bluuebunny/crossref_metadata_2025 huggingface dataset:
Infrared Absorption Study of HfO2 and HfO2/Si Interface Ranging from 200cm−1 to 2000cm−1
Authors: Tomida Kazuyuki , Shimizu Haruka , Kita Koji , Kyuno Kentaro , Toriumi Akira
Published: July 2011

In this paper, we report infrared absorption studies of HfO2, HfO2/Si interface and Hf(1−x)SixOy. Both HfO2 crystallization and SiO2 formation at the interface can be clearly detected in the absorption spectra in the far and middle infrared regions, respectively. By measuring the intensity change and the peak shift of infrared absorption spectra as functions of annealing temperature and time together with XRD patterns, we discuss a difference of the amorphous structure between HfO2 and SiO2, and also show an evolution of HfO2 crystallization in the monoclinic phase up to 1000 °C. On the other hand, it is shown that the interfacial SiO2 layer is qualitatively similar to the thermally grown SiO2. Furthermore, it is demonstrated that a Si incorporation into HfO2 film significantly changes the IR absorption spectra, and that the Hf(1−x)SixOy film is phase-separated with an appearance of modified monoclinic phase by higher temperature annealing.
An Advanced High-k Transistor Utilizing Metal-Organic Precursors in an ALD Deposition of Hafnium Oxide and Hafnium Silicate with Ozone as Oxidizer
Authors: Gutt J. , Brown G.A. , Senzaki Yoshi , Park Seung
Published: July 2011

The International Technology Roadmap for Semiconductors (ITRS) has projected that continued scaling of planar CMOS technology to the 65nm node and beyond will require development of high-k films for transistor gate dielectric applications to allow further scaling of overall device sizes according to Moore's Law [1]. Researchers have recently been studying hafnium-based high-k dielectrics as an alternative to SiO2 [2]. The method of deposition of these films has been found to impact the applicability of the films for both low standby power and high performance applications [3]. Atomic Layer Deposition (ALD) has been among the more widely studied deposition techniques for these films, but previous work has emphasized ALD utilizing inorganic precursors [4]. In this paper, we shall describe a process in which hafnium oxide and hafnium silicate films were deposited from alternating pulses of volatile metal-organic Hf/Si liquid precursors and ozone on 200mm diameter Si substrates using a single wafer ALD system. Electrical characterization of the films is presented, including equivalent oxide thickness (EOT), gate leakage, and electron mobility data, showing an achievement of EOT's ranging from 1.19 to 1.69 nm with high field mobilities from 74% to more than 90% of that of SiO2 (2.1 nm film), and Jg in the range of 80mA to 3 A/cm2.
Effects of Structural Properties of Hf-Based Gate Stack on Transistor Performance
Authors: Bersuker G. , Sim J. H. , Young C. D. , Choi R. , Lee B. H. , Lysaght P. , Brown G. A. , Zeitzoff P. M. , Gardner M. , Murto R. W. , Huff H. R.
Published: July 2011

Electron traps in ALD and MOCVD HfO2 and HfSiO high-k dielectrics were investigated using both conventional DC and pulse measurements. It was found that the traps in the gate stack could be associated with defects of different activation energies and capture cross-sections. This points to potentially different origins of the electrically active defects, which can be either intrinsic or process-related. Structural non-uniformity of the high-k film, associated with grain formation and phase separation, may lead to variation of electrical properties of the gate dielectric along the transistor channel. Effects of such dielectric non-uniformity, as well as electron trapping, on the measured transistor mobility were evaluated.
Leakage Current Behavior in CaZrO3 Thin Films for High-k Applications
Authors: Yu Ting , Zhu Weiguang , Chen Xiaofeng , Lu Yuekang
Published: July 2011

Electrical properties and leakage current mechanisms of perovskite CaZrO3 dielectric thin films have been studied in this paper. CaZrO3 thin films were deposited on Pt/SiO2/n-Si substrate by the sol-gel wet chemical technology, and then annealed at temperatures ranging from 550 to 700 °C for 1h in O2. The films with platinum (Pt) top and bottom electrodes were characterized with respect to the leakage current as a function of temperature and applied voltage. The CaZrO3 film annealed at 600 °C was amorphous and showed good electrical properties with a dielectric constant of about 15 and leakage current density of 10−8 A/cm2 at high applied electrical field of 2.5 MV/cm. The data can be interpreted via a Schottky barrier model. The conduction mechanism at low electric fields is due to Ohmic conduction. On the other hand Schottky mechanism dominates at the intermediate fields. The high dielectric constant, low leakage current density and high breakdown strength suggest that the CaZrO3 thin film is a promising candidate for high-k applications.
Influence of Pre-Oxidation of an Ir Film on Chemical Composition and Crystal Property of a PZT Film Deposited on the Ir Film by Sputtering
Authors: Horita Susumu , Shoga Makoto
Published: July 2011

