bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies concerning the anion exchange resins catalyzed esterification of epichlorohydrin with organic acids
Authors: Muresan Ioan , Malutan Teodor
Published: September 2009

The paper studies the esterification of carboxylic acids with epichlorohydrin over two macroporous strong base anion exchange resins with different polymer matrix. For both resins, the influence of reaction parameters (temperature, catalyst loading, molar ratio) on the reaction rate and the yields of the two isomeric esters were investigated.
Synthesis, spectral studies and antibacterial activity of Cu(II), Co(II) and Ni(II) complexes of 1-(2-hydroxyphenyl)-3-phenyl-2-propen-1-one, N2-[(3,5-dimethyl-1H-pyrazol- -1-yl)methyl]hydrazone
Authors: Tharmaraj Paulmony , Kodimunthiri Deivasigamani , Sheela Clarence , Priya Shanmuga
Published: September 2009

A new series of Cu(II), Co(II) and Ni(II) complexes with the 1-(2- -hydroxyphenyl)-3-phenyl-2-propen-1-one, N2-[(3,5-dimethyl-1H-pyrazol-1- -yl)methyl]hydrazone ligand, C21H22N4O (LH), were synthesized by the reaction of 1-(2-hydroxyphenyl)-3-phenyl-2-propen-1-one, hydrazone with (3,5-dimethyl- 1H-pyrazol-1-yl)methanol and characterized. The nature of the bonding and geometry of the complexes were deduced from elemental analysis, IR, electronic and 1H-NMR spectroscopy, and magnetic susceptibility and conductivity measurements. The studies indicated square-planar, tetrahedral and octahedral geometry for the copper(II), cobalt(II) and nickel(II) complexes, respectively. The ESR spectra of the copper(II) complex in acetonitrile at 300 and 77 K were recorded and their salient features are reported. The electrochemical behavior of the copper (II) complex was studied by cyclic voltammetry. The antimicrobial activity of the ligand and its metal complexes were studied against the following strains of microorganism: Staphylococcus aureus, Salmonella enterica typhi, Escherichia coli and Bacillus subtilis by the well diffusion method. Metal complexes showed enhanced antimicrobial activity compared with that of the free ligand.
Alkali-catalyzed production of biodiesel from waste frying oils
Authors: Predojevic Zlatica , Skrbic Biljana
Published: September 2009

The effects of the transesterification parameters on the yield and quality of the methyl esters (MEs) produced from waste frying oil (WFO) were investigated. A two-step alkali transesterification reaction followed by silica gel purification step was applied. The investigated reaction parameters were the methanol/oil molar ratio (6:1 and 9:1), the catalyst/oil weight ratio (1.0 and 1.5 mass %) and the type of catalyst (NaOH and KOH). The physical and chemical properties of the employed feedstock and the obtained biodiesel were determined in order to investigate the effects of both the properties of the WFO and the reaction parameters on the characteristics and yields of the product. It was found that the properties of the feedstock had a determinant effect on the physical and chemical properties of the MEs, as the majority of them did not differ significantly under the studied reaction parameters. However, the reaction parameters influenced the yields of the product. Higher yields were obtained with a 1.0 than with a 1.5 mass % catalyst to oil ratio. The increasing yield with decreasing catalyst/oil ratio was more pronounced with NaOH (9.15-14.35 %) than with KOH (2.84-6.45 %). When KOH was used as the catalyst, the yields were always higher (the mean yield was 94.86 %) in comparison to those obtained with NaOH (the mean was 84.28 %). Furthermore, the efficiency of KOH in conversion of WFO to purified MEs in comparison to NaOH was even more pronounced in the case of the higher methanol/oil ratio, i.e., for the 9:1 methanol/ oil ratio, the yield increase with KOH was about 2 times higher than the yield with NaOH, regardless of the applied catalyst/oil ratio.
Influence of mechanical activation on structural and electrical properties of sintered MgTiO3 ceramics
Authors: Filipovic S. , Obradovic N. , Pavlovic V. , Petrovic V. , Mitric M.
Published: September 2009

The aim of this work was to analyze the influence of mechanical activation on the MgCO3-TiO2 system. Mixtures of MgCO3-TiO2 were mechanically activated for 15, 30, 60 and 120 minutes in a planetary ball mill and after that sintered at 1100?C for 1h. XRD analyses were performed in order to give information about the phase composition and to determine a variety of microstructure parameters using Scherrer's method. Also, the effect of tribophysical activation and sintering process on microstructure was investigated by scanning electron microscopy. Electrical measurements were performed in order to determine electrical properties of sintered samples. Our conclusions are that the sample activated for 120 min showed the best electrical properties ( ? r=23.86, Q=233, ?=0.38) and exhibited the best sinterability.
Bonding evolution with sintering temperature in low alloyed steels with chromium
Authors: Fuentes-Pacheco L. , Campos M.
Published: September 2009

