bluuebunny/crossref_metadata_2025 huggingface dataset:
An improved ultra performance liquid chromatography-tandem mass spectrometry method for the determination of alloisoleucine and branched chain amino acids in dried blood samples
Authors: Alodaib A , Carpenter K , Wiley V , Sim K , Christodoulou J , Wilcken B
Published: July 2011

Background

Branched chain amino acid (BCAA) analysis is needed for the diagnosis and management of patients with maple syrup urine disease (MSUD). We report an improved ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the determination of BCAAs and Allo-Ile in dried blood spot (DBS) samples.

Methods

BCAAs were extracted from a 3 mm blood spot into methanol/water containing stable isotope internal standards. Eluents were dried and reconstituted in the mobile phase. Gradient elution was performed on an Acquity™ BEH C18 (100 × 2.1 mm, 1.7 μm) column. BCAAs were detected and quantified in the multiple reaction monitoring mode in a five-minute analysis.

Results

The assay was calibrated to give best possible alignment with plasma results. Retrospective analysis of newborn DBSs from six classic MSUD patients showed elevated alloisoleucine (Allo-Ile) in all cases. Two of four patients with mild disease had normal values; the other two had significant elevations in Allo-Ile.

Conclusions

Analysis of BCAA in DBS by UPLC-MS/MS is a useful second tier newborn screening test to identify classical MSUD and for monitoring of remote patients.
YrdC exhibits properties expected of a subunit for a tRNA threonylcarbamoyl transferase
Authors: Harris Kimberly A. , Jones Victoria , Bilbille Yann , Swairjo Manal A. , Agris Paul F.
Published: July 2011

The post-transcriptional nucleoside modifications of tRNA's anticodon domain form the loop structure and dynamics required for effective and accurate recognition of synonymous codons. The N6-threonylcarbamoyladenosine modification at position 37 (t6A37), 3′-adjacent to the anticodon, of many tRNA species in all organisms ensures the accurate recognition of ANN codons by increasing codon affinity, enhancing ribosome binding, and maintaining the reading frame. However, biosynthesis of this complex modification is only partially understood. The synthesis requires ATP, free threonine, a single carbon source for the carbamoyl, and an enzyme yet to be identified. Recently, the universal protein family Sua5/YciO/YrdC was associated with t6A37 biosynthesis. To further investigate the role of YrdC in t6A37 biosynthesis, the interaction of the Escherichia coli YrdC with a heptadecamer anticodon stem and loop of lysine tRNA (ASLLysUUU) was examined. YrdC bound the unmodified ASLLysUUU with high affinity compared with the t6A37-modified ASLLysUUU (Kd = 0.27 ± 0.20 μM and 1.36 ± 0.39 μM, respectively). YrdC also demonstrated specificity toward the unmodified versus modified anticodon pentamer UUUUA and toward threonine and ATP. The protein did not significantly alter the ASL architecture, nor was it able to base flip A37, as determined by NMR, circular dichroism, and fluorescence of 2-aminopuine at position 37. Thus, current data support the hypothesis that YrdC, with many of the properties of a putative threonylcarbamoyl transferase, most likely functions as a component of a heteromultimeric protein complex for t6A37 biosynthesis.
Pharmacotherapy for Acute Pouchitis
Authors: Wall Geoffrey C , Schirmer Lori L , Anliker Lynn E , Tigges Ashley E
Published: July 2011

Objective:

To review the current literature concerning the medical treatment of acute and chronic pouchitis.

Data Sources:

MEDLINE and International Pharmaceutical Abstracts were searched (both 1965-February 2011) using the following terms: pouchitis, Crohn's, ulcerative colitis, diagnosis, prophylaxis, and treatment. Bibliographies from key articles were also searched, and all pertinent articles were reviewed.

Study Selection And Data Extraction:

All available primary literature published in English on treatment for pouchitis was considered, with controlled trials receiving highest priority.

Data Synthesis:

Pouchitis occurs in up to 50% of ileal pouch–anal anastomosis (IPAA) patients with inflammatory bowel disease within 10 years of the procedure. Symptoms include abdominal pain, bloating, and fecal incontinence with frequent diarrhea. The diagnosis of pouchitis is usually made based on symptoms as well as endoscopic and histologic findings. Treatment of acute pouchitis includes antimicrobials such as ciprofloxacin, metronidazole, and rifaximin. If these fail, limited data suggest that oral budesonide, mesalamine, or infiiximab may be effective treatments. Surgical revision may be necessary if medical treatments fail. Emerging evidence suggests that the probiotic compound VSL#3 may be effective in preventing the recurrence of pouchitis.

Conclusions:

Pouchitis is a common complication of IPAA surgery. The strongest data suggest that antimicrobial therapy is an effective first-line treatment for acute pouchitis, and VSL#3 may be effective for prevention of recurrence.
Role of Rifampin-Based Combination Therapy for Severe Community-Acquired Legionella pneumophila Pneumonia
Authors: Varner Terra R , Bookstaver P Brandon , Rudisill Celeste N , Albrecht Helmut
Published: July 2011

Objective:

To review the literature concerning the role of rifampin in the combination treatment of Legionella pneumophila pneumonia.

