Thermal neutron irradiation of superconducting body compositions into which Li or B has been incorporated as a unit cell external or internal dopant introduces by the nuclear reaction of the dopant pinning centers which substantially improve the critical current density of the body.

The most distinctive property of a superconductive material is its absence of electrical resistance when it is at or below a critical temperature. This critical temperature (Tc) is an intrinsic property of the material.
Research into the ability of specific materials to superconduct began in 1911 with the discovery that mercury superconducts at a Tc of about 40xc2x0 K. Since then, many applications for superconducting materials have been conceived, but such applications could not be commercialized because of the extreme low Tc of the superconducting materials then available.
Although many materials have since been examined in an effort to find compositions which superconduct at higher temperaturesxe2x80x94temperatures at which the more economical and practical coolant of liquid nitrogen could be usedxe2x80x94until about 1986 the highest temperature superconductor known was Nb3Ge having a critical temperature, Tc, of approximately 23.2K. Before 1987, superconducting devices, even those which employed the Nb3Ge superconductor, required the use of liquid helium as the refrigerant-coolant.
In late 1986 Bednorz and Muller disclosed that certain mixed phase compositions of Laxe2x80x94Baxe2x80x94Cuxe2x80x94O appeared to exhibit superconductivity being at an onset temperature, Tco, of about 30K. Bednorz et al., Z. Phys. B., Condensed Matter, Vol. 64, pp. 189-198 (1986). Investigation of that Laxe2x80x94Baxe2x80x94Cuxe2x80x94O mixed phase system established that the crystalline phase therein responsible for superconductivity had a crystal structure like that of K2NiF4 (214). Since then it has been determined that whatever might be the rare earth metal or the alkaline earth metal constituent of a 214 system, the upper temperature limit of superconducting onset, Tco, of superconductors of a 214 type crystalline structure is no greater than about 38K. Liquid helium was still required as the coolant for such a 214 type of material.
Following the discovery of superconductivity in a rare earth-alkaline earth-Cu oxide system of a 214 crystalline structure, a new class of rare earth-alkaline earth-copper oxides was discovered which are superconductive at temperatures above the boiling point of liquid nitrogen, 77K. These new rare earth-alkaline earth-copper oxides are of the formula L1M2Cu3O7 wherein L is a rare earth metal and M is an alkaline earth metal. The L1M2Cu3O7 compositions are commonly referred to as xe2x80x9c123xe2x80x9d high-temperature superconductors in reference to the stoichiometry in which the rare earth, alkaline earth, and copper metal atoms are present, namely a ratio of 1:2:3. Subsequent to the discovery of the 123 high temperature superconductors, another form of high temperature superconductor was discovered having the formula T2Mxe2x80x22CanCun+1O6+2n wherein T is bismuth and Mxe2x80x2 is strontium or T is thallium and Mxe2x80x2 is barium, and xe2x80x9cnxe2x80x9d is 1, 2, or 3. Both types of xe2x80x9chigh temperature superconductingxe2x80x9d (HTS) compositions are ceramics materials.
The 123 high temperature superconducting compounds have a perovskite related crystalline structure. The unit cell of such 123 compounds consists of three sub-cells in alignment along the crystallographic C-axis wherein the center of the middle subcell is occupied by a rare earth metal atom, the center of each end subcell is occupied by an alkaline earth metal atom, and copper atoms occupy the corner positions in each subcell. X-ray and neutron powder diffraction studies indicate the structure of superconductive 123 compounds to be oxygen deficient and that the ordering of oxygen in the basal planes is critical to the existence of superconducting properties in such compounds. See C. Poole et al, Copper Oxide Superconductors (John Wiley and Sons 1988). The unit cell formula of a 123 compound is L1M2Cu3O6+xcex4(xcex4=0.1 to 1.0, preferably about 1.0) wherein the rare earth metal constituent, L, is yttrium, lanthanum, neodymium, samarium, europium, gadolinium, dysprosium, holmium, erbium, thulium, ytterbium, or lutetium, or mixtures thereof including mixtures with scandium, cerium, praseodymium, terbium and the alkaline earth constituent, M, is barium, strontium or mixtures thereof. Studies indicate that when xcex4 is between about 0.1 to about 0.6, the resulting 123 compound assumes a tetragonal unit cell crystallographic symmetry and is non-superconductive. In the tetragonal unit cell symmetry, the lattice dimension of the C-axis is approximately 11.94 angstroms and that of the A and B axis is approximately 3.9 angstroms. When xcex4 is between about 0.7 and 1.0, the resulting 123 compound has an orthorhombic unit cell crystallographic symmetry and is superconductive. The orientation of the oxygen atoms in the unit cell causes, the unit cell to compress slightly along the A crystallographic axis and thus the lattice dimension of the A axis is less than that of the B axis. Lattice constants in the orthorhombic symmetry are about A=3.82, B=3.89 and C=11.55 angstroms.
With the discovery of the new xe2x80x9chigh temperature superconductingxe2x80x9d (HTS) compoundsxe2x80x94HTS compounds are those which superconduct at a Tc above the temperature at which liquid N2 can be used as a refrigerantxe2x80x94it has become economically possible to pursue many previously conceived applications of the superconductivity phenomena which before were commercially difficult wherein cooling by liquid helium was required. Since they superconduct at temperatures greater than 77K, the new high temperature superconductors may in practical applications be cooled with liquid nitrogenxe2x80x94a more economically feasible refrigerant. The HTS compounds, both the 123 compositions and those containing bismuth or thallium, simplify and enhance the reliability of commercial applications of superconductors. Recent studies also show that the HTS compounds have better performance at 4K than the prior materials.
Nevertheless, the ceramic HTS compounds have been economically and technologically impractical for use in some applications due to the inability of bodies thereof (1) to carry high current loads (Jc(0)) (2) to carry high current loads in intense magnetic fields (Jc(H)) (3) and to entrap strong magnetic fields (Bt). As a result, significant commercial and technological barriers against use of the ceramic HTS compounds as a superconductor body in a variety of practical applications, such as in magnets, magnetic separators, transmission lines, trapped field magnets, levitation bearing and magnetically levitating trains (meglav), still exist.
In magnetic separators, for example, the body of a superconducting material is required, as a practical constraint, to have a critical current density (Jc) between about 103 to 105 amps/cm2 in a magnetic field between 0 to 10 T. To be practical for some magnet applications, bodies of a ceramic HTS compound must be capable of entrapping within its crystalline structure a high magnetic field. The critical current (Jc) which a body of a HTS compound is capable of carrying is strongly affected by the granular alignment and homogeneity of the polycrystals HTS compound comprising the body and by the distribution and force with which lattice defects within the HTS material can pin magnetic flux lines. Accordingly, one approach to improve the Jc of a ceramic HTS body has been directed to methods of processing the HTS composition into shaped bodies wherein the number and content of xe2x80x9cweak linksxe2x80x9d due to its granular ceramic nature is reduced. Another approach has examined techniques whereby strong flux pinning centers may be homogeneously introduced into the HTS composition of which a body article is composed.
The Jc and ability to entrap a magnetic field of a HTS compound body, particularly a 123 HTS compound, is dramatically influenced by several factors which introduces xe2x80x9cweak linksxe2x80x9d into the HTS material of the body. xe2x80x9cWeak linksxe2x80x9d exist in the forms of (1) grain boundaries; (2) micro-cracks; (3) impurity contentxe2x80x94i.e., the wt. % content of the body of nonsuperconducting phases (i.e., L2BaCuO5, BaCuO2, CuO, etc.); (4) the porosity of the body (i.e. body density); (5) chemical inhomogeneity; and (6) electrical anisotropy.
A xe2x80x9cweak linkxe2x80x9d is any non-superconducting defect which intervenes between the electrical communication from one part of an HTS body to an adjacent part of an HTS body. A 123 HTS compound crystallizes into xe2x80x9cgrainsxe2x80x9d which are comprised of individual unit cells of 123 compound which, with reference to each other unit cell of 123 compound in the grain, are in perfect alignmentxe2x80x94i.e., all xe2x80x9cABxe2x80x9d planes of each 123 unit cell are in perfect parallel alignment with each other 123 unit cell comprising that grain. Different xe2x80x9cgrainsxe2x80x9d of 123 may have their xe2x80x9cABxe2x80x9d plane out of perfect parallel alignment therebetween. The degree of such misalignment between the AB planes of adjacent grains of 123 may be very slight or very great. High angle grain boundariesxe2x80x94i.e., those wherein there is a high degree of misalignment of the intergranular xe2x80x9cABxe2x80x9d planes between adjacent grains is a xe2x80x9cweak linkxe2x80x9d (1).
The intervention of a non-superconducting composition between xe2x80x9cABxe2x80x9d planes of one grain of 123 to that of another grain is yet another form of xe2x80x9cweak link.xe2x80x9d Superconduction across the non-superconducting composition between the adjacent 123 grains can still occur, by the xe2x80x9cJosephson (or tunnelling) effect,xe2x80x9d in the absence of an externally applied magnetic field. However, such intervening insulator xe2x80x9cimpurity weak linkxe2x80x9dxe2x80x94depending upon its dimensionsxe2x80x94quickly become electrically resistive in the presence and in proportion to the extent of an externally applied magnetic field.
Such xe2x80x9cinsulatingxe2x80x9d weak links may be comprised of an xe2x80x9cinsulator impurity compositionxe2x80x9d which occupies the physical space between adjacent grains of 123 HTS or may be physical voids between such grains. When an insulator composition occupies such space, the xe2x80x9cweak linkxe2x80x9d is referred to as a xe2x80x9csecondaryxe2x80x9d or xe2x80x9cimpurityxe2x80x9d phase (3). When such weak link is a void of any material, it is referred to either as xe2x80x9cporosityxe2x80x9d (4) or as a xe2x80x9cmicrocrackxe2x80x9d (2), depending upon the nature of the processing circumstances by which such void in a body of the 123 HTS compound came into being.
Another form of xe2x80x9cweak linkxe2x80x9d may occur intragranularly wherein, although the AB planes of the 123 compound comprising such grain are perfectly parallel aligned, some portions of such AB planes are imperfectly oxygenated. That is, within a parallel alignment series of AB planes of individual unit cells comprising a 123 grain, some or a series of such aligned unit cells are comprised of a cell formula wherein the oxygen content is less than about 6.7 and hence such unit cells are of a nonsuperconducting tetragonal crystalline symmetry. Such xe2x80x9cweak linksxe2x80x9d are referred to as of the xe2x80x9clocal or global deficiency of oxygenxe2x80x9d kind (5).
The last form of weak link is associated with the different degrees of capability of a 123 grain to carry current in differt directions, e.g., easier along the AB-plane than perpendicular to the AB-plane. The misalignment of the AB-plane will force current to flow in part, no matter how small, within the 123 HTS body along the C-axis which will act as a weak-link to limit Jc. Each of the above weak link factors reduces the amount of current (I) which is able to flow from one end of a 123 HTS body to another end of the 123 HTS body before the body begins to exhibit an electrical resistance. One of the most significant weak link sources is high angle misaligned grain boundaries.
Weak links in the form of lack of densityxe2x80x94i.e., existence of porosity and/or the existence of micro-cracksxe2x80x94, impurities, or high angle misaligned grain boundaries in a body composed of 123 HTS compound, and the presence of oxygen deficiencies in the grain boundaries, each detract from the amount of current which that body of a 123 HTS compound is capable of carrying before it will exhibit electrical resistance to flow of that xe2x80x9ccriticalxe2x80x9d amount of currentxe2x80x94i.e., the critical current density, (Jc), of that body. A 123 HTS compound, whether produced by solid state reaction, coprecipitation or by a sol-gel technique has, as an intrinsic property, a Tc of xe2x89xa777K. However, the Jc of a body of a 123 HTS compound is highly dependent on the methodology used to produce the 123 HTS compound body. Accordingly, the process by which a body article of 123 HTS is formedxe2x80x94whether that body is in wire, ribbon, film, rod or plate formxe2x80x94dictates many of the practical uses to which that 123 HTS body form may be put, dependent upon the Jc of the body article.
Before the discovery of the 123 HTS compounds allowed use of liquid N2 as a more economical coolant, many possibilities of practical application of superconductivity were unattainable because of the high cost associated with; the use of liquid helium as the coolant required for superconducting materials previously known. Even though HTS compounds have overcome the refrigerant cost barrier which existed against various practical applications of superconductivity, various other practical applications to which a body of HTS compound may be put are, at this time, still limited by the difficulties associated with production of a HTS compound in a body form having a Jc or an ability to carry a large total amount of current (I) required for the practical practice for that particular application. For many applications, the body article must carry a large amount of total current (I). Total current carrying capacity of a body is governed by its cross-sectional dimension and the Jc of the HTS of which that body is composedxe2x80x94i.e., I=Jc(A/cm2)xc2x7cross-sectional dimensions (cm2).
A most serious obstacle to the use of high temperature superconductors (HTS""s) for large current applications is the limited total current carrying capacity of these HTS""s in bulk body forms. The limited Jc of the HTS compounds of which a body is composed seems to be consistent with the small pinning potential associated with the small coherent length of HTS materials. See, Y. Yeshurun et al., Phys. Rev. Lett. 60 2202-2205 (1988). However, experiments have shown that a Jc of up to 5xc3x97106 at A/cm2 exists in 123 HTS films at O T and 77K and 5xc3x97105 A/cm2 in intragrains at 0.9 T and 77 K when 123 HTS compounds are properly processed. See R. K. Singh, et al., Appl. Phys. Lett., 54 2271-2273 (1989) and R. B. van Dover, et al., Nature, 342 55-57 (1989).
