Comparison of accelerated climate ageing methods of polymer building materials by attenuated total reflectance Fourier transform infrared radiation spectroscopy

The degradation of the polymer building materials polypropylene (PP) and high density polyethylene (HDPE) intended for application as water barriers/repellants around building foundation walls have been studied. The PP and HDPE samples have been subjected to various accelerated climate ageing methods for comparison, including exposure to ultraviolet and infrared radiation, heated air, water spray and freezing. The climate ageing processes have been qualitatively and quantitatively investigated by attenuated total reflectance (ATR) Fourier transform infrared (FTIR) radiation spectroscopy.     

Efficacy of using multiple open-path Fourier transform infrared (OP-FTIR) spectrometers in an odor emission episode investigation at a semiconductor manufacturing plant

This study evaluated the efficacy of simultaneously employing three open-path Fourier transform infrared (OP-FTIR) spectrometers with 3-day consecutive monitoring, using an odor episode as an example. The corresponding monitoring paths were allocated among the possible emission sources of a semiconductor manufacturing plant and the surrounding optoelectronic and electronic-related factories, which were located in a high-tech industrial park.There was a combined total odor rate of 43.9% for the three monitoring paths, each comprised of 736 continuous 5-minute monitoring records and containing detectable odor compounds, such as ammonia, ozone, butyl acetate, and propylene glycol monomethyl ether acetate (PGMEA). The results of the logistic regression model indicated that the prevailing south wind and the OP-FTIR monitoring path closest to the emission source in down-wind direction resulted in a high efficacy for detecting odorous samples with odds ratios (OR) of 3.8 (95% confidence interval (CI): 2.9-5.0) and 5.1 (95% CI: 3.6-7.2), respectively. Meanwhile, the odds ratio for detecting ammonia odorous samples was 7.5 for Path II, which was downwind closer to the possible source, as compared to Path III, downwind far away from the possible source. PGMEA could not be monitored at Path II but could be at Path III, indicating the importance of the monitoring path and flow ejection velocities inside the stacks on the monitoring performance of OP-FTIR. Besides, an odds ratio of 5.1 for odorous sample detection was obtained with south prevailing wind comprising 65.0% of the monitoring time period.In general, it is concluded that OP-FTIR operated with multiple paths simultaneously shall be considered for investigation on relatively complicated episodes such as emergency of chemical release, multiple-source emission and chemical monitoring for odor in a densely populated plant area to enhance the efficacy of OP-FTIR monitoring.     

Differences in the molecular composition of fulvic acid size fractions detected by size-exclusion chromatography-on line Fourier transform ion cyclotron resonance (FTICR-) mass spectrometry

Size-exclusion chromatography was coupled to electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (SEC-FTICR-MS) to separate a fulvic acid isolate into three size fractions and to determine the elemental composition of fulvic acids in these fractions. Molecular formulas of about 3000 ions in the mass range of 200-700 Da were derived, many of which occur in all three fractions and follow the same system of elemental composition. Product ion spectra generated by SEC coupled to quadrupol-time-of-flight-MS (Q-TOF-MS) confirmed that the ions of all three fractions are basically polycarboxylates with hardly any other functional moiety. However, SEC-FTICR-MS revealed that the ions generated from the high molecular weight (HMW) fraction are enriched in carboxyl groups and are more aromatic as compared with the low molecular weight (LMW) fraction. These findings support the idea that the HMW fulvic acids are formed from LMW fulvic acids. The shift in the relative frequency of ions from the LMW to the HMW fraction is in line with different interaction mechanisms: HMW fulvic acids may be aggregates held together by electrostatic interaction of the carboxylate groups via hydrogen bonds or with polyvalent cations or by hydrophobic interaction of their carbon backbone, or consist of LMW fulvic acids covalently bound to each other or to (aliphatic) alcohols.     