At present, high performance PM steels for automotive applications follow a processing route that comprises die compaction of water-atomized powder, followed by sintering and secondary treatments, and finishing operations. This study examines Cr-alloyed sintered steels with two level of alloying. In chromium-alloyed steels, the surface oxide on the powder is of critical importance for developing the bonding between the particles during sintering. Reduction of this oxide depends mainly on three factors: temperature, dew point of the atmosphere, and carbothermic reduction provided by the added graphite. The transformation of the initial surface oxide evolves sequence as temperature increases during sintering, depending on the oxide composition. Carbothermic reduction is supposed to be the controlling mechanism, even when sintering in hydrogen-containing atmospheres. The effect of carbothermic reduction can be monitored by investigating the behavior of the specimens under tensile testing, and studying the resultant fracture surfaces.
The effect of structural changes during sintering on the electric and magnetic traits of the Ni96.7Mo3.3 alloy nanostructured powder
Authors: Ribic-Zelenovic L. , Spasojevic M. , Maricic A. , Ristic M.M.
Published: September 2009

Ni96.7Mo3.3 powder was electrochemically obtained. An X-ray diffraction analysis determined that the powder consisted of a 20% amorphous and 80% crystalline phase. The crystalline phase consisted of a nanocrystalline solid nickel and molybdenum solution with a face-centred cubic (FCC) lattice with a high density of chaotically distributed dislocations and high microstrain value. The scanning electronic microscopy (SEM) showed that two particle structures were formed: larger cauliflower-like particles and smaller dendriteshaped ones. The thermal stability of the alloy was examined by differential scanning calorimetry (DSC) and by measuring the temperature dependence of the electrical resistivity and magnetic permeability. Structural powder relaxation was carried out in the temperature range of 450 K to 560 K causing considerable changes in the electrical resistivity and magnetic permeability. Upon structural relaxation, the magnetic permeability of the cooled alloy was about 80% higher than the magnetic permeability of the fresh powder. The crystallisation of the amorphous portion of the powder and crystalline grain increase occurred in the 630 K to 900 K temperature interval. Upon crystallisation of the amorphous phase and crystalline grain increase, the powder had about 50% lower magnetic permeability than the fresh powder and 3.6 times lower permeability than the powder where only structural relaxation took place.
The influence of powder particle size on properties of Cu-Al2O3 composites
Authors: Rajkovic V. , Bozic D. , Popovic M. , Jovanovic M.T.
Published: September 2009

Inert gas atomized prealloyed copper powder containing 2 wt.% Al (average particle size ? 30 ?m) and a mixture consisting of copper (average particle sizes ? 15 ?m and 30 ?m) and 4 wt.% of commercial Al2O3 powder particles (average particle size ? 0.75 ?m) were milled separately in a high-energy planetary ball mill up to 20 h in air. Milling was performed in order to strengthen the copper matrix by grain size refinement and Al2O3 particles. Milling in air of prealloyed copper powder promoted formation of finely dispersed nano-sized Al2O3 particles by internal oxidation. On the other side, composite powders with commercial micro-sized Al2O3 particles were obtained by mechanical alloying. Following milling, powders were treated in hydrogen at 400 0C for 1h in order to eliminate copper oxides formed on their surface during milling. Hot-pressing (800 0C for 3 h in argon at pressure of 35 MPa) was used for compaction of milled powders. Hot-pressed composite compacts processed from 5 and 20 h milled powders were additionally subjected to high temperature exposure (800?C for 1 and 5h in argon) in order to examine their thermal stability. The results were discussed in terms of the effects of different size of starting powders, the grain size refinement and different size of Al2O3 particles on strengthening, thermal stability and electrical conductivity of copper-based composites.
The Vanderbilt PICC Service: Program, Procedural, and Patient Outcomes Successes
Authors: Burns Doug
Published: September 2009

Since its inception in early 2000, Vanderbilt University's Peripherally Inserted Central Catheter (PICC) Service has experienced a high level of success as measured by high proficiency rates and increasing patient procedures each year, low complication rates during and after PICC placements, and an increasing scope of influence within the Vanderbilt University Medical Center and Children's Hospital, the surrounding community, and in the Southeastern United States. Primary drivers of the PICC Service's continuing success include consistent applications of technique and technology, a data-driven approach to assessing the program's progress, and appropriately managing customers' expectations and needs. Over the past five years, data were collected on more than 12,500 PICC placements performed in this specialized nursing program. Retrospective analyses of the data demonstrate an increasing rate of successful placements (from 87.2% to 92.4%) since the program's inception in 2000 to late 2004. Furthermore, the choice of PICC technology has had a significant impact on the odds for occlusion or infection. The Vanderbilt PICC Service provides a model by which other programs can be established, maintained, and expanded into advanced practice.
The Making of an Infusion Therapy Nurse: Orientation of the Registered Nurse on an Infusion Therapy Team at a Comprehensive Cancer Center
Authors: Satterwhite Barbara R.
Published: September 2009

Orientation to a new job can be an anxiety-producing experience, particularly when the job is specialized, such as that of an infusion therapy nurse at a comprehensive cancer center. With a team approach and using a variety of teaching/learning strategies, as well as individualizing the education plan on the basis of the learner, the orientation process at The University of Texas M.D. Anderson Cancer Center has evolved. The current orientation program fosters the initial development of nurses who, in time, are recognized as experts in infusion therapy.
Standards of Care, and Strategies in the Prevention of Infection: A Primer on Central Venous Catheters (Part 2 of a 3-Part Series)
Authors: Richardson Deborah
Published: September 2009