To overcome some of the weak link problems in order to enhance Jc, one approach has been to use a melt-texturing technique to form bodies of a 123 HTS compound. See T. Aselage, et al., J. Mat. Res., Vol. 3, pp. 279-291 (1988) and, M. Murakami, et al., Jap. J. Appl. Phys., Vol. 28, pp. L399-L401 (1989). It is known that Y1Ba2Cu3O6+xcex4 undergoes the transition of (Y2O3+liquid)xe2x86x92(Y2BaCuO5+liquid)xe2x86x92(Y1Ba2Cu3O6+xcex4+liquid of BaCuO2 and CuO) as it cools from a single-phase liquid region to xcx9c900xc2x0 C. Near xcx9c1050xc2x0 C., Y1Ba2Cu3O6+xcex4 forms through a peritectic solidification according to Y2BaCuO5+liquid (3BaCuO2+2CuO)xe2x86x922Y1Ba2Cu3O6.5. The peritectic temperature for a L1Ba2Cu3O6+xcex4 compound is that temperature at which its constituents; namely, L2Ba1Cu1O5 (solid phase)+a liquid phase comprising 3BaCuO2 and 2CuO, react to form L1Ba2Cu3O6+xcex4. For a LiBa2CU3O6+xcex4 compound wherein L is Y, the peritectic temperature range has been reported to be about 1020-1050xc2x0 C, with peritectic solidification to produce Y1Ba2Cu3O6+xcex4 beginning at 1020xc2x120xc2x0 C. and continuing as the composition is cooled to about 950xc2x130xc2x0 C. See, for example, Terry Aselage and Keith Keefer J. Mater. Res., 3(16) November/December 1988, pp. 1279-1291.
It is also known that heating above the solidus temperature helps dissolve the impurity phases which are precipitated in the grain boundaries, and that crystal grains of 123 compound grow more easily in a liquid solution. Heretofore, all reported melt-textured methods to generate 123 HTS compound bodies of large Jc consist of rapid heating a body composed of a Y1Ba2Cu3O6+xcex4 compound above the solidus temperature (or even above the melting point) of the compound followed by slow cooling of the body through the xe2x80x9cperitectic temperaturexe2x80x9d of the compound. This has been achieved by a prescribed temperature schedule i.e., certain time (t) rates of temperature (T) variation (dT/dt). The temperature schedule has been shown to be critical to the morphology grains of the 123 compound obtained in the body article. For instance, both needle-like and platelet grain formations have been obtained in bodies composed of Y1Ba2Cu3O6+xcex4. See S. Jin, et al., Phys. Rev. B., 37, 7850-7853 (1988) and P. J. McGinn et al., Physica C, 156, 57-61 (1988).
In a melt-textured growth process for preparing bodies of Y1Ba2Cu3O6+xcex4 all portions of the entire body are simultaneously first elevated in temperature beyond the peritectic temperature of the compound to incongruently melt the 123 compound into Y2BaCuO5 and a liquid phase. Thereafter the body is allowed to cool, at a controlled rate (dT/dt), to a temperature below the solidus temperature wherein the Y2BaCuO5 and liquid phase react to reform the 123 compound which crystallizes. In the melt-textured growth process reported by Jin et al. in Appl. Phys. Lett., Vol. 52, pp. 2074-2076(1988) and Vol. 54, pp. 584-586 (1989) and Murakami et al. in Jpn. J. Appl. Phys., Vol. 28, pp. L1125-1127 (1989) the entire body of 123 compound is first heated above the solidus or peritectic temperature and thereafter the entire body is subjected to a thermal gradient to promote directional solidification of the 123 grains as the body is permitted to cool at a controlled rate to a temperature below the solidus temperature.
By use of a xe2x80x9cmelt textured growthxe2x80x9d process, a number of groups have reported making 123 compound bodies of enhanced Jc To date the highest reported Jc of a 123 body prepared by a melt textured growth technique is 1.7xc3x97104 A/cm2 by Jin et al., Phys. Rev. B. Vol. 37, pp. 7850-7853 (1988) and Appl. Phys. Lett., Vol. 42, pp. 2074-2076 (1988); later Salama et al. employed a liquid-phase processing method to obtain a Jcxcx9c7.5xc3x97104 A/cm2; both in bulk bodies of YBa2Cu3O7xe2x88x92xcex4 (Y123) at 0 T and 77 K after prolonged oxygen annealing. In each method of body treatment the enhanced Jc has been ascribed to the drastically improved grain alignment, phase purity, and densification in Y1Ba2Cu3O6+xcex4 compound of which the body is composed.
In a second approach for enhancing the Jc of a HTS compound body fast neutron irradiation of a body composed of sintered polycrystalline HTS and of single crystals of HTS has been examined for its effects upon the superconducting properties of such materials. A. Wisniewski, et al., Solid State Communications, Vol. 65 (1988) 577-580; H. Fxc3xcpfer et al., Z. Phys. B. 69 (1987) 167-171; Cost et al., Phys. Rev. B. 37 (1988) 1563-1568, report that fast neutron irridation of sintered polycrystalline bodies of Y1Ba2cu3O7 decreases the onset transition temperature of such bodies while increasing the Jc.
Fast neutron irradiation of single crystals of Y1Ba2Cu3O7 has been reported to increase Jc without significant adverse affect on Tc. See Umeqawa et al., Phys. Rev. B. 36 (1987) 7151-7154. Although it has been reported that nominally identical fast neutron irradiations have resulted in effects on critical current ranging from moderate enhancement to degradation, the suggestion has been made that fast neutron irradiation may enhance the Jc at 77K of a body article formed by the melt-textured growth of a HTS such as Y1Ba2Cu3O7. See Van Dover et al., Nature, Vol. 342 (1989) 55-57.
Other forms of neutron radiation of HTS bodies have also been studied. Hence, Hastings et al., J. Am. Ceram. Soc. 71 (1988) C505-506, reports that thermal neutron radiation of a sintered polycrystalline body of Y1Ba2Cu3O7 produced a loss of its 90K superconductive properties, although such 90K super-conducting properties could later be recovered by a post irradiation anneal of such body in flowing O2 at 760K. Fleicher et al., Phys. Rev. B, 40 (1989) 2163-2169, reports that thermal-neutron irradiation of a sintered polycrystalline body of Y1Ba2Cu3O7 doped with uranium enhanced the Jc of the body.
Further efforts to enhance the Jc of a HTS body have been reported by irradiation of such body with high energy protons, Van Dover et al., Information from High Tc Update. Vol. 4, No. 4, p.2, Feb. 15, 1990. But such technique is applicable only to thin films due to the small penetration depth of protons.
In many respects, the enhancement of the Jc of a body comprised of a HTS composition by irradiation with fast neutrons is undesirable since the source for fast neutrons is expensive and can impart to the body a higher than desirable degree of radioactivity. Likewise the use of uranium doped bodies of HTS composition which are irradiated with thermal neutrons to enhance Jc is undesirable because of the long-life radioactivity which would be imparted to such body by such technique.
It is desirable to develop a method by which the Jc of a bulk body composed of a HTS composition, particularly a body produced by melt texturizing, may be enhanced by creating a homogeneous distribution of strong flux pinning centers within such body without imparting thereto an undesirable level of radioactivity.
Enhancement of the Jc of bulk superconductors is a crucial and critical problem for high Tc superconductor applications. This invention comprises a new process to improve the Jc of bulk body articles composed of HTS compositions, particularly bodies composed of the L1M2Cu3O7 HTS compositions and the bismuth and thallium HTS compositions, by thermal neutron induced nuclear reaction in the superconductors doped by 6Li or 10B. The advantages of the process of this invention are simplicity, uniformity for bulk material processing, no long life-time radioactivity to be imparted to the superconductor body, and economy of the process.
A thermal neutron flux is a simple and relatively inexpensive particle source. Thermal neutron irradiation is a very uniform process in the bulk volume of a body composed of a HTS composition due to the very long penetration depth of thermal neutrons. The uniform irradiation of bodies composed of 6Li or 10B doped HTS compositions is an effective technique for modification of body articles thereof because of the large thermal neutron cross-section for 6Li (945 barns) and 10B (4010 barns). The thermal neutron induced reactions which the 6Li and 10B dopants within the body undergo are:                                                        6                              Li                +                  n                                xe2x80x83                    ⟶                                                                                3                                    H                                          xe2x80x83                                          (                          2.73                            MeV                        )                          +                                                           4                                    He                                          xe2x80x83                                          (                          2.05                            MeV                        )                                                                                10                              B                +                  n                                xe2x80x83                    ⟶                                                                                7                                    Li                    *                      (                          0.84                            MeV                        )                          +                                                           4                                    He                                          xe2x80x83                                          (                          1.47                            MeV                        )                                                  ⟶                                                                               7                                    Li                                          (                          1.01                            MeV                        )                          +                                                           4                                    He                                          xe2x80x83                                          (                          1.78                            MeV                        )
As a result of the long penetration depth of thermal neutrons into body articles composited of such superconductor compositions and the uniform doping of 6Li and 10B into these materials the distribution of the nuclear reaction and the flux pinning defects induced by the reaction products are very evenly distributed in the bulk materials of the HTS composition which comprise the body articles which are so treated.
The body article of HTS composition to which this process applies is one which contains 6Li or 10B in intimate and homogeneous admixture with the HTS composition. The dopant D, which is Li or B, may be incorporated into the HTS composition in either of two ways, as a unit cell external or as a unit cell internal dopant. In the former case the precursor composition comprises an intimate mixture of the L, M and Cu reagents in proportions which provide a ratio of L:N:Cu of 1:2:3 and this mixture further comprises a quantity of the Li or B reagent such that upon sintering an HTS composition of a L1M2Cu3O7 unit cell formula results. In this case, the Li or B content of the composition is dispersed at positions external to the L1M2Cu3O7 unit cells, such as at the grain boundaries between different grains of the 123 HTS composition which comprises the body article. In the unit cell internal method for incorporation of the dopant D, which is either Li or B, the L, M, Cu and D reagents are intimately mixed in proportions which provide for a ratio of metal atoms of the formula
(L+M)3-zDzCu3
wherein z is greater than zero and equal to or less than 0.3 and the atomic: ratio of L:M is from about 0.35 to about 0.6. When the precursor mixture is sintered or melt texturized to convert it into a HTS composition the product composition which results is of the formula
(L+M)3-zDzCu3O6+d
where d is 0.1 to 1.0, and the dopant atom D is incorporated into the 123 unit cell structure wherein it occupies either a L or a M atomic site. In the case of a Bi or Tl HTS composition, i.e., those of the formula T2Mxe2x80x22CanCun+1O6+2n, the dopant D may also be externally or internally incorporated. When internally incorporated the precursor reagents are mixed in proportions to provide a product composition, after sintering or melt texturizing, of the formula
T2Mxe2x80x22Can(Cu1-zxe2x80x2Dzxe2x80x2)n+1O6+2n
wherein zxe2x80x2 is greater than zero and equal to or less than 0.5.
The method of internal incorporation of the dopant D is preferred since this method is more adapted to the preparation of high quality HTS body articles by melt texturizing, i.e. greater grain alignment with less intergranular impurity weak link content. A dopant most preferred is Li, particularly preferred is a lithium which is enriched in 6Li. The 6Li or 10B containing HTS 123 composition may be prepared in a body article form by sintering or melt texturizing of preshaped bodies of intimately mixed L2O3, MCO3 and CuO powders to which has been added and mixed Li2Co3 or B2O3 to the level of 6Li or 10B desired. As a preferred alternative to simple sintering, the body article is treated by a melt texturizing process to produce a high degree of grain alignment in the body. Bismuth and thallium HTS bodies are prepared in like manner.
The irradiation of such 6Li or 10B doped bodies of HTS composition by thermal neutrons causes the 6Li or 10B content thereof to undergo an induced nuclear reaction. The energetic light particles from the nuclear reaction produce radiation damage and defects with the HTS composition of the body which uniformly introduces strong flux pinning centers within the bulk volume of the body, thereby substantially enhancing the Jc of the body compared to its unirradiated state. For highest attainable Jc it is preferred to practice this invention with 6Li or 10B internally doped articles that are prepared by a melt texturizing technique.
The invention comprises 6Li or 10B doped HTS compound, preferably a 123 HTS compound, having a predetermined body shape which, after irradiation with thermal neutrons, has a current density, Jc, of from about 103 to about 105 amps/cm2 or greater at zero magnetic field and a temperature of at least 77K.
The preferred 123 HTS composition to which the process of this invention is applicable is internally doped with Li to prepare preshaped 123 HTS compound body articles is (L+Ba)3-zLizCu3O7, most preferably wherein L is yttrium. The preferred T2Mxe2x80x22CanCun+1O6+2n HTS composition is one wherein T is bismuth and Mxe2x80x2 is strontium and the HTS body is internally doped with Li to provide a formula of Bi2Sr2Can(Cu1-zxe2x80x2Lizxe2x80x2)n+1O6+2n. The preferred dopant is one of lithium, most preferred is a lithium which is enriched in the 6Li isotope.