Data Sources:

A search of MEDLINE and Ovid databases was conducted (January 1970-May 2011) using the search terms Legionella pneumophila, pneumonia, Legionnaires' disease, rifampin or rifampicin, macrolide, fluoroquinolone, erythromycin, clarithromycin, levofloxacin, ciprofloxacin, and moxifloxacin

Study Selection and Data Extraction:

In vivo studies published in English that compared antimicrobial therapies including rifampin for the treatment of Legionella pneumonia, as well as in vitro studies including an assessment of rifampin bioactivity, were included.

Data Synthesis:

Macrolides and fluoroquinolones have been effective as monotherapy in the treatment of L. pneumophila pneumonia. This review includes evidence summaries from 4 bioactivity evaluations. 6 clinical studies, and 6 reported cases of combination rifampin use. Combined with supporting evidence, the role of combination rifampin therapy is further delineated.

Conclusions:

Interpretation of the data is limited by the potential for selection bias and lack of consistent comparators. Rifampin therapy should be considered only for patients with severe disease or significant comorbid conditions (eg. uncontrolled diabetes, smoking, or obstructive lung disease) including immunocompromised hosts and those refractory to conventional monotherapy regimens. Caution for significant adverse drug events and drug-drug interactions should be taken with the addition of rifampin.
Exploring Turkish biodiversity: A rich source of chemical diversity for drug leads discovery
Authors: Şener Bilge , Orhan İlkay
Published: July 2011

Bioresources offer tremendous potential by having excellent chemical diversity for drug discovery programs and by serving as templates for synthetic drugs. There are well-known examples of clinically important drugs derived from natural sources. The development of pharmaceutical, nutraceutical, agricultural, and industrial products from bioresources can be used to promote incentives for conservation by providing an economic return to innovative use. Of those sources, medicinal plants have a virtually untapped reserve of original drug molecules, which await determination and chemical and biological investigation. Marine organisms have also gained increasing attention from researchers worldwide due to their chemically diverse secondary metabolites with desirable biological activities. There is still a great need for novel compounds with unique mechanisms of action to treat diseases such as cancer, Alzheimer’s, arthritis, and diabetes. Besides, multiresistance development by the parasites to the present drugs also constitutes another problem for the treatment of parasitic diseases as well as tuberculosis. In this article, 209 plant species belonging to 11 plant families were investigated for cholinesterase inhibitory activity by in vitro Ellman method at 10 μg/ml and 1 mg/ml doses. Among them, Salvia, Rosmarinus, and Fumaria species were found to have the most significant cholinesterase inhibitory activity.
Nanostructures on surfaces by ion irradiation
Authors: Gnaser Hubert
Published: July 2011

The bombardment of the surface of a solid by energetic ions often results in pronounced surface modifications, leading to characteristic topographical features. In this report, the development of specific morphological nanostructures on surfaces under ion irradiation is discussed. The following aspects will be emphasized: (i) on an atomic scale, the generation of isolated defects such as adatoms and surface vacancies due to single-ion impacts, and their possible clustering; (ii) the transition from such individual defects toward extended morphological features on the surface and suitable scaling relations to describe them; (iii) the formation of highly periodic structures with nanoscale dimensions such as nanodots and “ripple”-like features, and the dependence of these nanostructcures on various ion-irradiation parameters and substrate materials; (iv) the theoretical concepts proposed to model the observed patterns which are thought to be related to (and caused by) the interplay between ion erosion and diffusion of adatoms (vacancies), thus inducing a surface reorganization.
A Temperature Controlled Triaxial Apparatus for Testing Unsaturated Soils
Authors: Uchaipichat Anuchit , Khalili Nasser , Zargarbashi Saman
Published: July 2011

This paper describes a modified Bishop–Wesley triaxial apparatus for testing unsaturated soils at elevated temperatures. The suction is applied using the axis translation technique. The cell liquid temperature is controlled through a heating element, and a thermal sensor installed inside the triaxial cell. Experiments are carried out at temperatures up to 60°C. Potential difficulties in the use of the equipment are identified and solutions are discussed for their mitigation. The image-processing and the cell liquid measurement techniques are used to measure the overall volume change of the sample. The performance of these two techniques is reported.
Development of a Laboratory Procedure to Evaluate the Consolidation Potential of Soft Contaminated Sediments
Authors: Erten Mustafa B. , Gilbert Robert B. , El Mohtar Chadi S. , Reible Danny D.
Published: July 2011

