Showing papers by "General Electric published in 1975"

Electrophoretic method of detecting antigen-antibody reaction

Abstract: A method of rapidly detecting presence of antibodies in a solution comprises depositing, on each of a plurality of microscopic particles, an antigen specific to the antibodies sought, and forming a dilute suspension of the particles in the solution to be examined. The suspension is stirred, and electrophoretic mobility of the particles is measured upon formation of the suspension and measured again at a subsequent time. Detection of a change in electrophoretic mobility of the particles between the two measurements indicates presence of the antibodies in the solution.

The Nelder-Mead Simplex Procedure for Function Minimization

Abstract: The Nelder-Mead simplex method for function minimization is a “direct” method requiring no derivatives. The objective function is evaluated at the vertices of a simplex, and movement is away from the poorest value. The process is adaptive, causing the simplexes to be continually revised to best conform to the nature of the response surface. The generality of the method is illust'rated by using it. to solve six problems appearing in the May 1973 issue of Technometrics.

Observation of a Spin-Peierls Transition in a Heisenberg Antiferromagnetic Linear-Chain System

Abstract: Magnetic-susceptibility and EPR measurements are reported which provide the first unambiguous evidence for a spin-Peierls transition in a system of linear one-dimensional antiferromagnetic Heisenberg chains. The material studied is TTFCu${\mathrm{S}}_{4}$${\mathrm{C}}_{4}$${(\mathrm{C}{\mathrm{F}}_{3})}_{4}$ (TFF stands for tetrathiafulvalinium). At 12 K, the spin-lattice system undergoes a second-order phase transition to a singlet ground state.

Photocurable epoxy compositions containing group Va onium salts

Abstract: Cationic polymerization of epoxy resin such as epoxy monomers or prepolymers, can be achieved by use of certain radiation sensitive aromatic onium salts of Group Va elements. Curable compositions are provided which can be used as sealants, coating compounds, encapsulants, etc.

Spin Pinning at Ferrite-Organic Interfaces

Abstract: Ultrafine particles of Ni${\mathrm{Fe}}_{2}$${\mathrm{O}}_{4}$ coated with organic molecules show a behavior consistent with extremely strong pinning of the ferrite surface spins. The low-temperature magnetization is only \ensuremath{\sim}75% saturated in fields of 200 kOe, and M\"ossbauer spectra show that the spins remain at large angles with respect to the direction of an applied field of 68.5 kOe. Uncoated ultrafine Ni${\mathrm{Fe}}_{2}$${\mathrm{O}}_{4}$ particles do not show this behavior.

Process for preparing a branched polycarbonate

Abstract: A process for preparing a thermoplastic randomly branched aromatic polycarbonate which process comprises reacting at least 20 weight percent of a stoichiometric quantity of a carbonate precursor with a mixture of a dihydric phenol and at least 0.05 mole percent of a polyfunctional aromatic compound in a medium of water and a solvent for the polycarbonate having present therein at least 1.2 mole percent of a polymerization catalyst, while concomitantly adding to the reaction medium sufficient alkali metal hydroxide to maintain a pH range of about 3.0 to about 6.0, and then adding sufficient alkali metal hydroxide to raise the pH to at least about 9.0 to less than about 12 while reacting the remaining carbonate precursor.

Magnetic separation of biological particles

Abstract: Small magnetic particles coated with an antibody layer are used to provide large and widely-distributed surface area for sorting out and separating select viruses, bacteria and other cells from multi-cell, bacteria or virus populations.

Results of subsynchronous resonance test at Mohave

Abstract: The results of the subsynchronous resonance test conducted on the number 2 turbine-generator at the Southern California Edison Company Mohave Generating Station are presented and discussed Comparisons are made between measured and calculated torsional natural frequencies and mode shapes, and the damping associated with each torsional mode stimulated is presented at various loads In addition, the methods of stimulating the mechanical torsionals of the turbine-generator set are discussed along with a description of the instrumention system that was used to obtain the data

Photocurable compositions containing group via aromatic onium salts

Abstract: Cationic polymerization of epoxy resin materials, such as epoxy monomers or prepolymers, can be achieved by use of certain radiation sensitive aromatic onium salts of Group VIa elements. Curable compositions are provided which can be used as sealants, coating compounds, encapsulants, etc.

