VOC Research Papers - Academia.edu (original) (raw)

Volatile organic compounds (VOCs) emitted from poultry production are leading source of air quality problems. However, little is known about the speciation and levels of VOCs from poultry production. The objective of this study was the... more

Volatile organic compounds (VOCs) emitted from poultry production are leading source of air quality problems. However, little is known about the speciation and levels of VOCs from poultry production. The objective of this study was the speciation of VOCs from a poultry facility using evacuated canisters and sorbent tubes. Samples were taken during active poultry production cycle and between production cycles. Levels of VOCs were highest in areas with birds and the compounds in those areas had a higher percentage of polar compounds (89%) compared to aliphatic hydrocarbons (2.2%). In areas without birds, levels of VOCs were 1/3 those with birds present and compounds had a higher total percentage of aliphatic hydrocarbons (25%). Of the VOCs quantified in this study, no single sampling method was capable of quantifying more than 55% of compounds and in several sections of the building each sampling method quantified less than 50% of the quantifiable VOCs. Key classes of chemicals quantified using evacuated canisters included both alcohols and ketones, while sorbent tube samples included volatile fatty acids and ketones. The top five compounds made up close to 70% of VOCs and included: 1) acetic acid (830.1 mug m -3); 2) 2,3-butanedione (680.6 mug m -3); 3) methanol (195.8 mug m -3); 4) acetone (104.6 mug m -3); and 5) ethanol (101.9 mug m -3). Location variations for top five compounds averaged 49.5% in each section of the building and averaged 87% for the entire building.

This paper presents a model of path dependence and change and focuses on the gaining of new institutional knowledge. The main thesis is that in ‘extraordinary’ historical situations the possibility of change increases as a result of... more

This paper presents a model of path dependence and change and focuses on the gaining of new institutional knowledge. The main thesis is that in ‘extraordinary’ historical situations the possibility of change increases as a result of external pressure and successful adaptation to it. The model is tested applying it to the case study of seventeenth-century United Provinces (Dutch Republic).

Brochure from an exhibition at iziko South African National Gallery for World Design Capital 2014, Cape Town South Africa. The visual culture of early Cape society was an expression of it's diverse and cosmopolitan character drawn... more

Brochure from an exhibition at iziko South African National Gallery for World Design Capital 2014, Cape Town South Africa.
The visual culture of early Cape society was an expression of it's diverse and cosmopolitan character drawn from Africa, Asia and Europe. Indeed it contributed a unique aesthetic and sense of design to contemporary South African style. Sourced from local collections are unique treasures from the Indian Ocean world and new visions by young designers .

In recent years, the health effects associated with air pollution have been intensively studied. Most studies focus on air pollution effects on the lung and the cardiovascular system. More recently, however, epidemiological and... more

In recent years, the health effects associated with air pollution have been intensively studied. Most studies focus on air pollution effects on the lung and the cardiovascular system. More recently, however, epidemiological and mechanistic studies suggest that air pollution is also affecting skin integrity. This state-of-the-art review focuses on this latter aspect; it was developed with the collaboration of European and Chinese board of experts with specific interests in environmental health, clinical and basic research in dermatology and cosmetic dermatology. A literature review limited to pollution and health effects and (sensitive) skin was performed using PubMed. Review and original articles were chosen. We summarize the existing scientific evidence that air pollution exerts detrimental effects on human skin, discuss potential clinical implications and suggest specific and unspecific cosmetic protective measures.

The Dutch East India Company (VOC) shared a history of two hundred years of coexistence with the locals in Bengal. And yet their official reports had little to say about this relation, except frequent complaints against the locals and the... more

The Dutch East India Company (VOC) shared a history of two hundred years of coexistence with the locals in Bengal. And yet their official reports had little to say about this relation, except frequent complaints against the locals and the accompanying, inherent distrust. There has been, however, a significant amount of historiography that has developed in the recent decades on Indo-Dutch contacts based on the information available in the sources. This article aims to add more nuances to these dynamics, by showing how the Company and its officials were seen by the locals in Bengal. It argues that the local–Dutch relation had not just been about static characterisations of 'partnership', 'cooperation' or 'conflict', but was rather dependant on personal networks and profit motives backed by diverse social positions. The Dutch in the perception of the locals had different meanings, images and implications. Through the study of three objects—local texts, a Dutch painting and a legal case—this article aims to capture precisely these very perceptions in contributing towards the complex of Indo-Dutch interactions in seventeenth century Bengal. I had a book in my hands to while away the time, and it occurred to me that in a way a landscape is not unlike a book—a compilation of pages that overlap without any two ever being the same. People open the book according to their taste and training, their memories and desires: for a geologist the compilation opens at one page, for a boatman at another, and still

