Stainless Steel Beads Research Articles

First Report of Sugar Beet Seedling Damping-Off Caused by Binucleate Rhizoctonia AG-A in China.

Sugar beet (Beta vulgaris L.) is grown worldwide and produces one-third of the world's sugar supply. Sugar beet seedling Rhizoctonia damping-off is an important disease mainly caused by Rhizoctonia solani AG-2, AG-4, and AG-5 (2). In 2010, diseased sugar beet seedlings with about 20% incidence affected by damping-off, which showed dark brown lesions on the stems just below the soil surface and portions of the roots, were collected from nurseries in three locations in Heilongjiang province, northeast China. Root fragments taken from the margins of healthy tissues and lesions on roots were surface disinfected with 0.5% sodium hypochlorite for 2 min, rinsed with sterile water, then placed on potato dextrose agar (PDA) and incubated at 25°C in the dark. Three (designed HLJ-RAA1, HLJ-RAB1, HLJ-RAB2) of nine Rhizoctonia isolates were obtained from diseased tissues and preliminarily identified as binucleate Rhizoctonia (BNR) anamorph (teleomorph Ceratobasidium Rogers) species-like. Fungal colonies were white with large amounts of floccose, aerial hyphae. Hyphal cells were determined to be binucleate when stained with 4'-6-diamidino-2-phenylindole (DAPI) (1). No sclerotia were produced after 14 days on PDA. Average hyphal diameter of the three isolates were 4.2, 4.3, and 4.8 μm, respectively. Further, the internal transcribed spacer (ITS) region of rDNA was amplified from the genomic DNA extracted from hyphae by bead beating in 2% CTAB solution using stainless steel beads with primers ITS1 and ITS4. The ITS sequences (GenBank Accession Nos. JX073668, JX073669, and JX073670) were over 99% identical to those of more than 50 Ceratobasidium sp. AG-A isolates (e.g., GenBank Accession No. JQ688054.1; strain HY-15). Therefore, based on morphological and molecular characteristics, these isolates were identified to be BNR AG-A. To determine the pathogenicity of the isolates, sugar beet (cv. HI0305) seedlings were inoculated with wheat seeds colonized with each of the isolated Rhizoctonia strains (one seed per seedling), and grew in pots under greenhouse conditions (3). After 3 weeks, some inoculated plants showed damping-off as observed in the nurseries, whereas noninoculated control plants (sterile wheat seeds only) remained healthy. Disease incidence from the trials averaged 53.3%, 70%, and 53.3% for the isolates HLJ-RAA1, HLJ-RAB1, and HLJ-RAB2, respectively. The three BNR cultures of the pathogens were consistently reisolated from symptomatic roots, and their identities confirmed by morphological and molecular characteristics as described above, fulfilling Koch's postulates. BNR AG-A was previously reported to be pathogenic to soybean, pea, snap bean, and pak choy in China (4). However, to our knowledge, this is the first report of BNR AG-A causing sugar beet seedling damping-off in China. Sugar beet is often grown in crop rotation with soya bean and such a rotation could increase the risk of soilborne infection to either crop by BNR AG-A.

Comment on “A random kinetic energy model for rock avalanches: Eight case studies” by T. Preuth et al.

Comment on “A random kinetic energy model for rock avalanches: Eight case studies” by T. Preuth et al.

Density segregation in a vertically vibrated granular bed

The dominant mechanism affecting the flow behavior of granular materials is the random motions of particles that results from the interactive collisions between particles. The velocity fluctuations induce the segregation in granular flows. The different densities of granular materials with different filling layers and packing ratios were used to investigate the segregation mechanisms in a vibrated granular bed in this study. The image processing techniques were employed to track the motion of granular materials. The fluctuating velocities of granular materials were measured under segregation in a vibrated granular bed. The segregation phenomena depend on the packing ratio and the filling layer of the stainless steel–glass mixtures. At the fewer filling layers, the heavier stainless steel beads migrate to the bottom regions with the lower granular temperature, so the granular temperature plays a significant role on density segregation. For the higher filling layers, the bulk convection motion is the main mechanism affecting segregation, so the heavier beads clump to the convection center and the clump size enlarges with the increasing packing ratio of heavier beads due to the bulk convection motion.

