Biomass ash-based mineral admixture prepared from municipal sewage sludge and its application in cement composites

Biomass as the biodegradable fraction of both agricultural products and industrial and municipal waste is currently a versatile energy resource. It can be stored and converted in practically any form of energy carrier and also into biochemicals and biomaterials from which, once they have been used, the energy content can be recovered to generate electricity, heat, or transport fuels. Moreover, the residues of its incineration can often be reused as pozzolanic additions to cement which can be considered as an environmentally friendly way of their disposal. In this paper, municipal sewage sludge with the organic carbon content of 27% was used for the preparation of biomass ash that should potentially find use as environmentally friendly mineral admixture to construction binders. Based on physical and chemical characterization of the raw material that showed a suitable chemical and phase composition, organic matter in a significant amount, and no thermal decomposition processes above 700 °C, biomass ash was produced. The biomass ash was obtained by incineration of sewage sludge at 700 °C, and mechanical activation contained 52% of amorphous phase which correlates with its good pozzolanic activity. The concentration of heavy metals, soluble chlorides, nitrates, and sulfates in biomass ash is found well below the standard permissible values. The composites prepared with a biomass ash dosage of 10, 20, and 30 wt% of Portland cement exhibited good functional properties. The increase in porosity up to 6% and decrease in compressive strength up to 3% were satisfactory. The results of leaching tests showed that composites with biomass ash contain only trace amounts of chlorides, nitrates, and sulfates. Apparently, the chlorides contained in biomass ash (0.7 mg/g) were immobilized in the cement matrix because the amounts of leached chlorides (0.04 wt%) were the same for all composites and well below the permissible limit for concrete. As revealed by the X-ray diffraction and thermogravimetric analyses, a significant decrease in portlandite content with increasing biomass ash content confirmed the pozzolanic reaction in biomass ash containing composite mixes. The environmental assessment showed a significant decrease in both carbon dioxide production and energy consumption with the increasing biomass ash content. For the composite with 30% biomass ash dosage, it was 21% of CO₂ and 11% of energy, as compared with the reference mix. The combination of good functional and environmental parameters of the analyzed composites makes good prerequisites for their application in construction industry. Taylor-made mineral admixture on biomass ash basis can find a broad use as eco-efficient admixture to cement- and lime-based binders.     

Using total beta-activity measurements in milk to derive thyroid doses from Chernobyl fallout

Following the Chernobyl accident, more than 200 childhood thyroid cancer cases have been observed in Brest Oblast of Belarus in territories slightly contaminated with 137Cs, but with suspected relatively high 131I fallout. The most helpful measurements available that can be used to estimate thyroid doses for the population of Brest Oblast are the total beta-activity measurements in cow's milk performed using DP-100 device within a few weeks after the accident. The 131I concentrations in milk were derived from the total beta-activity measurements on the basis of (1) a radioecological model used to estimate the variation with time of the radionuclide composition in milk and (2) the determination of the calibration factors of the DP-100 device for the most important radionuclides present in milk. As a result, 131I concentrations in milk were reconstructed for territories with different levels of 137Cs deposition. A non-linear dependence of the 131I concentration in milk on the 137Cs deposition density was obtained; it was used to estimate the thyroid doses from the consumption of 131I-contaminated cow's milk by the population of Brest Oblast. The average individual thyroid doses have been estimated to be 0.15, 0.18, 0.12, 0.06, 0.04 and 0.03 Gy for newborn, children aged 1, 5, 10 and 15 y and adults, respectively. The collective thyroid dose for the entire population of Brest Oblast is estimated to be 64,500 man Gy, the contribution from the adult population being about one half of the total. The methodology that is described could be applied in the framework of epidemiological studies of the relationship between radiation exposure to the thyroid gland and thyroid cancer in areas where numerous total beta-activity measurements in cow's milk were performed within a few weeks after the accident.     