Method for producing formed bodies of high temperature superconductors having high critical currents


The invention provides a data recording/reproducing apparatus for recording and reproducing data on and from a disklike recording medium while rotating the disklike recording medium by a spindle motor having ball bearings. In this apparatus, the ratio of the number of revolutions (the frequency of a minimum-frequency vibration component of a non-repeatable vibration) of each ball in the ball bearings, to the number of rotations (the rotational frequency) of the spindle motor is substantially set to 1/n, and servo track writing is performed in synchronism with every n rotations of the spindle motor.

1. Field of the Invention
This invention relates to a data recording/reproducing apparatus using a disklike recording medium such as a magnetic disk, and more particularly to a data recording/reproducing apparatus capable of performing high density recording by effectively reducing the interference between tracks due to the non-repeatable vibration of a spindle motor employed therein.
2. Description of the Related Art
Magnetic disk apparatuses, and in particular hard disk apparatuses are sold with tracks formed on their disks as a result of magnetically recording servo information thereon. To form such tracks in each apparatus as a semi-finished product, a magnetic head installed therein is moved over a magnetic disk mounted on a spindle motor, and is positioned on a certain point on the disk, thereby recording head-positioning information called "servo information" in the form of tracks. The process for recording servo information on a magnetic disk will be referred to as "servo track writing".
In such a servo track write method for forming tracks on a magnetic disk, as the density of tracks is increased so as to increase the recording capacity, adjacent tracks will interfere with each other, i.e. intersect with each other because of vibration of the spindle motor called "non-repeatable vibration". The "non-repeatable vibration" is mainly caused by the movement of balls contained in the ball bearing of the spindle motor, which is called "rolling element vibration". It is known that a minimum frequency component contained in the "rolling element vibration" is due to revolution of balls. For example, it corresponds to a vibration component with a low frequency of about 30 Hz! and a very large amplitude indicated by the arrow in FIG. 4. This vibration component will occur because of unevenness in size between the balls and often has the largest amplitude among all frequency components of the non-repeatable vibration, as is shown in FIG. 4. The vibration component may well cause the aforementioned interference between adjacent tracks at the time of servo track writing, and hence be a serious obstacle in increasing the density of tracks.