SU‐GG‐T‐301: Replacing Film with Computed Radiography for Routine Linear Accelerator QA

Purpose: To evaluate the feasibility of using diagnostic computed radiography (CR) plates to replace radiographic films for linear accelerator QA. Method and Materials: Type C Fujifilm CR plate (size 25.2×30.3cm) was tested with image reader FUJIFILM FCR PROFECT CS. Spatial resolution of 10 pixels/mm was used for image reading. The image plate was used without the cassette for linear accelerator QA. Plate or film was setup on the treatment table at isocenter (100cm SSD). A 3mm thick Plexiglas template with stainless steel beads markers was placed over the plate and aligned to the light filed. Exposure of 10 mus or 40 mus was delivered to a 10×10cm and 20×20cm field respectively using a 6 MV photon. The spatial accuracy and spatial uniformity of the CR image were evaluated and compared with Kodak X‐Omat V film. The distances measured in various directions on the CR image and Kodak X‐Omat V film were compared with the actual distances on the template to evaluate the spatial accuracy and image distortion under different conditions. Results: The distance measured in three different directions had error within 1%. Good spatial accuracy and good spatial uniformity were observed. Results were comparable for both FUJI CR plate and Kodak film. Conclusion: Uses of CR plate for routine QA give a comparable result to that of film. Similar results were also observed when used for light field‐radiation field coincidence test, star shot tests and MLC picker fence test. Hence the FUJIFILM CR plate is suitable for the linear accelerator routine QA procedure. With the facing out of films in most hospital, CR plates commonly used in diagnostic radiology made a good and relatively inexpensive substitute for use in routine linear accelerator QA procedure.

Non-ideal Behavior During Complete Dissolution of Organic Immiscible Liquid: 2. Ideal Porous Media

Column experiments were conducted using ideal natural sands and stainless-steel beads to examine the complete dissolution behavior of an organic immiscible liquid. Trichloroethene (TCE) was used as the representative organic liquid. The elution curves exhibited multi-step behavior, with multiple extended periods of relatively constant contaminant flux. These secondary steady-state stages occurred at concentrations several orders-of-magnitude below aqueous solubility for the well-sorted sands. In contrast, the secondary steady-state stages occurred within one log of aqueous solubility for the poorly-sorted sand. The nonideal behavior is hypothesized to result from constraints to hydraulic accessibility of the organic liquid to flowing water, which may be expected to be mediated by the pore-scale configuration of the flow field and the fluid phases.

Elastic waves in noncohesive frictionless granular crystals

An ordered structure of noncohesive spherical beads constitutes a phononic crystal. This type of media combines the properties of wave propagation in phononic crystals (dispersion due to the geometrical periodicity) with the properties of wave propagation in granular media (nonlinearities, rotational degree of freedom) and gives the opportunity to have interesting features as tunable frequency band gaps for example. In this work, the acoustic bulk modes of a hexagonal close packed (hcp) structure of beads, considered as rigid masses connected by springs, are theoretically evaluated and their associated resonance frequencies are compared to experimental results. When friction is neglected, the elastic interaction between the beads are reduced to a normal spring interaction given by the Hertz theory. According to this theory, the rigidity of the contact depends on its static loading. The theory predicts the existence of elastic transverse and longitudinal acoustical-type modes and transverse and longitudinal optical-type modes. The acoustic transfer function of a hcp crystal slab built with stainless steel beads is measured and its resonance frequencies are compared to the theoretical predictions. Despite some differences between theory and experiments, which could come for instance from the disordered character of the contact loads, the developed theory and the experimental results show relatively good agreement.

Simultaneous wet ball milling and mild acid hydrolysis of rice hull

AbstractBACKGROUND: Rice hull, an abundant residue but a big issue for the rice processing industry, has the potential to serve as a feedstock for production of ethanol because of its lignocellulosic composition. Simultaneous wet ball milling and mild acid hydrolysis of rice hull was studied in this work.RESULTS: Ball milling with 150 small stainless steel beads and rotation speed of 600 rpm in citrate solvent of pH 4 was the optimal condition for hydrolysis, and the yield of sugar increased with increased milling time. Corresponding structure transformations before and after milling analyzed by X‐ray diffraction (XRD), environmental scanning electron microscopy (ESEM) and transmission fourier transform infrared spectroscopy (FT‐IR) clearly indicate that this hydrolysis could be attributed to the crystalline and chemical structure changes of cellulose in rice hull during ball milling in mild acid solvent.CONCLUSION: This combined treatment of ball milling and citrate solvent greatly changed the crystalline and chemical structure and continuously generated sites accessible to citrate solvent, thus enabling hydrolysis of the rice hull. Copyright © 2009 Society of Chemical Industry