Characterisation of mahua and coconut biodiesel by Fourier transform infrared spectroscopy and comparison of spray behaviour of mahua biodiesel

Biodiesel is one of the most promising alternative fuels and occupies a prominent position among the alternatives to conventional petrodiesel fuel owing to various technical and economic factors and efficient analytical techniques that can be used for the quality control of these fuels. In the present work, an experimental method was developed for determining the concentration of Mahua biodiesel and coconut biodiesel in blends with petrodiesel; the method is based on infrared spectroscopy (Fourier transform infrared [FTIR]-attenuated total reflection [ATR]). The Mahua biodiesel and 20 V%V blends with petrodiesel were analysed using FTIR spectroscopy. Spray penetration depths of various spray models are compared with variations in injected pressure. The FTIR results show that the model obtained in this work has a good ability for determining the concentration of Mahua biodiesel in petrodiesel–biodiesel blends. The Mahua oil is taken as a biodiesel in the present study and the Hiroyasu model can be used for predicting the performance of Mahua biodiesel. The Hiroyasu model is found to be the best model among all models studied for high injected pressure. The penetration depth difference of Hiroyasu and Arregle models increased sharply with lapse of time.     

Dynamic real‐time monitoring of chloroform in an indoor swimming pool air using open‐path Fourier transform infrared spectroscopy

This study used open‐path Fourier transform infrared (OP‐FTIR) spectroscopy to continuously assess the variation in chloroform concentrations in the air of an indoor swimming pool. Variables affecting the concentrations of chloroform in air were also monitored. The results showed that chloroform concentrations in air varied significantly during the time of operation of the swimming pool and that there were two peaks in chloroform concentration during the time of operation of the pool. The highest concentration was at 17:30, which is coincident with the time with the highest number of swimmers in the pool in a day. The swimmer load was one of the most important factors influencing the chloroform concentration in the air. When the number of swimmers surpassed 40, the concentrations of chloroform were on average 4.4 times higher than the concentration measured without swimmers in the pool. According to the results of this study, we suggest that those who swim regularly should avoid times with highest number of swimmers, in order to decrease the risk of exposure to high concentrations of chloroform. It is also recommended that an automatic mechanical ventilation system is installed to increase the ventilation rate during times of high swimmer load.     

Determination of bromate ions in waters by diffusion reflection spectroscopy

The photometric method of determining trace amounts of bromates in drinking water has been developed. The method has been based on measuring diffusion reflection of tinted concentrated of the ionic associate of basic fuchsine with anionic surfactant; detection limit—0.5 μg/dm³. The analysis is not hampered by components usually interfering in determination of bromates by other methods such as chloride, chlorate, iodate, chloramines, etc. The proposed method makes it possible to control the content of bromates in water at the level and below the maximum accessible concentration.     

An X-ray diffraction (XRD) and Fourier transform infrared spectroscopic (FT-IR) investigation of the long-term effect on the solidification/stabilization (S/S) of arsenic(V) in Portland cement type-V

The long-term effects on solidification/stabilization (S/S) of As5+-bearing oxyanions (AsO4(3)-) in Portland cement type-V (OPC) have been investigated by X-ray diffraction (XRD) and Fourier transform infrared spectroscopic (FT-IR) techniques. The results of this study confirm our previous results that the early hydration of cement is inhibited by the presence of AsO4(3)-, and that the inhibition is mainly caused by the formation of highly insoluble Ca3(AsO4)2 on the surface of hydrating cement particles. Arsenate analog of ettringite [Ca6(Al2O6)(SO4)3 x 32H2O] was identified in the early stages of hydration of pure Portland cement and As(V)-treated Portland cement [OPC-As(V)], but not in 10-year-old similar samples. The XRD and FT-IR results indicated interactions of oxyanions and cement particles to produce minor quantities of As5+-bearing compounds in fresh as well as in 10-year-old samples. New As5+-bearing phases, NaCaAsO4 x 7.5H2O and Ca5(AsO4)3OH were identified in the 10-year-old OPC-As(V) samples by XRD analyses. Based on these results it is concluded that Portland cement may be considered as a potential matrix to immobilize As5+-bearing wastes.     

Characterization of low molecular weight dissolved natural organic matter along the treatment trait of a waterworks using Fourier transform ion cyclotron resonance mass spectrometry

Dissolved natural organic matter (DOM), particularly the low molecular weight DOM, can affect the performance of water treatment processes and serve as a main precursor of disinfection by-products (DBPs) during chlorination. In this study, electrospray ionization coupled to Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) was used to characterize the low molecular weight DOM along the treatment trait of a conventional drinking water treatment plant. The ESI FT-ICR MS data showed that various C, H, O-only class species were the major components in the source water. According to the van Krevelen diagram analysis, lignin- and tannin-like compounds were the most abundant components. Within an isobaric group, the DOM molecules with a high degree of oxidation (high O/C value) were preferentially removed during coagulation, while those with low degree of oxidation were found to be more reactive toward chlorine. In addition, 357 one-chlorine containing products and 199 two-chlorine containing products formed during chlorination were detected in the chlorination effluent sample at a high confidence level. The chlorinated products can be arranged into series, suggesting that they were originated from C, H, O-only precursor compounds, which were in series related by the replacement of CH₄ against oxygen. For the first time, this study explored the behavior of low molecular weight DOM along a drinking water treatment trait on the molecular level, and revealed the presence of abundant unknown chlorinated products, which are probably rich in carboxylic and phenolic groups, in drinking water.     