The use of vascular access devices is an inherent component of health care today. The varied situations calling for these devices include: the administration of antibiotics, fluids, pain medications, blood and blood products, and parenteral nutrition; hemodynamic monitoring; and blood sampling. Although these devices are common in the health care environment, they are not without risks. The most common life-threatening complication associated with central venous catheters is infection. Catheter-related bloodstream infection (CRBSI) is caused by colonization of the catheter, contamination of the catheter hub or infusate, and/or contamination of the catheter from the skin of the patient or health care worker. The health care worker, such as the vascular access nurse, can affect CRBSI rates by implementing the most current technologies; maintaining current knowledge related to intravenous therapy; implementing, and maintaining aseptic technique; and incorporating the standards, guidelines, and preventive strategies associated with vascular access nursing. This article provides an overview of central venous catheters (CVCs), the issue of CRBSI and CVCs, practice and technologies developed to prevent or decrease infections, current standards and guidelines, and preventive strategies.
Vein Preservation: An Algorithmic Approach to Vascular Access Placement in Patients With Compromised Renal Function
Authors: McLennan Gordon
Published: September 2009

Peripherally inserted central catheters (PICCs) have become ubiquitous in the current management of chronic inpatient and outpatient conditions. Many hospitals have developed practice patterns that allow placement of PICC lines by teams of nurses at the bedside. This practice has led to a proliferation of these central venous access devices, and their use has expanded. One of the consequences of a nurse-based placement team is the decrease in physician involvement in decisions regarding the placement of PICC lines. In some settings, PICC placement can become so routine that the type of access needed or the other clinical conditions affecting an individual patient may be overlooked. One example of this problem is the situation in which a patient with chronic kidney disease or end-stage renal disease needs venous access for a nondialysis reason, such as antibiotics, cancer therapy, or total parenteral nutrition. The author discusses ramifications of this problem as well as ways to reduce the chances of mistakes.
Ultrafiltration: A New Challenge for Vascular Access Specialists
Authors: Drafz Michael
Published: September 2009

Clinicians working in a facility specializing in cardiac care have probably seen patients with decompensated congestive heart failure (CHF) and renal failure. As a vascular access specialist, chances are that clinicians have recently been asked to provide vascular access for a relatively new treatment procedure called peripherally inserted veno-venous ultrafiltration or aquapheresis. This treatment, pioneered between 2002 and 2003, was designed for patients suffering from decompensated CHF, leading to acute fluid overload and renal failure. These patients no longer respond to the traditional diuretic and sodium-depleting therapies and often have no other treatment choices left. This article discusses the vascular access side of this treatment and the associated challenges.
Effects of INR Levels on Bleeding Occurrences During the First 24-hours of Ultrasound Guided PICC Line Insertions
Authors: Daniels Linda S. , Gouvas Margaret O.
Published: September 2009

A sample of 127 patients with an International Normalized Ratio (INR) of 1.5 or greater, undergoing a Peripherally Inserted Central Catheter (PICC) insertion, were observed for bleeding at the time of insertion and for 24 hours post insertion. Over 60% of patients experienced no or mild bleeding at insertion. For an INR less than 3.0, fewer than 10% of the sample experienced moderate bleeding within the first 24 hours. No PICCs were discontinued due to bleeding. Results suggest that INR levels below 3.0 did not appear to have an impact on amount of bleeding during PICC insertion. After 24 hours, INR levels of 3.0 and above did appear to have an impact on the amount of bleeding.
Perceptions of the Impact of “Smart Pumps” on Nurses and Nursing Care Provided
Authors: Rosenkoetter Marlene M. , Bowcutt Marilyn , Khasanshina Elena V. , Chernecky Cynthia C. , Wall Jane
Published: September 2009

Medication errors occur frequently in hospital settings, creating harmful consequences for patients and families, as well as tremendous financial losses. “Smart pump” technology is one means by which these errors can be reduced. The study reported here is a part of a three phase study and focused on the perceptions of nurses (n=512) in a tertiary care hospital regarding the impact of the implementation of “smart pump” technology and its impact on nursing care provided, medication errors, and job satisfaction. Sociotechnical System Theory and the Life Patterns Model were used to frame the study. The Infusion System Perception Scale was used to assess demographic information, and perceptions of nurses on a 30-item five-point Likert scale. Results indicate that nurses perceived the “pump” increased safe medication administration, did not decrease the perception of the punitive nature of reporting medication errors and did not increase the nurse's workload, but did make routines easier. The “pump” was perceived to increase self-confidence but had no effect on use of the pharmacy staff. Findings suggest that the “pump” could be implemented in a variety of settings, regardless of the age, gender, and educational background of the nurses. The “pump” offers an effective approach to the reduction of intravenous medication errors.
A Controlled Randomized Prospective Comparative Pilot Study to Evaluate the Ease of Use of a Transparent Chlorhexidine Gluconate Gel Dressing Versus A Chlorhexidine Gluconate Disk in Healthy Volunteers
Authors: Eyberg Chou I. , Pyrek Janine
Published: September 2009