We investigated the influence of pre-oxidation of an Ir film as a bottom electrode on the chemical composition and crystal property of the PZT film deposited on it by RF sputtering, changing the sputtering target composition ratio Zr/Ti to be 20/80, 52/48 or 80/20. The Ir film deposited on a thermally oxidized Si substrate was pre-oxidized at 600°C for 20 min in the O2 gas of 10 Pa. The XRD patterns showed a strong PbO(101) peak from the PZT film on the oxidized Ir film for Zr/Ti = 52/48, but no PbO peak from the film on a no oxidized Ir film. The RBS measurement showed that the film composition ratio of Pb/(Zr+Ti) on the pre-oxidized Ir film was much larger than that on the no oxidized Ir film. For Zr/Ti=20/80, the same tendency was observed. However, for Zr/Ti=80/20, the chemical composition of the PZT film on the pre-oxidized Ir film was almost equal to that without oxidation.
MOCVD Processes for Electronic Materials Adopting Bi(C6H5)3 Precursor
Authors: Bedoya C. , Condorelli G. G. , Anastasi G. , Lisoni J. , Wouters D. , Fragalà I.L.
Published: July 2011

MOCVD of Bi2O3 has been investigated using Bi(C6H5)3 precursor. The decomposition products obtained at various deposition temperatures were determined using in situ FT-IR analysis. Benzene was the main product formed in the heterogeneous decomposition of Bi(C6H5)3 at temperature lower than 450°C, while above 450°C typical products of the combustion of aromatic ring were observed. The effect of oxygen on the film composition and its role in the decomposition process was evaluated by XPS depth profiles. Moreover, preliminary studies on the initial step of the film deposition suggested that Bi2O3 nucleation rate depends upon precursor partial pressure.
Effect of La doping on the structural and electrical properties of SrBi2Ta2O9
Authors: Nora Ortega , Bhattacharyya S. , Bhattacharya P. , Das R.R. , Katiyar R.S.
Published: July 2011

The effect of anthanum substitution (0-20%) on phase formation, structural evolution and electrical properties of SrBi2Ta2O9 (SBT) ceramics were investigated. X-ray diffraction studies revealed that phase pure SBT bulk samples can be synthesized with lanthanum doping without any phase segregation. Raman spectroscopy was used to understand the lattice vibrational characteristics of La substituted SBT compound. The ferroelectric soft mode at 27 cm−1 was shifted towards the lower frequencies at room temperature with increase in La concentrations. The octahedral stretching mode (O-Ta-O) did not influenced by La substitution in SBT. The x-ray photoemission spectroscopy measurements showed the decrease of binding energy of Bi 4f core levels (5/2 and 7/2) upon La substitution in SBT. The dielectric constant was increased from 120 to 190 up to 10% La doping and decreased with further increase in La concentration.
Investigations of PbxSr1-xTiO3 Thin Films and Ceramics for Microelectronic Applications
Authors: Jain M. , Yuzyuk Yu.I. , Katiyar R.S. , Somiya Y. , Bhalla A.S. , Miranda F.A. , VanKeuls F.W.
Published: July 2011

We have investigated electrical and optical properties of the lead strontium titanate {(PbxSr1-x)TiO3 or PST} ceramic and dielectric properties of the thin films of PST at low and high frequencies. (PbxSr1-x)TiO3 compositions with × ≤ 0.4 are paraelectric at room temperature and exhibit ferroelectric phase transition below room temperature. Only one phase transition in the PST system (compared to three in BaxSr1-xTiO3) was recorded. The studies indicated that PST has potential for tunable microwave devices in the paraelectric phase. In the present studies, Pb0.3Sr0.7TiO3 (PST30) ceramic was prepared by the conventional solid-state reaction method and thin films of PST were prepared by sol-gel technique. Structural, microstructural, dielectric, and Raman measurements were performed on these samples. Sharp phase transition was observed in case of the ceramic by dielectric and Raman measurements at 283 K. Raman measurements revealed well-pronounced soft-mode behavior below the Curie temperature in PST ceramic. The thin film of PST deposited on lanthanum aluminate substrate was highly (100) oriented and showed dielectric maxima at ∼280 K, which was close to that in case of the bulk. Eight element coupled micro-strip phase shifters (CMPS) was fabricated on the PST film and tested in the frequency range of 15-17 GHz. The average figure of merit of 49 °/dB for PST30 film in the Ku band at 533 kV/cm suggests the potentiality of these films for high frequency tunable dielectric devices.
Highly Reliable Metal Gate nMOSFETs by Improved CVD-WSix films with Work Function of 4.3eV
Authors: Nakajima Kazuaki , Nakazawa Hiroshi , Sekine Katsuyuki , Matsuo Kouji , Saito Tomohiro , Katata Tomio , Suguro Kyoichi , Tsunashima Yoshitaka
Published: July 2011

In this paper, we first propose an improved CVD-WSix metal gate suitable for use with nMOSFETs. Work function of CVD-WSi3.9 gate estimated from C-V measurements was 4.3eV. The nMOSFET using CVD-WSi3.9 gate electrode showed that Vth variation of L/W=1 μm/10μm nMOSFETs can be suppressed to be lower than 8mV in 22chip. In CVD-WSi3.9 gate MOSFETs with gate length of 50nm, a drive current of 636μA/μm was achieved for off-state leakage current of 35nA/μm at 1.0V of power supply voltage. By using CVD-WSi3.9 gate electrode, highly reliable metal gate nMOSFETs can be realized.
On the Nature of Weak Spots in High-k Layers Submitted to Anneals
Authors: Pétry J. , Vandervorst W. , Richard O. , Conard T. , DeWolf P. , Kaushik V. , Delabie A. , Van Elshocht S.
Published: July 2011