Compost produced from organic fraction of municipal solid waste, primary stabilized sewage sludge and natural zeolite

The aim of this work is to present the physicochemical characteristics of the compost produced from dewatered anaerobically stabilized primary sewage sludge (DASPSS), organic fraction of municipal solid waste (OFMSW) and the metal uptaken by zeolite (clinoptilolite). The final results indicated that the composted material produced from clinoptilolite 20% w/w and 80% w/w DASPSS and OFMSW (60% and 40%, respectively) provided better soil conditioning compared to the compost produced from DASPSS. The co-composting products had a higher concentration of total humic and organic matter (O.M.) than the sewage sludge compost. Also, the heavy metals concentration in the final products was in lower concentration than in the sewage sludge compost. The zeolite appeared to uptake a significant (p<0.05) amount of metals. Specifically, the use of 20-25% w/w of clinoptilolite appears to uptake 100% of Cd, 10-15% of Cr, 28-45% of Cu, 41-47% of Fe, Mn 9-24% of Mn, 50-55% of Ni and Pb, and 40-46% of Zn. Although by the application of the composting process, the reduction in dry mass is between 30% and 40% for all samples.     

Inverse scattering from phaseless measurements of the total field on open lines

A new solution approach to inverse scattering from aspect-limited phaseless measurements of the total field is introduced and discussed. In analogy with the case of measurements on closed curves [J. Opt. Soc. Am. A21, 622 (2004)], the procedure splits the problem into two different steps. In the first step, amplitude and phase of the scattered field are estimated from only amplitude information of the total field. By properly extending the concept of reduced radiated field to the case of scattered fields (as a function of both illumination and measurement variables) and taking advantage of the properties of the square amplitude distribution of the total field, criteria are given for an optimal choice of the measurement setup and a successful retrieval. Then the complex permittivity profile is reconstructed in the second step, starting from the scattered fields estimated in the previous step. Numerical examples are provided to assess the effectiveness of the whole chain in the presence of noise-corrupted data and the relevance of the representation introduced for the scattered fields.     

Inverse scattering from phaseless measurements of the total field on a closed curve

A new approach for quantitative electromagnetic imaging of scatterers located in free space from phaseless data is proposed and discussed. The procedure splits the problem into two steps. In the first one, we solve a phase-retrieval problem for the total field, thus estimating the amplitude and phase of the scattered field. Careful analysis of properties and possible representations of both scattered and incident fields allow us to introduce a criterion for an optimal choice of the measurement setup and a successful retrieval. Then the complex permittivity profile is reconstructed in the second step by use of the estimated scattered field. Numerical examples are provided to check the whole chain in the presence of noise-corrupted data.     

Sustained release of diclofenac from polymer-containing suppository and the mechanism involved

Sustained release of diclofenac sodium (DcNa) from suppositories composed of triglycerides and polymer was investigated by dissolution testing through an artificial membrane. DcNa was slowly released from a suppository containing carboxyvinyl polymer (CVP), and the extent of the release decreased with the amount of CVP added. Little effect was noted with the addition of other water-soluble polymers, such as hydroxyethylcellulose (HEC), xanthan gum, and polyvinylalcohol (PVA). When sodium benzoate was used instead of DcNa, a similar result was obtained with the addition of CVP. The result of release rate analysis together with the viscosity and pH in these cases showed that the reduction of solubility and diffusion due to sodium exchange between DcNa and CVP played an important role in the sustained release from the suppository. Also, in comparison with the results when CVP was not used, the plasma concentration profile of diclofenac after the administration of CVP suppository displayed a twofold longer half-life time.     

Total concentrations and fractions of Cd, Cr, Pb, Cu, Ni and Zn in sewage sludge from municipal and industrial wastewater treatment plants