Bouncing trimer: a random self-propelled particle, chaos and periodical motions

A trimer is an object composed of three centimetrical stainless steel beads equidistant from each other and is predestined to show richer behaviour than a bouncing ball or a bouncing dimer. A rigid trimer was placed on the plate of an electromagnetic shaker and was vertically vibrated according to a sinusoidal signal. The horizontal translational and rotational motions of the trimer were recorded for a range of frequencies between 25 and 100 Hz, while the amplitude of the forcing vibration was tuned to obtain maximal acceleration of the plate up to 10 times gravity. Several modes have been detected such as, e.g., rotational and pure translational motions. These modes are found at determined accelerations of the plate and do not depend on the frequency. Chaotic behaviour is observed for other accelerations. By recording the time delays between two successive contacts when the frequency and the amplitude are fixed, a map of the bouncing regime was constructed and compared with that of the dimer and the bouncing ball. Period-2 and period-3 orbits were experimentally observed. In these modes, according to observations, the contact between the trimer and the plate is persistent between two successive jumps. This persistence erases the memory of the jump preceding the contact. A model based on the conditions for obtaining persistent contact is proposed and allows us to explain the values of the particular accelerations for which period-2 and period-3 modes were observed. Finally, numerical simulations allow us to reproduce the experimental results. This allows us to conclude that the friction between the beads and the plate is the major dissipative process.

Solvent-free production of nanoscale zero-valent iron (nZVI) with precision milling

Despite its effectiveness in degrading a wide array of environmental contaminants and superior physical characteristics for subsurface delivery, large-scale applications of nanoscale zero-valent iron (nZVI) for environmental remediation have been inhibited by the high costs associated with its conventional production technologies. In this contribution, an environmentally-benign and cost-effective production method of nZVI is demonstrated using a precision milling system. Unlike conventional methods such as chemical synthesis and vapor phase condensation, which typically involve toxic chemicals, sophisticated equipment and extensive labor, the precision milling method relies solely on the mechanical impact forces generated by stainless steel beads in a high-speed rotary chamber to break down the micro iron particles. The system uses no toxic solvents, is completely scalable to large-scale manufacturing. Scanning electron microscope (SEM) and BET surface area analysis independently verify that, after 8 hours of milling, the feed micro iron was effectively reduced to particles with sizes below 50 nm. The surface chemistry and crystal composition of the milled iron were characterized with high-resolution X-ray photoelectron spectroscopy (HR-XPS) and X-ray diffraction (XRD). Reactivity of the milled nZVI was probed through reactions with water and seven model chlorinated aliphatic compounds. The results demonstrate the milled nZVI (8 hour) is more reactive for contaminant degradation than the nZVI synthesized by the widely-adopted borohydride reduction method. The ball milling method thus stands as a promising green process for large-scale nZVI production and enhances the prospect of the nZVI technology for large-scale environmental remediation.

One-Trip Completion System Eliminates Perforations

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper SPE 101086, "One-Trip Sand-Control/Liner-Hanger/ Big-Bore Completion System," by C.R. Hoffman, SPE, Baker Oil Tools, prepared for the 2006 SPE Asia Pacific Oil & Gas Conference and Exhibition, Adelaide, Australia, 11–13 September. A new completion system replaces conventional tubing-conveyed perforating (TCP) and gravel packing. This technology also eliminates formation damage caused by perforating and reduces skin values. It is a new-generation, screenless-sand-control completion system. A telescoping conduit containing sand-control media composed of stainless-steel beads was chosen for its durability and erosion and plugging resistance. The system contains no explosives, eliminating many issues. Introduction A joint-investment project team consisting of three major operators, a service company, and an independent tool manufacturer was formed and charged with the task of developing a system that eliminated formation damage and greatly reduced skin values. Conventional perforating is a major cause of formation damage, so the primary goal was to eliminate perforations and still achieve connectivity with virgin reservoirs and maintain full-bore production and/or injection rates. Also, one-trip capability and user-friendliness were of primary concern; if this system were to cost operators more throughout the completion of a given well, it would have no merit in the marketplace. Therefore, the system was designed around conventional liner and cementing techniques. Purpose Fractured and compacted zones, perforation debris, and formation blockages are common types of damage that can occur in a conventional-perforation tunnel. Case histories have proved that skin values are significantly increased over the life of a well as a result of perforation-tunnel depth and fines that accumulate or are never properly cleaned from these tunnels. Studies have shown that for a 7½-in.-deep perforation tunnel, there may be as much as 60 lbm/ft of debris that must be cleaned from the wellbore. By design, this new technology addresses these factors affecting well productivity. The new technology had to satisfy the following criteria: one-trip deployment, primary cementing of casing tubulars, connectivity to a virgin reservoir, and sand control, all while maintaining cost effectiveness. One-trip installations reduce rig costs greatly. This new technology also addresses some of the problems associated with conventional cased-hole gravel packs such as incomplete perforation packing, voids in the annular pack, and poor communication with the reservoir. Drilling the New Well Use of a calcium-carbonate-based drill-in fluid while drilling the production or injection interval is quite common today. A manganese weighting agent may be used in these fluids to increase fluid density. The carbonate-based fluids provide a very thin, very uniform filter cake on the wellbore wall, providing stability to sensitive and unconsolidated formations. Also, the carbonate particles are acid soluble. This is imperative for this new system because when the telescoping conduits extend and contact the wellbore, a small amount of this material may be trapped on the face. With a barite-based mud there would be no way to remove this obstruction because barite is inert.