Defects in irradiated silicon: EPR and electron-nuclear double resonance of interstitial boron

Abstract: An EPR spectrum, labeled Si-$G28$, is identified as arising from neutral interstitial boron in silicon. It is produced by 1.5-MeV electron irradiation at 20.4\ifmmode^\circ\else\textdegree\fi{}K, presumably when a substitutional boron atom traps a mobile interstitial silicon atom which is produced in the original damage event. Three possible models are discussed which are consistent with the EPR and electron-nuclear double-resonance results: (a) a bent Si-B-Si bonded interstitialcy; (b) a similar Si-Si-B interstitialcy; or (c) a Jahn-Teller distortion of the boron from the hexagonal interstitial site in the silicon lattice. Uniaxial stress in the presence of light at low temperatures produces alignment in one of the distortional degrees of freedom for the defect. This is interpreted as stress alteration of the capture matrix elements for electrons into the differently distorted configurations. Polarized light is also found to produce alignment in the absence of stress into a second degree of freedom for the defect. Thermally activated recovery from this alignment reveals an activation energy for reorientation of 0.6 eV. Interstitial boron is unstable at room temperature, disappearing in \ensuremath{\sim} 30 min with an activation energy also of \ensuremath{\sim} 0.6 eV. It is suggested that annealing may result from long-range migration of the interstitial boron with the one-jump diffusional process being identical to the 0.6-eV reorientational process. This is a natural consequence of models (a) or (c). The reorientation stimulated by light at 4.2\ifmmode^\circ\else\textdegree\fi{}K, therefore, indicates that athermal migration may be induced by the light. An attempt to test this using 1.06-\ensuremath{\mu}m YAIG:Nd laser illumination was inconclusive.

Magnetic annealing of amorphous alloys

Abstract: Amorphous alloys with nominal composition of Ni 40 Fe 40 P 14 B 6 are shown to respond to annealing in a magnetic field. Coercive forces are reduced by a factor of 10 to 50 during annealing of straight ribbons to values of 0.003 Oe, as low as ever reported for potentially useful materials. Concurrently the ratio of the magnetization in 1 Oe applied field, to saturation, increases from about 0.5 to 0.95. These changes during annealing correlate with measured stress relief changes. It thus appears that most of the strain-magnetostriction contribution to the anisotropy is removed during annealing. Magnetic annealing at temperatures as low as 100°C results in noticeable changes in properties. From measurements transverse to the magneticaliy induced anisotropy axis, the induced anisotropy is calculated to be about 800 ergs/cm3, considerably smaller than obtained in crystalline Ni 50 Fe 50 . This field-induced anisotropy is reversible in direction and magnitude by reheating the sample to its Curie temperature and then cooling in a field. Annealing of 1.5 cm diameter toroids, made from 50 μm thick tapes, increases the initial permeability by more than a factor of 10 and decreases losses by more than a factor of 10. Losses and permeabilities after heat treatment compare favorably to the Permalloys with similar saturation magnetizations.

Photopolymerizable composition containing group Va aromatic onium salts

Abstract: Cationic polymerization of a variety of organic materials such as vinyl monomers, prepolymers, cyclic ethers, cyclic esters, cyclic amines, cyclic sulfides and organosilicon cyclics can be achieved by the use of certain radiation sensitive aromatic onium salts of Group Va elements. In addition, polymerizable compositions are provided which can be used as coating compounds, molding resins, adhesives, etc.