Data recording/reproducing apparatus having track interference reduction mechanism


The machine tool comprises a machine stand (10) with a vertically movable vertical carrier (12) carrying a spindle head (SK1) for treatment of a workpiece. To exchange the spindle head (SK1) against a new spindle head (SK2), an exchange unit (15) is provided, comprising an exchange arm (16) pivotable by 90.degree. about a vertical axis (37). Two holding couplings (17,18) are mounted above each other on the exchange arm (16), each adapted to carry a spindle head (SK1,SK2). A delivery means (21), gripping the spindle heads from above, is used to supply the spindle heads for transfer to the exchange unit (15). The exchange unit (15) grips the spindle heads from the side. By pivoting the exchange arm (16) over 90.degree., the spindle head is pivoted to a position in front of the machine stand (10) and thus can be taken over by the vertical carrier (12).

The present invention relates to a machine tool of the type comprising a machine stand and a changeover device for the exchanging of spindle heads fastened to a vertical carrier of the machine stand to perform treatment of a workpiece.
From DE 39 18 902 A1, a machine tool is known wherein the spindle head fastened to a vertical carrier can be exchanged. For this purpose, a changeover device is mounted to the machine stand, comprising two exchange arms pivotable by respectively 180.degree.. Each exchange arm can grip the upper end of a spindle head delivered from a magazine and, through a pivoting movement of 180.degree., position the spindle head adjacent the vertical carrier, so that the spindle head can be transferred to the vertical carrier to be locked thereon. The spindle head suspended on the exchange arm can be turned by 90.degree. relative to the exchange arm in such a manner that the tools projecting from the exchange arm, which in their operating position are oriented in the forward direction from to the machine stand, upon transfer to the spindle head magazine will project from the machine stand in a lateral direction. To allow a quick exchange of the spindle heads, two exchange arms are required, one exchange arm removing the spindle head from the vertical carrier while the other exchange arm supplies a new spindle head to the vertical carrier. Such an arrangement requires a high technical expenditure for the exchange arms. The spindle head magazine must extend to both sides of the machine stand and necessitates a complex transport mechanism.
Further, in a machine tool known from EP 0 204 151 B1, the spindle heads are suspended on a head exchange unit arranged on the machine stand for rotation about a vertical axis. The spindle heads are seized from above and pivoted to a position above the moving path of the vertical carrier which then will take over the spindle heads. This construction makes it necessary to provide a head exchange unit with a large turning radius on the machine stand, and the outwardly projecting spindle heads and tools require considerable space.
In a machine tool known from DE 92 02 245 U1, the machine stand is arranged next to a transfer station. The machine stand supports a vertical carrier which is movable in a vertical direction and is provided with an exchange arm pivotable about a horizontal axis. On the transfer station, two transfer sites are arranged above each other, each of them adapted to receive one spindle head. The exchange arm is laterally pivoted towards one of the two spindle heads and then pulls the spindle head horizontally to the vertical carrier. For exchange of the spindle heads, not only a vertical movement of the vertical carrier but also several reciprocating movements of the exchange arm must be performed. Additionally, it is required that the spindle heads at the transfer station and on the vertical carrier be guided in vertical guide bars, while a wide gap must be bridged for transfer of the spindle heads.

Honsberg Lamb Sonderwerkzeugmaschinen GmbH


An illumination optical system includes: a light source that generates excitation light; a fluorescent body that generates fluorescent light by irradiation with the excitation light and that is disposed in a region wider than the irradiation spot of the excitation light; a plate in which the fluorescent body is disposed; and a driving mechanism that moves the plate so that the irradiation spot of the excitation light can intermittently move over the fluorescent body.

There have been offered various illumination optical systems used in projectors such as a LED (Liquid Crystal Display) projector and a DLP (Digital Light Processing) projector.
JP 2010-86815A (hereinafter, Patent Literature 1) discloses an illumination optical system that irradiates a fluorescent body with excitation light emitted from a laser light source to acquire illumination light from the fluorescent body. In the illumination optical system disclosed in Patent Literature 1, the irradiation spot of the excitation light is periodically moved over the fluorescent body by rotating or moving a substrate on which the fluorescent body is disposed. This may prevent the reduction of light emission efficiency caused by a temperature increase.

Illumination optical system and projector using the same


A differential case assembly includes a differential case and an integral end cap and ring gear assembly. The differential case has an open end and a side wall with an exterior surface. The integral end cap and ring gear assembly is disposed over the open end of the differential case and adjacent the exterior surface. A first interior portion of the integral end cap and ring gear assembly abuts the exterior surface of the differential case to define a weld joint interface. The integral end cap and ring gear assembly is configured to permit a welding operation at the weld joint interface.

A differential is a device, usually employing gears, that is capable of transmitting torque and permitting rotation of different shafts at different speeds. Known differentials have cases that are cast from metals such as iron, and are often heavy and volumetrically undesirable. Assembly of known differentials can be difficult, oftentimes requiring bolting as well as welding. The use of "feed-in and rotate processes" when cast iron differential cases are manufactured is also known. Welding of the differentials formed from cast iron, in particular, can undesirably require the use of filler wire to provide an acceptable weld.
A particular differential case assembly is described in Assignee's co-pending U.S. Patent Application Publication No. 20110263374 to Cripsey, filed on Apr. 26, 2011, the entire disclosure of which is hereby incorporated herein by reference. The differential case assembly includes a differential case having an open end and a side wall with an interior surface, A plurality of major internal splines is formed on the interior surface of the side wall. The differential case assembly further includes a gear assembly. The gear assembly has a retainer insert and a cross pin. The retainer insert is disposed adjacent the interior surface of the side wall between a pair of the major internal splines. The retainer insert has a hole formed therein. The cross pin has an end mounted in the hole of the retainer insert. The cross pin aligns the gear assembly within the differential case.
There is a continuing need for a differential case assembly that is lighter compared to known cast iron designs, minimizes a required packaging space, minimizes assembly complexity, and can be employed with different numbers of gears. A differential case assembly that facilitates welding and eliminates a need for multiple nuts/bolts in the assembly process is also desired.


A method, information processing system, and computer readable medium for modifying at least one data warehouse schema based on detected changes in an associated observation model are disclosed. The method includes determining if at least one new observation model has been created. The method also includes determining if at least one existing observation model is associated with the new observation model. In response to the existing observation model being associated with the new observation model, at least one changed attribute is identified by comparing the new observation model and the existing observation model. A set of files associated with the existing observation model is updated to reflect the changed attribute between the new observation model and the existing observation model.

Businesses are getting more event-driven and adaptive in nature. They are exposed to large amounts of data every day. For Sense and Respond and Business Process Monitoring (BPM), this data needs to be transformed and stored in a database for analysis purposes. Once stored, for example, in a data warehouse businesses use the stored data for analyzing business activities and performing decision making tasks. Traditional data warehouse schemas are designed, in general, independent from the business process and source data. Another type of data warehousing is adaptive data warehousing, as is described in the co-pending U.S. patent application Ser. No. 10/994,232 filed Nov. 23, 2004, entitled "Adaptive Data Warehouse Meta Model", which is commonly owned by International Business Machines and is hereby incorporated by reference in its entirety.
Businesses typically use a business operations models ("BOM") and observation models ("OM") when modeling particular aspects of the business. BOMs generally comprise several packages that include constructs to model a particular aspect of business operations (e.g. processes, resources, information structure, and the like). An OM covers business performance management, which comprises business performance monitoring (observation) and control. OMs are typically constructed top-down starting from the business metrics or key performance indicators ("KPI") that are to be observed. OMs can also be constructed from business situations that are to be monitored and the metrics needed for defining the business situations.
Monitoring contexts for processing specific events can be designed using OMs. For each relevant incoming event, a monitoring context will typically compute one or more metrics. These metrics are stored in a data warehouse for subsequent analysis. In the context of the data warehouse, some of these metrics are treated as dimensions (e.g. Customer, Time, Location, and the like) and the others as measures (e.g. Revenue, Cost, Profit, and the like). As part of the model-driven approach to design, a database schema of the data warehouse is generated from the OM.
One problem with current data warehouse models is in the way updated OMs are handled. For example, when a new version of an exiting OM is created, the associated data warehouse schema is re-generated. This requires the migration of the already collected data to the new data warehouse schema associated with the new OM. The migration of data causes unnecessary downtime of the data warehouse and disruption of existing data.
Therefore a need exists to overcome the problems with the prior art as discussed above.

Updating a data warehouse schema based on changes in an observation model

International Business Machines Corporation


A silicone rubber-based hardening composition includes a linear organopolysiloxane having a vinyl group (A), an organohydrogen polysiloxane (B), and a silica filler (C) of which surface is treated with a silane coupling agent having a trimethylsilyl group. The linear organopolysiloxane having a vinyl group (A) includes a first linear organopolysiloxane having a vinyl group (A1), and a second linear organopolysiloxane having a vinyl group (A2).