Consolidation settlement of non-aqueous phase liquid (NAPL) contaminated sediments may trigger NAPL mitigation. The consolidation potential and resulting NAPL mobilization of the sediments should be evaluated in the laboratory; however, due to the highly compressible and weak nature of riverbed sediments, it is usually not possible to conduct conventional consolidation tests on sediment specimens. In this study, a triaxial setup was modified to work effectively under low stresses. Kaolinite was used to represent the soil solid phase and Soltrol 130 (a type of mineral oil) was used to represent the NAPL. Both oil-wetted and water-wetted regimes were analyzed. Hexane Extraction and moisture content tests results confirmed the final fluid amounts in the specimen obtained by measuring the effluent volume during consolidation. The results of the tests show that approximately 0.1 g of NAPL per 1 g of soil solids is unlikely to be mobilized by consolidation. The developed procedure could also be employed to define the mobile and immobile fractions of NAPL and the expected compression of contaminated sediments. The volume of NAPL in excess of the retained residual can be used to design NAPL collection systems or to size layers of NAPL sorbent materials such as organo-clays.
Towards a Tensiometer Based Suction Control System for Laboratory Testing of Unsaturated Soils
Authors: Lourenço Sérgio D. N. , Gallipoli Domenico , Toll David G. , Augarde Charles E. , Evans Fred D.
Published: July 2011

This paper presents the development of an automated tensiometer based suction control system for testing unsaturated soil samples. The system is able to dry and wet soil, while measuring suction (pore water pressure – air pressure) and water content. The system uses air circulation within a closed loop to dry the soil, or water injection to wet the soil, to achieve the required pore water pressure while the air pressure is kept atmospheric. Pore water pressure is controlled by using a feedback computer system that dries or wets soil samples according to measurements obtained from sample-mounted high suction tensiometers. Excess moisture in the air circulation loop is captured by an in-line moisture trap consisting of a sealed cell containing a desiccant (silica gel), which is placed on an electronic balance to give continuous measurements of retained water. Changes of the sample water content are measured as the difference between the amount of water injected and that retained by the moisture trap. The system is fully automated and runs controlled by software with minimum assistance. The proposed suction control system presents advantages over the conventional axis translation technique as it avoids the need for elevated pore air pressures and hence better replicates the natural processes of wetting and drying of soils. The system was developed for use in a triaxial cell, but could also be used with other instruments and for the determination of water retention curves.
A Brief History of the Development and Growth of the Corrugated Polyethylene Pipe Industry in North America
Authors: Goddard James B.
Published: July 2011

From 1966 to 2009, the corrugated polyethylene pipe industry has grown from its first introduction to greater than a $2.5 × 109 industry in North America and from 4 in. (100 mm) only to a product diameter range of 2 in. (50 mm) through 60 in. (1500 mm). Markets have changed and grown as well, from predominantly agricultural drainage applications to housing, commercial development, transportation, mining, industry, forestry, storm sewer, sanitary sewer, turf drainage, and stormwater treatment. Increases in diameters and expansion of markets have led to corresponding changes in manufacturing processes and development of appropriate standards and specifications.
North America’s Cinderella Pipe Story: A Look at PVC Pipes’ Climb to the Top
Authors: Walker Bob
Published: July 2011

Remember the story of Cinderella? Cinderella was too poor and unworthy to ever become a princess. Similarly, when first introduced into the North American pipe market in the 1950s, PVC pipe was admonished by competitors and skeptics as having little chance to succeed. As a substitute for the well-established pipe mainstays of that era—iron, steel reinforced concrete, asbestos cement, and vitrified clay; PVC pipe was initially viewed as having insufficient strength and stiffness to be a viable contender. All of these early views had to be changed. This paper summarily chronicles how the questions and doubts surrounding PVC pipe’s performance capabilities were overcome, including the resolution of subsequently raised concerns. Through the consistent treatment of every issue with rational, technical, research based approaches; combined with an extensive in-service record of admirable performance; the use of PVC pipe has grown steadily through more than five decades. As a direct consequence, PVC pipes now account for the majority of all new water and sanitary sewer installations, exceeding the market shares of all the aforementioned established pipe materials combined. PVC pipe’s fairy godmother is proud, indeed!
Environmental Stress Cracking of Commercial CPVC Pipes
Authors: Hauser Ray L.
Published: July 2011

A study has been made by the author to learn effects of single and of mixed glycols causing environmental stress cracking of CPVC pipes made by four different manufacturers from two different resin suppliers. The study has shown that a mixture of ethylene glycol and propylene glycol is more damaging to CPVC pipe than either of the glycols by itself in the same relative concentration in water. The study also showed that one pipe resin containing a “tail” of lower molecular weight resin is somewhat more susceptible to cracking than the other resin. A secondary study also shows that the test method is appropriate for quickly evaluating chemicals in anti-corrosion treatments on steel pipes in sprinkler systems that can be particularly damaging to CPVC pipe.
Effect of Temperature and Pressure on Wear Properties of Ion Nitrided AISI 316 and 409 Stainless Steels
Authors: Pires Fernandes Frederico Augusto , Cristaldo Heck Stênio , Gomes Pereira Ricardo , de Paula Nascente Pedro Augusto , Casteletti Luiz Carlos
Published: July 2011

