Showing papers by "Toyota published in 1993"

Mechanical properties of nylon 6-clay hybrid

Abstract: Various nylon 6-clay hybrids, such as molecular composites of nylon 6 and silicate layers of montmorillonite and saponite, NCH's and NCHP's, respectively, have been synthesized. To estimate the mechanical properties of these hybrids, tensile, flexural, impact, and heat distortion tests were carried out. NCH was found superior in strength and modulus and comparable in impact strength to nylon 6. The heat distortion temperature (HDT) of NCH (montmorillonite: 4.7 wt. %) was 152 °C, which was 87 °C higher than that of nylon 6. In NCHP, saponite had a smaller effect on the increase of these mechanical properties. The modulus and HDT of NCH and NCHP increased with an increase in the amount of clay minerals. It was found that these properties were well described by the contribution of the constrained region calculated from the storage and loss modulus at the glass transition temperature. According to the mixing law on elastic modulus, the following expression was obtained between the modulus E at 120 °C and the fraction of the constrained region C, En = Ecn = C, where the values of n and Ec (modulus of the constrained region) were 0.685 and 1.02 GPa, respectively.

Synthesis of nylon 6-clay hybrid

Abstract: It was found that montmorillonite cation exchanged for 12-aminolauric acid (12-montmorillonite) was swollen by ∊-caprolactam to form a new intercalated compound. Caprolactam was polymerized in the interlayer of montmorillonite, a layer silicate, yielding a nylon 6-clay hybrid (NCH). The silicate layers of montmorillonite were uniformly dispersed in nylon 6. The carboxyl end groups of 12-aminolauric acid in 12-montmorillonite initiated polymerization of ∊-caprolactam, and as 12-montmorillonite content became larger, the molecular weight of nylon was reduced. From the result of end-group analysis, carboxyl end groups were more than amino end groups. The difference between the carboxyl and the amino end groups was attributed to ammonium cations (-NH3+) of nylon molecules, because the difference agreed with the anion site concentration of the montmorillonite in NCH. It is suggested that the ammonium cations in nylon 6 interact with the anions in montmorillonite.

Synthesis and properties of polyimide–clay hybrid

Abstract: A polyimide hybrid with montmorillonite clay mineral has been synthesized from a dimethylacetamide (DMAC) solution of poly(amic acid) and a DMAC dispersion of montmorillonite intercalated with an ammonium salt of dodecylamine. Montmorillonite consists of stacked silicate sheets about 2000 A in length, 10 A in thickness. In this hybrid, montmorillonite is dispersed homogeneously into the polyimide matrix and oriented parallel to the film surface. Thanks to this special structure, this hybrid showed excellent gas barrier properties. Only 2 wt % addition of montmorillonite brought permeability coefficients of various gases to values less than half of those of ordinary polyimide. Furthermore, this hybrid had low thermal expansion coefficient. © 1993 John Wiley & Sons, Inc.

Synthesis of highly ordered mesoporous materials from a layered polysilicate

Abstract: The ion exchange reaction of interlayer Na+ ions of a layered polysilicate kanemite with alkyltrimetnylammonium ions, followed by calcination, gives highly ordered mesoporous materials with a hexagonal array of uniform channels.

Swelling behavior of montmorillonite cation exchanged for ω-amino acids by ∊-caprolactam

Abstract: Natural Na-montmorillonite was cation exchanged for the ammonium cations of various ω-amino acids [H3N+(CH2)n−1 COOH, n = 2, 3, 4, 5, 6, 8, 11, 12, and 18]. X-ray diffraction (XRD) results suggested that the chain axes of ω-amino acids with a carbon number of eight or less were parallel to the silicate layers, and that the chain axes of those with a carbon number of 11 or more were slanted to the layers. The cation-exchanged montmorillonites form intercalated compounds with ∊-caprolactam at 25 °C. The montmorillonites intercalated with both ω-amino acid and ∊-caprolactam were studied by XRD measurement at room temperature and 100 °C. We propose a model where amino acid molecules were arranged perpendicular to silicate layers and ∊-caprolactam molecules filled the space between them. When the ∊-caprolactam was melted at 100 °C, the basal spacing for the montmorillonite increased, in which the carbon number exceeds 11. This phenomenon will be applicable to obtaining the nylon 6-clay hybrid, a molecular composite of nylon 6 and montmorillonite.