Heavy metals are one of the important factors that affect the final disposal of sewage sludge. In this paper, the metal mobility and bioavailability of heavy metals in sewage sludge were studied by using Community Bureau of Reference (BCR) sequential extraction procedure to get more information for the reasonable disposal of sludge. Sewage sludge was collected from five municipal wastewater treatment plants and three industrial wastewater treatment plants. The sludge was examined for and the total concentrations and different chemical fractions of Cd, Cr, Pb, Cu, Ni and Zn. The total metal concentrations of heavy metals in sludge varied greatly. The contents of Zn and Cu were the highest, followed by then Cr, Ni and Pb and the content of Cd was the least. There was no significant difference in total metal concentration between municipal and industrial wastewater treatment plants. Fractions extracted by the BCR sequential procedure were acid soluble/exchangeable, reducible and oxidizable fraction. Sludge pH was found to have profound effect on the chemical fractions of heavy metals. Acidic sludges (Xiamen and Jinlin Petrochemical Group Co., wastewater treatment plant) had higher proportion of the acid soluble/exchangeable fractions than in neutral sludge. In neutral sludges, Pb and Cr were principally distributed in between the oxidizable fraction and the residual fraction; Cu was in the oxidizable fraction; Cd mainly in the residual fraction in municipal wastewater treatment plants and had high percentage of acid soluble/exchangeable and reducible fractions in industrial wastewater treatment plants; Ni and Zn had higher percentage in the acid soluble/exchangeable and the oxidizable fraction.     

Variations in the mechanical properties and temperature of concrete subjected to cyclic loads,including high loads

Concrete structures are subjected to cylic loading throughout their service life. This article examines the changes taking place in the mechanical properties of concrete specimens under a limited number of compressive loading cycles involving high loads.     

Segmented flow injection,UV digestion,and amperometric detection for the determination of total cyanide in wastewater treatment plant effluents

The currently approved method for the analysis of total cyanide (TCN) in wastewaters has remained virtually unchanged in the 25 years since its initial use; this despite its subjection to a number of interferences, many of which provide a positive bias in cyanide measurements, including the formation of TCN during sample processing and some of which remain undocumented to this day. In particular, many municipal wastewater treatment plant chlorinated effluents throughout North America have often been cited for permit violations on the levels of total cyanide in their effluents measured using this methodology. A recently developed procedure for the analysis of TCN in various matrixes that utilizes segmented flow injection for sample transport and reaction, on-line acidic UV digestion for conversion of complexed cyanide to HCN, and amperometric detection achieved within 4 min of sample injection is demonstrated on chlorinated effluents discharged from municipal wastewater treatment plants. Through a systematic evaluation of the chemistry of the processes involved in this method and an understanding of the complexity of the wastewater matrix, an application was developed that showed consistent reproducibility in measuring TCN in a variety of effluents. The method was employed initially on synthetic solutions containing controlled levels of constituents identified in the literature as interfering with the measurement of TCN through the traditional distillation/colorimetric approach. In its application to the analysis of TCN in chlorinated wastewaters, an approach was evolved that ensured that dechlorination carried out during sample processing did not bias the results of analysis.     

Exposures to 222Rn from consumption of underground municipal water supplies in Pakistan

This paper presents the results of radon ((222)Rn) concentration measurements in municipal supply drinking water in metropolitan Lahore city of Pakistan and evaluation of consequent radiological effects. In this respect, water samples were collected in all nine municipal towns of Lahore city and analysed employing a high-resolution gamma spectrometric system. Radon concentration varied from 2.0 +/- 0.3 to 7.9 +/- 2.1 Bq l(-1). Mean value of annual effective dose for an individual consumer was assessed to be 16.5 +/- 12.8 microSv y(-1). (222)Rn mean concentration measured in this study is comparable with the reported values for drinking water determined worldwide and found to be less than the limit of 100 Bq l(-1) recommended by the World Health Organisation for public water supplies. The results of this study may be helpful in establishing background levels of radon in drinking water that could be used not only to distinguish additional contributions when a contamination event occurs but also to implement water quality standards by the concerned authorities to maintain radioactive contamination free drinking water supplies for the population.     

Application of microwave-assisted extraction to the analysis of PCBs and CBzs in fly ash from municipal solid waste incinerators

Polychlorinated biphenyls (PCBs) and chlorobenzenes (CBzs) are two classes of dioxin precursors formed in municipal solid waste incinerators (MSWIs) producing negative health effects similar to those of dioxins. Reducing the analytical time required for determining the concentrations of these compounds in MSWIs is important for quickly evaluating their importance and associated health risks. In the present study, microwave-assisted extraction (MAE) is compared with traditional Soxhlet extraction (SE) to determine the extraction efficiencies attained for PCB and CBz analysis. The efficiencies of MAE are compared with those of SE under various experimental conditions, using fly ash spiked with standards. Water is used as a safe and environmentally friendly solvent in MAE for PCB and CBz analyses and MAE has high extraction efficiency for spiked fly ash compared with that of SE. Furthermore, the extraction time and organic solvent consumption are reduced with MAE compared with SE. The optimum conditions for MAE established in this study are using a 30-ml volume of toluene/acetone (1/1) or a 15-ml volume of toluene, samples with less than 60% water content (WC), and an irradiation time of 15 min.     