Products and technologies that aid health care professionals in vascular access practice save staff time, and while promoting patient safety and prevention of infection can provide excellent opportunities for evaluations to support evidence-based practice. This was an industry sponsored, prospective, single site, controlled, randomized clinical evaluation pilot study of two catheter dressings, 3M™ Tegaderm™ Chlorhexidine Gluconate (CHG) IV Securement Dressing (CHG gel dressing) (3M Health Care, St. Paul, MN) and BIOPATCH® Antimicrobial Dressing with Chlorhexidine Gluconate (BIOPATCH® Protective Disk with CHG, Johnson & Johnson, Somerville, NJ). Twelve intravascular (IV) therapy health care professionals (Clinicians) were asked for their professional evaluations of the catheter dressings: the ease of application and performance factors featured in specific questions. Catheters were secured on 12 healthy volunteers to simulate inserted jugular catheters (IJ) and peripherally inserted central catheters (PICC) using StatLock® PICC Plus and 3M™ Steri-Strip™. Each clinician applied and removed one CHG gel dressing and one CHG disk on one simulated PICC and one simulated IJ site, according to the manufacturers' instructions.

The clinicians concluded, based upon a 1 to 5 rating scale, that the CHG gel dressing is better in regard to ease of application, ease of applying correctly, ease of removal, ability to visualize the insertion site, ease of training another clinician to apply the dressing, and more intuitive application. Twelve out of 12 clinicians favored the CHG gel dressing over the CHG disk in overall performance.
Peripherally Inserted Central Venous Catheters: First Results after the Introduction in a Dutch University Medical Center
Authors: van Boxtel Anton J.H. , Fliedner Monica C. , Borst Dirk M. , Teunissen Saskia C.C.M.
Published: September 2009

Purpose: To analyze patient outcomes and processes of insertion after the introduction of the peripherally inserted central catheter (PICC) in the University Medical Center Utrecht (UMC Utrecht) in the Netherlands.

Patients and method: A prospective analysis of PICC inserted in the UMC Utrecht looking at patient characteristics, dwell time and infections.

Results: A total number of 510 PICCs in 439 patients with 17655 catheter days were analyzed using ultrasound (US) and modified Seldinger technique (MST). Overall there were 2.35 catheter-related bloodstream infections (CRBSI) per 100 devices and 0.68 infections per 1000 catheter days. When used specifically for home infusion, the CRBSI rates were 1.09 per 100 devices and 0.23 per 1000 catheter days. One advanced nurse practitioner (ANP) inserted all PICCs. Although a full sterile barrier (no hat and gown) was not used during insertion, the infection rate in our study was lower compared to the 1.1 infection per 1000 catheter days reported in a meta-analyses on CRBSI (Maki, Kluger, & Crnich, 2006).

Conclusion: Through the use of modern techniques like US and MST and upper arm insertion of PICCs, the complication rate is lower compared to older techniques as shown in most prospective studies. Extended dwell time, as a positive outcome of using PICCs made more doctors decide to choose a PICC. Age of the patient did not influence dwell time or complications. Further research, preferably a randomized controlled trial, is needed to compare the subclavian catheter with the PICC as well as exploration of the effects of anticipatory choice for PICCs, specifically in immune compromised patients.
A Retrospective Analysis of Our 15-year Experience with Bedside ‘Blind’ Positioning of Long-term Tunneled Groshong® Catheters in the Pre-ultrasound Era
Authors: Pittiruti Mauro , Malerba Marina , La Greca Antonio , Emoli Alessandro , Nanni Lorenzo , Cozza Tiziana
Published: September 2009

Long-term tunneled Groshong catheters have been widely used in our institution since 1987, both in adult and pediatric patients, for different purposes (chemotherapy, parenteral nutrition, etc.). In the period 1987–2003, most of these catheters were inserted adopting the ‘blind’ percutaneous venipuncture of the internal jugular vein, by the so called ‘low lateral’ approach (Jernigan's technique). Also, with the exception of selected pediatric cases, they have been inserted at the bedside, without intra-operative fluoroscopy. A retrospective analysis of 1848 tunneled Groshong catheters inserted at our institution over a 15 year period (1987–2003) showed that this protocol was particularly safe (low incidence of complications) and cost-effective (low costs: limited use of fluoroscopy and the operating room).
Making the Case for a Nurse-Led Vascular Access Team Utilizing a Quality Assurance Conceptual Framework
Authors: Beerman Amanda L.
Published: September 2009

The cost of complications of central venous access devices (CVADs) in today's health care setting is creating a financial burden, increasing the expenditures of resources, and consuming the time of health care providers to resolve. As the roles of nurses continue to evolve, nurses may be in a position to recognize and prevent many of these complications. This paper proposes a conceptual model to address the issues related to caring for and monitoring CVADs, while reducing complications and increasing quality of patient care.
Impact of the Positive Pressure Valve on Vascular Access Device Occlusions and Bloodstream Infections
Authors: Khalidi Nabil , Kovacevich Debra S. , Papke-O'Donnell Lorelei F. , Btaiche Imad
Published: September 2009

Background/Purpose: The use of needleless positive pressure connector valves (PPVs) on venous access devices (VADs) has been shown to have possible benefits in decreasing VAD occlusion rates. Catheter-related bloodstream infection (CRBSI) rates, however, have been variable. With this potential for improving patient outcomes, decreasing costs, and facilitating nursing care and catheter management, the use of PPV devices becomes both advantageous and desirable.

