Nylon Balls Research Articles

Structure and dose effects on improved wear properties of ion-implanted polymers

Polyethylene, polypropylene, polystyrene and polyethersulfone, representing an increasing complexity in molecular structure, were implanted with 200 keV boron to three doses of 1.7, 5 and 17 × 10 18 ions m −2. Polystyrene was also implanted with 100 keV boron to the same three doses. The polymers were investigated for near-surface micromechanical property changes using a nanoindentation technique. Wear properties of the polymers were studied using a reciprocating tribometer with a nylon ball as the counterface. Tests were conducted for 10000 sliding cycles using a 1 N normal load, a stroke length of 3 mm and an oscillation frequency of 100 cycles min −1. The ion implantation increased the near-surface hardness of the four polymers and the increase was proportional to the dose and beam energy. A clear structure dependence was observed for the hardness changes that were related to cross-linking of molecular chains caused by the ion irradiation. In general, the implantation also significantly improved the wear properties of the four polymers. For each polymer, an optimum dose was identified that yielded the best wear improvement. With increasing dose, the dominant wear mechanism shifted from adhesive and abrasive wear to no observable wear to surface fatigue. Remarkable wear improvements were observed for polystyrene and polyethersulfone for which, at the optimum dose, no wear damage was visible even after 10000 sliding cycles.

Improved hardness and wear properties of B-ion implanted polycarbonate

Polycarbonate (Lexan) was implanted with 100 and 200 keV B+ ions to doses of 0.26, 0.78, and 2.6 × 1015 ions/cm2 at room temperature (<100 °C). Mechanical characterization of implanted materials was carried out by nanoindentation and sliding wear tests. The results showed that the hardness of implanted polycarbonate increased with increasing ion energy and dose, attaining hardness up to 3.2 GPa at a dose of 2.6 × 1015 ions/cm2 for 200 keV ions, which is more than 10 times that of the unimplanted polymer. Wear properties were characterized using a reciprocating tribometer with nylon, brass, and SAE 52100 Cr-steel balls with 0.5 and 1 N normal forces for 10000 cycles. The wear mode varied widely as a function of ion energy, dose, wear ball type, and normal load. For given ion energy, load, and ball type conditions, there was an optimum dose that produced the greatest wear resistance and lowest friction coefficient. For polycarbonate implanted with 0.78 × 1015 ions/cm2, the nylon ball produced no wear after 10000 cycles. Moreover, the overall friction coefficient was reduced by over 40% by implantation. The results suggest that the potential of ion-beam technology for improving polycarbonate is significant, and that surface-sensitive mechanical properties can be tailored to meet the requirements for applications demanding hardness, wear, and abrasion resistance.

Reliable amperometric determination of glycerol and glycerol-3-phosphate with a bienzymatic nylon membrane electrode

An enzymatic biosensor for glycerol and glycerol-3-phosphate was designed, based on the co-immobilization of two enzymes, glycerol kinase and glycerol-3-phosphate oxidase, on a nylon membrane activated by a process recently reported for nylon balls. Optimum conditions for immobilization, use and storage were defined. A detection limit as low as 7 × 10 −8 M for glycerol and 1 × 10 −7 M for glycerol-3-phosphate was obtained and assays could be performed in the linear ranges 1 × 10 −7–5 × 10 −4 and 2 × 10 −7–2 × 10 −3 M for glycerol and glycerol-3-phosphate, respectively. The response time is < 3 min. No significant difference in the sensitivity was found after 7 h of continuous use and 75% of the initial sensitivity was maintained after 50 days of storage at 4°C. The electrode was tested with various samples such as standard serum and standards of di- or triglycerides and the results were in good agreement with the theoretical values.

Elastic and Viscous Effects on Particle Migration in Plane‐Poiseuille Flow

Experimental results are reported for cross‐flow migration of solid spherical nylon balls (0.238 cm diameter and volume fraction φ=0.02) in three different mediums carried out under plane‐Poiseuille flow conditions in a perspex slit channel (length=226 cm, width=27 cm, height=3.97 cm). The three different fluids employed for suspensions are pure corn syrup (a Newtonian medium), 0.2 wt% polyacrylamide in corn syrup (a nonshear‐thinning elastic medium), and an aqueous solution containing 2.5 wt% polyacrylamide (a shear‐thinning elastic medium). Gamma radiation technique is used to monitor the distribution of nylon particles in the transverse direction at four altitudes of 0.35, 0.7, 1.05, and 1.4 cm, respectively from the top of the slit channel. Measured profiles and visual inspection indicated different flow patterns in the three fluid mediums studied. In the Newtonian medium, particle distribution was found to be uniform, whereas in a nonshear‐thinning medium, migration tended toward the center line resulting in formation of a narrow core. In the viscoelastic shear‐thinning medium, the solid particles concentration is observed between two altitudes measured at about 0.35 cm from top and bottom sides of the slit channel and at about 0.6 cm from the central axis of the channel. Analysis for these different flow patterns based on the contribution of the elastic and viscous effects is given in terms of the rheological behavior of the carrier fluids.

