaminant diffusivities in building materials from porosimetry tests. Indoor Air 13, 302–310; Seo, J., Kato, S., Ataka, Y., Zhu, Q., 2005. Evaluation of effective diffusion coefficient in various building materials and absorbents by mercury intrusion porosimetry. In Proceedings of the Indoor Air, Beijing, China, pp. 1854–1859], the proposed model relates the volatile organic compound (VOC) diffusion coefficient of building material not only to the porosity of the building material, but also to the pore size distribution and pore connection modes. To verify the model, a series of experiments of VOC emissions of three types of medium-density board were conducted. The comparison of the model and experimental results shows that the proposed model agrees much better with the experimental results than the traditional models in the literature. More validation for other building materials is needed. The proposed model is useful for predicting the VOC diffusion coefficient of porous building materials and for developing low VOC emission building materials. [Copyright &y& Elsevier]

Abstract: The thermal performance of a south-facing direct-gain room with shape-stabilized phase change material (SSPCM) plates has been analysed using an enthalpy model. Effects of the following factors on room air temperature are investigated: the thermophysical properties of the SSPCM (melting temperature, heat of fusion and thermal conductivity), inner surface convective heat transfer coefficient, location and thickness of the SSPCM plate, wall structure (external thermal insulation and wallboard material) etc. The results show that: (1) for the present conditions, the optimal melting temperature is about 20°C and the heat of fusion should not be less than 90kJkg−1; (2) it is the inner surface convection, rather than the internal conduction resistance of SSPCM, that limits the latent thermal storage; (3) the effect of PCM plates located at the inner surface of interior wall is superior to that of exterior wall (the south wall); (4) external thermal insulation of the exterior wall obviously influences the operating effect and period of the SSPCM plates and the indoor temperature in winter; (5) the SSPCM plates create a heavyweight response to lightweight constructions with an increase of the minimum room temperature at night by up to 3°C for the case studied; (6) the SSPCM plates really absorb and store the solar energy during the daytime and discharge it later and improve the indoor thermal comfort degree at nighttime. [Copyright &y& Elsevier]

Abstract: Thermal performance of two phase change material (PCM) composites, mixed type PCM-gypsum and shape-stabilized PCM plates, has been numerically evaluated in a passive solar building in Beijing with an enthalpy model. Effects of the melting temperature and phase transition zone of the PCM are analyzed and a comparison between the two types of PCM composites is performed. The results show that: (1) for the present conditions, the optimal melting temperature is about 21°C; (2) PCM composites with a narrow phase transition zone provide better thermal performance; (3) both mixed type PCM-gypsum and shape-stabilized PCM plates effectively shave the indoor temperature swing by 46% and 56%, respectively; (4) the shape-stabilized phase change material (SSPCM) plates respond more rapidly than the mixed type PCM-gypsum and prove to be thermally more effective in terms of utilizing the latent heat. [Copyright &y& Elsevier]

Abstract: This Letter studies analysis and design of set-stability for impulsive control systems. A new comparison theorem of asymptotic set-stability for impulsive differential system is presented. Based on the new result, we derive some less conservative conditions for asymptotic set-stability of impulsive control systems with impulse at fixed times, and the results are used to design impulsive control laws of nonlinear systems for set-stability. A numerical example is used to verify the theoretical result. [Copyright &y& Elsevier]

Abstract: Performance of a hybrid heating-system, combined with thermal storage using shape-stabilized phase-change material (SSPCM) plates, is investigated numerically. A direct gain passive solar house in Beijing is considered, which includes SSPCM plates as the inner linings of walls and the ceiling. Unsteady simulation is performed using a verified enthalpy model, with a time period covering the winter heating-season. Additional heat supply is employed during load hours at late night and early morning (23:00–07:00 in Beijing) or during the whole day necessary to keep the minimum indoor air temperature above 18°C. The results indicate the thermal storage effect of SSPCM plates, which improves the indoor thermal comfort level and saves about 47% of normal-and-peak-hour energy use and 12% of total energy consumption in winter in Beijing. [Copyright &y& Elsevier]