Methodology: This was a randomized, prospective, parallel clinical study of 160 medical and surgical step-down unit patients requiring parenteral therapies. Patients were equally randomized to two study groups to assess the impact on occlusion and CRBSI rates, using a PPV versus a standard cap without PPV. VADs included both peripherally inserted catheters (PICCs) and midlines.

Results: Seven VAD occlusions occurred; six in the experimental group, one in the control group (p = 0.43). Also, two CRBSIs occurred in the experimental group, with none in the control group (p = 0.497). All incidents occurred in doublelumen PICCs. The lack of statistical difference between the two groups for occlusions and CRBSIs indicates that the use of PPVs had no impact in preventing such outcomes. However, it was observed that the number of double-lumen PICCs and their dwelling time in the experimental group was significantly higher (p = 0.003).

Conclusion: There was no difference in the rate of catheter occlusions or CRBSIs when using PPVs or standard caps. We consider that the study outcomes may be due to the study's small sample size, and we speculate that longer dwell time of double lumen catheters may have contributed to these outcomes. These observations deserve further investigation. However, the use of PPVs may still be advantageous from a nursing process perspective.
50 Years of the Paul Karrer Gold Medal: 1959–2009
Authors: Siegel Jay S.
Published: September 2009

Founded on the occasion of Paul Karrer's 70th Birthday, the Paul Karrer Medal in Gold celebrates its 50th anniversary having recognized the outstanding science of 34 molecular scientists.
Contribution of the Chemistry Institutes to the Early Development of Stereochemistry
Authors: Hermann Kurt
Published: September 2009

This article is a translation from German of a paper submitted by Kurt Hermann to the University of Zurich Prize committee in 1968, with additional editing by Jay Siegel. It covers a survey of the historical contributions of faculty at UZH to the fundamental development of stereochemistry.
It is appropriate in light of the 90th birthday of Andre Dreiding, pioneer of stereochemistry and founder of the Buergenstock stereochemistry meeting, that we reflect on the chain of historical events responsible for UZH's leading role in this important molecular discipline.
Synthesis and NMR Spectroscopic Characterization of Organometallics in the Laboratory of Wolfgang von Philipsborn: Reminiscences of Former Graduate Students
Authors: Hafner Andreas , Nanz Daniel , Piantini Umberto , Rentsch Daniel , Täschler Carlo , Zerbe Oliver
Published: September 2009

On the occasion of his 80th birthday, former graduate students from the group of Prof. Wolfgang von Philipsborn from the Institute of Organic Chemistry, University of Zurich, describe from a personal perspective the scientific achievements of his group in the field of nuclear
magnetic resonance, mainly applied to transition metals and in the field of organometallic chemistry. Interest in metal chemical shifts is driven by the need to understand reactivity of organometallic compounds in catalysis. Progress in the field is very much related to the technical development
of NMR instruments. The range of experiments spans from simple 1D experiments with direct metal detection to 2D NMR experiments, in which metal frequencies are encoded via their attached protons or phosphorous ligands. Other examples come from the structural biology of metal-containing
proteins or form the measurement of scalar couplings to quadrupolar nuclei via lineshape analysis. A particular emphasis is presented on how collaborations from various groups at the campus have been fruitful to the scientific progress in the von Philipsborn group. The article also
contains a number of personal anecdotes that document life of the graduate students in his group at that time.
The Co-Construction of Opposition in a Low-Track Mathematics Classroom
Authors: Hand Victoria M.
Published: September 2009

Student opposition in school is traditionally cast in terms of individual dispositions, whereby particular students or groups of students are said to “resist” or “oppose” school structures and identities aligned with the dominant cultural group. The author examined instead how the teacher and students in a low-track mathematics classroom jointly constructed opposition through their classroom interactions. Analysis of the classroom interaction revealed the emergence and escalation of a number of classroom practices that became oppositional. These practices were related to the nature of the mathematical activity, the framing and positioning of student participation in this activity, and multiple interpretations of student competence in and out of the classroom. The author found that classroom opposition is fostered by weak opportunities for meaningful mathematical engagement and the transformation of a polarized participation structure into an oppositional one.
RFI Mitigation in Microwave Radiometry Using Wavelets
Authors: Camps Adriano , Tarongí José Miguel
Published: September 2009