In the path to the introduction of high-k dielectric into IC components, a large number of challenges have still to be solved. Some of the major issues concern the low mobility of carriers and the reliability of the devices. Trapped charges in the stack have been identified as being the cause of these issues. With this in mind, we used Conducting Atomic Force Microscopy, combined with physical analysis to understand the nature of these charges. In this contribution, we have studied the uniformity of thin HfO2 layers, with and without anneal. The Conducting Atomic Force microscopy measurements show spots of higher conductivity. Recording local IV's in those ‘weak’ spots suggests that they consist of positive charge. On the other hand, XPS and ToFSIMS analysis show a diffusion of the interfacial SiO2 upwards into the high-k layer. Finally, the comparison of samples with differing high-k material and crystallinity indicates a strong correlation between the weak spots and the presence of silicon in the film.
Nitridation of Hafnium Silicate Thin Films
Authors: Chatham Hood , Senzaki Yoshi , Bailey Jeff , Nieveen Wesley
Published: July 2011

We discuss the nitridation of ALD-deposited hafnium silicate films by exposure to atomic nitrogen generated in a remote nitrogen plasma. Nitrogen concentration [N] as measured by X-ray photoelectron spectroscopy (XPS) is determined as a function of the nitridation temperature and other process conditions. Nitrogen concentrations up to 13.7 atomic % were achieved.
Comparison of Chemical Vapor Deposited Hafnium Dioxide and Silicon Doped Hafnium Dioxide using either O2, N2O, H2O, O2 plasma, or N2O plasma, and Hf (IV) t-butoxide
Authors: Bhandari Harish B. , Chen Ping , Klein Tonya M.
Published: July 2011

Hafnium oxide (HfO2) and silicon containing hafnium oxide (HfSixOy) thin films were deposited by thermal and plasma enhanced chemical vapor deposition (PECVD) using Hf (IV) t-butoxide and either O2, N2O, H2O, O2 plasma or N2O plasma as an oxygen source. Silane, 2% in He, was added to the reactant gas mixture to incorporate Si. Deposition rate and composition dependence on substrate temperature was studied and the deposited films were annealed in air for 30 min at 1100°C to observe changes in crystallinity and composition. Silicon incorporation was higher for H2O deposited HfSixOy films (5 at.%) than O2 and N2O deposited films (2 at.%) and had a lower deposition rate. Arrhenius plots reveal a non-simplistic reaction scheme since higher temperatures result in lower deposition rates due to precursor desorption. XRD indicate that as-deposited films using H2O are amorphous while O2 and N2O deposited films are microcrystalline with a monoclinic phase.
MOCVD of SrTa2O6Thin Films for High-k Applications
Authors: Regnery Stephan , Thomas Reji , Haselier Hans , Ehrhart Peter , Waser Rainer , Lehnen Peer , Miedl Stefan , Schumacher Markus
Published: July 2011

SrTa2O6thin films with thickness between 6 and 150nm were deposited in a multi-wafer planetary MOCVD reactor combined with a TRIJET® liquid delivery system using a single source precursor, strontium-tantalum-(methoxyethoxy)-ethoxide dissolved in toluene. A rather narrow process window for the deposition of stoichiometric SrTa2O6was found for this precursor at low pressures and a susceptor temperature around 500°C. Films were grown on Pt/TiO2/SiO2/Si, TiNx/Si, and SiO2/Si substrates. The as-deposited films were X-ray amorphous and could be crystallized by post-annealing at a temperature ≥700°C. The SrTa2O6phase was dominating within a broad range of compositions (Sr/Ta: 0.4–0.7) and a perovskite type phase was observed for Sr/Ta > 0.7. The electrical properties have been investigated with MIM and MIS capacitors after sputter deposition of Pt top electrodes. The amorphous films had a relative permittivity, ε, in the range of 25–45, and low leakage currents. Crystallized films were investigated with Pt MIM capacitors. For stoichiometric SrTa2O6the dielectric permittivity reached values of ε = 100–110, but the leakage currents were increased. Remarkably, the permittivity is not very sensitive to deviations from the exact stoichiometry of the SrTa2O6phase (Sr/Ta: 0.40.7), but a decrease to values of ε = 30–40 is observed along with the phase transition at high Sr contents.
Neoplastic Meningitis from Solid Tumors: New Diagnostic and Therapeutic Approaches
Authors: Lombardi Giuseppe , Zustovich Fable , Farina Patrizia , Della Puppa Alessandro , Manara Renzo , Cecchin Diego , Brunello Antonella , Cappetta Alessandro , Zagonel Vittorina
Published: July 2011

Learning Objectives

After completing this course, the reader will be able to: Compare the use of i.t. therapy and systemic therapies for patients with neoplastic meningitis.Describe new drugs showing promise for neoplastic meningitis.

This article is available for continuing medical education credit at CME.TheOncologist.com

Neoplastic meningitis is a result of the spread of malignant cells to the leptomeninges and subarachnoid space and their dissemination within the cerebrospinal fluid. This event occurs in 4%–15% of all patients with solid tumors and represents an important prognostic factor for poor survival. Neoplastic meningitis should be diagnosed in the early stages of disease to prevent important neurological deficits and to provide the most appropriate treatment. Despite new diagnostic approaches developed in recent years, such as positron emission tomography–computed tomography and new biological markers, the combination of magnetic resonance imaging without and with gadolinium enhancement and cytology still has the greatest diagnostic sensitivity.

Recently, no new randomized studies comparing intrathecal (i.t.) with systemic treatment have been performed, yet there have been a few small phase II studies and case reports about new molecularly targeted substances whose successful i.t. or systemic application has been reported. Trastuzumab, gefitinib, and sorafenib are examples of possible future treatments for neoplastic meningitis, in order to better individualize therapy thus allowing better outcomes.