Stainless steels are widely used in chemical and other industries due to their corrosion resistance. However, because of their low hardness and wear properties, their applications are limited. Many attempts have been made to increase the surface hardness of these materials by using plasma techniques. Plasma nitriding is distinguished by its effectiveness, and for presenting a relatively low cost and being a clean process, producing hard surface layers on stainless steels. Aiming to verify the influence of the temperature and pressure on the modified resultant layers, samples of AISI 316 and 409 stainless steels were plasma nitrided in two different temperatures (450 and 500°C) and pressures of 400, 500, and 600 Pa for 5 h. After the nitriding treatment, the layers were analyzed by means of optical microscopy and wear tests. Wear tests were conducted in a fixed-ball micro-wear machine without lubrication. After the plasma nitriding treatment on AISI 316 and 409 samples, homogeneous and continuous layers were produced and their thicknesses increased as the temperature increased and as the pressure decreased. The nitriding treatment on the AISI 316 steel resulted on the formation of expanded austenite layers at 450°C and chromium nitrides (CrN and Cr2N) phases at 500°C. The nitriding treatment on AISI 409 yielded the formation of similar layers for both treatment temperatures; these layers constituted mainly chromium (Cr2N) and iron (Fe2N, Fe3N, and Fe4N) nitrides. After the nitriding treatment, the AISI 316 steel sample presented higher wear resistance for lower temperature and pressure values. The increase on layer fragility, for higher temperature and pressure values, can be responsible for this inverse tendency. The wear resistance of the nitrided AISI 409 sample followed a logic tendency: the harder the layer, the better the performance, i.e., the performance was improved with the increase in both the temperature and pressure.
Influence of Structure on Brittleness of Boron Nitride Coatings Deposited on Cemented Fine-Grained Carbides
Authors: Kupczyk Maciej Jan , Siwak Piotr
Published: July 2011

The article presents the brittleness study of boron nitride coatings deposited on cutting edges made of fine-grained cemented carbides by the pulse-plasma method (PPD). Influences of the structure (density, pores, microcracks) of coating material on the brittleness and on selected technological parameters of boron nitride formation by PPD method particularly taking into account discharge voltage on brittleness are shown. Differences between values of total average crack length ΣL, critical loads (Pk300, Pk500), and coefficients (a1(300) and a1(500)) characterized susceptibility to cracking of investigated coatings manufactured using different values of production process were defined. Results of investigations have confirmed the usefulness of Palmqvist’s method for measurement of coating susceptibility to brittle cracking.
Impact Wear Performance of Thin Hard Coatings on TiC Cermets
Authors: Veinthal Renno , Sergejev Fjodor , Emrah Yaldiz Can , Mikli Valdek
Published: July 2011

During metal forming processes like deep drawing of steel, tools are subjected to various loads. Besides adhesion, abrasion, and tribo-oxidation, successive impacts during forming induce Herzian contact pressures and cause fatigue failure. The present study focuses on TiC-based composites with Ni/Mo binders and thin coatings (TiN, (Ti,Al)N, TiCN, nc-(Al,Ti)N/α-Si3N4) produced by the physical vapor deposition technique. The adhesion of the coatings was characterized by Rockwell test and nanoscratch tests in single- and multi-scratch mode. The impact wear tests were performed using the rotating hammer-type surface fatigue wear tester for single spot testing. The effect of substrate surface roughness on the overall substrate/coating system was investigated. Selected surface contact damage sites in all materials were subjected to close examination by high power optical microscopy. Nanocomposite nc-(Al,Ti)N/α-Si3N4 coatings showed the highest hardness value. In addition, these coatings also have lower modulus values, which make them the best candidate for demanding wear applications. TiCN coatings have the second highest hardness value, but due to poor adhesion qualities, especially at higher roughness values, delamination was found to be present even directly after the coating process without any load. This is assumed to be related to the higher inherent residual stresses of TiCN coatings with TiC–Ni/Mo cermets. In this system the gradient nature of the top layer and presence of more ductile additional layer provide better performance in impact wear conditions.
Dependence of the Heat Transfer Coefficient at Quenching on Diameter of Cylindrical Workpieces
Authors: Liščić Božidar , Singer Saša , Beitz Hartmut
Published: July 2011

For computer simulation of a quenching process, the fundamental prerequisite is to have the relevant heat transfer coefficient (HTC) calculated as function of workpiece’s surface temperature and time respectively. In order to calculate the HTC, experimental measurement of the temperature-time history (cooling curve) near the workpiece surface is necessary. In this investigation, cylindrical probes of 20, 50, and 80 mm diameter are used. The cooling curve was measured always at 1 mm below the surface of the probe. Special care has been taken to keep all other factors (design of the probes, temperature measurement, quenching conditions, and calculation procedure), which can influence on the calculated HTC, constant to assure that the only variable is the diameter of the probe. Supposing a radially symmetrical heat flow at half length of the probe, the HTC was calculated using one-dimensional (1-D) inverse heat conduction method. The unexpected striking result of this investigation is the fact that for biggest probe diameter (80 mm), the calculated HTC as function of surface temperature does not show the film boiling phase. A plausible explanation of this effect is given based on the critical heat flux density. The possibility to establish a simple fixed relation (a correction factor) between the HTC and the diameter of cylinders is discussed.
Polyalkylene Glycols as Next Generation Engine Oils
Authors: Woydt Mathias
Published: July 2011

