bluuebunny/crossref_metadata_2025 huggingface dataset:
Hammer Motor Breaks Ground In China
Authors: Herrington D. , Barton S. , Sha D. , Cote B. , Gaines M. , Morrison R.
Published: October 2012

Bit and bottomhole assembly (BHA) dynamics are a challenge when drilling in hard and interbedded formations. Dynamic conditions such as stick-slip and whirl can limit performance or in the worst case destroy downhole components. A new percussive mud hammer motor is being implemented in China to improve drilling performance by imparting a controlled impact to the bit while drilling.

Conventional technologies to address these challenges may have limited improvement significant added costs:

Conventional motors can generate large amounts of torque to the bit but can be difficult to control tool face and depth of cut as the bit transitions through various formations. This can result in stick-slip and bit bounce that can quickly damage or destroy the bit and BHA. Rotary steerable systems can control downhole dynamics with complex electronic, hydraulic and mechanical components but are very expensive, require higher system pressures and on-site supervision. Turbines with impregnated diamond bits can provide smooth drilling but can have limited rates of penetration in the softer portions of interbedded formations. In operation they also require higher pressure drops, have limited build rates and require on-site supervision by a turbine technician.

These conventional system limitations created an opportunity for a new technology that is simpler and brings greater value to the drilling operation. The hammer motor is a conventional power section and drivetrain with the patent pending hammer mechanism fitted in place of the lower bearing. This assembly has the same geometry of a bent housing motor with all of its capability plus the impact of a rotary hammer.

A series of field trials in China have recently been performed to validate the performance increases created by the hammer motor. These trials demonstrated significant cost savings, improved drilling performance, and simplicity of operation.
Laboratory Evaluation and Analysis of Physical Shale Inhibition of an Innovative Water-Based Drilling Fluid with Nanoparticles for Drilling Unconventional Shales
Authors: Ji Lujun , Guo Quanxin , Friedheim Jim , Zhang Rui , Chenevert Martin , Sharma Mukul
Published: October 2012

Although key shale gas plays vary considerably in terms of reservoir pressure, temperature, mineralogy, and in-situ stresses, the principal drilling-related issues are wellbore stability, shale inhibition, hole cleaning and rate of penetration. Because many of the shale reservoirs are in either environmentally sensitive or densely populated areas, stricter environmental regulations will require new types of environment-friendly water-based drilling fluids. The traditional shale inhibition method through either chemical inhibition or use of invert emulsion drilling fluid is not enough to satisfy the stricter environmental requirements.

This paper focuses on the lab techniques and the performance results of evaluating and analyzing an innovative water-based drilling fluid system containing nanoparticles as a physical shale inhibitor. The physical shale inhibition is achieved by plugging the pores and microfractures in shale with nanoparticles and thus preventing water invasion into the shale. A series of transient pressure penetration or flow-through tests, also known as shale membrane efficiency tests, were performed to evaluate water invasion rates into various shale core samples, with initial brine permeabilities varying from less than 1 nD to over 100,000 nD. Permeability reduction was used as a proxy of water invasion reduction and the effectiveness of plugging of pores and microfractures in shale by the nanoparticles. Many orders of permeability reduction were consistently observed for the drilling fluids with nanoparticles.

Pressure increases in the near-wellbore region due to water invasion during a given time also were analytically calculated using the permeabilities for various fluids which were interpreted from these transient flow-through tests. These pressure increases then were compared to illustrate the approximate impact depth of water invasion and give an indication of shale stability and shale inhibition performance of these drilling fluid systems.

Test results and pressure increase analyses showed that this new water-based drilling fluid with nanoparticles provides an entirely different type of shale inhibition by physically plugging pores and microfractures in shale and meets the strictest environmental regulations for shale gas drilling. The tests also showed that although nanoparticles alone may be effective in preventing water invasion into shale samples with no microfractures, the combination of properly formulated drilling fluid and nanoparticles of appropriate size and concentration is the key to prevent water invasion into shale gas core samples with or without microfractures.
Failure Probability with Time under Different Operational Conditions for Low-Density System Based on Hollow Microspheres Supported By Long Term Lab Studies and Field Cases
Authors: Al-Yami Abdullah S. , Yuan Zhaoguang , Schubert Jerome
Published: October 2012

Cementing a string in one stage is a challenging task, especially in the presence of weak formations. Cement slurry losses during placement is highly possible if the equivalent circulating density (ECD) exceeds 82 pcf during placement. A conventional method to overcome this challenge is to use multi-stage cementing by setting the stage tool above the loss circulation zone. However, field data indicate that the tool can fail, thus causing serious delay and economic loss. In addition, stage tools are considered weak point and not good for long term seal. A second method for zonal isolation is to use low density cement.

In this study, we present extensive lab evaluation of a low density system based on the use of hollow microspheres for one year at field conditions. The tests included one year mechanical properties measurement such as compressive strength development, Young's modulus and Poisson's ratio. The low-density system (70 pcf) was tested at 300 ºF. An earlier study has shown the suitability of using low density cement in the field, Al-Yami et al. (2007). However, there is no available Investigation in the literature about the durability of low density cement at higher temperature and at different operational scenarios.

The finite element method was used to analyze the failure probability of HPHT wells over with time. At the variation of bottom whole pressure, the casing, cement, and formation system failure probability was studied for this type of cement.