仪器柔度对压入法测试结果的误差影响与校准

分析了仪器柔度及其标定精度对压人法测试微机电系统（MEMS）材料弹性模量和硬度结果的误差影响规律,并得出了系统误差公式。通过溯源分析,认为柔度标定误差是压人法测试的3个基本源误差之一。利用间接法对微压人测试仪柔度进行了标定和校准,校准后得到的单晶硅（100）弹性模量和硬度测试值分别为151．5GPa和12．8GPa,与文献值符合较好,而未校准直接得到的测试值明显偏低。理论分析和实验结果均表明：仪器柔度的准确标定和位移校准是获得压人法可靠测试结果的必须步骤。     

地铁负荷计算及采用冰蓄冷系统的负荷分析

介绍了一种地铁空调计算比较简单，行之有效的计算方法。地铁环境控制中的制冷系统采用冰蓄冷节约运营费用。本方法用于冰蓄冷制冷系统的空调负荷计算，需根据其负荷的特点，计算逐时负荷。     

Multivariate analysis of trace metals in textile effluents in relation to soil and groundwater

This paper deals with the multivariate analysis of metal data in effluents, soil and groundwater to find the distribution and source identification of the selected metals in the three media. Samples were collected from three textile industries located in Hattar Industrial Estate, Pakistan. Metals were estimated by flame atomic absorption spectrophotometry. The results showed elevated levels of Cr, Pb, Ni, Co, Fe, Ca, Na, K and Zn in these media, following the order: soil>effluent>water. Principle component analysis (PCA) of the data showed that the textile effluents are contaminating the soil wherein Cr and Pb were dominant toxic metals having concentrations of 5.96 mg/kg and 4.46 mg/kg, respectively. Other toxic metals such as Co, Cd, Zn, Ni, Mn and Fe, were found to have common origin in the textile effluents. The correlation study along with linear regression and PCA, supported the fact that various elevated metal concentrations emerged from the textile industrial effluents ultimately leading to contamination of the soil and groundwater in their proximity. The estimated metal levels in the water/soil system are compared with the safe limits laid down by WHO.     

Contribution of Radionuclides Associated with Microparticles to Their Migration from the Shelter and Its Service Area to Groundwater

Radionuclide distribution over coarsely dispersed particles (>0.1 µm), colloidal particles (0.01-0.1 µm), and ionic species in water samples taken in 2003 from the Shelter Object and the observation wells situated in the service area are reported. New data on americium distribution in water from the Shelter Object are also analyzed. These data as well as our previous results show that radionuclides associated with microparticles contribute significantly to their migration from the soil surface to groundwater.__________Translated from Radiokhimiya, Vol. 47, No. 1, 2005, pp. 89–90.Original Russian Text Copyright © 2005 by Rudenko, Khan.     

Patent evolution in relation to public/private R&D investment and corporate profitability: Evidence from the United States

Summary In this paper we analyze the (historical) co-evolution of technological development and economic progress (by relating public and private R&D investment, patenting, and corporate profitability). We relate to the work ofSchmookler(1966),Griliches(1990),Pakes&Griliches(1980) andPakes(1986) who all have studied the techno-economic interplay by considering patents as in indicator of technological performance. We use United States industry and government data over the period 1953-1998 (45 years). Co-evolution analysis over this period reveals a strong interdependency among the variables. Patent evolution is strongly related to the development of private R&D and corporate profitability; the levels of public and private R&D expenditure in combination with the level of technological output (i.e. patents) have a strong predictive and explanatory power towards corporate profitability (R² value of 94.9%). Causality tests reveal a joint determination between R&D investment and corporate profitability (L=2; p<0.01).