In this review, we analyze the most recent and interesting developments on diagnostic and therapeutic approaches.
Heavy metals, PAHs and toxicity in stormwater wet detention ponds
Authors: Wium-Andersen T. , Nielsen A. H. , Hvitved-Jakobsen T. , Vollertsen J.
Published: July 2011

Concentrations of 6 different heavy metals and total polycyclic aromatic hydrocarbons (PAHs) were determined in stormwater runoff and in the pond water of two Danish wet detention ponds. The pond water samples were analyzed for toxic effects, using the algae Selenastrum capricornutum as a test organism. Stormwater and pond water from a catchment with light industry showed high levels of heavy metals, especially zinc and copper. The pond water showed high toxic effects and copper were found to be the main toxicant. Additionally, a large part of the copper was suspected to be complex bound, reducing the potential toxicity of the metal. Another catchment (residential) produced stormwater and pond water with moderate concentration of heavy metals. The pond water occasionally showed toxic effects but no correlation between heavy metals and toxicity was identified. PAHs concentrations were for both catchments low and no correlations between PAH concentrations in the pond and toxicity were found.
Methane conversion efficiency as a simple control parameter for an anaerobic digester at high loading rates
Authors: Charles W. , Carnaje N. P. , Cord-Ruwisch R.
Published: July 2011

The anaerobic digestion process is globally applied to the treatment of highly concentrated wastes such as industrial and rural effluents, and sewage sludge. However, it is known to be relatively unstable. When loaded with high concentrations of organic material, unwanted volatile fatty acids (VFA) are often produced rather than methane (CH4) gas which can lead to digester acidification and failure. This study investigated digester behaviour under high loading rates, testing the usefulness of stoichiometric methane conversion efficiency as a digester control parameter at high loading rates. Our results show that, in general, the CH4 production rate was proportional to the feed rate (loading rate). However, at very high loading rates, the CH4 production rate was not proportional to the increase in the feeding rate. Consequently, VFA accumulated and the H2 partial pressure increased. The proportionality of the loading rate and gas production rate is stoichiometrically expressed as the conversion efficiency. We found that conversion efficiency was a useful indicator as an early warning of digester imbalance. The digester remained stable at conversion efficiencies above 75%. Dropping below 70% signified the onset of digester failure. As loading rate and methane production data are readily available on-line in most anaerobic digestion plants, the conversion efficiency can be monitored on-line and used as an efficient control technique to maintain safe operation of anaerobic digesters at high loading rates.
PLIO: a generic tool for real-time operational predictive optimal control of water networks
Authors: Cembrano G. , Quevedo J. , Puig V. , Pérez R. , Figueras J. , Verdejo J. M. , Escaler I. , Ramón G. , Barnet G. , Rodríguez P. , Casas M.
Published: July 2011

This paper presents a generic tool, named PLIO, that allows to implement the real-time operational control of water networks. Control strategies are generated using predictive optimal control techniques. This tool allows the flow management in a large water supply and distribution system including reservoirs, open-flow channels for water transport, water treatment plants, pressurized water pipe networks, tanks, flow/pressure control elements and a telemetry/telecontrol system. Predictive optimal control is used to generate flow control strategies from the sources to the consumer areas to meet future demands with appropriate pressure levels, optimizing operational goals such as network safety volumes and flow control stability. PLIO allows to build the network model graphically and then to automatically generate the model equations used by the predictive optimal controller. Additionally, PLIO can work off-line (in simulation) and on-line (in real-time mode). The case study of Santiago-Chile is presented to exemplify the control results obtained using PLIO off-line (in simulation).
Synthesis of polyaspartic acid–aminobenzenesulfonic acid grafted copolymer and its scale inhibition performance and dispersion capacity
Authors: Xu Ying , Wang Lina , Zhao Linlin , Cui Yuanchen
Published: July 2011

Polysuccinimide (abridged as PSI) was synthesized by urea and maleic anhydride. Aminobenzenesulfonic acid (ABSA) was introduced at different mole ratio to PSI to generate polyaspartic acid (abridged as PASP)/ABSA graft copolymer. The scale inhibition behavior of resultant PASP/ABSA copolymer was evaluated by using static scale inhibition method. The transmittance of the supernatant of the copolymer solution was measured to evaluate its dispersion ability for ferric oxide. The corrosion inhibition performance of the copolymer for iron plates immersed in the refined testing water (including 0.555 g of CaCl2·2H2O, 0.493 g of MgSO4·7H2O, 50 mg PASP/ABSA graft copolymer and 0.168 g of NaCl) was tested. It was found that PASP/ABSA copolymer was able to efficiently inhibit CaCO3 and Ca3(PO4)2 scales and had good corrosion inhibition ability as well, and it also had good dispersion ability for Fe2O3. Besides, the inhibition efficiency of PASP/ABSA against CaCO3 and Ca3(PO4)2 scales and its dispersion capacity for Fe2O3 was highly dependent on dosage. The reason may lie in that PASP/ABSA copolymer simultaneously possesses carboxylic ion and sulfonic group which can chelate Ca2+ to form stabilized and dissoluble chelates, resulting in increase of solubility of calcium salts in water. Also it may lie in that the introduction of acidic hydrophilic sulfonic group with a strong electrolytic capacity into PASP molecule simultaneously enhances the dispersion of the inhibitor molecules and hinders the formation of Ca3(PO4)2 scale.
A novel technology for on-site cupric oxide recovery from cupric chloride etchant waste
Authors: Kobayashi T. , Kano K. , Suzuki T. , Kobayashi A.
Published: July 2011