Synthesis of nylon 6-clay hybrid by montmorillonite intercalated with ε-caprolactam

Abstract: It was found that montmorillonite was intercalated with ϵ-caprolactam. X-ray diffraction revealed that the chain axes of the ϵ-caprolactam were parallel to the montmorillonite plates. The intercalated montmorillonite was swollen by molten ϵ-caprolactam at 200°C. ϵ-Caprolactam and 6-aminocaproic acid (accelerator) were polymerized with the intercalated montmorillonite at 260°C for 6 h, yielding a nylon 6-clay hybrid. X-ray diffraction and transmission electron micrography revealed that the silicate layers of the hybrid were uniformly dispersed in the nylon 6 matrix. Mechanical properties of the hybrid were improved. The strength and the modulus of the hybrid increased compared with the previously reported nylon 6 clay-hybrid (NCH) synthesized by montmorillonite intercalated with 12-aminolauric acid. The heat distortion temperature (HDT) of the hybrid was 164°C, which was 12°C higher than that of NCH. © 1993 John Wiley & Sons, Inc.

One‐pot synthesis of nylon 6–clay hybrid

Abstract: Nylon 6–clay hybrid is a molecular composite of nylon 6 and uniformly dispersed silicate layers of montmorillonite. One-pot synthesis of the hybrid was carried out by the following procedures. Montmorillonite was dispersed in water, and then e-caprolactam, acid (phosphoric acid, hydrochloric acid, benzenesulfonic acid, isophthalic acid, trichloroacetic acid, or acetic acid), and 6-aminocaproic acid were added to the dispersion. The mixtures were reacted at 260°C for 6 h, yielding the nylon 6–clay hybrids (1potNCHs). X-ray diffraction revealed that the silicate layers of 1potNCH by phosphoric acid were uniformly dispersed in the nylon 6 matrix. The 1potNCH had excellent mechanical properties. The strength and the modulus of the hybrid increased compared with previously reported nylon 6–clay hybrid (NCH) synthesized by montmorillonite intercalated with 12-aminolauric acid. The heat distortion temperature (HDT) of the 1potNCH was 160°C, which was 8°C higher than that of NCH. In other 1potNCHs, montmorillonite had a smaller effect on the increase of those properties, and interlayer spacing of montmorillonite was observed at ca. 20 A. © 1993 John Wiley & Sons, Inc.

Sorption of water in nylon 6-clay hybrid

Abstract: Various nylon 6-clay hybrids, such as molecular composites of nylon 6 and silicate layers of montmorillonite and saponite, NCHs and NCHPs, respectively, have been synthesized. Sorption of water in those hybrids was measured to estimate the resistance to water permeation. The diffusion coefficient D and the partition coefficient K were obtained from the sorption curves. The resistance to water permeation of NCH was superior to that of nylon 6 because of a decrease in D. In NCHP, saponite had a smaller effect on the increase of the resistance. The diffusion coefficients in NCH and NCHP decreased with an increase in the amount of clay minerals. It was found that those diffusion coefficients were well described by the contribution of the constrained region calculated from the storage and the loss modulus at the glass transition temperature. According to the mixing law, the following equation was obtained between the diffusion coefficient D and the fraction of the constrained region C, D = Da(1 – C)1/n, where the values of Da (diffusion coefficient in amorphous nylon 6) and n (morphology parameter) were 12.6 X 10−7cm2/s and 0.585, respectively. © 1993 John Wiley & Sons, Inc.

Apparatus and method for controlling light distribution of headlamp

Abstract: An apparatus for controlling the light distribution of a headlamp includes a vehicle speed sensor; a calculating device for estimating a position to be reached by the vehicle after a predetermined time along a forward roadway of the vehicle on the basis of a vehicle speed and information representing a route of the forward roadway, and for calculating a direction of illumination or a range of illumination by the headlamp so that light is illuminated onto an estimated position; and a control device for controlling the direction of illumination or the range of illumination by the headlamp on the basis of a result of calculation by the calculating device. The light is illuminated onto a position, which is located ahead of the vehicle and which is viewed by a driver, for obtaining an optimum light distribution for a field of view of the driver.