This paper introduces the operational envelope for this type of cement in order to achieve successful operations. Field cases were discussed to validate the results of this investigation.
Is There A Better Way to Determine The Viscosity in Waxy Crudes?
Authors: Daungkaew Saifon , Fujisawa Go , Chokthanyawat Suchart , Ludwig John , Houtzager Fred , Platt Christopher , Last Nick , Limniyakul Theeranun , Phaophongklai Wattanaporn , Comrie-Smith Nick , Thaitong Thanagit
Published: October 2012

Accurate viscosity measurement is difficult even under the best of conditions and the lengthy time required to send and receive results from a lab prohibit basing important decisions on the viscosity of the reservoir fluid. Those challenges increase for reservoirs with complex fluids such as the highly viscous, waxy crudes found in many of the oil fields in South East Asia.

While correlations have been developed to determine the viscosity of waxy crudes, the accuracy can be limited under certain conditions. The objective of the paper is to review visc sity correlations for waxy crude and examine their applications to the actual field data. Limitations on the use and accuracy of these correlations will then be discussed. This paper also discusses the viscosity obtained in real-time from the suite of Downhole Fluid Analysis (DFA) measurements, and the result is then compared to standard PVT analysis over a wide range of viscosities, temperatures, and pressures.

Results of the DFA viscosity measurements in several fields in South East Asia are discussed together with other fluid properties such as GOR, density, and fluid compositions. The viscosity is then examined at the field scale to help understand the reservoir complexity in terms of compartmentalization in these waxy oil environments.

The technical contribution from this paper is that it presents the variation of the viscosity in waxy oil reservoirs and its impact on real time decision making, especially for purposes of pressure transient analysis. This paper covers the evolution of the DFA viscosity measurement including a description of the hardware, discusses the limitation of the DFA measurement for certain conditions, and summarizes the accuracy of the DFA viscosity measurement for different fluids and the ongoing development for covering more fluids in the lower end of the viscosity spectrum.
An Operator's Experience of the Successful Deployment of a Subsea Multiphase Boosting System Offshore Western Australia
Authors: Nallipogu Tim , Oppedal Jørn H , Mckay Linda , Glucina Andrew
Published: October 2012

The field was developed in a deepwater setting by Woodside Energy Ltd (WEL) and Mitsui E&P Australia Pty Ltd and commenced production in 2008. The field is located some 50 km offshore Western Australia, in approximately 400m water depth. Similar to other projects in the area, the development of the field was based on a subsea tieback to an Floating Production Storage and Offtake vessel (FPSO). The artificial lift for the field was based on the deployment of a subsea multiphase boosting system, to ensure satisfactory production rates and recovery of hydrocarbons.

This paper will address the typical applications and characteristics for subsea multiphase boosting systems, and provide an overview of the system deployed, as well as the drivers for selecting this technology. The benefits to the users are normally related to reduced investments, and more importantly, increased recovery and optimum utilization of hydrocarbons in place. The potential extension of field life for producing assets through multiphase boosting may have significant impact on the overall economics of the development.

The operational experience of the subsea boosting system will be discussed, including the performance of the subsea boosting system. The operation of the boosting system is based on the concept of integrated operations, and thus the performance of the subsea pumps and all auxiliaries are condition monitored on a real-time basis. The experience and added value generated through integrated operations of subsea rotating machinery will be discussed, including the potential upside with regards to system availability and maintenance.

Based on the successful deployment of a subsea multiphase boosting system the operator gained experience with the operation of subsea rotating machinery and production boosting. It is the objective of this paper to share considerations, advantages and future expectations of the technology, and put forward recommendations for future deployments of the same.
3-Phase Flow Correlation Selection for Production Logging Interpretation
Authors: Jongkittinarukorn Kittiphong , Kerr Robert
Published: October 2012

Production Log analysis is based on the calculation of fluid flow velocity, usually from a spinner, some fluid identification sensors to work out the holdups of fluids along the wellbore with a lookup of the slippage between the fluid phases from a correlation. The fluid rates are a result of the calculations and very dependent on the attributed slippage velocities. There are a number of slippage correlations in the Emeraude Production Logging (PL) analysis program from Kappa. The choice can be significant as the results from using different correlations may move the apparent water production from one zone to another. Usually the analyst just uses the correlation that gives the result closest to the surface test and keeps that correlation for all other zones.

The object of this paper is to find a more systematic way to pick the flow correlation to use in a 3-phase well. In Emeraude there are 7 Oil-Water (O-W) correlations and 2 full 3-phase flow correlations. For the O-W correlations, one has to pick a Gas-Liquid (G-L) correlation first. We used the correlation recommended by our previous study (Jongkittinarukorn and Kerr, 2011) to work out the G-L slippage and then used a similar statistical technique to determine which correlation works best determine the O-W slippage.

This study finds that 3-Phase G-L correlations perform better than 3-Phase correlations do. Choquette, ABB-Deviated, and Stanford Drift Flux LL correlations are the best three flow correlations and are recommended for PL analysis in a 3-phase well. The results of the statistical analysis indicate that gas rate, oil rate, and water cut are critical for flow correlation selection.
Development of MEG Regeneration Unit Compatible Corrosion Inhibitor for Wet Gas Systems
Authors: Bikkina Chaitanya , Radhakrishnan Narayanan , Jaiswal Sumit , Harrington Ryan M , Charlesworth Mark
Published: October 2012

Transportation of hydrocarbons and water in long subsea flow lines from satellite fields to a platform or to an onshore facility presents new challenges in the control of gas hydrates, corrosion, and mineral scale. Gas hydrates form at high pressure and low temperature and are a common problem in offshore wet gas pipelines due to low seabed temperatures and elevated pressures in these remote subsea developments. Monoethylene glycol (MEG) is widely used as a thermodynamic hydrate inhibitor in these developments to manage the risk of hydrate formation during production and transportation of multiphase fluids from subsea wells.