Determination of nitrate ion in waste and treated waters by laser raman spectrometry

The determination of NO₃⁻ ion in pure and natural waters by laser Raman spectrometry has been examined. It is shown that in the case of pure water samples, the detection limit of NO₃⁻ is about 2 ppm, and that the analytical curve in 6–100 ppm can be fitted well enough to a straight line. In the case of waste and treated waters, the detection limit becomes about an order of magnitude higher than that in the case of pure water because of the strong luminescence of water samples. In this study, the reduction of this background has been pursued by various methods, and it is demonstrated that the addition of potassium iodide as a quencher makes the background markedly smaller. By this procedure, the sensitivity becomes comparable to that in the case of pure water samples. It is proved that under such circumstances, laser Raman spectrometry can be applied satisfactorily enough to the analysis of NO₃⁻ in actual waste and treated waters.     

Electric thawing of permafrost foundation beds using horizontal current-conducting layers (HCL)

Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 1, pp. 10–13, Jamuary–February, 1991.     

Simultaneous determination of total organic carbon and total nitrogen in waters by pyrolysis-gas chromatography-mass spectrometry

An apparatus with a pyrolysis unit, gas chromatograph and quadrupole mass spectrometer was assembled for the simultaneous determination of total organic carbon (TOC) and total nitrogen (TN) in waters. The mass numbers used for the determination of TOC and TN were m/e 44 (CO₂⁺) and m/e 30 (NO⁺), respectively. The short-term stability (relative standard deviation) was 3.3% for TOC, and 5.0% for TN. The detection limits were 0.076 μg ml⁻¹ for TOC and 1.3 μg ml⁻¹ for TN. TOC and TN in water samples were determined by this method, and the results agreed well with those obtained by a combustion-infrared method for TOC and a combustion-coulometric method for TN.     

Determination of organoarsenic warfare agents in sediment samples from Skagerrak by gas chromatography-mass spectrometry

In 1945 the Norwegian authorities gave permission to scuttle ships loaded with captured chemical ammunition on board in an area approximately 14x4 km in size, 25 nautical miles south-east of Arendal. An investigation was carried out in 2002 to inspect four wrecks by using a remote-operated vehicle with video cameras. The Norwegian Defence Research Establishment (Forsvarets forskningsinstitutt, FFI) carried out the project on behalf of the Norwegian Pollution Control Authority (SFT). Sediment samples were collected at eight positions around each wreck. One of the wrecks was broken up into several smaller parts. Here sediments were collected at one additional position close to one of the parts. From each position, at least two sediment cores were taken up to the surface. One of the cores from each position was sliced into three parts that were immediately frozen. The other whole cores were frozen on board the ship and transported back to the laboratory in a freezer. In total, sediment samples from 33 different locations were collected and analysed for organoarsenic warfare agents and some of their decomposition products by gas chromatography-mass spectrometry (GC-MS) after derivatisation with 1-propanethiol. Most of the identified organoarsenic compounds found in the sediment samples are parts of the arsine oil mixture produced by Germany during World War II. The compounds were found both close to the wreck and at a somewhat longer distance from the wrecks. The highest concentrations were found in a sediment sample collected close to a bomb seen on the seabed. The organoarsenic warfare agents adamsite or lewisite were not found in any of the samples. Lewisite is not reported to have been produced during World War II, but was nevertheless looked for in the samples.     