For on-site copper recovery in print circuit board factories, we propose a novel technology to obtain cupric oxide with a low content ratio of chloride from high chloride concentration waste, such as cupric chloride etchant waste. Our technology is designed to avoid formation of double salt and accumulation of cupric hydroxide. In the proposed method, etchant waste mixed with hydrogen peroxide solution is added to sodium hydroxide solution by stepwise addition. We performed lab-scale experiments on the influence of reaction pH conditions on the content ratio of chloride in recovering cupric oxide. The results show that recycled cupric oxide tends to contain a lower content ratio of chloride under higher starting temperatures and higher final pH conditions of the reaction. We also confirmed the optimized conditions; the starting temperature of the sodium hydroxide solution is higher than 70 °C, and the final pH of the reaction is 11.5 to 12. Based on the optimized temperature and pH conditions, we also performed a pilot trial to recover cupric oxide from real etchant waste. Then, we successfully obtained cupric oxide with a content ratio of chloride in 80 mg-Cl/kg-CuO.
Dewatering sludge originating in water treatment works in reed bed systems
Authors: Nielsen S. , Cooper D. J.
Published: July 2011

The dewatering process of the liquid water works sludge was examined in a trial with a series of six trial beds, each 20 m2. These were monitored from April 2008 to June 2010. It is possible to get the vegetation to grow in ferric sludge (∼300,000 mg Fe/kg dry solid, pH 7,7). It has not been necessary to use fertilizer. The influence of the loading programs (15–50 kg dry solid/m2/year) was tested with 1–5 days of loading and 35–55 days of rest. It is possible to drain and treat ferric sludge. Generally the dewatering profile is a peak with a maximum over 0.015–0.025 L/s/m2. The times for dewatering of 6–12 m3 are ∼15 h and over 90% of the load is dewatered in that period. The dry solid (0.16–0.20%) in the sludge has been concentrated ∼200 times. The dewatering phase results in ferric sludge with 30–40% dry solid which cracks up very quickly. The volume reduction is over 99%. The trend shows that the main volume of reject water has a turbidity level below 5 NTU even in the loading periods.
Enhancement of the conventional anaerobic digestion of sludge: comparison of four different strategies
Authors: Pérez-Elvira S. I. , Fdz-Polanco M. , Fdz-Polanco F.
Published: July 2011

Anaerobic digestion (AD) is the preferred option to stabilize sludge. However, the rate limiting step of solids hydrolysis makes it worth modifing the conventional mesophilic AD in order to increase the performance of the digester. The main strategies are to introduce a hydrolysis pre-treatment, or to modify the digestion temperature. Among the different pre-treatment alternatives, the thermal hydrolysis (TH) at 170 °C for 30 min, and the ultrasounds pre-treatment (US) at 30 kJ/kg TS were selected for the research, while for the non-conventional anaerobic digestion, the thermophilic (TAD) and the two-stage temperature phased AD (TPAD) were considered. Four pilot plants were operated, with the same configuration and size of anaerobic digester (200 L, continuously fed). The biogas results show a general increase compared to the conventional digestion, being the highest production per unit of digester for the process combining the thermal pre-treatment and AD (1.4 Lbiogas/Ldigester·day compared to the value of 0.26 obtained in conventional digesters). The dewaterability of the digestate became enhanced for processes TH + AD and TPAD when compared with the conventional digestate, while it became worse for processes US + AD and TAD. In all the research lines, the viscosity in the digester was smaller compared to the conventional (which is a key factor for process performance and economics), and both thermal pre-treatment and thermophilic digestion (TAD and TPAD) assure a pathogen free digestate.
The role of SSVF and SSHF beds in concentrated wastewater treatment, design recommendation
Authors: Gajewska M. , Obarska-Pempkowiak H.
Published: July 2011

The return flows of reject water from sewage sludge dewatering alter the activated sludge process in a conventional WWTP and increase TN concentration in the final effluent from WWTP. The objective of the investigation carried out was to consider the application of multistage treatment wetland (MTW) for the treatment of reject water from sewage sludge dewatering in a centrifuge (RWC). This paper aims to present the design and performance of each stage of the treatment as well as the efficiency of total MTW. The full scale pilot plant for RWC, consisting of two vertical flow beds (SS VF) working in series, followed by an horizontal flow bed (SS HF), was built in 2008. The applied configuration ensured a very high removal efficiency of principal pollutant (COD – 76.0% and NH4+-N – 93.6%). In the investigated facilities, the SS VF beds ensured an effective removal of nitrogen compounds, especially NH4+-N, whereas the decomposition of hardly degradable Org-N and COD took place in SS HF. This research illustrates that the MTW could be successfully applied for the treatment of RWC.
Application of sequencing batch membrane bioreactors (SB-MBR) for the treatment of municipal wastewater
Authors: Laera G. , Jin Bo , Lopez A.
Published: July 2011