Due to large amounts of MEG required for effective hydrate control, it is necessary to recycle and re-use it. The main processes for recycling of MEG are regeneration and reclamation. Typical conditions of regeneration and reclamation processes are ambient to vacuum pressures and temperatures in the range of 120°C −150°C1. In addition to the use of MEG for hydrate control, corrosion inhibitors are also applied for corrosion control in the subsea pipelines and infrastructure. These corrosion inhibitors must be able to perform under high shear and highly corrosive environments without losing their effectiveness after having been subjected to the system conditions present in the MEG regeneration process. Inappropriate selection of corrosion inhibitors for MEG based applications can lead to severe fouling/formation of solids, emulsion and foaming issues in the receiving facilities. The corrosion inhibitors developed for use in facilities operating with glycol regeneration systems should remain active after multiple MEG Regeneration Unit (MRU) cycles without causing fouling/formation of solids, emulsion and foaming.

The current paper presents MRU compatible corrosion inhibitors developed based on the stringent testing methods adopted from real time MRU process.
Reservoir Geomechanics Study for Deepwater Field Identifies Ways to Maximize Reservoir Performance While Reducing Geomechanics Risks
Authors: de Souza Antonio Luiz , de Souza Jorge André , Meurer Gustavo Bechara , Naveira Vanessa Palma , Chaves Ricardo Alexandre , Frydman Marcelo , Pastor Jorge , Chaves Michelle
Published: October 2012

Several Petrobras fields in Campos Basin are soft sandstone with a large number of faults, which demands a careful reservoir geomechanics study in order to maximize their production and minimize geomechanical risks. Those risks are associated with compaction and/or dilation, subsidence and in special with fault reactivation due to water injection, which can lead to a connection between different layers and reservoirs.

The object of this study is a faulted turbidity reservoir in Campos basin where a water injection project has started. The Mechanical Earth Model (MEM) was developed. It was identified that the planned injection pressure would increase the risks for fault reactivation, and recommendations for a safe water injection project was obtained. Special emphasis is on factors that may have enhanced leakage pathways at some point during injection, reducing its effectiveness and bringing other related risks. Reservoir performance and associated reservoir deformation was estimated. The predicted stress and strain changes that were induced by production/injection were used to assess the wellbore stability, faults reactivation potential, cap rock integrity and rock fracturing. Understanding of the various potential processes and being able to predict the field behavior are critical to the optimal management of the reservoir for maximum productivity and recovery.
A Fully Air Deployable Well Capping Stack and ROV Tooling System for Worldwide Support
Authors: Karlsen Geir
Published: October 2012

BP's intent is to maintain well control from spud to abandonment. However, if for any reason well control is lost, we are designing our wells with the capability to stop or minimize the flow of oil into the water column using a capping system. The cap can stop the flow completely or we can minimize the flow where a collection system or plan could be required.

As part of BP's commitment to enhance deepwater safety and response preparation, BP has developed a comprehensive Global Deepwater Well Cap and Tooling Package. The system can be rapidly deployed to any of BP's operational regions in response to a well control event.

The system includes an Upper and a Lower capping stack, flow-back assembly, flex joint riser adapters, flex joint stiffeners, a comprehensive remote operated vehicle (ROV) tooling package, debris removal tools, dispersant distribution system, subsea hydraulic power unit with a launch and recovery system, subsea accumulator and 60-inch pipe shears for shearing a drilling riser. In total, the system contains over 250 components, 65 lifts, and weighs approximately 500 mT. The Global Deepwater Well Cap and Tooling Package is rated at 10,000 ft. water depth, 15,000psi and is fully air transportable onboard Antonov AN-124 and Boeing B747 200, 400 and 800 series heavy-lift aircraft. No disassembly is required to airfreight the system.
Assessment of vulnerability of river basins in Ghana to water stress conditions under climate change
Authors: Obuobie Emmanuel , Kankam-Yeboah Kwabena , Amisigo Barnabas , Opoku-Ankomah Yaw , Ofori Deborah
Published: October 2012

The Falkenmark indicator was used to assess vulnerability of the White Volta (106,000 km2) and Pra (20,023 km2) river basins in Ghana to water stress under climate change for the periods 2006–2035 (representing the 2020s) and 2036–2065 (2050s). The indicator is a commonly used measure of water stress and defines thresholds of 1,700, 1,000 and 500 m3/capita/annum as water stress, water scarcity and absolute scarcity, respectively. Downscaled data from ensemble averages of two global climate models, ECHAM4 and CSIRO, were used to drive the Soil and Water Assessment Tool for estimation of basin surface water resources under climate change. The simulated water resources in the two basins showed significant reduction of 22% for 2020. Further reductions were estimated for 2050 (50% and 46% for the White Volta and Pra, respectively). Without climate change, the White Volta basin will attain water stress and water scarcity by 2020 and 2050, respectively; the Pra is already water stressed and expected to worsen to water scarcity by 2020 and absolute scarcity by 2050. Climate change will aggravate the conditions in both basins. Implementation of integrated water resources management and population control measures are recommended for sustainable use and management of water resources in both basins.
Rural livelihoods and household adaptation to desiccation in the Okavango Delta, Botswana
Authors: Motsholapheko Moseki R. , Vanderpost Cornelis , Kgathi Donald L.
Published: October 2012