Exhaust gas purification apparatus for an internal combustion engine

Abstract: An NOx absorbent (6, 6A) is installed in an exhaust conduit (4) of an internal combustion engine (2) capable of fuel combustion at lean air-fuel ratios. An oxygen concentration is repeatedly or continuously decreased by, for example, switching the air-fuel from the lean air-fuel ratio to a stoichiometric or rich air fuel ratio when the exhaust gas temperature is higher than 550°C or when NOx absorbent temperature is higher than 500°C. As a result, the SOx absorbed in the NOx absorbent (6, 6A) during lean air-fuel ratio, low temperature operation is released from the NOx absorbent (6, 6A), and the SOx-poisoned NOx absorbent is recovered.

A method for dynamic simulation of rigid and flexible fibers in a flow field

Abstract: A method is proposed for simulating the dynamic behavior of rigid and flexible fibers in a flow field. The fiber is regarded as made up of spheres that are lined up and bonded to each neighbor. Each pair of bonded spheres can stretch, bend, and twist, by changing bond distance, bond angle, and torsion angle between spheres, respectively. The strength of bonding, or flexibility of the fiber model, is defined by three parameters of stretching, bending, and twisting constants. By altering these parameters, the property of the fiber model can be changed to be rigid to flexible. The motion of the fiber model in a flow field is determined by solving the translational and rotational equations for individual spheres under the hydrodynamic force and torque exerting on. This method was applied to simulate rotational motions with and without bending deformation of the fiber in a simple shear flow under the conditions of infinitely dilute system, no hydrodynamic interaction and low Reynolds number of a particle. For the rigid fiber, the computed period of rotation and the computed distribution of orientation angle agree with those calculated by Jeffery’s equation with an equivalent ellipsoidal aspect ratio. For the flexible fiber, the period of rotation decreases rapidly with the growth of bending deformation of the fiber and rotation orbits deviate from a circular one of the rigid fiber. These tendencies are similar to experimental ones described by Forgacs and Mason. These results show that the proposed method using bonded spheres’ model can reproduce the dynamic behavior of rigid and flexible fibers in a flow field successfully.

First-principles calculation of the structural, electronic, and vibrational properties of gallium nitride and aluminum nitride

Abstract: First-principles pseudopotential calculations have been performed on GaN and AlN in the wurtzite and zinc-blende structures. The mixed-basis approach is employed due to the localized nature of the valence charge density in these materials. In the stress calculation within the mixed-basis set, a correction term is introduced to the stress expression in order to make it consistent with the pressure given by the total-energy calculations. The lattice constants in the wurtzite structure are in good agreement with the experimental data. The band gap appears to be direct except for zinc-blende AlN, which has the conduction-band minimum at the X point. The effective mass of the electron is found to be nearly isotropic for both wurtzite GaN and AlN. The agreement of the optical \ensuremath{\Gamma}-phonon frequencies with the Raman experimental data is excellent for wurtzite GaN and good for wurtzite AlN, except for ${\mathit{A}}_{1}$--transverse-optical (${\mathit{A}}_{1}$-TO) mode. The calculated ${\mathit{A}}_{1}$-TO mode frequency of AlN is 11% smaller than the experimental value. Both GaN and AlN are found to have the wurtzite structure in the ground state.

Thermostable Farnesyl Diphosphate Synthase of Bacillus stearothermophilus: Molecular Cloning, Sequence Determination, Overproduction, and Purification.

Abstract: The structural gene for thermostable farnesyl diphosphate synthase from Bacillus stearothermophilus was cloned, sequenced, and overexpressed in Escherichia coli cells. A 1,260-nucleotide sequence of the cloned fragment was determined. This sequence specifies an open reading frame of 891 nucleotides for farnesyl diphosphate synthase. The deduced amino acid sequence shows a 42% similarity with that of E. coli FPP synthase [Fujisaki et al. (1990) J. Biochem. 108, 995-1000]. Comparison with prenyltransferases from a wide range of organisms, from bacteria to human, revealed the presence of seven highly conserved regions. In contrast to thermolabile prenyltransferases, which have four to six cysteine residues, the thermostable farnesyl diphosphate synthase carries only two cysteine residues. This enzyme is also unique in that some of the amino acids that are fully conserved in equivalents from other sources are replaced by functionally different amino acids. Construction of an overproducing strain provided a sufficient supply of this enzyme and it was purified to homogeneity. The purified recombinant enzyme is immunochemically identical with the native B. stearothermophilus enzyme, and it is not inactivated even after treatment at 65 degrees C for 70 min.