Packing Characteristics for Mass Transfer in a Rotating Packed Bed

This work investigated the mass transfer of a rotating packed bed (RPB) with emphasis on the effects of the packing's size, shape, material, and surface property. Experimental results show that there is no obvious relationship between at and kLa. Among the various shapes of the packings, the mass transfer coefficients of Raschig rings and Intalox saddles are lower than those of the others, while the kLa of the wire meshes is the highest. As to materials, the mass transfer coefficients are similar for acrylic, glass, ceramic, and stainless steel beads. Besides, the kLa values of the hydrophobically treated packings are 8−27% lower than those of the original glass and ceramic packings. A modified correlation of kLa, which includes the effects of various packings, is proposed based on our RPB experimental results. Further, this correlation can also reasonably estimate most of the kLa data in the Higee literature.

Synthesis of Poly(styrene-co-divinylbenzene)-stainless Steel Beads through a Factorial Design of Experiments

Microbeads consisting of a stainless steel nucleus covered with a layer of poly(styrene-co-divinylbenzene) have been synthesized. To determine the influence of several operation variables in the characteristics of the final product, a 2IV8-3 fractional factorial design of experiments was conducted. Eight factors were studied in 32 experiments instead of the 256 experiments required by a full design. The process responses were the thickness of polymeric layer, the absence of particle agglomeration, and the total amount of polymeric material in the nonagglomerated particles (global yield). Empirical equations relating the values of each response to the coded values of the levels of the significant factors were obtained. The results showed that the thickness of polymeric layer response was influenced in a positive way by prepolymerization and double polymerization but in a negative manner by the addition of ammonium hydroxide to the reaction mixture. By contrast, in the absence of particle agglomeration resp...

Adsorption isotherm and atomic force microscopy studies of the interactions between polymers and surfactants on steel surfaces in hydrocarbon media

The adsorption isotherms for certain polymer and surfactant molecules (and in some cases their mixtures) on stainless steel beads from isooctane have been obtained, together with corresponding adsorbed layer thicknesses, using an atomic force microscope. The polymer is a terminally functionalised (ethylene diamine), low molecular weight polyisobutylene (PIB) derivative and the surfactants are basically alkyl or alkyl phenol alkoxylate molecules, which in one case has been derivatised with an amino functionality. The results indicate the presence of multilayers at the stainless steel–isooctane interface. Theoretical analysis of the surfactant adsorption isotherms suggests molecular aggregation at the interface with an aggregation number between 2 and 6, at the highest coverages. The adsorption of the polymer is reduced in the presence of the surfactant molecules. The polymer leaches metal ions from the steel surface at higher concentrations.

Effects of surface properties on the tribocharging characteristics of polymer powder as applied to industrial processes

Experiments performed on different powders of different size distributions tribocharged with stainless-steel (SS) beads showed the charge acquired by the powder could be correlated with the actual work function difference between the powder and SS. Ultraviolet and X-ray photoelectron spectroscopy were performed on various materials involved, and showed the work function increased with surface contamination and oxidation, and the difference narrowed for metals and polymers. Such a small difference in work function may contribute to bipolar charging. Experiment data showed that while charge acquired increased with particle size, the charge distribution was generally bipolar. Both surface analysis and charge distribution studies suggest that for tribocharging, minimization of oxidation and surface contamination are needed. It also appears that the relative humidity must also be controlled to obtain reliable tribocharging. Semiempirical molecular modeling calculations of the work function of several polymers showed good agreement with experiment. Surface plasma treatment is presented as a viable method for modifying the work function.

Deposition studies of carbon particles on stainless steel surfaces from hydrocarbon media

Abstract The adsorption isotherms for carbon particles of about 200 nm size, in the presence of various combinations of a terminally functionalised (amine) polyisobutylene polymer and alkylpropoxylate/alkylbutoxylate surfactant molecules, on 7 μm diameter stainless steel beads from isooctane solutions have been obtained. The deposition of carbon particles on stainless steel plates was achieved using a flow-cell and analysed using scanning electron microscopy. The flow-cell was also used to study the “cleaning” properties of various polymer/surfactant solutions, in their ability to remove deposited particles. It was found that the polymer molecules were much more effective dispersants and stabilisers for the carbon particles, but the surfactant molecules were much better at effecting anti-deposition and subsequent removal of deposited carbon particles, and provide carried adsorbed polymer chains.