Since silicone rubber is excellent in heat resistance, flame resistance, chemical stability, weather resistance, radiation resistance, electrical properties, and the like, it has been used for a variety of uses in a wide range of areas. In particular, since silicone rubber is physiologically inactive and reacts little with body tissues when the silicone rubber is in touch with a living body, it has been used as a material for medical instruments such as medical catheters.
The medical catheter is a tube which is inserted into a body cavity such as a thoracic cavity and an abdominal cavity, a lumen such as an alimentary canal and a ureter, and a blood vessel, and used to discharge a body fluid, or injecting or dripping a drug solution, nutrition, or a contrast medium. The medical catheter is required to have scratch resistance (tear resistance), kink resistance (tensile strength), transparency, flexibility (tensile elongation properties), and the like, in addition to biocompatibility. Specifically, the medical catheter is used as a drainage tube of an aspirator for removing an effluent such as blood, and pus after a surgery operation, and a tube for intaking nutrient after a surgical operation such as percutaneous endoscopic gastrostomy (PEG). In addition, in order to make silicone rubber for an extremely fine tube as a catheter, the silicone rubber composition, which is a raw material of the silicone rubber, is required to have extrusion molding properties.
As a material for medical catheters, soft polyvinyl chloride is also widely used in addition to silicone rubber. Compared with polyvinyl chloride, silicone rubber is excellent in biocompatibility and flexibility, but required to have improved strength such as tear resistance, and tensile strength, in particular, tear resistance. When the tear resistance is insufficient, the catheter may be torn by the damage made by a needle or a blade used during a surgical operation. When the tensile strength is insufficient, the catheter may be bent and closed (kinked), and thereby, a flow of a body fluid which should be discharged or a drug solution which should be injected may be stagnated.
Therefore, in order to improve the tear strength and tensile strength of silicone rubber, various methods have been suggested (for example, Patent Documents Nos. 1 to 8).
For example, Patent Document No. 1 discloses a hardening silicone rubber composition which contains mainly organopolysiloxane having high viscosity and containing a small amount of a vinyl group (crude rubber (A)), and is added with organopolysiloxane having low viscosity and containing a large amount of a vinyl group (silicone oil (B)), an organopolysiloxane copolymer containing a vinyl group (silicone resin containing a vinyl group (C)), organo-hydrogen siloxane (crosslinking agent (D)), platinum or a platinum compound (hardening catalyst (E)), and fine powdered silica (filler (F)).

Silicone rubber-based hardening resin composition, molded article, and medical tube


The present invention relates to polymerizable compositions comprising at least one monomer and at least one modified metal oxide comprising the reaction product of a metal oxide and at least one coupling agent. In addition, polymer compositions comprising a polymer and the modified metal oxide are also disclosed. Finally, methods for preparing the polymerizable compositions and polymer compositions are described as are optical devices comprising the polymer compositions.

1. Field of the Invention
The present invention relates to polymerizable compositions comprising at least one monomer and at least one modified metal oxide as well as to polymer compositions prepared from these polymerizable compositions and methods of preparing them.
2. Description of the Related Art
Polymer compositions have been used to replace glass compositions in a variety of different applications, including optical devices such as lenses. The specific requirements of the application determine the type of polymer chosen. For example, in some applications, it may be desirable to provide a polymer composition having improved physical properties, such as mechanical strength, heat resistance, or toughness. In addition, processiblity, moldability, and cost may also need to be considered.
For optical devices, improved optical properties such as refractive index, transparency or clarity, and optical uniformity may also be important, and polymer compositions have these improved properties have been prepared. For example, U.S. Pat. No. 4,990,653 describes the preparation of a sulfur-containing oligomer composition which can be polymerized to form a cured product having a refractive index of 1.60 or higher along with excellent transparency and optical uniformity. In addition, U.S. Pat. No. 5,683,628 describes a photochromic resin composition comprising a specific class of di(meth)acrylate compounds which are described as having excellent heat resistance, mechanical strength, adhesion properties, moldability, and light resistance. These can be used, for example, as an antireflection film on a lens. The refractive index of the composition can be controlled by varying the amount of specific di(metha)acrylate compound and can be 1.54 or higher. However, with the ever-increasing demands for improved optical performance, along with the need for improved physical properties, processability and reduced cost, the use of these types of tailored polymers is limited.
Several types of metal oxides are known to have high refractive indexes. For example, in general, titanium dioxide (titania), zirconium oxide (zirconia), cerium oxide (ceria), zinc oxide, and barium titanate have a refractive index that is greater than or equal to about 1.7. However, metal oxides may be difficult to disperse well in a polymeric system, and poor dispersions typically have poor optical properties. In order to provide improved dispersibility in various matrices, including solvents and polymer systems, modified metal oxides have been prepared, and the type of modification used depends on the specific system. For example, silane coupling agents having functionality capable of reacting with silica and with a rubber matrix have been used to prepare modified silica particles for use in tire applications. Modifications to other metal oxides, including those with high refractive indexes, are also known. However, the modification made to the metal oxide would be expected to greatly decrease the material's refractive index, thereby reducing the effectiveness of the modified metal oxide for an optical application.
Thus, there is a need in the industry to provide polymer compositions for optical devices which have good overall performance, including mechanical properties and processability, along with improved optical properties, especially high refractive index.

Compositions comprising modified metal oxides


The lock bolt has a bolt tip (2) a bolt head (3) whose back wall (4) is intended to rest against a housing pin for sliding this pin into the rotary closure cylinder (24). The bolt tip (2) is supported on the bolt head (3) with a spring engaged between the bolt tip (2) and the bolt head (3) so that it can slide in a limited fashion between an inner and an outer position. The bolt head (3) has a longitudinal bore (5) in which the bolt tip (2) is supported so that it can slide. The lock bolt to a large extent prevents unlocking attempts in which vibrational movements are exerted on the tumblers.

1. Technical Field of the Invention
The invention relates to a lock bolt for a rotary closure cylinder of a safety lock, having a bolt tip and a bolt head whose back end is intended to rest against a housing pin when slid radially outward for sliding the housing pin into the rotating closure cylinder.
2. Prior Art
Lock bolts of this kind have been known for a long time. They are also called core pins and in a rotary closure cylinder, form the part of the tumblers that is supported in a radial stepped bore of the rotor. Lock bolts of this kind have been disclosed for example in the applicant's WO 87/05654. These each have a sleeve-shaped slider element that makes it difficult to immobilize the lock bolt when attempting to damage it. The security of rotary closure cylinders is also impaired by so-called "electropicks". With these, a tool is used to spin the rotor around its rotational axis with a particular torque and at the same time, the tumblers are moved radially outward by means of vibration until all of the housing pins are disposed behind the shoulder formed by the rotation of the rotor. The rotor can then be released for rotation. Unauthorized unlocking attempts of this kind impair the unlocking security of rotary closure cylinders. Unlocking security is understood by one skilled in the art to mean the degree of difficulty involved in circumventing the tumblers of a rotary closure cylinder using devices, without force, without knowledge about the affiliated key, and without destroying the lock.


Described is an inflatable implant suitable for placement in the human body and left there for an indeterminate and potentially lengthy period of time. The implant includes at least one bladder wall. The bladder wall will define at least one fillable volume and may form more than one independent fillable volumes. The wall and filler material may be selected to deliver treatment materials to the locale of the implant site or to remove amounts of harmful materials from such a region. The implant may, with an appropriate filler material or bladder wall material, be used in cooperation with an appropriate radio frequency (RF) source to cause the increase of a localized internal temperature and a resulting tissue change such as coagulation, ablation, or the like. Methods of using the implant are also described.

Described is an inflatable, expandable implant suitable for implantation in a human body. In general, it is a device that may be implanted in the body at a placement site in a lower profile form and expanded after placement. The implant may be used, for instance, to occlude or to support some region of the body.
The described implant may have a bladder with a substantially non-elastic bladder wall that defines a volume, and at least one bladder wall opening for introduction of filler material. In some examples of the implant, the bladder will have no passageway exterior to the bladder wall for passage of a body fluid from an end of the bladder to the other end. The bladder may have at least one closure for each of the at least one bladder wall openings. The closures operate to maintain the filler material within the bladder after its introduction. If the filler material is selected to be of the type that reacts in the bladder to form a non-flowing mass, a closure may not be necessary.
The use of occluding materials or implants over the past few years to occlude various areas in the body has expanded. For instance, in treating many vascular problems, the artificial blocking of blood flow, known generically as "embolization," is used. The embolization of a blood vessel in an organ may be used to treat a variety of maladies; typically, though, embolization is used: 1) to control the bleeding caused by trauma, 2) to prevent profuse blood loss during an operation requiring dissection of blood vessels, 3) to obliterate a portion of or a whole organ having a tumor, or 4) to block the blood flow into abnormal blood vessel structures such as arterio-venous malformations (AVM's) and aneurysms. For such treatments, a variety of mechanical and chemical occludants are available. Such occluding materials include platinum and stainless steel microcoils. Platinum microcoils sold as Guglielmi Detachable Coils (GDC) by Boston Scientific Corporation are effective in many instances. However, significant skill is required to choose a coil size proper for the malady prior to delivery. Many anatomical sites are not suitable for use of microcoils, and removal is difficult.
Other occludants include polyvinyl alcohol sponges (Ivalone) and cyanoacrylate glues (n-butyl and iso-butyl cyanoacrylates). Of these, the cyanoacrylate glues have an advantage over other embolic materials in ease of delivery in that they are the only liquid embolics currently available to physicians. However, the constituent cyanoacrylate polymers have the disadvantage of being biodegradable. The degradation product, formaldehyde, is highly toxic to the neighboring tissues. See Vinters et al, "The Histotoxocity of Cyanoacrylate: a Selective Review", Neuroradiology 1985; 27:279-291. Another disadvantage of cyanoacrylate materials is that the polymer will adhere both to the blood vessel and to the tip of the catheter. Thus physicians must retract the catheter immediately after injection of the cyanoacrylate embolic material or risk adhesion of the cyanoacrylate and the catheter to the vessel. Removal and choice of occludant size are major problems.
Another class of liquid embolic materials, precipitative materials, was invented in late 1980's. See Sugawara et al, "Experimental investigations concerning a new liquid embolization method: Combined administration of ethanol-estrogen and polyvinyl acetate", Neuro Med Chir (Tokyo) 1993; 33:71-76; Taki et al, "A new liquid material for embolization of arterio-venous malformations", AJNR 1990:11:163-168; Mandai et al, "Direct Thrombosis of aneurysms with cellulose acetate polymer. Part I: Results of thrombosis in experimental aneurysms." J. Neurosurgery 1992; 77:497-500. These materials employ a different mechanism in forming synthetic emboli than do the cyanoacrylate glues. Cyanoacrylate glues are monomeric and rapidly polymerize upon contact with blood. Precipitative materials, on the other hand, are pre-polymerized chains that precipitate into an aggregate upon contact with blood.
In the precipitation method, the polymer is dissolved in a solvent that is miscible with blood, and upon contact with that blood, the solvent is diluted and the water-insoluble polymer precipitates. Ideally, the precipitate forms a solid mass and thus occludes the vessel.
The first such precipitative material used in this way was polyvinyl acetate (PVAc). Also, poly(ethylene-co-vinyl alcohol) (EVAL) and cellulose acetate (CA) dissolved in 100% dimethyl sulfoxide (DMSO) have also been used in clinical procedures. See Taki et al, "A new liquid material for embolization of arteriovenous malformations", AJNR 1990; 11:163-168 and Mandai et al, "Direct thrombosis of aneurysms with cellulose polymer: Part I: Results of thrombosis in experimental aneurysms", J. Neurosurgery 1992; 77:497-500. Partially hydrolyzed polyvinyl acetate in, e.g., ethanol, is also an available member of this class.
Each of these precipitative materials shares potential use problems in that: (1) they introduce organic solvents into the body, materials that can damage microcapillary vessels and surrounding tissues and are also known to cause vasospasm of blood vessels, and (2) placement of a precipitating polymer and estimation of the resulting precipitated mass is, at best, an inexact science.
The filled bladder implant described herein does not share any of these problems when used as an occluding device, may placed with better precision, and (when designed to do so) may be removed from the implantation site.