Technical note: The yield stress—An engineering reality

A simple experiment using the falling ball technique was used to demonstrate unambiguously that a 2500 wppm aqueous Carbopol 960 solution has a yield stress. A series of photographs taken over a period of several months revealed that a nylon ball with a density of 1.156 g/cm3 showed no measurable movement when placed well within a Carbopol solution having a density of 1.008 g/cm3.

５０ｋＨｚ超音波の球体群反射と透過に関する基礎的研究

By using the 50 kHz fish finder the measurements were carried out at an indoor 50 ton-water tank. Some nylon balls (diameter 15.8mm) were used instead of fish. The horizontal and vertical settings of these balls were made at random by a personal computer. A transducer of the fish finder received the reflected waves, and a hydrophone received the transmitted waves. These signals were analyzed by means of the signal analyzer.The results obtained were as follows:(1) The relationship between the density and the transmitted voltage is more reliable than that between the density and the reflected voltage.(2) When each distance of the respecive ball from the transducer changes within a pulse length, the transmitted voltage is far more stable than the reflected voltage in all the measured densities.The applicability of the transmitted voltage in determining the density of the fish school is suggested by these two items, (1), (2).

Impact testing of light objects

This paper investigates the design of a measurement system that measures the impact signature of a light object. The design is based on a freely supported piezoelectric force transducer. Effects of top mass, base mass, and stiffness of the transducer were investigated. Two models were used in the analysis of the impact, a linear model with a 3 degree of freedom system and a Hertzian model. Using the Hertzian model, a criterion for choosing the optimum size of the base mass was developed. This criterion is based on the least‐square error in the force spectrum. Similar results were obtained by the linear model and numerical simulations. Experimental confirmation of the results was conducted using small Teflon and nylon balls and a piezoelectric force transducer. The results agreed well with the model predictions.

Une méthode d'immobilisation d'anticorps par liaisons covalentes sur nylon 66. Application en test immunoenzymatique

AbstractA new method of immobilization of low‐molecular‐weight compounds or antibodies on nylon 66 was developed. Secondary amide groups of nylon 66 were converted into secondary imidate groups by O‐alkylation with sulfuric acid and methanol. The methoxycarbonimidoyl groups react with amino compounds to produce stable amidine links. Antibodies and several low‐molecular‐weight compounds (amino acids) were immobilized by covalent linkage on nylon balls. Fixed antibodies were used in solid phase enzyme linked immunoassay, i.e. applied for the detection of K99+ Escherichia Coli in calves.

Some design considerations of a draft tube gas-liquid-solid spouted bed

The optimal design of a draft tube gas-liquid-solid spouted bed was experimentally evaluated by considering four design variables including the draft tube diameter, gas-liquid injector, top (above-draft-tube) spacing and bottom (below-draft-tube) spacing. The effects of these design variables on the overall gas holdup were comprehensively examined for various gas and liquid velocities and solid particle properties. The diameter of the outer column of the draft tube three-phase spouted bed was fixed at 15.24 cm. The overall gas holdup increases with an increase in gas or liquid velocity. It was found that, of the three diameters of draft tubes considered (7.62, 10.16 and 12.7 cm), the draft tube of 7.62 cm inside diameter has the highest overall gas holdup. Of the two liquid velocities considered (2.28 and 3.41 cm s −1), a higher overall gas holdup is obtained at a higher liquid velocity for each of the four bottom spacings considered (0.44, 1.27, 2.54 and 5.08 cm). Of these four bottom spacings, the 1.27 cm spacing has the highest overall gas holdup. The overall gas holdup increases with decreasing top spacing. 2.5 mm nylon balls have the highest overall gas holdup, followed by 4 mm glass beads. 3 mm glass beads have the lowest overall gas holdup. The concentric tube gas-liquid injector with the gas distributor plate of smallest pore size placed on the top of the outer tube gives rise to the highest overall gas holdup.