Desiccation of river channels, resulting from low inflows, is among the major shocks affecting household livelihoods in the Okavango Delta, Botswana. Household coping and adaptive strategies against this shock are believed to be inadequate owing to changes in policy, land use and environmental conditions. This paper aims to improve knowledge on household capacity to adapt to desiccation in the Okavango Delta. It identifies and assesses the impacts of desiccation on rural livelihoods, the household strategies, and the impacts of institutional changes on household responses. Informed by the sustainable livelihood and socio-ecological frameworks, the study used a survey of 526 households and other qualitative methods. The results show that desiccation adversely affected livelihood activities. Household responses included livestock relocation to wetter areas, livelihood diversification, digging of wells and boreholes, and switching from flood recession to rain-fed cultivation. Land use and institutional changes inhibited household adaptation to desiccation. Additionally, households did not sufficiently use opportunities resulting from desiccation. The study concludes that the ability to capitalise on opportunities created by climatic shocks needs to be developed at all levels, as this can improve adaptation to the impacts of, and reduce losses from, future climate variability and change in Botswana and other developing countries.
Increased Myocardial Uptake of Dietary Fatty Acids Linked to Cardiac Dysfunction in Glucose-Intolerant Humans
Authors: Labbé Sébastien M. , Grenier-Larouche Thomas , Noll Christophe , Phoenix Serge , Guérin Brigitte , Turcotte Eric E. , Carpentier André C.
Published: October 2012

Impaired cardiac systolic and diastolic function has been observed in preclinical models and in subjects with type 2 diabetes. Using a recently validated positron emission tomography (PET) imaging method with 14(R,S)-[18F]-fluoro-6-thia-heptadecanoic acid to quantify organ-specific dietary fatty acid partitioning, we demonstrate in this study that overweight and obese subjects with impaired glucose tolerance (IGT+) display significant increase in fractional myocardial dietary fatty acid uptake over the first 6 h postprandial compared with control individuals (IGT−). Measured by [11C]acetate with PET, IGT+ subjects have a significant increase in myocardial oxidative index. IGT+ subjects have significantly reduced left ventricular stroke volume and ejection fraction (LVEF) and tend to display impaired diastolic function, as assessed by PET ventriculography. We demonstrate an inverse relationship between increased myocardial dietary fatty acid partitioning and LVEF. Fractional dietary fatty acid uptake is reduced in subcutaneous abdominal and visceral adipose tissues in IGT+ directly associated with central obesity. Fractional dietary fatty acid uptake in skeletal muscles or liver is, however, similar in IGT+ versus IGT−. The current study demonstrates, for the first time, that excessive myocardial partitioning of dietary fatty acids occurs in prediabetic individuals and is associated with early impairment of left ventricular function and increased myocardial oxidative metabolism.
31P-Magnetization Transfer Magnetic Resonance Spectroscopy Measurements of In Vivo Metabolism
Authors: Befroy Douglas E. , Rothman Douglas L. , Petersen Kitt Falk , Shulman Gerald I.
Published: October 2012

Magnetic resonance spectroscopy offers a broad range of noninvasive analytical methods for investigating metabolism in vivo. Of these, the magnetization-transfer (MT) techniques permit the estimation of the unidirectional fluxes associated with metabolic exchange reactions. Phosphorus (31P) MT measurements can be used to examine the bioenergetic reactions of the creatine-kinase system and the ATP synthesis/hydrolysis cycle. Observations from our group and others suggest that the inorganic phosphate (Pi) → ATP flux in skeletal muscle may be modulated by certain conditions, including aging, insulin resistance, and diabetes, and may reflect inherent alterations in mitochondrial metabolism. However, such effects on the Pi → ATP flux are not universally observed under conditions in which mitochondrial function, assessed by other techniques, is impaired, and recent articles have raised concerns about the absolute magnitude of the measured reaction rates. As the application of 31P-MT techniques becomes more widespread, this article reviews the methodology and outlines our experience with its implementation in a variety of models in vivo. Also discussed are potential limitations of the technique, complementary methods for assessing oxidative metabolism, and whether the Pi → ATP flux is a viable biomarker of metabolic function in vivo.
Metabolic Syndrome and Risk of Cancer
Authors: Esposito Katherine , Chiodini Paolo , Colao Annamaria , Lenzi Andrea , Giugliano Dario
Published: October 2012

OBJECTIVE

Available evidence supports the emerging hypothesis that metabolic syndrome may be associated with the risk of some common cancers. We did a systematic review and meta-analysis to assess the association between metabolic syndrome and risk of cancer at different sites.

RESEARCH DESIGN AND METHODS

We conducted an electronic search for articles published through October 2011 without restrictions and by reviewing reference lists from retrieved articles. Every included study was to report risk estimates with 95% CIs for the association between metabolic syndrome and cancer.

RESULTS

We analyzed 116 datasets from 43 articles, including 38,940 cases of cancer. In cohort studies in men, the presence of metabolic syndrome was associated with liver (relative risk 1.43, P < 0.0001), colorectal (1.25, P < 0.001), and bladder cancer (1.10, P = 0.013). In cohort studies in women, the presence of metabolic syndrome was associated with endometrial (1.61, P = 0.001), pancreatic (1.58, P < 0.0001), breast postmenopausal (1.56, P = 0.017), rectal (1.52, P = 0.005), and colorectal (1.34, P = 0.006) cancers. Associations with metabolic syndrome were stronger in women than in men for pancreatic (P = 0.01) and rectal (P = 0.01) cancers. Associations were different between ethnic groups: we recorded stronger associations in Asia populations for liver cancer (P = 0.002), in European populations for colorectal cancer in women (P = 0.004), and in U.S. populations (whites) for prostate cancer (P = 0.001).