This patent is subject to a terminal disclaimer.


A system includes a system time counter associated with a micro controller and a secure clock module having a real time clock and an elapsed time counter. The system synchronizes operation between the secure clock module and the system time counter. The synchronized time entered into the system time counter is utilized in the operation of the system. The real time clock time can be caused to be entered into the elapsed time counter at certain point in the operation of the system. The relationship of the time provide enhanced systems security.

Electronic postage metering systems have been developed which include both a single printing arrangement associated with a single accounting arrangement. These printing and accounting systems have been usually housed in a single secure housing to provide for protection against tampering to provide for security. Other types of electronic postage metering systems have involved the utilization of portable detachably connectable accounting systems such as smart cards and other portable type devices.
These postage meter systems involve both prepayment of postal charges by the mailer (prior to postage value imprinting) and post payment of postal charges by the mailer (subsequent to postage value imprinting). Prepayment meters employ descending registers for securely storing value within the meter prior to printing, while post payment (current account) meters employ ascending registers to account for value imprinted. Postal charges or other terms referring to postal or postage meter or meter system as used herein should be understood to mean charges, meters or systems, for either postal charges, tax charges, private carrier charges, tax service or private carrier service, as the case may be, and other value metering systems, such as certificate metering systems such as is disclosed in U.S. Pat. No. 5,796,841 for SECURE USER CERTIFICATION FOR ELECTRONIC COMMERCE EMPLOYING VALUE METERING SYSTEM, issued Aug. 18, 1998.
Postage metering systems have also been developed which employ encrypted information on a mailpiece. The postage value for a mailpiece may be encrypted together with the other data to generate a digital token. A digital token is encrypted information that authenticates the information imprinted on a mailpiece such as postage value. Examples of postage metering systems which generate and employ digital tokens are described in U.S. Pat. No. 4,757,537 for SYSTEM FOR DETECTING UNACCOUNTED FOR PRINTING IN A VALUE PRINTING SYSTEM, issued Jul. 12, 1988; U.S. Pat. No. 4,831,555 for SECURE POSTAGE APPLYING SYSTEM, issued May 15, 1989; U.S. Pat. No. 4,775,246 for SYSTEM FOR DETECTING UNACCOUNTED FOR PRINTING IN A VALUE PRINTING SYSTEM, issued Oct. 4, 1988; U.S. Pat. No. 4.725,718 for POSTAGE AND MAILING INFORMATION APPLYING SYSTEMS, issued Feb. 16, 1988. These systems, which may utilize a device termed a Postage Evidencing Device (PED) or Postal Security Device (PSD), employ an encryption algorithm which is utilized to encrypt selected information to generate the digital token. The encryption of the information provides security to prevent altering of the printed information in a manner such that any change in a postal revenue block is detectable by appropriate verification procedures.
Encryption systems have also been proposed where accounting for postage payment occurs at a time subsequent to the printing of the postage. Systems of this type are disclosed in U.S. Pat. No. 4,796,193 for POSTAGE PAYMENT SYSTEM FOR ACCOUNTING FOR POSTAGE PAYMENT OCCURS AT A TIME SUBSEQUENT TO THE PRINTING OF THE POSTAGE AND EMPLOYING A VISUAL MARKING IMPRINTED ON THE MAILPIECE TO SHOW THAT ACCOUNTING HAS OCCURRED, issued Jan. 3, 1989; U.S. Pat. No. 5,293,319 for POSTAGE METERING SYSTEM, issued Mar. 8, 1994; and, U.S. Pat. No. 5,375,172, for POSTAGE PAYMENT SYSTEM EMPLOYING ENCRYPTION TECHNIQUES AND ACCOUNTING FOR POSTAGE PAYMENT AT A TIME SUBSEQUENT TO THE PRINTING OF THE POSTAGE, issued Dec. 20, 1994.
Other postage payment systems have been developed not employing encryption. Such a system is described in U.S. Pat. No. 5,319,562 for SYSTEM AND METHOD FOR PURCHASE AND APPLICATION OF POSTAGE USING PERSONAL COMPUTER, issued Feb. 21, 1995. This patent describes a system where end-user computers each include a modem for communicating with a computer and a postal authority. The system is operated under control of a postage meter program which causes communications with the postal authority to purchase postage and updates the contents of the secure non-volatile memory. The postage printing program assigns a unique serial number to every printed envelope and label, where the unique serial number includes a meter identifier unique to that end user. The postage printing program of the user directly controls the printer so as to prevent end users from printing more that one copy of any envelope or label with the same serial number. The patent suggests that by capturing and storing the serial numbers on all mailpieces, and then periodically processing the information, the postal service can detect fraudulent duplication of envelopes or labels. In this system, funds are accounted for by and at the mailer site. The mailer creates and issues the unique serial number which is not submitted to the postal service prior to mail entering the postal service mail processing stream. Moreover, no assistance is provided to enhance the deliverability of the mail beyond current existing systems.
Recently, the United States Postal Service has published proposed draft specifications for future postage payment systems, including the Information Based Indicium Program (IBIP) Indicium Specification dated Jun. 13, 1996; the Information Based Indicia Program Postal Security Device Specification dated Jun. 13, 1996; and, the Host Specification dated Oct. 9, 1996. These are Specifications disclosing various postage payment techniques including various types secure accounting systems that may be employed, as for example, a single chip module, multi chip module, and multi chip stand alone module (See for example, Table 4.6-1 PSD Physical Security Requirements, Page 4-4 of the Information Based Indicia Program Postal Security Device Specification).
In the above identified information based indicium program, the United States Postal Service has specified particular inspection periods which must be implemented for a personal security device or metering type device to remain in service. For such a system to have a high level of security, it is desirable to incorporate a secure clock which is inaccessible by the user so that the unit may not be maintained in operation beyond the inspection expiration date. In systems of this type, the clock may be used to disable operation or disable certain operations of the personal security device. Additionally, another critical function of secure clocks that may be employed in an encrypted indicia type of system is the utilization of the date and time (or portions thereof as part of the encrypted indicia which may be used in verification to insure the validity of the imprint. In such a case, the secure clock, among other functions, provides a changing time which precludes the same personal security device from printing two encrypted indicias having the exact same attributes. This facilitates detection of fraudulent copies of indicias.
Additionally, other enhanced functionalities are obtained by utilization of a secure clock. For example, maintenance cycles can be assured as being initiated within predetermined periods of time since the secure clock may not be altered by the user or service personnel, except under controlled conditions.

Electronic postage meter system having plural clock system providing enhanced security


A four-wheel drive anti-lock brake control in which the existence of torque transfer between the front and rear wheels of the vehicle is detected based on differences in the duration of ABS control used at each of the independently controlled wheels. Such differences are used to determine a ratio of rear-to-front (or front-to-rear) ABS control. If the ratio indicates the presence of torque transfer, the wheel causing the transfer is identified and its brake pressure released as required to alleviate the detected torque transfer, so long as the release will not cause a change in vehicle deceleration.