Three-dimensional ultrasound-guided core needle breast biopsy

A new core needle breast biopsy system guided by 3-D ultrasound (US) is proposed. Our device provides rapid imaging and real-time guidance, as well as breast stabilization and a needle guidance apparatus using 3-D imaging. The targeting accuracy of our device was tested by inserting a 14-gauge biopsy needle into agar phantoms under 3-D US guidance. A total of 18 0.8-mm stainless-steel beads embedded in the phantoms defined each of the four target positions tested. Positioning accuracy was calculated by comparing needle tip position to the preinsertion bead position, as measured by three observers three times each on 3-D US. The interobserver standard error of measurement was no more than 0.14 mm for the beads and 0.27 mm for the needle tips. A 3-D principal component analysis was performed to obtain the population distribution of needle tip position relative to the target beads for the four target positions. The 3-D 95% confidence intervals were found to have total widths ranging from 0.43 to 1.71 mm, depending on direction and bead position. (E-mail:afenster@irus.rri.on.ca)

Change in charging characteristics of polymer powder by plasma treatment

Polyethylene powder was treated in Ar, O2 and N2 gas plasma in a rotating small glass bottle with larger stainless steel beads in order to prevent blocking of powder particles. After the treatment of 40s in plasma at 0.55W, the charging characteristics of the powder were remarkably changed. The charge on the powder particles generated by mixing with the stainless steel beads was 8, 12 and 13 times as large as those before treatment. Each powder particle was confirmed to be well treated by using this procedure.

568 多孔質層内におけるNaCl水溶液の凍結(OS19-2 固-液相変化を伴う移動現象の数値シミュレーション(2))(OS19 固-液相変化を伴う移動現象の数値シミュレーション)

This paper deals with heat conduction in porous media with solidification of NaCI-water solution. The porous media consists of stainless steel beads or glass beads. The porous media filled with NaCI-water solution is cooled from bottom. Temperature are mainly investigated experimentally and theoretically. The measured temperature distribution in the porous media is in good agreement with calculated one.

Electroless Gold Plating of 316 L Stainless Steel Beads

This paper describes an electroless gold plating process for particulate 316L stainless steel. The process is based on a mildly acidic gold sodium thiosulfate/ascorbic acid plating solution and is performed under an inert environment at room temperature. The process affords a gold deposition efficiency of ∼50% as inferred from a modified tin chloride based spectrophotometric assay for gold ion concentration. Successful gold deposition depended on the removal of the thin, passivating surface oxide layer on the stainless steel; this was accomplished by an initial cleaning step with 2 M HCl. In situ cyclic voltammetry experiments on a stainless steel electrode and atomic force microscopy scans on small coupons were used to further characterize the oxide removal and gold deposition reactions. © 1999 The Electrochemical Society. All rights reserved. ©2001 American Geophysical Union

Illustration of important mechanisms controlling mass transfer in supercritical fluid extraction

Supercritical fluid extraction profiles are presented for various model systems. The purpose is to illustrate some mechanisms encountered in supercritical fluid extraction by using simplified systems and also to give examples of how pre-extraction steps can be utilized to improve the mass-transfer rate. Extraction of clevidipine (a calcium antagonist) from different, allegedly inert materials, showed significant differences in extraction efficiency. Extraction from stainless-steel beads gave complete recovery with pure carbon dioxide, whereas the extraction from filter paper required the addition of 4% methanol. This indicates that interactions between matrix and analyte can be strong and that a modifier can be used, not only to increase solubility in the carbon dioxide, but also to break analyte/matrix bindings. Recovery of oil applied on an inert material was constant in terms of recovery per volume of extraction fluid for different flow rates, illustrating a solubility-limited behavior. Metal rods with drilled orifices filled with lubricating oil were used in experiments designed to reveal the influence of matrix characteristics on the extraction profile. The plots obtained showed a decreased recovery at higher flow rates, demonstrating diffusion limited behavior due to slow mass transfer through stagnant regions of the supercritical fluid. Bad recovery can sometimes be improved by changing the matrix in a pre-extraction step thus making the analytes more accessible to the extraction fluid. Static pre-extraction improved the extraction efficiency for target compounds from fat samples. Also recovery of clevidipine from a fat containing emulsion was considerably increased when water was removed in a dynamic pre-drying step.