CONCLUSIONS

Metabolic syndrome is associated with increased risk of common cancers; for some cancers, the risk differs betweens sexes, populations, and definitions of metabolic syndrome.
Effect of Postoperative Peroxide Bleaching on the Stability of Composite to Enamel and Dentin Bonds
Authors: Dudek M , Roubickova A , Comba L , Housova D , Bradna P
Published: October 2012

This study investigated the effect of peroxide bleaching gel on the durability of the adhesive bond between composite material, enamel, and dentin created with the etch-and-rinse adhesive Gluma Comfort Bond (GLU) and with the self-etch adhesives Clearfil SE Bond (CLE), Adper Prompt (ADP), and iBond (IBO). The adhesives were applied to flattened enamel and dentin of extracted human molars and built up with a microhybrid composite (Charisma). After 25 eight-hour cycles of bleaching with a 20% carbamide peroxide bleaching gel (Opalescence PF 20), the shear bond strength was measured and compared with one-day and two-month control specimens stored in water. The data were analyzed using nonparametric Mann-Whitney and Kruskal-Wallis statistics (p<0.05). Detailed fractographic analysis was performed using scanning electron microscopy. The bleaching gel significantly decreased the bond strength on both enamel and dentin for the simplified single-step self-etch adhesives ADP and IBO and markedly affected a fracture pattern of ADP specimens at the periphery of their bonded area. The results of our study indicate that the durability of adhesive restorations can be detrimentally influenced by carbamide peroxide bleaching and that different adhesives show varying sensitivity levels to the bleaching gel.
Laser cladding using scanning optics
Authors: Pekkarinen I. J. , Kujanpää V. , Salminen A.
Published: October 2012

Laser cladding using scanning optics is a relatively little studied matter. Scanning optics makes the adjustment of laser beam interaction zone numerically possible and it is, therefore, a more flexible optical tool than the conventional static optics. A series of cladding test were conducted using a 5 kW fiber laser and an oscillating linear scanner with dynamic powder feeding to determine the process characteristics and their possibilities and limitations. This study was carried out using 316L powder as an additive material and S355 mild steel plate as a substrate material. It was noticed that by using scanning optics, it is possible to vary the width and thickness of clad beads on a large scale. With scanning optics, it is possible to affect clad bead geometry so that only a 20% overlapping ratio is used. However, certain cladding parameter combinations expose the clad bead to cladding defects. Also, a fast moving scanned laser beam causes a wave formation to the melt pool which further causes stirring in the melt pool. Another studied matter was the effect of the cladding speed to dilution in laser cladding with scanning optics. The dilution was increased with increase in the cladding speed. However, the increase of the dilution was dependent on the scanning amplitude.
A comparative study of cut front profiles and absorptivity behavior for disk and CO2 laser beam inert gas fusion cutting
Authors: Daniele Scintilla Leonardo , Tricarico Luigi , Mahrle Achim , Wetzig Andreas , Beyer Eckhard
Published: October 2012

Results of experimental investigations on disk and CO2 laser beam fusion cutting cold-work tool steel 90MnCrV8 are presented. The study was performed with the aim to detect features of the cut front geometry and differences in the corresponding absorptivity behavior as a function of the laser wavelength. Longitudinal sections of the cut front were prepared for different sheet thicknesses, focal plane positions, and cutting speeds. The digitalization of the geometrical cut front data enabled the determination of local inclination angles and the calculation of corresponding Fresnel absorptivity values. The analysis revealed that particular areas of the cut front geometry are preferably inclined to values close to the Brewster angle which offer the theoretical maximum absorptivity for both laser types.
Fully automated chip-based nanoelectrospray combined with electron transfer dissociation for high throughput top-down proteomics
Authors: Flangea Corina , Schiopu Catalin , Capitan Florina , Mosoarca Cristina , Manea Marilena , Sisu Eugen , Zamfir Alina
Published: October 2012

The conventional protocol for protein identification by electrospray ionization mass spectrometry (MS) is based on enzymatic digestion which renders peptides to be analyzed by liquid chromatography-MS and collision-induced dissociation (CID) multistage MS, in the so-called bottom-up approach. Though this method has brought a significant progress to the field, many limitations, among which, the low throughput and impossibility to characterize in detail posttranslational modifications in terms of site(s) and structure, were reported. Therefore, the research is presently focused on the development of procedures for efficient top-down fragmentation of intact protein ions. In this context, we developed here an approach combining fully automated chip-based-nanoelectrospray ionisation (nanoESI), performed on a NanoMate robot, with electron transfer dissociation (ETD) for peptide and top-down protein sequencing and identification. This advanced analytical platform, integrating robotics, microfluidics technology, ETD and alternate ETD/CID, was tested and found ideally suitable for structural investigation of peptides and modified/functionalized peptides as well as for top-down analysis of medium size proteins by tandem MS experiments of significantly increased throughput and sensitivity. The obtained results indicate that NanoMate-ETD and ETD/CID may represent a viable alternative to the current MS strategies, with potential to develop into a method of routine use for high throughput top-down proteomics.
Measurement and prediction of binary mixture flash point
Authors: Hristova Mariana
Published: October 2012