The performance of microwave radiometers can be seriously degraded by the presence of radio-frequency interference (RFI). Spurious signals and harmonics from lower frequency bands, spread-spectrum signals overlapping the “protected” band of operation, or out-of-band emissions not properly rejected by the pre-detection filters due to the finite rejection modify the detected power and the estimated antenna temperature from which the geophysical parameters will be retrieved. In recent years, techniques to detect the presence of RFI have been developed. They include time- and/or frequency domain analyses, or statistical analysis of the received signal which, in the absence of RFI, must be a zero-mean Gaussian process. Current mitigation techniques are mostly based on blanking in the time and/or frequency domains where RFI has been detected. However, in some geographical areas, RFI is so persistent in time that is not possible to acquire RFI-free radiometric data. In other applications such as sea surface salinity retrieval, where the sensitivity of the brightness temperature to salinity is weak, small amounts of RFI are also very difficult to detect and mitigate. In this work a wavelet-based technique is proposed to mitigate RFI (cancel RFI as much as possible). The interfering signal is estimated by using the powerful denoising capabilities of the wavelet transform. The estimated RFI signal is then subtracted from the received signal and a “cleaned” noise signal is obtained, from which the power is estimated later. The algorithm performance as a function of the threshold type, and the threshold selection method, the decomposition level, the wavelet type and the interferenceto-noise ratio is presented. Computational requirements are evaluated in terms of quantization levels, number of operations, memory requirements (sequence length). Even though they are high for today’s technology, the algorithms presented can be applied to recorded data. The results show that even RFI much larger than the noise signal can be very effectively mitigated, well below the noise level.
Detecting Proteins in Highly Autofluorescent Cells Using Quantum Dot Antibody Conjugates
Authors: Orcutt Karen M. , Ren Shanshan , Gundersen Kjell
Published: September 2009

We have applied quantum dot (Qdot) antibody conjugates as a biomolecular probe for cellular proteins important in biogeochemical cycling in the sea. Conventional immunological methods have been hampered by the strong autofluorescence found in cyanobacteria cells. Qdot conjugates provide an ideal alternative for studies that require long-term imaging of cells such as detection of low abundance cellular antigens by fluorescence microscopy. The advantage of Qdot labeled probes over conventional immunological methods is the photostability of the probe. Phycoerythrin bleaches in cyanobacterial cells under prolonged UV or blue light excitation, which means that the semiconducting nanocrystal probe, the Qdot, can yield a strong fluorescent signal without interference from cellular pigments.
RESEARCH INTO THE METHODS OF ANALYSING THE PRODUCTIVITY INDICATORS OF TRANSPORT TERMINALS
Authors: Jaržemskienė Ilona
Published: September 2009

The measurement of terminal productivity is the issue of extreme importance to both terminal owners and management and customers. As the sector of transport is highly intensive in terms of investments into the infrastructure, the productivity of a terminal may play a crucial role in competing with other terminals. Productivity is defined in terms of inputs and output. The majority of the available studies, wherein this issue is addressed, are generally focused on the determination of functional dependence between inputs and output using the method of regressive analysis. The present article provides an insight into the Data Envelopment Analysis method as a tool for measuring productivity. This technique enables a rather accurate evaluation of terminal productivity by means of comparative analysis, which, in fact, appears to be the only feasible alternative in cases where statistic data required for performing regressive analysis is lacking.
RESEARCH ON MODEL APPLICATION TO RESTRUCTURING THE RAILWAY TRANSPORT SECTOR IN LITHUANIA
Authors: Jarašūnienė Aldona
Published: September 2009

There is no economic grounding and estimation of costs incurred to the State by the establishment and operation of the railway infrastructure management enterprise. In this regard, the article deals with the evaluation of reforming the railway transport sector in other countries and analyses the comparison of restructuring models according to the experience of the EU member states as well as evaluates the selection of models proposed by foreign theoreticians and from an economic point of view justifies the most relevant model of reforming Lithuanian railway transport sector.
COMBINED MODAL SPLIT AND ASSIGNMENT MODEL FOR THE MULTIMODAL TRANSPORTATION NETWORK OF THE ECONOMIC CIRCLE IN CHINA
Authors: Li Shuang , Deng Wei , Lv Yisheng
Published: September 2009

Economic circles have been formed and developing in China. An economic circle consists of more than one closely adjoining central cities and their influence zones. It is always the major engine for the development of one country's economy and even for the world economy. A combined modal split and assignment model with deterministic travel demand is proposed for modelling passengers’ choices of intercity bus and train which are two main competing modes in the multimodal transportation network of the economic circle. The generalized travel cost model of highway and railway are used incorporating travel time, ticket fare and passenger's discomfort. On the highway network, the interactions of private vehicles and intercity buses are asymmetric. Thus, a variational inequality formulation is proposed to describe the combined model. The streamlined diagonalization algorithm is presented to solve the combined model. The multimodal transportation network based on Yangtze River Delta economic circle is presented to illustrate the proposed method. The results show the efficiency of the proposed model.
Development of a Multimedia Toolkit for Engineering Graphics Education
Authors: Zgoul Moudar , Kilani Mohammad
Published: September 2009

This paper focuses upon the development of a multimedia toolkit to support the teaching of Engineering Graphics Course. The project used different elements for the toolkit; animations, videos and presentations which were then integrated in a dedicated internet website. The purpose of using these elements is to assist the students building and practicing the needed engineering skills at their own pace as a part of an e-Learning solution. Furthermore, this kit allows students to repeat and view the processes and techniques of graphical construction, and visualization as much as needed, allowing them to follow and practice on their own.
A Graphical Tool for Visualizing Bernoulli Stochastics
Authors: Zhai Xiaomin , Von Collani Elart
Published: September 2009

This paper continues the work of the article â??Strategies for Teaching a Novel Approach to Handling Uncertainty Scientifically via Internet
Evaluation of Electrochemical Behaviour and Surface Properties for Oxinium-Like Zr-Nb Biomedical Alloys
Authors: Branzoi Ioan Viorel , Iordoc Mihai , Branzoi Florina
Published: September 2009