This invention relates to an anti-lock brake system (ABS) for a four-wheel drive vehicle, and more particularly to an ABS system in which torque transfer between the front and rear of the vehicle is detected and alleviated.
In four wheel drive vehicles, the front wheels are mechanically coupled to the rear wheels through a transfer case, so that the sum of the front wheel speeds is made equal to the sum of the rear wheel speeds. When the vehicle has an anti-lock brake system (ABS) that is configured to control slip independently at the front and rear wheels, the sum of the front and rear wheel speeds becomes unequal during ABS braking. This results in an undesired torque transfer between the front and rear wheels which can degrade the performance of the ABS control.
It has been proposed to detect the existence of torque transfer based on wheel slip or the brake pressure ratio between the front and rear wheels, but these techniques either provide only limited information or require expensive pressure sensors. In some systems, the pressure may be estimated in lieu of using pressure sensors, but many ABS controls utilize on/off solenoid control, rendering pressure estimation impractical. One example of a known torque transfer detection and control is anonymously disclosed in the July, 1995 issue of Research Disclosure.
The present invention is directed to an improved four-wheel drive anti-lock brake control in which the existence of torque transfer between the front and rear wheels of the vehicle is detected based on differences in the duration of ABS control used at each of the independently controlled wheels. Such differences are used to determine a ratio of rear-to-front (or front-to-rear) ABS control. If the ratio indicates the presence of torque transfer, the wheel causing the transfer is identified and its brake pressure released as required to alleviate the detected torque transfer, so long as the release will not cause a change in vehicle deceleration.

Four wheel drive anti-lock brake control having torque transfer alleviation


A toe-cap molding machine has a body, a clamping device and a shoe-tree mount. The body has a base panel, a connecting mount, a clamping cylinder and a shoe-tree cylinder. The clamping device is detachably connected to the body and has two quick-release groups and a mold group. The quick-release groups are securely mounted on the assembling panel, and each has a quick-release mount, a clamping mount and a first spring. The quick-release mount has a releasing hole, a holding pin and a mounting recess. The clamping mount is pressably connected to the quick-release mount and has an engaging block, an elongated hole and an engaging head. The mold group is connected to the quick-release groups and the assembling panel and has two guiding shaft, a limiting panel, two second springs and a clamping mold. The shoe-tree mount is detachably connected to the shoe-tree cylinder below the clamping device.

1. Field of the Invention
The present invention relates to a toe-cap molding machine, and more particularly relates to a toe-cap molding machine that can be assembled and disassembled conveniently.
2. Description of Related Art
A conventional toe-cap molding machine has a body, a clamping device and a shoe-tree mount. The body has at least two cylinder groups. The clamping device is securely connected to the body by screws and is connected to one of the at least two cylinder groups to enable the clamping device to move relative to the body. The shoe-tree mount is securely connected to the body by fasteners and is connected to other one of the at least two cylinder groups to enable the shoe-tree mount to move relative to the body. In use, the clamping device and the shoe-tree mount can be moved to each other relative to the body by the at least two cylinder groups. Then, a material for a toe-cap of shoe that is mounted on the shoe-tree mount can be molded by the clamping device and the shoe-tree mount.
However, the conventional toe-cap molding machine can provide a molding effect to the material for the toe-cap of shoe, when the conventional toe-cap molding machine is needed to change with different sizes of the clamping devices and the shoe-tree mounts, a user needs to loosen the screws and the fasteners from the body to separate the clamping device and the shoe-tree mount from the body and this will increase the time of disassembling and assembling the different sizes of the clamping devices and the shoe-tree mounts. In addition, the screws and the fasteners may be damaged after a long time in use and this will influence the stability and the operation between the body, the clamping device and the shoe-tree mount of the conventional toe-cap molding machine.
Therefore, the present invention provides a toe-cap molding machine to mitigate or obviate the aforementioned problems.


A controller with energy economy rating (EER) calibration logic is configured to adjust a look-ahead time and feed-forward mapping window for vehicle controls according to EER.

The present disclosure relates to vehicle controllers that operate the vehicle according to historical vehicle performance data.
Energy Economy Rating (EER) is an energy-based metric used in fuel economy testing to quantify fuel economy variability due to drive quality. The EER gives a quantitative measure of drive quality that includes the effects of both the energy expended and the distance driven on the fuel economy results. Some standardized fuel economy tests, such as those defined by the Environmental Protection Agency (EPA), require that the EER of the test vehicle be within specified limits. If the EER value violates these limits, the fuel economy results are deemed invalid. Numerical vehicle models simulate various vehicle physics including vehicle dynamics and fuel usage. These models can predict the fuel economy of the vehicles. A numerical cycle driver is the part of the numerical vehicle model that simulates human inputs including: braking, accelerating, shifting gears, engaging the clutch, and steering. In simulations used to predict fuel economy, the numerical cycle driver's goal is to calculate values of acceleration, braking, and possibly gear shifting events to get the velocity of the numerical vehicle model to match a target velocity trace (as defined by a drive cycle). For fuel economy predictions to reflect those obtained by human drivers, the values of acceleration, braking, and/or shifting calculated by the numerical cycle driver should be representative of human drivers. The numerical cycle driver applies some type of control strategy to cause the numerical vehicle model's velocity to match the target velocity (drive cycle). One type of control strategy is feedback control, such as Proportional Integrated Differential (PID) control. Numerical cycle drivers based solely on feedback control rely on the instantaneous difference between a target velocity and a simulated vehicle velocity from the model to calculate acceleration, braking, and shifting events. Such driver models do not have the ability to "look ahead"; therefore, numerical cycle drivers based solely on feedback control do not accurately represent a human driver's ability to anticipate future changes in vehicle velocity. As a result, the cycle driver overcompensates, applying too much acceleration and too much braking in order to achieve the target velocity. This overcompensation can affect the EER and/or cause the simulated fuel economy results to poorly reflect those achieved by human drivers.
It is desirable to allow the numerical cycle driver to anticipate and incorporate future values of target velocity. In some cases it is also desirable to tune the numerical cycle driver to be able to achieve a specified EER value while simultaneously achieving fuel economy ratings similar to those obtainable by human drivers. Therefore, it would be beneficial to take a desired EER value as an input when designing numerical cycle driver controllers used to simulate fuel economy tests.

Vehicle driver-model controller with energy economy rating adjustments


The present invention relates to an optical pointing system and a method for calculating a movement value thereof, comprising: an image sensor for detecting light reflected from a worktable surface to generate an image signal, a maximum search window variable circuit for inputting at least one of the image signal and a movement value to change a size of a maximum search window, and a movement value calculation circuit for calculating the movement value of the image signal using the maximum search window with the changed size. Therefore, an exact movement value can be found by changing at least one of the maximum search window and a sampling rate according to at least one of a quantity of light and a movement speed to calculate the movement value.

1. Field of the Invention
The present invention relates to an optical pointing system and, more specifically, to an optical pointing system capable of adaptively changing a maximum search window and/or a sampling rate according to a quantity of incident light and a movement speed and a method for calculating a movement value thereof.
2. Description of the Related Art
FIG. 1 shows a general optical pointing system comprising a light source 8, a lens 5, and an image sensor of a sensor circuit 3 (not shown).
In FIG. 1, Reference numeral 2 represents a worktable surface, and 4, 6 and 7 represent light.
In the optical pointing system shown in FIG. 1, the light 7 emitting from the light source 8 is reflected from the worktable surface 2, and the reflected light 6 passes through the lens 5. And then, the light 4 passing through the lens 5 is input to the image sensor 3 composed of a CMOS (Complementary Metal Oxide Semiconductor) device.
An image of the worktable is successively detected by means of the image sensor 3 and is stored in a memory (not shown) of the sensor circuit as image data. The sensor circuit calculates a correlation value between the image data currently inputted to the memory and the image data previously stored in the memory, calculates the movement value, and transmits it to a system such as a computer.
FIG. 2 shows a block diagram of a sensor circuit of a conventional optical pointing system, comprising an image sensor 210, an A/D converter 220, a shutter control circuit 230, a movement value calculation circuit 240, and a PC interface circuit 250.
A function of each block shown in FIG. 2 is described as follows.
The image sensor 210 receives light reflected from a workable surface through the lens under the control of a shutter control signal SHCO to detect image data. The A/D converter 220 receives an analog signal outputted from the image sensor 210 to convert the analog signal to a digital signal. The shutter control circuit 230 generates the shutter control signal SHCO for controlling an electronic shutter (not shown) in the image sensor 210 such that an output of the AND converter 220 has a uniform distribution using the image data, which is an output signal of the A/D converter 220. The electronic shutter not shown comprises a CMOS device in the sensor circuit. The movement value calculation circuit 240 calculates and outputs the movement value of the image data, which is the output signal of the A/D converter 220, at a fixed sampling rate using a fixed maximum search window and mask window. The PC interface circuit 250 transmits the movement value outputted from the movement value calculation circuit 240 to a computer (not shown) at a fixed report rate. In other words, the PC interface circuit 250 stores the movement value outputted from the movement value calculation circuit 240, and then transmits the movement value at the fixed report rate required in the computer (not shown).
The sensor circuit of the conventional optical pointing system as described above always calculated a correlation value between image frame data previously inputted to the memory and newly inputted image frame data at the fixed sampling rate to output the movement value. For example, all the circuits in the sensor circuit were operated at the sampling rate fixed with 1500 or 2000 times per second as a reference one. Further, the sensor circuit of the conventional optical pointing system found the movement value and transmitted the result to the computer at the fixed report rate.
Moreover, the conventional optical pointing system could change a quantity of incident light only within a shutter exposure time, which has a predetermined operation time of the electronic shutter adjusting the quantity of incident light inputted to the image sensor 210, and the movement value calculation circuit 240 also calculated the correlation value at the predetermined sampling rate using the fixed maximum search window.
Meanwhile, when the sampling rate, the shutter exposure time, and the maximum search window are predetermined, if the quantity of light is extremely reduced, the optical pointing system is operated such a state that the quantity of light is increased by extending the exposure time of the electronic shutter in order to suffice the quantity of incident light. However, although the maximum time of a shutter exposure period adapted to the predetermined sampling rate is reached, when the required quantity of light is not inputted, the image sensor cannot represent a workable surface pattern as it is. As such, when the quantity of light is insufficient, the optical pointing system cannot discriminate a value of the workable surface pattern, so that the movement value cannot be found.