The flash points of three binary mixtures, containing n-heptane, o-xylene, m-xylene and ethylbenzene, were measured by Pensky-Martens closed cup tester. The experimental data were compared with the calculated values using Liaw’s Model with the application of Raoult’s Law and Wilson equation. These equations were in good qualitative agreement.
Determination of formaldehyde and cyanide ion in human nasal discharge by using simple spectrophotometric methods
Authors: Narkowicz Sylwia , Polkowska Żaneta , Namieśnik Jacek
Published: October 2012

Environmental tobacco smoke (ETS) contains many toxic compounds which include substances classified as aldehydes (e.g. formaldehyde) and inorganic substances such as cyanide ions. The information on the determination of these compounds in water is available, but the monitoring data on the level of these substances in human body fluids are still lacking. In this work the procedure for determining cyanide ions and formaldehyde in samples of human nasal discharge by simple spectrophotometric technique is presented.
QSAR study and molecular docking on indirubin inhibitors of Glycogen Synthase Kinase-3
Authors: Crisan Luminita , Pacureanu Liliana , Bora Alina , Avram Sorin , Kurunczi Ludovic , Simon Zeno
Published: October 2012

The current study describes the development of in silico models based on a novel alternative of the MTD-PLS methodology (Partial-Least-Squares variant of Minimal Topologic Difference) developed by our group to predict the inhibition of GSK-3β by indirubin derivatives. The new MTD-PLS methodology involves selection rules for the PLS equation coefficients based on physico-chemical considerations aimed at reducing the bias in the output information. These QSAR models have been derived using calculated fragmental descriptors relevant to binding including polarizability, hydrophobicity, hydrogen bond donor, hydrogen bond acceptor, volume and electronic effects. The MTD-PLS methodology afforded moderate but robust statistical characteristics (R2
Y(CUM) = 0.707, Q2(CUM) = 0.664). The MTD-PLS model obtained has been validated in terms of predictive ability by joined internal-external cross-validation applying Golbraikh-Tropsha criteria and Y-randomization test. The information supplied by the MTD-PLS model has been evaluated against Fujita-Ban outcomes that afforded a statistically reliable model (R2=0.923). Furthermore, the results originated from QSAR models were laterally validated with docking insights that suggested the substitution pattern for the design of new indirubins with improved pharmacological potential against GSK-3β. The new restriction rules introduced in this paper are applicable and provide reliable results in accordance with physico-chemical reality.
Surface modification and adhesion improvement of polyester films
Authors: Cammarano Aniello , Luca Giovanna , Amendola Eugenio
Published: October 2012

Facile surface modification of polyester films was performed via chemical solutions treatment. Surface hydrolysis was carried out by means of sodium hydroxide solutions, leading to the formation of carboxylate groups. Three commercial polyester films of 100 μm in thickness were used in this work: AryLite™, Mylar™, and Teonex™, hydrolysis time being the main modification parameter. FTIR-ATR analysis, topography and contact angle (CA) measurements, surface free energy (SFE) and T-Peel adhesion tests were carried out to characterize the modified films. A quantitative estimate of the carboxylates surface coverage as a function of treatment time was obtained through a supramolecular approach, i.e. the ionic self-assembly of a tetracationic porphyrin chromophore onto the film surface. The surface free energy and critical surface tension of the hydrolyzed polyesters was evaluated by means of Zisman, Saito, Berthelot and Owens-Wendt methods. It was shown that NaOH solution treatment increases roughness, polarity and surface free energy of polymers. As a result, T-Peel strengths for modified Mylar™ and Teonex™ films were respectively 2.2 and 1.8 times higher than that for the unmodified films, whereas AryLite™ adhesion test failed.
Effect of solution pH on the stability of mixed silica -alumina suspension in the presence of polyacrylic acid (PAA) with different molecular weights
Authors: Wiśniewska Małgorzata , Terpiłowski Konrad , Chibowski Stanisław , Urban Teresa , Zarko Vladimir , Gun’ko Vladimir
Published: October 2012

The influence of solution pH (in the range 3–9) on mixed silica-alumina suspension in the absence and presence of polyacrylic acid (PAA) was studied. The composition of the adsorbent was SiO2 (97%) and Al2O3 (3%). The turbidimetry method was applied to record changes in the stability of the investigated systems as a function of time. It was shown that the suspension without the polymer is less stable at pH 3, whereas at pH 6 and 9, the systems were stable. PAA with molecular weights 100 000 and 240 000 at pH 3 (improvement of system stability conditions) and PAA 2 000 at pH 6 (deterioration of suspension stability) have a great effect on the silica-alumina suspension stability. The stabilization-flocculation properties of polyacrylic acid are a result of a specific conformation of its chains on the solid surface where it depends on the solution pH and the polymer molecular weight.
Adsorption of tert-butanol at the electrode from concentrated NaClO4 solutions
Authors: Nieszporek Jolanta
Published: October 2012

The parameters of the double layer for tert-butanol adsorption determined in the supporting electrolytes: 2 mol dm−3, 3 mol dm−3 and 4 mol dm−3 NaClO4, show an increase of tert-butanol adsorption on the mercury electrode together with the increase of NaClO4 concentration. The adsorption of tert-butanol on the electrode takes place via the −CH3 group which is shown by the changes in the values of zero charge potentials, E
z. On the basis of the analysis of the changes of relative surface excess values, Γ′, and the parameters determining the maximum adsorption, the process of adsorption in the discussed systems can be recognized as a physical process. Besides, it can be said that a major drawback in the process of adsorption of the organic substance on the electrode is to remove water from the electrode surface.
The effect of chemical activation method on properties of activated carbons obtained from pine cones
Authors: Nowicki Piotr , Kuszyńska Izabela , Przepiórski Jacek , Pietrzak Robert
Published: October 2012