The aim of this study is to evaluate the influence of Nb amount on electrochemical behaviour and surface properties for Oxinium-like Zr-Nb biomedical alloys. Oxinium (heat treated Zr-2.5%Nb alloy) represents the newest metal-ceramic composite used in orthopaedic surgery for total hip and total knee replacement. We used potentiodynamic polarization measurements and electrochemical impedance spectroscopy (EIS) as electrochemical techniques and Vickers micro-hardness as surface properties evaluation technique.
Effect of Drinking Water on Formation of Renal Calculi
Authors: Iosub Ion , Malinovschi Viorel , Grigorie Victor , Murariu Alina , Meghea Aurelia
Published: September 2009

The environmental impact on human health is of increasing concern mainly due to the complex interaction between various hazardous factors both on environment and within human organism. The aim of this paper is to investigate possible correlations between the quality parameters of drinking water and the formation of uroliths. The constituents of some kidney calculi sampled after surgery from 90 patients coming from the Horezu – Valcea area have been analysed, this region being identified as having the most cases of kidney lithiasis and that might be related with hard drinking waters. The study has been made during the period of 2004 – 2008. Physical – chemical methods specific for characterization of the quality of drinking waters have been used in parallel with determination of composition and structural characterization by X-ray diffraction, thermal analysis TG, ATD, FT-IR spectroscopy, optical microscopy. Four groups of uroliths have been identified: multiphase oxalate and urate, phosphate (hydroxiapatite) and carbonate, monohydrated oxalate (whewellite), and urate stones. Such research might be useful, from both chemical and biochemical point of view, for identifying the conditions that cause the inhibition of the processes related to kidney calculi formation.
Evaluation of Scavenger Properties of some Flavonoidic Vegetal Extracts Obtained from Crataegus monogyna Jacq.
Authors: Nichita Cornelia , Neagu Georgeta , Vulturescu Virginia , Pirvu Lucia , Badea Nicoleta Maria , Albulescu Radu , Giurginca Maria
Published: September 2009

The scavenger properties of some flavonoidic vegetal extracts obtained from Crataegus monogyna Jacq have been studied using the chemiluminescence technique and ex vivo lipid peroxidation assay. A correlation between antioxidant activity and phenolic/flavonoidic content was observed for all the seven extracts, and a parallel behaviour with the antioxidant activity determinated by ex vivo lipid peroxidation assay and in vitro chemiluminescence tests was also noted.
Effect of Surfactants on Stability of Colloidal Sols as Precursors in Sol-Gel Encapsulation
Authors: Lacatusu Ioana , Badea Nicoleta Maria , Meghea Aurelia
Published: September 2009

This paper aims to study the effect of three alkyl quaternary salts on stability of colloidal sols further used as water-insoluble oligomers for encapsulation of an active flavonoid compound – quercitin. The preparation procedure is described and practical remarks on silica-based sol-gels are included. It is also demonstrated how to exploit the sol-gel preparation route in order to improve the thermal resistance of quercitin and to increase an optical function - fluorescence. The evolution in time of competitive hydrolysis and condensation processes has been observed by dynamic light scattering measurements. The sol-gel materials with entrapped quercitin molecule have been characterised by spectral methods (FT-IR, UV-VIS-NIR), fluorescence and by thermal analysis as well. Sol-gel materials doped with active flavonoid compound may be used in preparation of some functional materials with bioactive properties.
Considerations on Reducing the Experimental Duration of Electrochemical Impedance Spectroscopy Measurements Used for the Evaluation of Ionic Conductivity in Polymer Electrolyte Membrane Electrolysers and Fuel Cells
Authors: Vaireanu Danut Ionel , Cojocaru Anca , Maior Ioana , Caprarescu Simona , Ionescu Alexandra , Radu Valentin
Published: September 2009

In this paper one attempted to discuss the effect of reducing the experimental duration of electrochemical impedance spectroscopy (EIS) measurements by reducing the sampling frequency without affecting the measured parameters. The experimental setup is based on a novel cell consisting of two electrodes or three electrodes cell configuration. The experimental layout allows a precise evaluation of the membrane thickness, at micrometer resolution, during the determination of the electrochemical impedance spectra.
Influence of Various Binder of the Protective Properties of Paint Coatings
Authors: Pirvu Cristian , Stancu Rodica , Drob Paula , Vasilescu Ecaterina , Vasilescu Cora , Mindroiu Mihaela
Published: September 2009

The paper presents the results of the electrochemical and surface study concerning the binder influence on protective properties of paint coatings. The protective films realized with various binders were applied on carbon steel substrate. The experiments carried out in a 3% NaCl solution, normal aerated at the room temperature. The experimental results show that the paint films containing binders with three-dimensional (3D) structure provide good protective properties. The best performance is exhibited by the paint films with the alkyd binder, due to their 3D structure formed as a result of chemical reactions of the binder with the oxygen from atmosphere during the curing process.
Research on the CAD/CAM Integrated Technique of Superhard Grinding Tools Based on PDM
Authors: Liu Nan Bo , Niu Hong Bin , Cui Zhong Ming
Published: September 2009