The reactions of chlorine atoms and activated carbon have been studied over the temperature range of 200–400 °C using an isothermal flow reactor in conjunction with 337 nm laser photolysis of Cl2. These studies have shown that carbon... more

The reactions of chlorine atoms and activated carbon have been studied over the temperature range of 200–400 °C using an isothermal flow reactor in conjunction with 337 nm laser photolysis of Cl2. These studies have shown that carbon tetrachloride is the major product, with chloroform, methylene chloride, and methyl chloride being formed in progressively decreasing yields. Trace quantities of methane, ethane, and dichloroethylenes were also observed. Mechanisms of carbon fragmentation by successive addition of chlorine atoms are proposed. The formation of small chlorinated hydrocarbons by the direct reaction of chlorine with carbon may be a key link in both the de novo and precursor pathways of formation of PCDD/F.

Volatile aldehydes are produced during degradation of paper-based materials. This may result in their accumulation in archival and library repositories. However, no systematic study has been performed so far. In the frame of this study,... more

Volatile aldehydes are produced during degradation of paper-based materials. This may result in their accumulation in archival and library repositories. However, no systematic study has been performed so far. In the frame of this study, passive sampling was carried out at ten locations in four libraries and archives. Despite the very variable sampling locations, no major differences were found, although air-filtered repositories were found to have lower concentrations while a non-ventilated newspaper repository exhibited the highest concentrations of volatile aldehydes (formaldehyde, acetaldehyde, furfural and hexanal). Five employees in one institution were also provided with personal passive samplers to investigate employees’ exposure to volatile aldehydes. All values were lower than the presently valid exposure limits. The concentration of volatile aldehydes, acetic acid, and volatile organic compounds (VOCs) in general was also compared with that of outdoor-generated pollutants. It was evident that inside the repository and particularly inside archival boxes, the concentration of VOCs and acetic acid was much higher than the concentration of outdoor-generated pollutants, which are otherwise more routinely studied in connection with heritage materials. This indicates that further work on the pro-degradative effect of VOCs on heritage materials is necessary and that monitoring of VOCs in heritage institutions should become more widespread.

Two methods for determining fuel contamination in groundwaters are compared. The first is based on headspace extraction, while the other utilizes purge and trap. Analyses, in both cases, are made by gas chromatography/flame ionization... more

Two methods for determining fuel contamination in groundwaters are compared. The first is based on headspace extraction, while the other utilizes purge and trap. Analyses, in both cases, are made by gas chromatography/flame ionization detection, with benzene, toluene, and xylene isomers as monitoring agents for fuel leaks. When compared, results show satisfactory agreement if we take into account the high

ABSTRACT Silicon nanowire (SiNW) field effect transistors (FETs) have been widely investigated as biological sensors for their remarkable sensitivity due to their large surface to volume ratio (S/V) and high selectivity towards a myriad... more

ABSTRACT Silicon nanowire (SiNW) field effect transistors (FETs) have been widely investigated as biological sensors for their remarkable sensitivity due to their large surface to volume ratio (S/V) and high selectivity towards a myriad of analytes through functionalization. In this work, we propose a long channel (L > 500 nm) junctionless nanowire transistor (JNT) SiNW sensor based on a highly doped, ultrathin body field-effect transistor with an organic gate dielectric εr = 1.7. The operation regime (threshold voltage Vth) and electrical characteristics of JNTs can be directly tuned by the careful design of the NW/Fin FET. JNTs are investigated through 3D Technology Computer Aided Design (TCAD) simulations performed as a function of geometrical dimensions and channel doping concentration Nd for a p-type tri-gated structure. Two different materials, namely, an oxide and an organic monolayer, with varying dielectric constants εr provide surface passivation. Mildly doped Nd = 1 × 1019 cm−3, thin bodied structures (fin width Fw < 20 nm) with an organic dielectric (εr = 1.7) were found to have promising electrical characteristics for FET sensor structures such as Vth ~ 0 V, high relative sensitivities in the subthreshold regime S > 95%, high transconductance values at threshold gm,Vfg=0 V > 10 nS, low subthreshold slopes SS ~ 60 mV/dec, high saturation currents Id,max ~ 1–10 μA and high Ion/Ioff > 104–1010 ratios. Our results provide useful guidelines for the design of junctionless FET nanowire sensors that can be integrated into miniaturized, low power biosensing systems.