A method for obtaining carbonaceous adsorbents from pine cones by chemical activation with NaOH is described. Activated carbons were obtained by two methods of activation (physical mixing and impregnation) and two variants of thermal treatment. It has been shown that pine cones can be successfully used as cheap precursor of carbonaceous adsorbents of well-developed surface area, large pore volume and good sorption properties. All activated carbon samples obtained show strongly microporous structure and surface of acidic character. The best physicochemical properties and greatest sorption capacity towards iodine were found for the carbon samples obtained by physical mixing of the precursor with the activating agent and then subjected to thermal activation at 600°C.
Collineation group as a subgroup of the symmetric group
Authors: Bogomolov Fedor , Rovinsky Marat
Published: October 2012

Let ψ be the projectivization (i.e., the set of one-dimensional vector subspaces) of a vector space of dimension ≥ 3 over a field. Let H be a closed (in the pointwise convergence topology) subgroup of the permutation group $\mathfrak{S}_\psi $ of the set ψ. Suppose that H contains the projective group and an arbitrary self-bijection of ψ transforming a triple of collinear points to a non-collinear triple. It is well known from [Kantor W.M., McDonough T.P., On the maximality of PSL(d+1,q), d ≥ 2, J. London Math. Soc., 1974, 8(3), 426] that if ψ is finite then H contains the alternating subgroup $\mathfrak{A}_\psi $ of $\mathfrak{S}_\psi $. We show in Theorem 3.1 that H = $\mathfrak{S}_\psi $, if ψ is infinite.
Iodobenzene Diacetate (PIDA)/Zn(II)-Mediated Oxidation and Cleavage of C–C Bond: Formation of Substituted N-aryl Carbamoyl Methyl Diacetates and Derivatives from 3-oxo-butanamides
Authors: Wenjun Hu , Zhaohui Deng , Chen Cui , Liu Wei-Bing
Published: October 2012

Various substituted N-aryl carbamoyl methyl diacetates have been synthesized from N-aryl-3-oxobutanamides via a diacetoxylation mediated by the combination of iodobenzene diacetate (PIDA)/Zn(OAc)2. This provides a new convenient method to form C–O bonds and cleave C–C bonds. Ten examples were obtained from easily available materials in good to excellent yields.
Synthesis of β-Amino Ketones Containing Organosilicon Groups: Catalytic Enantioselective Three-Component Mannich-Type Reaction
Authors: Safa Kazem D. , Abolfathi Mahtab , Ghorbanpour Khatereh
Published: October 2012

Aldimines, generated in situ from 4-[2,2-bis(trimethylsilyl)ethenyl]benzaldehyde and aromatic amines, undergo Mannich-type reactions with cyclic and acyclic ketones. The one-pot reaction is efficiently catalysed by zirconium oxychloride (ZrOCl2.8H2O) at room temperature. β-Amino carbonyl compounds containing bis(trimethylsilyl)ethenyl groups are obtained in acceptable to good yields with moderate to high stereoselectivity under solvent-free conditions.
Synthesis and Biological Evaluation of Novel Pyrazole Derivatives as Antibacterial Agents
Authors: Daemi Fariba , Allameh Sadegh , Pordel Mehdi
Published: October 2012

The synthesis of a novel series of 5-[(X-benzoylamino)]-1-(2,4-dinitrophenyl)-1 H-4-pyrazolecarboxamide derivatives is described. Their antibacterial activity (MIC) against methicillin-susceptible and methicillin-resistant Staphylococcus aureus (MRSA) were determined. The results revealed that two of the compounds, X = 4-MeO and X = 4-NO2, displayed greater antibacterial activity against MRSA than did cephalexin, cloxacillin and erythromycin.
A Novel Route for the Synthesis of 3-(pyrrol-1-yl)-indolin-2-ones
Authors: Sarkar Swarbhanu , Saha Bidula , Naskar Subhendu
Published: October 2012

A high yielding environmentally benign protocol has been developed for the synthesis of 3-(pyrrol-1-yl)-indolin-2-ones using a Lewis acid surfactant combined catalyst in water.
Synthesis of Aryl Nitriles using the Stable Aryl Diazonium Silica Sulfates
Authors: Habibi Davood , Heydari Somayyeh , Nasrollahzadeh Mahmoud
Published: October 2012

An efficient method for preparation of aryl nitriles is reported using Cu(I) to catalyse the reaction of aryl diazonium silica sulfates with sodium cyanide under mild conditions at room temperature in water. This method has the advantages of high yields, simple methodology, short reaction times and easy work-up.
Chiral Schiff base Ligated Dioxomolybdenum (VI) Complexes and their Asymmetric Catalytic Properties in the Epoxidation of Styrene
Authors: Sui Yan , Liu Dongsheng , Hu Ronghua , Que Xiaobo
Published: October 2012