Nonlinear Analysis of RC Shells of General Form

Abstract: A general finite element method of analysis is developed to analyze reinforced concrete shells of general form and slabs of arbitrary geometry under dead load and monotonically increasing live loads. The method can be used to trace the load-deformation response and crack propagation through the elastic, inelastic, and ultimate ranges. The nonlinear analysis includes cracking with a tension stiffening effect and the elastoplastic behavior of the concrete and steel reinforcement. The coupling between the membrane action and the bending action due to material asymmetry is also included. Validity of the method is studied by comparing analytical results with experimental data. It is found that the tension stiffening effect has a significant influence on the post-cracking response of underreinforced concrete structures. The importance of the failure criteria and flow rules is also studied.

Direct bonding of metals to ceramics and metals

Abstract: Disclosed is a method of bonding metals to substrates such as ceramics or metals. A bonding agent forms a eutectic alloy with the metal to provide bonding. Several methods of supplying the bonding agent to the system are disclosed. However, regardless of which method of introducing the bonding agent into the system is employed, the quantity of the bonding agent is carefully controlled so that the compound in the region of the bond is hypoeutectic. To form the bond, the metal and the substrate are placed adjacent each other and the bonding agent is introduced into the system. The system is then heated to a temperature between the eutectic temperature and the melting point of the metal for a preselected time. The system is then cooled to form a bond. The heating is carried out in an inert atmosphere or a vacuum.

Strength and Microstructure in Lithium Disilicate Glass-Ceramics

Abstract: The effect of heat treatment on the microstructure of Li2O-Al2O3·SiO2 glass-ceramics which contain crystals of either Li2SiO3, Li2Si2O5, or both was investigated quantitatively. Strength determinations for abraded rods were correlated with heat treatment on the basis of both size and distribution of crystals and the type and amount of crystal phases present. The presence of Li2Si2O5 crystals enhanced the strength, whereas the presence of Li2SiO3 crystals did not change the strength of the abraded parent glass. The interrelation between strength and microstructure is discussed.

Cationically polymerizable compositions containing group VIa onium salts

Abstract: Cationic polymerization of a variety of organic materials such as vinyl monomers, prepolymers, cyclic ethers, cyclic esters, cyclic sulfides and organosilicon cyclics can be achieved by the use of certain radiation sensitive aromatic onium salts of Group VIa elements. In addition, polymerizable compositions are provided which can be used as coating compounds, molding resins, adhesives, etc.

Diagnostic method and device employing protein-coated magnetic particles

Abstract: Small magnetic particles are used to provide large and widely-distributed surface area for separating a select protein from a solution to enable detection thereof when present in low concentrations. The particles are coated with a protein that will interact specifically with the select protein.

Loss of excitation protection for modern synchronous generators

Abstract: This paper presents the results of a study into the application and performance of the offset mho distance relay for the loss of excitation protection of synchronous generators. Included is information on the loss of excitation characteristics of modern generators, on relay performance during transient swings and low frequency disturbances and on generator protection.

Spread spectrum correlation receiver

Abstract: A spread spectrum communication system having a correlation receiver for decoding an information signal transmitted on a pseudo-noise (PN) carrier. The receiver synchronizes to the transmitted signal by performing a continuous sequence of correlations until a correlation output exceeding a predetermined threshold level is detected. Thereafter, the receiver performs a plurality of correlations during a sampling interval which is timed to occur at approximately the time when high subsequent correlation output signals are likely to appear. After enhancement through adaptive filter processing, the correlation outputs generated during each sampling interval are accumulated (integrated and the summed output present at the end of the sampling interval is representative of the transmitted data message (a binary bit). The adaptive filter develops and stores weighting values representing the expected signal strength of the correlation outputs and the actual correlation outputs are multiplied by the weighting values. Received signal energy representing atmospheric and specular multipath signal components are detected and channeled to the accumulator along with the main signal component. The accumulator thus realigns the multipath signals with the main signal, resulting in a significant increase in processing gain. An audio version of the system is also disclosed.

Gas turbine temperature sensor validation apparatus and method

Abstract: An arrangement for determining the validity of temperature sensor readings of a gas turbine hot gas stream which includes means for comparing each reading to predetermined bounds. The temperature sensors are arranged so that a temperature streak caused by a combustion system malfunction would affect more than one sensor. In some cases, when a suspect reading is identified, the readings from adjacent sensors are examined before the suspect reading is rejected.