Some of the properties intrinsically present in the backbone of polyalkylene glycols (PAGs), which have nowadays attracted the automotive original equipment manufacturers (OEMs), are presented, such as bio-no-tox properties, heat capacity, extended drains, low friction, low AlSi-liner wear, fuel economy, and very high viscosity indices, and are achieved with metal-, ash-, and polymer-free formulations, which guarantee no adverse contamination of the lambda sensor and the active centers of the catalyzer as well as not to increase the exhaust back pressure of the particulate filter through ash deposits. This paper illuminates the latest results from OEM’s engine bench and road testing supporting the following functional benefits: (a) bio-no-tox, (b) improvements of fuel economy, even when compared with latest hydrocarbon-based prototype oils, (c) reduced wear, (d) reduced engine friction, (e) extended drains, (f) suited for bio-fuels, (g) no adverse effects on after-treatment devices through ash-, metal-, and polymer-free formulations, etc.
Particle Characterization and Sizing: SEM Utilizing Automated Electron Beam and AFA Software for Particle Counting and Particle Characterization
Authors: Herguth William Robert , Nadeau Guy William
Published: July 2011

In recent decades oil analysis laboratories have used automatic particle counters to determine the number and size of particles in many oil wetted systems. Once determined, there has been the question of “what are they?” Logically, the next step is to investigate the make-up of the particles by extracting the particles and analyzing using emission spectroscopy and/or a filter membrane for view them under magnification. Characterizing the make-up of the particles is very useful in determining the source. A cost-effective action plan can be undertaken to rectify the identified problem once the particle type is determined. The problem with these two approaches is; emission spectroscopy analysis is often unreliable in identifying larger particles and; under optical magnification it is not possible to tell for sure the makeup of the particles. In some cases scanning electron microscopy (SEM) analysis is undertaken to further identify the particles. This proves to be time-consuming for the SEM operator and is left to the operator to judge which areas of the sample to investigate. This study illustrates the performance and innovative approach to resolving the aforementioned limitations on sizing and identifying particles using an “Automated Electron Beam Particle Analyzer” equipped with “Automated Feature Analysis” (AFA) software to characterize complex matrix of particles extracted onto a membrane filter from oil samples.
CFD-Simulation of Film Boiling at Steel Cooling Process
Authors: Kulju Timo , Pyykkönen Juha , Martin David C. , Muurinen Esa , Keiski Riitta L.
Published: July 2011

This paper analyzes film boiling phenomena on a flat, horizontal hot steel plate using the volume of fluid method. The influence of water delivery velocity and plate surface temperature on film boiling behaviour has been quantified for the case of a single laminar flow jet assuming two-dimensional radial symmetry. In the present study, the model includes both convection and radiation induced mass and heat transfer, where the latter was found to be more important to maintain the film layer and film boiling at high temperatures. The model estimated heat and mass transfer behaviours at impingement velocities between 1 and 5 m/s and temperatures between 500 and 1300 K were found to be qualitatively consistent with available literature. The initial results obtained with the simulation suggest that computational fluid dynamics (CFD) simulation techniques represent a promising alternative for studying complex and difficult to measure phenomena such as high temperature film boiling, and hint at a new class of experimental methods for mechanistic analysis of fluid mechanical and thermal processes using purely computational methods.
Biomechanical Cyclical Loading on Cadaveric Cervical Spines in a Corpectomy Model
Authors: Cheng Boyle C. , Cook Daniel J. , Cuchanski Mathieu , Pirris Stephen M. , Welch William C.
Published: July 2011

Approved posterior cervical spinal fixation systems have been submitted to the U.S. Food and Drug Administration with results from standardized test protocols from the ASTM. The bench top mechanical studies are designed to minimize biologic and laboratory variability. However, for implant tests such as ASTM F1717 to be more clinically relevant, anatomical and physiologic considerations must be understood. The specific aim of this study was to determine if a human cadaveric cervical spine with a corpectomy and posterior fixation was effective in maintaining stability prior to and following cyclical loading. Six fresh frozen cadaveric human cervical specimens were harvested and prepared. A C5 corpectomy was performed. Posterior cervical instrumentation was implanted from C3 and C7 spanning across the C4–C6 defect. Each specimen followed an established pure moment test protocol to characterize the instrumented spine in flexion extension, lateral bending, and axial torsion at ±2.5 N m and axial compressive loading to 150 N. Subsequently, each specimen was subjected to 10 000 flexion extension cycles. Following the cyclical loading, each specimen was characterized a second time via the same test protocol. Statistical analyses were then performed on the third cycle data between the two pure moment tests. The mean FE bending range of motion (ROM) was 18.0° ± 10.7° prior to the 10 000 cyclical bending protocol. Following cyclical loading, the mean ROM measured 22.0° ± 19.9°. In axial compression, the mean ROM was 4.1 mm ± 1.9 mm prior to cycling and 4.2 mm ± 1.4 mm post-cycling. A statistically significant difference was detected only in the axial torsion mode of loading (p = 0.030). Although the ASTM standard provides consistent test methodologies, biomechanical cadaveric testing remains an important step in the validation of all spinal instrumentation. The pure moment biomechanical cadaveric test protocol for the same construct was capable of detecting significant changes pre- and post-flexion extension fatigue cycling only in the axial torsion mode of loading.
Beryllium Measurement by Optical Fluorescence in Samples Contaminated by Strongly Fluorescent Impurities
Authors: Agrawal Anoop , Adams Lori , Agrawal Akshay , Cronin John P. , Lopez Tonazzi Juan Carlos , Duran Brandy
Published: July 2011