Two series of Schiff base dioxomolybdenum (VI) complexes of the general formula [MoO2(L)(MeOH)] (L = D-glucosamine-derived Schiff base) have been synthesised, characterised and their asymmetric catalytic activities evaluated through the epoxidation of styrene. The molybdenum complexes with acetyl-protected D-glucosamine Schiff base ligands exhibited higher enanatioselectivity than those with unprotected sugar ligands. Protecting D-glucosamine by acetyl groups is an effective way to improve asymmetric catalytic epoxidation activities.
A One-Dimensional Coordination Chain Constructed by Mercury (II) Chloride and bis[4-(pyridine-2-yl)Pyrimidin-2-Ylthio]Methane
Authors: Zhu Hai-Bin , Yang Wen-Na , Shan Ru-Yu
Published: October 2012

Reaction of HgCl2 with bis[4-(pyridine-2-yl)pyrimidin-2-ylthio]methane (2-bppt) gave [(HgCl2)2(HgCl2)(2-bppt)]n, which consists of a one-dimensional inorganic (HgCl2)n chain surrounded by 2-bppt bridging ligands.
Synthesis of New Fluorescent Compounds from Benzimidazole
Authors: Pordel Mehdi
Published: October 2012

Nucleophilic substitution of hydrogen in 5-nitrobenzimidazole derivatives occurs upon reaction with 4-methylbenzyl cyanide under basic conditions and proceeds with concomitant cyclisation. This sequence offers a one-pot synthesis of new fluorescent heterocyclic compounds, 3-alkyl-8-methyl-3 H-imidazo[4,5- a]acridines.
Regioselective Friedel–Crafts Acylation of Indoles Catalysed by Zinc Oxide in an Ionic Liquid
Authors: Zhang Li-Rong , Yi Feng-Ping , Zou Jian-Zhong , Zhang Xuan , Wang Zhen
Published: October 2012

A facile method for the regioselective Friedel–Crafts acylation of indoles with acyl chlorides catalysed by zinc oxide in an ionic liquid medium has been developed. The corresponding 3-acylindoles were obtained in good to high yields under mild reaction conditions. Zinc oxide, which is easily available and requires no special handling procedures, is an efficient catalyst for acylation of indoles.
Synthesis and Characterisation of a Cd(II) Complex with a Chiral Framework Constructed from Achiral 1,1′-[bis-3-(3-pyridyl)pyrazol-5-yl]ferrocene via Spontaneous Resolution
Authors: Liu Wei , Li Xia , Zhao Jin'an , Wu Benlai , Zhang Hongyun
Published: October 2012

The chiral Cd(II) complex {[Cd(L)(CH3COO)2(H2O)]·H2O} n {L = 1,1′-[bis-3-(3-pyridyl)pyrazol-5-yl]ferrocene} has been synthesised. The Cd(II) ion is coordinated by two pyridyl nitrogen atoms, two chelating acetate anions and one water molecule, showing a distorted pentagonal-bipyramidal coordination environment. Each ligand L serves as a bisconnector, bridging two Cd atoms through its two pyridyl moieties, to afford an infinite 1D left-handed helical chain along the a-axis with a short pitch of 5.8761 (9) Å. Moreover, all of the left-handed helical chains are joined by hydrogen bonds to form a left-handed homochiral crystal.
One-Pot Three-Component Synthesis of 1,4-bis[thiazolo[4,5-d]pyrimidin-7(6H)-one]piperazine derivatives
Authors: Fang Zheng Dong , Wei Xian Hong
Published: October 2012

A simple one-pot efficient method is described for the synthesis of 1,4-bis[thiazolo[4,5-d]pyrimidin-7(6 H)-one] piperazine derivatives by a domino three-component process involving an aza-Wittig reaction/heterocyclisation in the presence of sodium ethoxide as catalyst. Ethyl 4-[(triphenylphosphanylidene)amino]-2,3-dihydro-3-phenyl-2-thioxothiazole-5-carboxylate reacted with aromatic isocyanates to give carbodiimide intermediates. This was followed by the addition of piperazines to give the corresponding guanidine intermediates. The guanidine intermediates were then cyclised in the presence of catalytic amount of sodium ethoxide to give 1,4-bis[thiazolo[4,5-d]pyrimidin-7(6 H)-one]piperazine derivatives in good yields.
A Green Recyclable Poly(4-Vinylpyridine)-Supported Copper Iodide Nanoparticle Catalyst for the Chemoselective Synthesis of Pentaerythritol Diacetals from Aromatic Aldehydes
Authors: Albadi Jalal , Iravani Nasir , Shirini Farhad , Dehghan Farzaneh
Published: October 2012

Poly(4-vinylpyridine)-supported copper(I) iodide nanoparticles have been used as an efficient, green recyclable catalyst for the chemoselective synthesis of pentaerythritol diacetals from aromatic aldehydes and pentaerythritol under solvent-free conditions. This catalyst was reused six times without any loss of its activity.
Solvent and Substituent Effects on the Electronic Spectra of 3-Arylazo-Imidazo[1,2-b]pyrazolo[4,3-d]-pyridazines
Authors: Shawali Ahmad S. , Farghaly Thoraya A. , Nawar Tarek M.S.
Published: October 2012

A series of new 3-arylazo-6-methyl-2,8,9-triphenyl-8 H-imidazo[1,2- b]pyrazolo[4,3- d]pyridazines was prepared via reaction of hydrazonoyl halides with 3-hydrazonoacetyl-4-cyano-1,5-diphenylpyrazole. The structures of the compounds prepared were confirmed by spectral and elemental analyses. The solvatochromic and substituent effects on the absorption spectra of these azo dyes were interpreted by correlation of absorption frequencies with Kamlet–Taft and Hammett equations, respectively.