Abstract: A kind of electrical floor heating system with a shape-stabilized phase change material (PCM) which has been studied at Tsinghua University in our previous studies, can provide space heating during the whole day and can be controlled conventionally. However, this is not suitable for office buildings where no space heating is needed at night. The effective control is very important for the heating system in such buildings. In this paper, we studied a kind of new electrical floor heating system with ductless air supply and shape-stabilized PCM for thermal storage in order to overcome the shortcomings of the passive under-floor electric heating system with thermal storage. In this paper, we investigated its thermal performance by experiments and simulation, calculated the effects of various factors and discussed the application feasibility in different climate regions. The results show that the total electrical energy consumption was shifted from the peak period to the off-peak period, which would provide significant economic benefits because of the different day and night electricity tariffs. The system can be designed by choosing PCM with proper melting temperature and be controlled by varying velocity of air supply in different conditions. [Copyright &y& Elsevier]

The diffusion coefficient, D, partition coefficient, K, and the initial volatile organic compounds (VOCs) in dry building materials, are the three key parameters used to predict the VOC emissions. D and K may be strongly affected by temperature. We have developed a new and simple method, the C-history method, to measure the diffusion coefficient, D and the partition coefficient, K of formaldehyde in dry building materials at temperatures of 18, 30, 40 and 50°C. The measured variations of the diffusion coefficients and the partition coefficients with temperature for particle board, vinyl floor, medium-and high-density board are presented. A formula relating the partition coefficient and related factors is obtained through analysis. This formula can predict the partition coefficient in principle and provide an insight for fitting experimental data, and it agrees well with the experimental results. [Copyright &y& Elsevier]

We have developed a new method, the mass transfer based (MTB) method, for measuring the Langmuir–Hinshelwood (L–H) rate form reaction coefficients of photocatalysts. The conventional method for determining the reaction coefficients disregards the effect of mass transfer on the reaction surface by designing and controlling a reaction process to be reaction-limited. In contrast, the new MTB method takes the mass transfer effect into account by using a computational fluid dynamics (CFD) method. The reaction coefficients can be regressed by the measured reaction rates and the calculated VOC concentrations in the air adjacent to the reaction surface. Thus, by using the new method, the reaction coefficient of a reaction process can be accurately determined even if it is not reaction-limited. This is very important in cases where it is difficult to realize reaction-limited processes, such as photocatalytic oxidation of VOCs with strong UV radiation intensity. The relative error of the regressed reaction coefficients obtained by the new method is analyzed. To illustrate, we apply this method to measuring the reaction coefficients of TiO2 photocatalytic decomposing formaldehyde. This method is very useful in determining the reaction coefficients of the photocatalytic oxidation of various VOCs simultaneously. [Copyright &y& Elsevier]

Abstract: Based on the most recently published mass transfer model of volatile organic compound (VOC) emissions from dry building materials, it is found that the dimensionless emission rate and total emission quantity are functions of just four dimensionless parameters, the ratio of mass transfer Biot number to partition coefficient (Bi m/K), the mass transfer Fourier number (Fo m), the dimensionless air exchange rate (Nδ 2 /D m) and the ratio of building material volume to chamber or room volume (Aδ/V). Through numerical analysis and data fitting, a group of dimensionless correlations for estimating the emission rate from dry building materials is obtained. The predictions of the correlations are validated against the predictions made by the mass transfer model. Using the correlations, the VOC emission rate from dry building materials can be conveniently calculated without having to solve the complicated mass transfer equations. Thus it is very simple to estimate VOC emissions for a given condition. The predictions of the correlations agree well with experimental data in the literature except in the initial few hours. Furthermore, based on the correlations, a relationship between the emission rates of a material in two different situations is deduced. With this relationship, the results for a given building material in a test chamber can be scaled to those under real conditions, if the dimensionless parameters are within the appropriate region for the correlations. The relationship also explicitly explains the impacts of air velocity, load ratio, and air exchange rate on the VOC emission rate, which determines the feasibility of assuming that the VOC emission rates in real conditions are the same as those in the test chambers. [Copyright &y& Elsevier]