A fluorescence method for determination of beryllium and beryllium oxide particles has been approved as a standard test method by ASTM International and the National Institute for Occupational Safety and Health. The procedure involves dissolution of samples in ammonium bifluoride solution and adding a small aliquot of extract to a basic hydroxybenzoquinoline sulfonate fluorescent dye and measuring itsfluorescence. This method is specific to beryllium and is not affected by the presence of other metals. However, the results from such a method may be compromised by organic fluorescent impurities which have optical characteristics similar to the beryllium-bonded hydroxybenzoquinoline sulfonate. This study demonstrates that such impurities can be effectively removed by activated charcoal without compromising the sensitivity of the method or any other test attributes.
Approaches towards Design of Green Matrices to Formulate Agricultural and Bio-active Materials and Provide Improved Efficacy
Authors: Narayanan Kolazi S. , Patel Jayanti , Jon Domingo , Qu Xin , Zhang Tom
Published: July 2011

Agricultural formulations containing hydrophobic active ingredients and spray solutions are used in aqueous medium. Typical concentrates are formulated as (a) solvent-based emulsifiable concentrates, (b) water-based suspension concentrates, (c) oil-based suspensions, and (d) solid forms like water-dispersible granules form the bulk of agricultural formulations. Efficacy of the active ingredients depends upon the particle/droplet size distribution in the spray solution and it is advantageous to have submicron size distribution with additional protection against wash off. Global awareness and strong regulatory initiative are the driving force for the design of green and environmentally friendly delivery matrices. Following approaches are viable solutions to address the green delivery targets. This paper will address typical examples of solvent pairs to formulate solvent-based formulations; stable micro-emulsion concentrates using all EPA approved (exemption from tolerance) components usable for food-crops. Water-based suspension concentrates with excellent suspensibility were developed by using newly developed polymer composites. Proprietary derivatized vegetable oils were used as self-emulsifying oils to formulate stable concentrates with good emulsification on dilution in water, without having to use conventional emulsifiers. Additional benefit with such compositions would be sustained release capability. Solventless zero volatile organic compounds (VOC) compositions were also developed for end-use applications with acceptable bio-activity by using proprietary polymer surfactant pairs.
Duration of the Transient Nucleate Boiling Process and Its Use for the Development of New Technologies
Authors: Kobasko N. I.
Published: July 2011

In the paper a review of the transient nucleate boiling process duration is widely discussed. It has been established that duration of transient nucleate boiling process is directly proportional to square of the thickness of steel parts and inversely proportional to thermal diffusivity of a material, depends on the configuration of steel parts, liquid properties, and its velocity. The transient nucleate boiling (self-regulated thermal process) is followed by amazing regularities: The surface temperature during nucleate boiling is maintained at the level of the boiling point of the liquid, which is used as a quenchant. During this period, average effective heat transfer coefficients and average generalized Biot numbers and Kondratjev numbers can be found which significantly simplify core cooling time and cooling rate calculations. Using established characteristics of the transient nucleate boiling process, the new intensive quenching (IQ) technologies were developed: IQ-1; IQ-2: IQ-3. In the paper the steel super-strengthening phenomenon and optimal quenched layer, which provides maximal residual compressive stresses at the surface of steel parts, are discussed, which increase service life of products. Instead of oils, plain water is used as a quenchant, environmental conditions are significantly improved.
How Frequency Affects Fatigue Testing of an Artificial Disc With a Viscoelastic Polymer Core
Authors: Blice R. L. , Zimmers K. B. , Linovitz R.
Published: July 2011