Kinetics of nitrate and perchlorate reduction in ion-exchange brine using the membrane biofilm reactor (MBfR)

Several sources of bacterial inocula were tested for their ability to reduce nitrate and perchlorate in synthetic ion-exchange spent brine (30-45 g/L) using a hydrogen-based membrane biofilm reactor (MBfR). Nitrate and perchlorate removal fluxes reached as high as 5.4 g N m⁻² d⁻¹ and 5.0 g ClO₄ m⁻² d⁻¹, respectively, and these values are similar to values obtained with freshwater MBfRs. Nitrate and perchlorate removal fluxes decreased with increasing salinity. The nitrate fluxes were roughly first order in H₂ pressure, but roughly zero-order with nitrate concentration. Perchlorate reduction rates were higher with lower nitrate loadings, compared to high nitrate loadings; this is a sign of competition for H₂. Nitrate and perchlorate reduction rates depended strongly on the inoculum. An inoculum that was well acclimated (years) to nitrate and perchlorate gave markedly faster removal kinetics than cultures that were acclimated for only a few months. These results underscore that the most successful MBfR bioreduction of nitrate and perchlorate in ion-exchange brine demands a well-acclimated inoculum and sufficient hydrogen availability.     

Evaluation of wastewater nitrogen transformation in a natural wetland (Ulaanbaatar, Mongolia) using dual-isotope analysis of nitrate

The Tuul River, which provides water for the daily needs of many residents of Ulaanbaatar, Mongolia, has been increasingly polluted by wastewater from the city's sewage treatment plant. Information on water movement and the transformation of water-borne materials is required to alleviate the deterioration of water quality. We conducted a synoptic survey of general water movement, water quality including inorganic nitrogen concentrations, and isotopic composition of nitrogen (δ¹⁵N-NO₃⁻, δ¹⁸O-NO₃⁻, and δ¹⁵N-NH₄⁺) and water (δ¹⁸O-H₂O) in a wetland area that receives wastewater before it enters the Tuul River. We sampled surface water, groundwater, and spring water along the two major water routes in the wetland that flow from the drain of the sewage treatment plant to the Tuul River: a continuous tributary and a discontinuous tributary. The continuous tributary had high ammonium (NH₄⁺) concentrations and nearly stable δ¹⁵N-NH₄⁺, δ¹⁵N-NO₃⁻, and δ¹⁸O-NO₃⁻ concentrations throughout its length, indicating that nitrogen transformation (i.e., nitrification and denitrification) during transit was small. In contrast, NH₄⁺ concentrations decreased along the discontinuous tributary and nitrate (NO₃⁻) concentrations were low at many points. Values of δ¹⁵N-NH₄⁺, δ¹⁵N-NO₃⁻, and δ¹⁸O-NO₃⁻ increased with flow along the discontinuous route. Our results indicate that nitrification and denitrification contribute to nitrogen removal in the wetland area along the discontinuous tributary with slow water transport. Differences in hydrological pathways and the velocity of wastewater transport through the wetland area greatly affect the extent of nitrogen removal.     

Contamination by chlorinated hydrocarbons (DDT,PCBs) in surface sediment and macrobenthos of the river Adige (Italy)

Surface sediments and macrobenthos communities have been employed as contamination indicators for halogenated hydrocarbons (DDT and PCBs) in the river Adige and its tributaries Fibbio and Alpone in the province of Verona. Two sampling campaigns were carried out, before and after the spring-summer floods, to determine the effects of this event on the contamination of the river. The halocarbons in the sediment were found to be associated with the fine fraction (< 53 μm) and organic carbon. From the relative concentrations of contaminants determined at various sampling stations, some information has been obtained on the sources.     

Characteristics of nitrate reduction by zero-valent iron powder in the recirculated and CO(2)-bubbled system

In this study, the Fe(0)/CO(2) process was investigated for removing nitrate from aqueous solution under different operating conditions such as CO(2) bubbling rate (0-400 mL/min), Fe(0) dosage (1-6g/L), initial nitrate concentration (6-23 mgN/L), batch mode, and fresh Fe(0) supplementing (0-1g/L). Results show that the bubbling of CO(2) flow rate at 200 mL/min was sufficient for supplying H(+) into solution to create an acidic environment favorable to nitrate reduction reaction. It was found that sigmoidal model equation describes the S-curve behaviors of nitrate reduction, ferrous accumulation and ammonium formation satisfactorily, and the parameter t(1/2) of the proposed model equation serves as a powerful tool for the comparison of nitrate reduction rate. Sustainability test demonstrates that Fe(0) powder began to deteriorate after three batches operation. Concerning the operating modes, the batch mode with the treated solution emptied and freshly refilled outperforms the one, which was operated by retaining the treated solution and spiking concentrated nitrate into it for the next batch treatment. To guarantee satisfactory nitrate removal using the former mode, supplement of appropriate amount of Fe(0) needs to be optimized.     