Implantable electrochemical sensor

Abstract: This in vivo sensor assembly, consisting of a sensing electrode and an insertion catheter, is capable of calibration and recalibration in situ without blood sampling because the sensing electrode can be retracted into its insertion catheter where it can be contacted with calibrating solution furnished by a drip line in which the reference electrode also contacts the calibrating solution.

Vessel examination system

Abstract: A system for on-site, non-destructive examination of the seam welds or other portions of the walls of a vessel, for example, a nuclear reactor pressure vessel, including an instrument carrying, remotely controlled vehicle with magnetic adherence means which may be selectively propelled to any position on the walls of the vessel and including an ultrasonic signal system utilizing a triangulation technique for remotely indicating the position of the vehicle on the vessel.

Ground fault circuit breaker

Abstract: Ground fault circuit breaker structure characterized by an insulating integral housing having a pair of side-by-side compartments that are separated by a partition wall. A circuit breaker is located in one compartment and a ground fault detector is located in the other compartment and isolated from the circuit breaker. The ground fault detector comprises a differential transformer comprising a current monitoring core, a plurality of primary windings on the core, each being one of a line and a neutral conductor of an A.C. electrical distribution system, a secondary winding sensing current unbalance between the primary windings, means responsive to a predetermined sensing signal to open the line conductor; and the line conductor extending between the circuit breaker trip means and through aperture means in the partition wall and through the magnetic core and back through the aperture means to the load terminal. The means responsive to a predetermined sensing signal including a pivotally movable member extending through the aperture means and movable against the trip member to unlatch the trip member.

Curable compositions and process

Abstract: Self-bonding one-package room temperature vulcanizing silicone compositions, curable in the presence of moisture to rubbery materials, comprise (a) a silanol chain-stopped polydiorganopolysiloxane; (b) a fluid polysiloxane having a high degree of tri- and/or tetrafunctionality; (c) a silica filler; (d) a cross-linking silane evolving relatively low volatility carboxylic acid fragments on hydrolysis; and (e) a highly reactive tin-containing silanol condensation catalyst. Such compositions can be applied to a variety of difficulty bondable substrates. They are especially useful when subjected to hot oil environments, as in automobile engines. High temperature performance is markedly improved with the addition of an iron oxide thermal stabilizer. Gasketed constructions and methods for forming them are also disclosed.

Coated cemented carbide product

Abstract: A HIGH-STRENGTH, COATED CEMENTED CARBIDE PRODUCT COMPRISING A CEMENTED CARBIDE SUBSTRATE AND A FULLY DENSE ALPHA ALUMINUM OXIDE COATING ON THE SUBSTRATE. THE COATING HAS A THICKNESS OF FROM 1-20 MICRONS AND IS FIRMLY AND ADHERENTLY BONDED TO THE CEMENTED CARBIDE SUBSTRATE THROUGH A THIN INTERMEDIATE NONMETALLIC LAYER OF AN IRON GROUP METAL ALUMINATE. THE COATED PRODUCT COMBINES A WEAR RESISTANCE SUBSTANTIALLY AS HIGH AS ALUMINUM OXIDE CUTTING MATERIALS AND A TRANSVERSE RUPTURE STRENGTH OF AT LEAST 150,000 P.S.I. THE COATED PRODUCT IS PREPARED BY PASSING WATER VAPOR, HYDROGEN GAS AND AN ALUMINUM HALIDE OVER THE SUBSTRATE AT A TEMPERATURE OF FROM 900*-1250* C., THE RATIO OF WATER VAPOR TO HYDROGEN GAS BEING BETWEEN ABOUT 0.025 AND 2.0.

Photocurable compositions and methods

Abstract: Epoxy compositions are provided which can be cured with visible radiant energy based on the use of certain organic dyes in combination with diarylhalonium salts. Cationic polymerization of various olefinic and cyclic organic compounds and organosilicon cyclics also can be effected in a similar manner.