The purpose of this study was to determine the highest appropriate test frequency for a viscoelastic total disc replacement (VTDR). Natural intervertebral discs display viscoelastic behavior. Viscoelasticity is the time-dependent property of a material to show sensitivity to the rate of loading or deformation, having stress and strain reactions that are out of phase. If frequency is too high during mechanical testing of a viscoelastic polymer or medical device, the specimen is unable to recover fully before the next load application. Polymers absorb energy with each cycle. Since work (or energy utilized) is defined as the area under the force–displacement curve [Giordano, N. J., College Physics: Reasoning and Relationships, Brooks/Cole Publishing, Pacific Grove, CA, 2010], a frequency increase which decreases displacement will by definition also decrease the energy the polymer is using to achieve that decreased displacement. By reducing both total displacement and energy, a high test frequency would “protect” a viscoelastic device. A frequency of 2 Hz was used to determine the expected response of the VTDR during axial compression testing between 400 and 4000N. The response was defined as mean peak-to-peak displacement of five test cycles after 1000 cycles of preconditioning. Comparative data was collected at test frequencies of 3, 6, and 10 Hz. Displacement and energy utilized decreased with increasing test frequency. There were no significant differences between the viscoelastic responses in tests at 2 and 3 Hz. However, there were significant decreases in displacement and energy utilized at 6 and 10 Hz compared to 2 Hz. Over a 10 × 106 million cycle fatigue test, for this device, the total displacement would be 548 000mm less at 6 Hz and 988 000mm less at 10 Hz compared to 2 Hz. By decreasing the displacement, by definition it decreases the amount of overall work the disc has done when tested at these high frequencies [Giordano, N. J., College Physics: Reasoning and Relationships, Brooks/Cole Publishing, Pacific Grove, CA, 2010]. Viscoelastic devices should not be tested at high frequencies which “protect” the device by reducing the energy the device has to use overall by decreasing the total displacement it sees. To accurately evaluate in vivo behavior, fatigue testing should utilize test frequencies which do not significantly change the device’s viscoelastic response from that experienced at a physiologic loading frequency.
Comparison of Self-Drilling and Self-Tapping Cervical Spine Screws Using ASTM F543-07
Authors: Konz Regina J. , Jensen Laura M. , Kincaid Brian L.
Published: July 2011

ASTM F543-07 is used to evaluate insertion load (Annex A4), driving torque (A2), and axial pullout (A3) characteristics of self-tapping metallic medical bone screws. F543-07 was designed to evaluate screws that utilize a pre-drilled pilot hole and was not intended for self-drilling screws. The objectives of this study were to (1) adapt the F543-07 test methods to allow evaluation of both self-drilling and self-tapping screws and (2) quantify differences in performance between the two screw types. For all three tests (A4, A2, A3) appropriately sized pilot holes were pre-drilled into the surrogate test medium for all the self-tapping screw designs per ASTM F543-07. No pilot holes were created for the self-drilling screws. During the insertion load tests (A4), a constant rotation was applied to the screws under an initial, near-zero axial force state. While monitoring axial load, torque, and displacement, the axial load was gradually increased. The maximum load at which there was a marked increase in torque and displacement on the graph was indicative of the force required to engage the self-drilling or the self-tapping feature. To measure driving torque (A2), a constant rotation was applied. To maintain screw driver–screw contact, a constant-force axial pre-load was required. The axial insertion load, determined during the insertion load testing (A4), was used as the preload for the driving torque testing. Axial pullout testing (A3) measured the axial tensile force required to remove a screw from the test medium. Quantifiable differences in mean insertion load, driving torque, and pullout load were found, demonstrating that these methods are able to discern differences in performance between different screw designs. Finally, this study demonstrated it is possible to adapt the test methods outlined in ASTM F543-07 to evaluate the insertion load, driving torque, and axial pullout performance of self-drilling screws in addition to self-tapping screws.
USDA Programs to Support Development and Use of Biobased Industrial Products
Authors: Bailey Carmela A.
Published: July 2011

Nonfood, nonfeed uses of agricultural and forestry materials offer the best opportunities to realize the full economic potential which agriculture and forestry can play, beyond the traditional food, feed, and fiber markets. U.S. Department of Agriculture (USDA) has a portfolio of programs that support research, development, and commercialization of biobased lubricants as well as other industrial products that can replace petroleum-based products, such as plastics, paints, coatings, and adhesives. The National Institute of Food and Agriculture (NIFA) administers competitive grant programs to support basic and applied research through the Agriculture and Food Research Initiative, and pre-commercialization research is supported through the Small Business Innovation Research program www.nifa.usda.gov. NIFA collaborates with the Department of Energy through joint solicitations for the Biomass Research and Development Initiative, which supports developmental research and demonstration projects. USDA is the lead Federal agency for implementing the BioPreferredSM purchasing program. Many products, including lubricants, have been officially designated as biobased and must be given first preference for purchase by Federal agencies, thus creating a tremendous market pull for new products through the purchasing power of the Federal government. This program will allow agencies to meet their environmental goals with products that can also meet performance requirements and are cost competitive. (www.biopreferred.gov). Through partnerships with industry, Academia and other Federal agencies, these programs are making a significant contribution to the development and adoption of alternative technologies to increase energy independence and to open new opportunities for agriculture.
Lubricating Oils Evaluation of Dispersancy Capacity of Lubricating Oils and the Impact of Biofuels on Lubricant Dispersancy
Authors: Abellaneda Gerard , Pigeon Didier
Published: July 2011