Sorption of dichlorodiphenyltrichloroethane (DDT) and its metabolites by activated carbon in clean water and sediment slurries

Polyethylene-water partitioning coefficients (K_PE) and mass transfer coefficients (k_PE) for the ortho and para isomers of the organochlorine pesticide dichlorodiphenyltrichloroethane (DDT) and its metabolites dichlorodiphenyldichloroethane (DDD), dichlorodiphenyldichloroethylene (DDE) and, dichlorodiphenylmonochloroethylene (DDMU) were measured. These data were used to derive activated carbon (AC) sorption isotherms in clean water in the sub-nanogram per litre free aqueous concentration range for a virgin and a regenerated AC. The sorption strength of AC for DDT and its metabolites was very high and logarithmic values of the AC-water partitioning coefficients, log K_AC, ranged from 8.47 to 9.26. A numerical mass transfer model was calibrated with this data to interpret previously reported reductions in DDT uptake by semipermeable membrane devices after AC amendment of sediment from Lauritzen Channel, California, USA. The activated carbon-water partitioning coefficient values (K_AC) measured in clean water systems appear to overestimate the AC sorption capacity in sediment up to a factor 32 for DDT and its metabolites at long contact time with fine-sized AC. Modelling results show decreased attenuation of the AC sorption capacity with increased sediment-AC contact time. We infer that increased resistance in mass transfer of DDTs to sorption sites in the microporous region likely caused by deposits of dissolved organic matter in the macro- and mesopores of AC appears to be the most relevant fouling mechanism. These results suggest that DDTs may diffuse through possible deposits of dissolved organic matter over time, implying that the effects of sediment on the sorption of DDTs by AC may be more kinetic than competitive.     

Analysis of the QUESTOR water quality model using a Fourier amplitude sensitivity test (FAST) for two UK rivers

This paper presents the sensitivity analysis of a well-known in-stream water quality model, QUESTOR (QUality Evaluation and Simulation TOol for River systems) as applied to two rivers of contrasting land-use in the northeast of England: the 'rural' Ouse and the 'urban' Aire. The analysis employed a version of the Fourier Amplitude Sensitivity Test (FAST) that quantifies the contribution of changes in individual parameters and combination of parameters to the variance of the model output (here the Nash-Sutcliffe) in an efficient way. The quantification of the sensitivity of the model output to the parameters led to the identification of the most influential parameters. Differences between the Aire and the Ouse were found, reflecting their different water quality regime. Results highlighted the importance of interactions between two, or more, parameters on the model output. It led to question the one-at-a-time calibration method currently applied with QUESTOR and underlined the importance of including interactions between parameters in sensitivity analyses. Comparison of the relative influence of parameters versus input data showed contrasting results. In the urban system, the inputs from discharges (sewage treatment works and industrial effluents) were highly influential on model outputs and generally more important than the model parameters. For the rural river, the tributary discharges were most influential, but only at a similar or a lower level than the model parameters.     

The measurement of electron transport system (ETS) activity in freshwater sediment

Electron transport system (ETS) activity was measured in freshwater sediment at 4, 10 and 20°C by following the reduction of 2-(p-iodophenyl)-3-(p-nitrophenyl)-5-phenyl tetrazolium chloride (INT) to iodonitrotetrazolium (INT-formazan). The rate of INT-formazan formation was dependent upon the incubation temperature and nutrient amendments. Electron transport system activity also correlated very highly with O₂ consumption rates in the same sediment.     

Experimental investigations of anchoring of open caissons by means of horizontal piles (for purposes of discussion)

Conclusions Investigations established a high bearing capacity from a vertical load of piles horizontally jacked in at a considerable depth. Thus, the possibility of using horizontal piles for anchoring open caisson against buoyancy is confirmed. Editor's Note. For the wide use of progressive designs of thin-walled open caissons sunk in a thixotropic jacket it is important to solve the problem of anchoring the latter. The present article, which considers one of the possible methods of anchoring open caissons, is published (for purposes of discussion) in connection with this.Kharkov Institute for General Construction and Sanitary Engineering Planning of Industrial Establishments. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 5, pp. 13–14, September–October, 1975.