. Grinding of Superhard grinding tool has the properties of high efficiency, high precision and low cost. In this paper, grinding process of superhard grinding tools was analyzed, and the design method of PDA and the development of CAD/CAM integrated system were discussed. The key technologies of information database, eigen information extracting and output of process results are settled by establishing the superhard grinding tool integrated system, and organic combination between design and manufacture of tools and PDM system. The whole program and system are practicable and universal.
Nano-Precision Finishing Technology Based on Magnetorheological Finishing
Authors: Li Yao Ming , Shen Xing Quan , Wang Ai Ling
Published: September 2009

Surface roughness is normally regarded as an important criterion for assessing the quality of optic elements; surface roughness of a high-quality optic element is required to be less than RMS1nm. In this paper, a series of experiments has been conducted on the sample magnetorheological finishing machine by using self-prepared magnetorheological liquid as finishing liquid, to assess the removing efficiency of magnetorheological finishing. Optimization of technological parameters enables the authors to obtain a glass-ware with an ideal surface roughness of RMS0.56nm. Magnetorheological finishing (MRF) is an advanced technology for processing optic elements that has been developed in recent years. The technology polishes optic elements by using viscoplastic soft media produced by the MRF liquid under the variation of gradient magnetic field. Better than traditional polishing method in shape precision, surface roughness and inner surface destruction, MRF is an ideal technology for obtaining super-precision optic surface.
Study on the Dynamic Characteristics of Ultrahigh Speed Grinding Spindle Based on Squeeze Film Damping Technology
Authors: Yu Tian Biao , Gong Ya Dong , Li Hu , Wang Wan Shan
Published: September 2009

For improving grinding quality of ultrahigh speed grinding a new design method for ultrahigh speed grinding spindle is put forwarded based on squeeze film damping technology. Working principle of squeeze film damper of ultrahigh speed grinding spindle is study and differential equations of motion of the ultrahigh speed grinding wheel spindle with a squeeze film damper are set up according to d'Alembert principle. Effects of design parameters of the damper on the motion section of the spindle are studied by the way of simulation based on it. Research works show that the dynamic characteristic of ultrahigh speed grinding spindle can be improved well through adding a squeeze film damper. Research works provides a new technology for the design of the ultrahigh speed grinding spindle system.
Dynamics Model Research of Centrifugal Barrel Surface Finishing Based on 3D Discrete Element Method
Authors: Song Chun Hua , Yang Shi Chun
Published: September 2009

Dynamics model on abrasive particles and workpieces during the centrifugal barrel surface finishing process was built by Discrete Element Method (DEM). The motion status of abrasive particles and workpieces was visually simulated and some important process parameters were numerically studied. The influence of fill ratio on finishing efficiency was analyzed, and finishing efficiency was the highest as the fill ratio is 65%. the simulation results are basically coincident to the experimental results. Both results have proved that filling ratio is the main parameter that changes medium motion laws, which provides an very efficient way to further optimize design parameters and process parameters, as well as to improve production efficiency.
Research on Surface Roughness of Ultrasonic Polishing without Abrasive Based on Orthogonal Experiments
Authors: Jiang Jian Jun , Zheng Jian Xin , Liu Chuan Shao
Published: September 2009

Experiments of ultrasonic polishing the 45# steel shaft without abrasive are carried out by using orthogonal test method to study the polished surface roughness, and experimental results are analyzed with range method. The influence of polishing parameters on the polished surface roughness could be arranged as follows: feed rate, power of generator, preload pressure and radius of the tool head, in which the feed rate brings the most remarkable influence on the polished surface roughness. The surface roughness value reduces at first and then increases when the radius of tool head, preload pressure and power of the generator increase. The surface roughness value increases with the feed rate. Comparative experimental results of ultrasonic polishing without abrasive and the conventional rolling indicate that lower surface roughness value may be obtained by ultrasonic polishing without abrasive.
Study on the Properties of New Ultrasonic Vibration Internal Grinding System
Authors: Li Hua , Yin Zhen , Li Zheng
Published: September 2009

Based on the FEM, the properties of the vibrator and the shaft in new ultrasonic vibration internal grinding system were studied in this paper. The design method of new ultrasonic vibration internal grinding (UVG) system by using rotary non-contact transmission device was proposed according to the influence of the sleeve length and thickness to ultrasonic vibration shaft. Experiments about the vibrator，the shaft and the ultrasonic vibration internal grinding system were studied by using PSV-400 Laser scanning vibrometer, and the consistency between the new ultrasonic vibration internal grinding prototype and theoretical design was confirmed.
The Modeling and Simulation of Pneumatic Loading System of Double-Sided Polishing Machine
Authors: Xing Tong , Zheng Hai Hui , Li Wei
Published: September 2009

Double-sided polishing machine is widely used to high precision dimension, high accuracy surface, and ultra-smooth surface without damage layer for some hard and brittle workpiece such as silicon wafer, sapphire, ceramic, magnetic substrates, electronic materials, etc. Pneumatic loading system is the very crucial part of the double-sided polishing machine. The polishing machine’s performances are directly determined by the loading precision. This paper establishes the modeling and simulation of pneumatic load system by AMESim and then gives optimization parameters to improve system performance, and the cure of load capacity is given.