A nylon ball solid-phase radioimmunoassay for specific antibodies in human sera. Application to measurement of IgG antibodies to pollen allergens

The principle of the radioallergosorbent test (RAST) has been used to measure IgG antibodies to timothy grass pollen allergens in sera from desensitized allergic subjects. 125I-labeled goat anti-human IgG was used as detector protein. Non-specific binding was eliminated by use of a non-porous nylon ball an antigen carrier and by use of a special buffer with high ionic strength and pH, containing 1% bovine gamma globulin and 5% normal rabbit serum as ‘balance proteins’. At dilution 1 : 80 non-specific binding was only 0.28% and the binding ratio for a high-titer serum was about 10. By inhibition experiments the assay was demonstrated to be specific for IgG antibodies to timothy grass pollen. The results obtained with this assay correlated statistically significant with those found with double-antibody method ( r S = 0.68, n = 20, t = 3.93, P < 0.001). Serum dilution curves were parallel, indicating that the assay is in allergen excess. The within-assay coefficient of variation ranged from 3.9 to 7.6%; the between-assay coefficient of variation from 8.4 to 19.5%. The assay is very simple to perform, requiring no centrifugation. The allergen-coated balls are stable for at least 3 months. The assay should be applicable to measurement of IgG antibodies and IgG subclass antibodies to any protein antigen of interest.

The site of arterial wall rupture in transluminal angioplasty: an experimental study.

The site of arterial rupture following arterial balloon dilatation was studied in postmortem canine arteries. An atherosclerotic plaque was simulated by insertion of a solid nylon ball. Longitudinal tears of intima and media were produced at the level of the nylon ball. The site of arterial rupture can therefore be predicted if localized changes of wall strength can be neglected. On the other hand, the site of arterial rupture in clinical cases will depend mainly on the consistency and tensile strength of the diseased artery.

Immobilization of antibodies on nylon for use in enzyme-linked immunoassay

Antibodies were immobilized by covalent linkage on nylon balls and powder for use in solid-phase enzyme-linked immunoassays. Covalent linkage of antibody to nylon was accomplished by treatment of partially hydrolyzed nylon with glutaraldehyde or carbodiimides. Up to 0.74 μg of immunoglobulin G per mm 2 nylon could be immobilized, whereas only 0.02 μg per mm 2 could be adsorbed to polystyrene, and the binding to nylon was stable. This eliminated the problem of antibody desorption noted in conventional enzyme-linked immunosorbent assays which are based on simple adsorption to plastics, and gave more reproducible results. The methods was also more sensitive, detecting levels of approximately 1 ng per ml of immunogbulin E in clinical samples. Further, antibodies coupled to nylon balls remained bound under conditions that dissociate antibody-antigen complexes, which permitted reuse of the immobilized antibodies for immunoassays.

Instruments for Non-Surgical Collection and Transfer Bovine Embryos

Further development of the Danish embryo-collector which has been in use under practical farm conditions since 1976 is described in detail. For non-surgical transfer of embryos a new embryo-transferator has been constructed based on a disposable flexible nylon catheter with a nylon ball fixed on the distal end and stiffened by a metal stylet. After insertion of the catheter into one horn the stylet is replaced by an egg-injector. The embryo is released from a small, exchangeable nylon tube in the distal part of the catheter.

A STUDY OF MISBEHAVIOR: TOKEN REINFORCEMENT IN THE RAT1

The purpose of this research was to investigate the phenomenon of misbehavior described by Breland and Breland (1961). Rats were trained to obtain ball-bearings and drop them in a hole for food or water reinforcers. In confirmation of the Brelands' observation, many subjects were slow to deliver the balls, and frequently attempted to chew them before they were dropped. A series of four experiments, in which the same rats were used throughout, showed that delivery times tended to be longer with food than with water, and that these times increased when nylon balls were substituted. The effect of motivational level was investigated by varying both deprivation and amount of prefeeding; no effect on delivery time was detected, although other measures of performance were affected by motivational factors. Similar results were obtained in a final experiment that employed a new set of naive subjects. The studies demonstrated that misbehavior can be studied in an experimental situation, and the results supported an analysis in terms of competition between stimulus-reinforcer and response-reinforcer contingencies. The question of why such effects have not been reported in previous token reinforcer studies was unanswered.

The Analysis of Mixtures of Glutamic and α-Ketoglutaric Acids by Infrared Spectroscopy

An analytical procedure utilizing infrared techniques has been developed for the quantitative determination of glutamic and α-ketoglutaric acids for samples containing milligram quantities of these acids. The infrared spectra of the samples in KBr pellets was determined on a Beckman IR-8 infrared spectrophotometer using double beam, slow scan, gains of 5.2% to 5.6% and attenuation to 97% T at 3846.2 cm−1. For preparation of the pellets, approximately 400 mg of KBr (IR grade, E. Merck, Darmstadt, Germany), was used. Better dispersion of the sample was achieved by mixing a part of the KBr with the sample in an agate mortar and combining this mixture with the rest of the KBr in the capsule of a Wig-L-Bug (Crescent Dental Mfg. Co., Chicago, Ill.) along with a nylon ball (⅛ in.). Twenty seconds agitation completed the mixing. The mixture was transferred to the die and the pellet prepared in the usual manner.