One of the primary functions of a lubricant is to preserve the cleanliness of a combustion engine’s mechanical parts. The cleanliness of the mechanical parts is facilitated by the introduction of “detergency” and “dispersancy” additives to the engine oil. This last property, dispersancy, is the property that allows the oil to suspend and carry away “pollutants” of diverse sources, such as soot from combustion, metallic particles from wear, corrosion of mechanical parts, and insoluble products resulting from the aging of the oil, etc. Recently, with the arrival of new fuels (e.g., biodiesel, ethanol blends, etc.) we notice that the existing or traditional lubricants present an important variability in terms of durability and resistance to pollutants, such as the fuel or the biofuel. Our studies show that the dispersancy capacity of certain types of lubricants is significantly degraded by the presence of specific pollutants, and in particular fatty acid methyl esters of the biofuels, which have a significant impact. It is therefore important to quantify the degradation of the oil in-service (engines or transmission oils) and to monitor the evolution of the oil’s dispersancy properties during use to be able to determine steps and intervals for maintenance. Additionally, for the development of new lubricants it is necessary to define a criterion of acceptance of the oil by its dispersancy capacity. This new method will define and quantify this criterion. The writers will present the results of these studies with particular emphasis on the impact of biofuels on the dispersancy capacity of both gasoline and diesel engine oils. They will describe a method of analysis using an automated instrument providing precise, objective measurement of this important parameter. This method will therefore be able to estimate the dispersancy capacity of lubricants, as well as the implication of various pollutants on this parameter.
Influence of Edge Restraint on Clip Fastener Loads of Standing Seam Metal Roof Panels
Authors: Dixon Craig R. , Prevatt David O. , Datin Peter L.
Published: July 2011

This study investigates the effect of boundary conditions on the structural load paths within standing seam metal roof (SSMR) panel specimens subjected to uplift wind pressures. The objective is to determine the effect of boundary conditions (restrained or free) on observed load distributions among clip fasteners installed within a SSMR test specimen. Two roof specimens with instrumented clip fasteners were installed in a steel pressure chamber and subjected to static uplift pressures, while measuring panel deflection and clip fastener load distributions. The test specimen boundary conditions were modified in turn to represent field panel location (all free boundaries), gable panel (one restrained boundary, long dimension), eave panel (one restrained boundary, short dimension), and a corner panel (having two adjacent restrained boundaries). The load-displacement characteristics of the SSMR system were determined in a third specimen. The study found statistically significant differences in clip fastener loads, among the first three fastener rows away from the crosswise panel restraint, i.e., eave boundary condition. The gable boundary appeared to have less influence on load on the nearest fasteners. For the eave boundary condition, the measured load on the three exterior fasteners was about 40 % lower than the total fastener load on interior clips located just 3 m (10 ft) away. The results suggest why clip failures seldom occur in corner locations during uplift pressure tests. An empirical design method is proposed for predicting loads on clip fasteners installed near roof boundaries. More importantly, the design of SSMR roofing can be made more efficient, since it is shown that eave clip fasteners carry less than half the load of the interior fasteners, if other failure mechanisms (i.e., sheet tearing or boundary anchor failure) do not control the roof edge failures of installed SSMR.
A New Environmentally Friendly Solvent of Low Toxicity for Crop Protection Formulations
Authors: Vidal Thierry , Bramati Valerio , Murthy Krishnamurthy , Abribat Benoit
Published: July 2011

A new solvent for the crop protection formulations is described. Solvents are essential components in various pesticide formulations. Many traditional solvents used in agricultural applications are currently under scrutiny because of increasing environmental and regulatory concerns. Agrochemical formulators are facing a need to find alternative solvents that are environmentally friendly while continuing to deliver traditional solvent performance. A new polar solvent, an archetype of a novel class of products containing a tertiary amide group combined with an ester function namely Methyl 5-(dimethylamino) 2-methyl 5-oxopentanoate (RHODIASOLV Polarclean) (RHODIASOLV is the registered trade mark of Rhodia, Cranbury, NJ) is described. This new solvent exhibits an outstanding safety and non toxic environmental profile. Additionally, many agrochemical active ingredients have good solubilities in this new solvent. Hansen solubility parameters demonstrate the high level of solvency properties of this ester-amide when compared to the commonly used agrochemical solvents. In addition to meeting the customer requirements on delivering good solvent performance, the raw material utilized in the manufacture of this solvent is a by-product of polyamide manufacture and has been selected to meet the sustainability criteria.
Creep-Fatigue at High Temperature of Notched Single Crystal Superalloys
Authors: Filippini Mauro
Published: July 2011

The effect of hold time on the high temperature notched fatigue strength of the CMSX-4 single crystal superalloy has been experimentally investigated. Notched specimens with orientation 〈001〉 have been tested at 950°C in load control in the low-cycle fatigue (LCF) life regime both without and with dwell. For the same applied stress range (net-section stress), the effect of hold time results in an appreciable reduction of fatigue life. Several scanning electron microscope (SEM) observations of the failed specimens have been made in order to associate the actual failure (crack initiation) location to the correct crystallographic orientation and to the critical location in the notch as given by suitable multiaxial fatigue parameters. Moreover, SEM observations reveal the change of the failure mode from pure fatigue to fatigue/creep conditions. In order to model the material behavior in the notch, stress-strain analysis of the notched specimens was performed by an elastic-plastic finite-element method (FEM) procedure; the parameters describing the material behavior of the single crystal superalloy have been identified by comparison with experimentally determined stress-strain fatigue behavior and creep data of smooth specimens. A suitable model for the assessment of the reduction of fatigue life in creep-fatigue conditions is proposed.