Hugo Grotius (1583-1645) wrote the text of 'De Iure Praedae Commentarius' or 'De Indis' between September 1604 and November 1606 at the request of the directors of the Dutch East India Company, the Vereenigde Oostindische Compagnie (VOC),... more

Hugo Grotius (1583-1645) wrote the text of 'De Iure Praedae Commentarius' or 'De Indis' between September 1604 and November 1606 at the request of the directors of the Dutch East India Company, the Vereenigde Oostindische Compagnie (VOC), who (apparently) foresaw the need for a further defence of the taking of the Portuguese vessel Santa Catarina in the Strait of Malacca by their captain Jacob van Heemskerk in February 1603. The Admiralty of Amsterdam had declared the ship legitimate booty in September 1604, just prior to the VOC directors' request to Grotius to write a defence. The exact intentions and intended audience of IPC are not known, although various hypotheses have been put forward.
Judging by its appearance, the manuscript BPL 917 seems originally to have been a 'fair copy' intended for example for circulation among persons involved with the issue at stake, or for a typesetter to print the work from. However, the work remained unpublished after completion. Grotius subsequently made many changes in the text, which are written in the manuscript in the form of deleted text, and words and passages added in margins or between lines. It seems likely that this process continued for many years. However one part of IPC was actually published: chapter 12 appeared separately as De Mari Libero ('The Free Sea', also known as Mare Liberum) in 1609.

This paper presents the transport of volatile organic compounds (VOC) through contaminated subsoil to groundwater using one dimensional vadose zone transport model, VLEACH. The model is applied using field specific data for a typical... more

This paper presents the transport of volatile organic compounds (VOC) through contaminated subsoil to groundwater using one dimensional vadose zone transport model, VLEACH. The model is applied using field specific data for a typical Toluene at Fuel pumping station and Transformer dumping yard. Laboratory column leaching studies were conducted to assess the mass flow rate of Toluene flux through subsoil and compared with VLEACH model output. The research also focused on the sensitivity of the model output with the varying input parameters, one at a time, across its maximum range of values identified from the study area. The observed Toluene fluxes are not consistent with the experimentally input concentrations and may not be valid due to its lower density of 0.865 g/ml. Hence, liquid phase transport of Toluene for experimental column leaching studies is not suitable. The sensitivity analysis results reveals that, model output is a function of fractional organic carbon content as well as water content.

Coffee cultivation in Java is a mixture of several transitions in the existing scenario, both for native people and nature. This paper, which tries to bring together all these transitions or changes, is a holistic study of the coffee... more

Coffee cultivation in Java is a mixture of several transitions in the existing scenario, both for native people and nature. This paper, which tries to bring together all these transitions or changes, is a holistic study of the coffee cultivation in Java. The approach is not chronological, but trying to see the system with pre-occupied notion of stagnation and transitions, with the divisions integrated by three grand themes- transition in ecological system, transition in the power and positions of the intermediate groups between Company and direct producers and finally the transitions in peasant life and condition. First, in the ecological system, new phenomenon came on the place of centuries-long interaction between the nature and peasantry; second, formation of new class to control the system, the gradual, trial-and –error construction of a more centrally controlled system that eventually became the basis for the colonial exploitation of Indonesian economy. Each of these themes has the same logic of focusing on the changes. By their interaction they give an overall picture of the unique character of coffee cultivation in Java.

Poly(furfuryl alcohol)/SiO2 hybrid material was prepared and properties characterized in comparison with those of neat poly(furfuryl alcohol) (PFA) thermoset. A morphological study conducted by transmission electron microscopy (TEM) on... more

Poly(furfuryl alcohol)/SiO2 hybrid material was prepared and properties characterized in comparison with those of neat poly(furfuryl alcohol) (PFA) thermoset. A morphological study conducted by transmission electron microscopy (TEM) on the hybrid material reveals well-dispersed silica nanoclusters. Combination of micro- and submicro-structural organizations between the organic and inorganic networks generates new thermo-mechanical performances. A study of relaxation process by dynamic mechanical analysis (DMA) gives some evidence of the nanoconfinement effect on the hybrid network. These restrictions on the molecular mobility lead to an increase of thermal stability of the PFA/SiO2 material compared to the unfilled matrix. Thermogravimetric analyses (TGAs) coupled with GC–MS have permitted us to highlight a multi-step degradation pathway and chain scission reactions are proposed based on identified VOCs.