Abstract: Free-cooling is understood as a means to store outdoors coolness during the night, to supply indoors cooling during the day in summer, while free-heating is understood as a means to store the solar radiation during daytime, to supply indoors heating during the night in winter. In principle, free-cooling or free-heating can make the indoor air temperature in the comfortable region all the year if the thermophysical properties of building envelope material are in the desired range (defined as ideal thermophysical properties in this paper). Those properties are obviously related to the outdoor climate condition, internal heat source intensity, building configuration, ventilation mode etc. For a given region and a given building, the critical values of those ideal thermal physical properties can be determined through modeling and simulation. Two parameters, I win and I sum, are defined to describe the overcool degree in winter and the overheat degree in summer, respectively. To illustrate, the critical values of thermophysical properties of building envelope of a building located in Beijing are obtained through modeling and simulation. The simulated results are validated with experiments. The model, the methodology and the results are helpful for selection of suitable building envelope materials and for design of energy efficient buildings. [Copyright &y& Elsevier]

This paper sets up an analytic model of double surface emission of volatile organic compound (VOC) from dry, flat-plate building materials. Based on it, the influence of factors including air change rate, loading factor of materials in the room, mass diffusion coefficient, partition coefficient, convective mass transfer coefficient, thickness of materials, asymmetric convective flow and initial VOC concentration distribution in the building material on emission is discussed. The conditions for simplifying double surface emission into single surface emission are also discussed. The model is helpful to assess the double surface VOC emission from flat-plate building materials used in indoor furniture and space partition. [ABSTRACT FROM AUTHOR]

This paper sets up an analytic model of double surface emission of volatile organic compound (VOC) from dry, flat-plate building materials. Based on it, the influence of factors including air change rate, loading factor of materials in the room, mass diffusion coefficient, partition coefficient, convective mass transfer coefficient, thickness of materials, asymmetric convective flow and initial VOC concentration distribution in the building material on emission is discussed. The conditions for simplifying double surface emission into single surface emission are also discussed. The model is helpful to assess the double surface VOC emission from flat-plate building materials used in indoor furniture and space partition. [ABSTRACT FROM AUTHOR]

Abstract: Shape-stabilized phase change material (PCM) is a kind of novel thermal energy storage material. Its thermal conductivity is low, which limits its application in many conditions. In this paper, additives with high thermal conductivities were doped in it to improve its thermal conductivity. The thermal conductivity was measured by a thermal probe at room temperature. The experimental results show that the thermal conductivity of the shape-stabilized PCM can be improved greatly by adding exfoliated graphite. An empirical equation was developed for calculating the effective thermal conductivity of the shape-stabilized PCM with different mass fraction of graphite additive. By using the so-called numerical element method, a theoretical equation was obtained for predicting the effective thermal conductivity, which agrees well with the experimental results. The empirical equation and the theoretical prediction are useful for “designing” and controlling the thermal conductivity of the shape-stabilized PCM. [Copyright &y& Elsevier]

Abstract: Shape-stabilized phase change material (PCM) is a kind of novel PCM. It has the following salient features: large apparent specific heat for phase change temperature region, suitable thermal conductivity, no container. In the present paper, a kind of shape-stabilized PCM floor is put forward which can absorb the solar radiation energy in the daytime and release the heat at night in winter. Therefore, in winter the indoor climate can be improved and the energy consumption for space heating may be greatly reduced. A model of analyzing the thermal performance of this shape-stabilized PCM floor is developed. By using the modeling, the influence of various factors (thickness of PCM layer, melting temperature, heat of fusion, thermal conductivity of PCM, etc.) on the room thermal performance was analyzed. The model was verified by the experimental results. The model and the analysis are helpful for the application of shape-stabilized PCM floor in solar buildings. [Copyright &y& Elsevier]