Bending of ionic polymer gel caused by swelling under sinusoidally varying electric fields

Abstract: Deformation of poly(vinyl alcohol)–poly(sodium acrylate) composite hydrogel (PVA–PAA gel) under sinusoidally varying electric fields was studied in electrolyte solutions. The PVA–PAA gel was prepared by repeatedly freezing and thawing a mixed solution of PVA and polyacrylic acid. A cyclic bending–straightening motion of the PVA–PAA gel rods of about 1 mm in diameter have been observed in Na2CO3 aqueous solutions under the fields. The PVA–PAA gel had a response time of less than several hundreds milliseconds. The bending has also been observed in organic solvents containing an electrolyte when the organic solvent is electrolyzed. It was found that the motion of the gel under electric fields of less than 1 Hz occurred mainly through swelling due to the change of the osmotic pressure based upon the difference of the ion concentration. However, it has not been determined whether the motion at higher frequencies is caused by the osmotic effect. © 1993 John Wiley & Sons, Inc.

Light-emitting device of gallium nitride compound semiconductor

Abstract: Disclosed herein is a light-emitting diode of GaN compound semiconductor which emits a blue light from a plane rather than dots for improved luminous intensity. It has an electrode 80 for the high-carrier density n + -layer 3 and an electrode 70 for the high-impurity density i H -layer 52. These electrodes 70 (80) are made up a first Ni layer 71 (81) (100A thick), a second Ni layer 72 (82) (1000A thick), an Al layer 73 (83) (1500A thick), a Ti layer 74 (84) (1000A thick), and a third Ni layer 75 (85) (2500A thick). The Ni layers of dual structure permit a buffer layer to be formed between them. This buffer layer prevents the Ni layer from peeling. The direct contact of the Ni layer with GaN lowers the drive voltage for light emission and increases the luminous intensity.

Malfunction detection apparatus for detecting malfunction in evaporative fuel purge system

Abstract: A malfunction detection apparatus for detecting a malfunction in an evaporative fuel purge system, which malfunction detection apparatus is able to suppress a fluctuation of an air-fuel ratio. A negative pressure inside an intake passage is introduced into the evaporative fuel purge system. The existence/nonexistence of a malfunction in the evaporative fuel purge system is determined by using pressure values inside the evaporative fuel purge system which values are detected and supplied by a pressure detecting unit. The apparatus is provided with an air-fuel ratio fluctuation suppressing unit for suppressing a fluctuation of the air-fuel ratio of air suctioned into an engine when introducing the negative pressure into the evaporative fuel purge system.

Early diagnosis of lumbar spondylolysis by MRI

Abstract: Radiography and CT and MRI scans of the lumbar spine were performed in young patients complaining of pain during extension of the lumbar spine but without neurological signs in the lower limbs. T1-weighted MR images in the coronal plane showed a hypo-intense area in the pars interarticularis before the detection of spondylolysis at that site by plain radiography or CT. We suggest that this may be useful in the early diagnosis of spondylolysis.

Navigation system for guiding vehicle by voice

Abstract: A vehicle navigation system for orally issuing route guidance, capable of changing a point at which the route guidance is issued depending on the moving situation of a vehicle. The moving situation is at least one of a number of lanes in a road being traveled, a width of a crossroad intersecting the road being traveled and a speed of the vehicle. The moving situation is detected by a moving situation detector section and based on the detected moving situation, the route guidance issuing point is changed to the optimum point for the moving situation at that time by a guidance issuing point changer of a route guide controller.