Sequencing batch membrane bioreactors can be a good option in up-grading small municipal plant and for industrial applications, maintaining some of the advantages of both original technologies (effluent quality improvement, flexibility and simplicity of realization, operation and control). In this study, the effects of volumetric exchange ratio (VER) and aeration/filtration strategy have been evaluated. Moreover, with the adoption of cycles shorter than 8 h, the opportunity of further simplification of the membrane operation has been tested by choosing a continuous filtration mode instead of the usual short cycle of permeation/relaxation. Two lab-scales MBR equipped with Zenon hollow fiber modules were fed on real primary effluent. For all tests, hydraulic retention time of 10 h and sludge retention time of 60 days have been adopted. Different cycles have been investigated, lasting between 1 and 8 h and all comprising an anoxic phase to allow for denitrification. Operation at low VER resulted in better effluent quality with no limitations to the denitrification phase. For VER >33% a pre-aeration step was required before effluent withdrawal for optimal ammonium removal. Moreover, VER appeared to have limited negative effect on sludge concentration and yield, while the membrane cleaning frequency slightly increased for increasing VER.
Evaluation of cattle bedding and grazing BMPs in an agricultural watershed in Alberta
Authors: Olson Barry M. , Kalischuk Andrea R. , Casson Janna P. , Phelan Colleen A.
Published: July 2011

This paper highlights the environmental impacts of implementing beneficial management practices to address cattle bedding and direct access to the creek in a study watershed in southern Alberta, Canada. Approximately 35 cow–calf pairs grazed 194 ha of grass forage and had direct access to the creek in the spring and summer. During winter, the cattle were fed adjacent to the creek at an old bedding site. The practice changes included off-stream watering, bedding site relocation and fencing for rotational grazing. The cost was $15,225 and 60 h of labour. Four years of data were used in a before-and-after experimental design to evaluate the practice changes. After two years of post-implementation monitoring, riparian assessments showed an increase in plant diversity, but no change in the percent cover of the riparian species Salix exigua and Juncus balitus and a decrease in Carex sp. (P < 0.05). Water quality monitoring showed a decrease in the difference between upstream and downstream concentrations of total phosphorus, total dissolved phosphorus, total nitrogen, organic nitrogen and Escherichia coli (P < 0.10). These results showed that improved environmental changes in riparian and water quality can be measured following the implementation of beneficial management practices for cattle bedding and grazing.
The impact of cyanobacteria on growth and death of opportunistic pathogenic bacteria
Authors: Bomo Anne-Marie , Tryland Ingun , Haande Sigrid , Hagman Camilla H. C. , Utkilen Hans
Published: July 2011

Climate change may cause increased microbial growth in water sources and more knowledge is required on how this may affect the hygienic water quality, i.e., whether increased occurrence of cyanobacteria and algae may stimulate the growth rate of opportunistic pathogenic bacteria. Laboratory experiments were performed to investigate if the presence of the cyanobacteria Anabanea lemmermannii and Microcystis aeruginosa affected the survival and growth rate of the opportunistic pathogenic bacteria Aeromonas hydrophila and Pseudomonas aeruginosa, and the faecal indicators Escherichia coli and coliforms. Cyanobacteria were cultured in bottles containing the nutrient-poor medium O2. Sewage, A. hydrophila or P. aeruginosa was added to cyanobacterial cultures and the bacterial growth and survival was followed. E. coli and coliforms from sewage died within few days and the decay rate was not affected by the presence of cyanobacteria. The presence of Anabaena stimulated the growth rate of P. aeruginosa, but had no effect on the growth rate of A. hydrophila. Microcystis had no effect on the growth rate of P. aeruginosa and an inhibiting effect on the growth rate of A. hydrophila.
Treatment of wastewater from a cotton dyeing process with UV/H2O2 using a photoreactor covered with reflective material
Authors: Fernandes de Melo Claudinei , da Silva Flavio T. , de Paiva Teresa C. B.
Published: July 2011

Wastewater containing several dyes, including sulfur black from the dyeing process in a textile mill, was treated using a UV/H2O2 process. The wastewater was characterized by a low BOD/COD ratio, intense color and high acute toxicity to the algae species Pseudokirchneriella subcaptata. The influence of the pH and H2O2 concentration on the treatment process was evaluated by a full factorial design 22 with three replicates of the central experiment. The removal of aromatic compounds and color was improved by an increase in the H2O2 concentration and a decrease in pH. The best results were obtained at pH 5.0 and 6 g L−1. With these conditions and 120 min of UV irradiation, the removal of the color, aromatic compounds and COD were 74.1, 55.1 and 44.8%, respectively. Under the same conditions, but using a photoreactor covered with aluminum foil, the removal of the color, aromatic compounds and COD were 92.0, 77.6 and 59.4%, respectively. Moreover, the use of aluminum foil reduced the cost of the treatment by 40.8%. These results suggest the potential application of reflective materials as a photoreactor accessory to reduce electric energy consumption during the UV/H2O2 process.
Pulse shear stress for anaerobic membrane bioreactor fouling control
Authors: Yang Jixiang , Spanjers Henri , van Lier Jules B.
Published: July 2011