Five year prospective study on blood pressure and maximal oxygen uptake

Abstract: 1. The relationship between physical fitness (maximal oxygen uptake VO2max) and incidence of hypertension was investigated through a prospective study for a total of 16,525 human-years of observation. 2. This study involved 3305 Japanese males whose blood pressure (BP) was normal when they received their first physical examination before the age of 50. They were monitored from 1983 to 1988. The BP of 425 subjects was diagnosed as hypertension in the fifth year. 3. Fitness levels were divided into quintiles according to VO2max levels, and were compared with the changes of BP and relative risk of hypertension after adjustment for age, initial percentage of body fat (PFAT), initial BP, alcohol consumption, cigarette smoking status and familial history of hypertension. The increase in BP of subjects in the least fit group was higher than in any other group. Relative risk was calculated using a multiple logistic regression and was 1.9 x higher in the least fit group compared with the fittest group. 4. The subjects were classified into three groups: the improved VO2max group, the deteriorated VO2max group and the unchanged VO2max group. The increase in BP of the improved VO2max group was significantly lower than the other two groups after adjustment for changes in PFAT, age, initial PFAT, initial BP, fitness level, alcohol consumption, cigarette smoking status and familial history of hypertension. 5. It is concluded that low VO2max level is related to higher incidence of hypertension. An improved VO2max would therefore be able to prevent hypertension.

Shift control system for manually shiftable automatic transmission

Abstract: A shift control system for an automatic transmission, comprises: a plurality of frictional engagement means adapted to be hydraulically engaged for setting a plurality of gear stages; and a shift lever for switching an automatic mode, in which a gear stage is set on the basis of the running state of a vehicle, and a manual mode in which a gear stage selected by manipulating the shift lever is set. Further comprised are: a shift detector for detecting that a gear stage should be selected for the shift in the manual mode state: and a shift start timing adjuster for accelerating, if the shift in the manual mode state is detected, the switching rate of the frictional engagement means which are switched for executing the detected shift.

Residual capacity meter for electric car battery

Abstract: The voltage and current of a main battery used to drive a motor of an electric car is detected by a voltmeter and ammeter. The V-I characteristic is detected by a V-I characteristic computing means by reading the voltage and current when the battery current is equal to or greater than 0.75 C and is increasing (high load state). The relation between the two is stored, and from the actually measured V-I characteristic and the stored relation, the residual capacity of the battery is computed. The SOC is also determined by a SOC computing means 20 according to the power integration method, and the degree of deterioration of the battery is computed from this SOC and the residual capacity. By correcting the full charge capacity from the power integration method based on this degree of deterioration in order to compute the SOC, errors arising in the power integration method are prevented and measurement precision is improved.

Impact wrench having an improved air regulator

Abstract: An impact wrench having an improved air regulator comprises a cylindrical pipe provided on a handle, an air supply valve movably inserted in a back section of the cylindrical pipe, and a changeover valve movably inserted in a front section of the cylindrical pipe. The cylindrical pipe has a first air supply inlet and a second air supply inlet. The air supply valve has several air supply regulating slots of different diameters. The changeover valve has an an air supply reversing slot. The desired one of the air supply regulating slots is adapted to communicate with the first air supply inlet, so that the air flow to the air motor is regulated in the cylindrical pipe, thus obtaing a desired torque. The air supply reversing slot is adapted to communicate with the second air supply inlet only when the air motor is rotated counterclockwise. A compressed air is introduced into the air motor via the second air supply inlet, as well as the first air supply inlet communicating with the desired one of the air supply regulating slots. A more compressed air is supplied to the air motor when the air motor is rotated counterclockwise to produce an unfastening torque than when the air motor is rotated clockwise to produce a fasteing torgue.

Generalized Theory of Brake Noise

Abstract: Eliminating brake noises generated during brake application is an important issue in the improvement of comfort in vehicles. Brake noises (frequency 1–15 kHz) are often called brake squeal. On the other hand, brake noises (frequency 200–500 Hz) are often called brake groan noise. The studies on drum brake squeal, disc brake squeal and disc brake groan noise have already been presented in references (2), (3) and (4), where theoretical analyses on these brake noises were described. This paper shows that the equations of motion are represented by the same type of equations. Based on these analyses. It is clear that drum brake squeal, disc squeal and disc brake groan noise are generated by the same cause—dynamic instability of the brake system with friction force variations.