Increase of shear stress at membrane surfaces is a generally applied strategy to minimize membrane fouling. It has been reported that a two-phase flow, better known as slug flow, is an effective way to increase shear stress. Hence, slug flow was introduced into an anaerobic membrane bioreactor for membrane fouling control. Anaerobic suspended sludge was cultured in an anaerobic membrane bioreactor (AMBR) operated with a side stream inside-out tubular membrane unit applying sustainable flux flow regimes. The averaged particle diameter decreased from 20 to 5 μm during operation of the AMBR. However, the COD removal efficiency did not show any significant deterioration, whereas the specific methanogenic activity (SMA) increased from 0.16 to 0.41 g COD/g VSS/day. Nevertheless, the imposed gas slug appeared to be insufficient for adequate fouling control, resulting in rapidly increasing trans membrane pressures (TMP) operating at a flux exceeding 16 L/m2/h. Addition of powdered activated carbon (PAC) enhanced the effect of slug flow on membrane fouling. However, the combined effect was still considered as not being significant. The tubular membrane was subsequently equipped with inert inserts for creating a locally increased shear stress for enhanced fouling control. Results show an increase in the membrane flux from 16 L/m2/h to 34 L/m2/h after the inserts were mounted in the membrane tube.
Effect of xylose and nutrients concentration on ethanol production by a newly isolated extreme thermophilic bacterium
Authors: Tomas Ana F. , Karakashev Dimitar , Angelidaki Irini
Published: July 2011

An extreme thermophilic ethanol-producing strain was isolated from an ethanol high-yielding mixed culture, originally isolated from a hydrogen producing reactor operated at 70 °C. Ethanol yields were assessed with increasing concentrations of xylose, up to 20 g/l. The ability of the strain to grow without nutrient addition (yeast extract, peptone and vitamins) was also assessed. The maximum ethanol yield achieved was 1.28 molethanol/molxylose consumed (77% of the theoretical yield), at 2 g/l of initial xylose concentration. The isolate was able to grow and produce ethanol as the main fermentation product under most of the conditions tested, including in media lacking vitamins, peptone and yeast extract. The results indicate that this new organism is a promising candidate for the development of a second generation bio-ethanol production process.
Technical Writing and the Development of the English Paragraph 1473–1700
Authors: Tebeaux Elizabeth
Published: July 2011

What is currently known about the history of the paragraph has relied on the work of the first English and American compositionists, humanists, and philologists of the late nineteenth century. Alexander Bain and his followers defined the requirements for the English paragraph and believed it had not existed prior to the eighteenth century. Their sole focus, on humanist and historical writing, yielded a distorted, if not an incorrect history of the paragraph. This article begins to correct that view, prevalent since 1866, by examining paragraphs of practical works, such as printed how-to books of the early English Renaissance until 1700. The variety and quantity of how-to documents increased with the growth of knowledge, advent of printing, and emergence and expansion of middle-class English readers eager for books written in an accessible, non-Latinate style. When we examine paragraphs from technical books printed as early as 1490, we find paragraphs that exemplify the qualities stipulated by Bain nearly 400 years later. The existence of well defined and formulated paragraphs throughout the English Renaissance and the seventeenth century in a wide variety of technical book—works ignored by literary scholars pursuing the history of English—suggests that the paragraph is clearly indigenous to the English composition, much more so than modern composition theory has acknowledged. This article explores example paragraphs of these first English printed technical works and begins to expand the history of the English paragraph. Further studies of later Middle English paragraphs in incunabula of practical, liturgical, and historical works will likely show the indigenous nature of the paragraph to English composition and allow scholars to see how the formation of the paragraph helped English writers over 500–700 years ago create complete texts.
Practicing “Safe” Technical Communication
Authors: Dombrowski Paul M.
Published: July 2011

The nuclear power industry is undergoing a renaissance, led by initiatives from the Obama administration and several states. In light of this development and the growing information economy, it is crucial that the public be well-informed, effective, and responsible regarding important technological issues. For this reason, undergraduate education, whether for technical or non-technical majors, must include an awareness of the complexity, ambiguity, and interestedness of the use of technical language and information. This is particularly important in communication involving public discourse and perceptions. I discuss here how I foster such awareness in my junior-level technical writing course for non-majors. We focus on the concept “safe” in relation to radiation and nuclear power. This is done in the overall context of making a recommendation for nuclear power as an energy source for the state of Florida for the next two decades, a realistic and urgent technical communication situation. Students see that standards and even the definitions of crucial terms shift depending on context and social circumstances, and that real-world choices involve trade-offs and balances between advantages and disadvantages.
A Stochastic Markov Model of Cellular Response to Radiation
Authors: Fornalski Krzysztof Wojciech , Dobrzynski Ludwik , Janiak Marek Krzysztof
Published: July 2011

A stochastic model based on the Markov Chain Monte Carlo process is used to describe responses to ionizing radiation in a group of cells. The results show that where multiple relationships linearly depending on the dose are introduced, the overall reaction shows a threshold, and, generally, a non-linear response. Such phenomena have been observed and reported in a number of papers. The present model permits the inclusion of adaptive responses and bystander effects that can lead to hormetic effects. In addition, the model allows for incorporating various time-dependent phenomena. Essentially, all known biological effects can be reproduced using the proposed model.
Effect of ventilation in enclosure machine system on MWF aerosol properties
Authors: Sokolovic Dunja , Höflinger Wilhelm , Zavargo Zoltan , Secerov-Sokolovic Radmila
Published: July 2011

In this paper the influence of ventilation air velocity on properties of
metal working fluids (MWF) aerosol/mist is presented. Aerosol
characteristics were monitored in the chamber as well as at the entrance of
ventilation pipe by optical particle size analyzer. Aerosol was generated
from 6% water emulsion of three commercial MWF. Four different velocities,
less than the velocity of secondary atomization, were examined (1, 3, 6, 8
m/s). Droplets size distribution, mass concentration (mg/m3), as well as
number concentration (P/cm3) were measured and analyzed. From the results
obtained it may be seen that coalescence is more pronounced as the velocity
increases, although the number concentration decreases, due to higher air
dilution. Therefore, more droplets are in a whirling motion at higher air
velocities, hence more random collisions are possible. Further analysis
shows that there is one value of air velocity under which the maximum
difference between the aerosol in chamber and the aerosol at the entrance of
the pipe can be observed. This velocity could be named specific velocity and
depends on the given aerosol properties. It could be assumed that specific
velocity is conditioned by the properties of oil from which emulsion is
prepared. Oil viscosity and molar mass have greatest influence on the
specific velocity.
Contracting Benefits of Corporate Giving: An Experimental Investigation
Authors: Balakrishnan Ramji , Sprinkle Geoffrey B. , Williamson Michael G.
Published: July 2011

We use a laboratory experiment to examine whether corporate giving to charity motivates employees. We find a strong altruism effect. Even when employees cannot be remunerated for their actions, employee contributions to employers significantly increase as the level of corporate giving increases. We also find a signaling effect. When employees can be remunerated for their actions, employee contributions initially increase as the level of corporate giving increases. Thus, even though corporate giving to charity decreases the amount that can be shared between employees and employers, employees behave as if more charitable employers will return proportionally more to employees. It is not until relatively high levels of corporate giving that employee contributions to employers eventually decrease. Collectively, our results suggest that corporate giving is an effective lever for motivating employee effort and contributions to organizational endeavors. Corporate giving can increase the efficacy of implicit (relational) contracts and reduce the need for formal accounting-based reward systems and controls.
Comparing the Value Relevance, Predictive Value, and Persistence of Other Comprehensive Income and Special Items
Authors: Jones Denise A. , Smith Kimberly J.
Published: July 2011

Gains and losses reported as other comprehensive income (OCI) and as special items (SI) are often viewed as similar in nature: transitory items with little ability to predict future cash flows and minimal implications for company value. However, current accounting standards require SI gains and losses to be recognized in net income, while OCI gains and losses are deferred until realized. This study empirically compares OCI and SI gains and losses using a model that jointly estimates value relevance, predictive value, and persistence. Results show that both SI and OCI gains and losses are value-relevant, but SI gains and losses exhibit zero persistence (i.e., are transitory), while OCI gains and losses exhibit negative persistence (i.e., partially reverse over time). Further, we find that SI gains and losses have strong predictive value for forecasting both future net income and future cash flows, while OCI gains and losses have weaker predictive value.

Data Availability: All data are publicly available from sources indicated in the text.
The effects of application time of a self-etching primer and debonding methods on bracket bond strength
Authors: Parrish Brandon C. , Katona Thomas R. , Isikbay Serkis C. , Stewart Kelton T. , Kula Katherine S.
Published: July 2011

Objective:

To test the manufacturer's recommendation for the application rubbing time of a self-etching primer (Transbond Plus, 3M Unitek) and to compare the resulting bond strength of a resin composite (Transbond XT, 3M Unitek) in the traditional laboratory tension on all four wings with a simulation of the clinical single-wing lift-off debonding instrument (LODI; 3M Unitek).

Materials and Methods:

Flattened stainless-steel maxillary incisor orthodontic brackets (Victory Series, 3M Unitek) were bonded to 108 flattened bovine incisors. The enamel was rubbed with the self-etching primer for 0, 5 (the manufacturer's recommendation), and 10 seconds during a 10-second application. Traditional four-wing and LODI simulated debonding forces and the adhesive remnant index (ARI) were recorded.

Results:

One-way analysis of variance testing among rubbing times and debonding methods indicated a significant difference in strength with 0 and 5 seconds of rubbing and between traditional and LODI simulated tension. The bond strengths were higher in the ARI  =  1 subset compared to the ARI  =  3–5 subsets.

Conclusions:

The manufacturer's recommendation for primer rubbing time produced the highest bond strength. Less force is required for debonding when tension is applied to one wing (LODI simulation) vs on all four wings.
Interleukin-18 Promoter Gene Polymorphisms are not Associated with Myocardial Infarction in Type 2 Diabetes in Slovenia
Authors: Kariž S , Petrovič D
Published: July 2011

Interleukin-18 Promoter Gene Polymorphisms are not Associated with Myocardial Infarction in Type 2 Diabetes in Slovenia

Type 2 diabetes is a major risk factor for myocardial infarction (MI) and chronic inflammation may play a central role in both diseases. Interleukin (IL)-18 is a potent proinflammatory cytokine, which is considered important in acute coronary syndromes and type 2 diabetes. We investigated the association of the -137 (G>C), polymorphism (rs187238) and the -607 (C<A) polymorphism (rs1946518) of the IL-18 gene promoter region in 495 Caucasians with type 2 diabetes, of whom 169 had MI and 326 subjects had no clinically evident coronary artery disease (controls). We also investigated the impact of these polymorphisms on the serum IL-18 level in subsets of both groups and in a normal group. Genotype distributions of the polymorphisms showed no significant difference between cases and controls. However, IL-18 serum levels were significantly lower in diabetics with the137 CC genotype than in those with other genotypes (241.5 ± 132.7 ng/Lvs.340.2 ± 167.4 ng/L; p <0.05). High sensitivity C-reactive protein and IL-18 serum levels were higher in diabetics in the MI group than in the control group. We conclude that these IL-18 promoter gene polymorphisms are not risk factors for MI in Caucasians with type 2 diabetes.