Optical pointing system and method for controlling a sampling rate and a maximum search window thereby


Suspending multiple virtual machines executed simultaneously a hypervisor a data processing system, including: sending, by a control instance, a request to the hypervisor to suspend virtual machines at a given future first point in time; the hypervisor determining if its virtual machines can be suspended at the first point in time, and, if the suspending is possible, returning a suspend handle to the control instance and storing the suspend handle, otherwise returning an invalid handle; when receiving a suspend handle from the hypervisor in return to the request to suspend virtual machines, the control instance sending a suspend command to the hypervisor, wherein the respective suspend handle is provided to the corresponding hypervisor; the hypervisor determining if the received suspend handle is equal to its stored handle and, if yes, suspending its virtual machines at the first point in time.

The present disclosure relates in general to data processing systems, and in particular, to a method and a system for suspending and resuming multiple virtual machines executed simultaneously by hypervisors on data processing systems.
In virtualized computer systems it may be desirable in certain circumstances to suspend a virtual machine (VM) and resume it at a later time. In order to save resources concerning e.g. computing power, energy or memory it may also be worthwhile to suspend a virtual machine and resume it at a later time. Also, for example, changes to the VM's configuration file cannot be made while the VM is executing. In order to make such changes, the VM is first suspended. This causes the VM execution to halt and the VM's state to be serialized and written to a file, commonly known as a checkpoint file or a suspend file. After the VM is suspended, the desired change can be made to the VM's configuration file. The VM having the changed configuration can then be resumed from the saved state.

Suspending and resuming virtual machines


A steel material is useful for producing the upper part of engine pistons with high wear, corrosion and heat resistance. This steel has the following composition (in % by weight): 1.20 to 150 Mn; 0.50 to 0.80 Si; 0.35 to 0.40 C; 0.10 to 0.50 Mo; 0.08 to 0.13 V; 0.010 to 0.065 S; 0.015 to 0.050 Al; .ltoreq.0.035 P, the remainder being iron and production impurities.

The invention relates to a steel material for producing engine piston upper parts.
In diesel motors, extremely high compressions with good fuel utilization, low emissions and high km life expectancy can be obtained with steel forged piston upper parts. In this connection, the piston upper parts are generally quenched and tempered from the material 42CrMo4 in a range from 800 to 1100 N/mm.sup.2, i.e. hardened by heating from room temperature to 860.degree. C. and subsequently quenching in heavy-duty oil and tempered by renewed heating to ca. 480.degree. to 660.degree. C. with final cooling in a container. The temperatures in the hardening and/or tempering furnace are adjusted according to the respective steel analysis and the customer instructions with respect to strength.
The wear, corrosion and thermal resistance properties of the piston upper parts which are required by the consumer can only be obtained with the above mentioned steel and the forging method. However, the construction principle of the pendulum shaft piston with a steel forged upper part and aluminum skirt has the disadvantage that the motor is expensive in comparison to the one-piece pistons produced from aluminum which is also caused by the quenching and tempering (heat treatment) of the steel piston upper part.
The object of the present invention is to provide a material with which steel forged piston upper parts can be produced without quenching and tempering, and hence more economically, without negatively influencing the wear, corrosion and heat resistance properties.

Steel material with high thermal-resistance for producing engine piston upper parts


A safety device to be used with a vial, or capsule, has a collar dimensioned to slidably fit about the body of the vial. Extending from the collar is a neck member that has connected to its other end a housing pivotable to a position along the longitudinal axis of the vial. A latch member having a lip is integrated to the neck member and extends out from the neck member in a direction towards the center of the collar. Neck member is fabricated to have an elastic characteristic so that if it is not biased by any external force, it will return to its original position. As the collar of the safety device is moved along the body of the vial, neck member is biased away from the vial as the latch member maintains contact along the outer surface of the vial, and then the outer surface of the hub formed at the top end of the vial. Once the collar of the safety device is moved to a position adjacent the hub, given the configuration of the neck member forms a space between the top of the collar and the lip of the latch member, the hub of the vial would fit within the space thus formed, as neck member snaps back to its original position. At which time the lip of latch member latches onto a shoulder portion of the hub. Once latched onto the hub, the latch member would prevent the safety device from being removed from the vial. Instead of the neck member, another embodiment of the inventive safety device has extending from the collar a rigid support frame and an elongate elastic latch member.

Needle protection devices for use with a vial that contains medicament to be used with applicators such as Tubex and Carpuject holder applicators are disclosed in the aforenoted '819 application (the '857 patent). One of the related devices disclosed in the '819 application has a collar that slidably fits over the hub of a vial and is secured thereto by means of a number of extending fingers. Another of the '819 devices has an open collar that mounts about the vial. A pair of interlocking extensions from the collar coact to secure the collar about the vial. Although worked well, these devices fail to take full advantages of the structure of the vial itself and the interaction between the vial and the holder applicators, in order to be securely coupled to the vial. The '089 co-pending application discloses the use of the hub of the vial as a means for securing the collar fitted about the vial. The present invention discloses yet another needle safety device that takes into consideration the inherent characteristic of the vial, and the relationship between the vial and its hub, for securing itself to the vial.


The present invention provides a bird catching apparatus for deploying a catching net rapidly and surely, thereby catching birds surely. Each end of one side edge of the catching net is respectively connected to a pair of deploying arms of each deploying device via a pole member. Each deploying arm is pulled by a pair of extension springs of a deploying unit, and are locked by a locking unit. At the same time, the deploying arms are pulled upward by an auxiliary arm of an auxiliary urging unit. When the deploying arms locked by the locking unit are released, the deploying arms are surely rotated upward, thereby rotating along a vertical surface for over 180.degree.. The catching net is thus deployed.

Birds such as ducks and pheasants are usually caught by guns or nets. Bird hunting grounds for birds such as ducks can include a lake, watercourses, a paddy field, damp ground, and ponds or the like. In a hunting ground area, people can also be engaged in fishing, agriculture, and leisure. Therefore, it is dangerous to catch birds by using guns, which may hurt people and do hurt birds, and are thereby not preferable. On the other hand, in the case of catching birds by using a net, there is no fear of hurting people who enter the hunting ground. The net has the advantage that it can set birds free without any harm.
A net can be woven of silk, cotton, twine, or nylon. Birds are entwined with the net and thereby caught. To catch birds, a catching net is provided on the surface of the earth, and birds such as ducks are collected by sprinkling food. After birds gather, the catching net is manually moved to cover the birds, thereby catching them. Moreover, a method of providing the catching net on a slope banked up to a height of about 40-50 cm has been recently developed.
In catching birds by using the above net, the catching net must be moved so as to cover the birds. Therefore, in case that the moving speed is slow, the birds can flee and there is the possibility that it cannot catch the birds. In particular, moving the net may be manually performed by pulling a rope arranged with the catching net, which causes a problem because moving the catching net at high speed requires skill. If the rope is pulled in the vicinity of the catching net, moving the catching net requires relatively weak power, but there is the possibility that the birds will keep away if they recognize the existence of operators in the area of the catching net. In order to gather the birds in the area of the catching net, the rope must be pulled from a relatively remote place, wherein moving the catching net requires strong power.
Moreover, the catching net is provided on the surface of the earth in a widely spread state, thereby causing a problem wherein the birds easily recognize the spread catching net and keep away from the vicinity of the catching net. When the catching net is moved to cover the birds so as to catch them, it confines the birds only due to its own weight, and there is the possibility that the birds can easily flee through a clearance between the catching net and the surface of the earth.
The present invention resolves the above problems, and has the object of providing a bird catching apparatus for enabling birds such as ducks to be surely caught. Another object of the present invention is to provide a bird catching apparatus wherein there is no possibility that the caught birds can flee.


A system for controlling functions of a propeller having a plurality of blades is disclosed. The system comprises an electronic control for controlling the functions of the propeller. A plurality of backup devices are provided for backing up the electronic control upon the occurrence of conditions. These conditions include at least one of testing, manual override, and a malfunction in the electronic control causing at least one of the functions to endanger safety. The system further includes a bypass device for bypassing the electronic control and for invoking at least one of the plurality of backup devices to acquire control over at least one of the functions. The bypass devices include a mechanism for determining the occurrence of at least one of the conditions and for actuating electronic control override.

Variable pitch propeller systems incorporate mechanisms to protect the systems against uncommanded blade angle excursions towards low pitch or low blade angle, typically in the event of hydraulic failure. Propeller designs which use counterweighted blades also allow for the use of a simple pitch change actuator. Accordingly, hydraulic pressure required to adjust propeller blade pitch or angle may be supplied directly to the coarse pitch and fine pitch chambers of the pitch change actuator usually found in such systems, on command from a propeller control.
An electronic control system is typically operable to control and monitor blade angle thereby changing blade angle as demanded by flight conditions. In the typical case, such commands are implemented by an electronically operated valve which directs and cuts off hydraulic fluid to the coarse and fine pitch chambers of the pitch change actuator.
In the event that there is an electronic failure within the propeller control system or loss of aircraft electrical power, a backup system must be deployed, which system is typically mechanical, to monitor, control and adjust the pitch change actuator for adjusting blade angle in accordance with flight conditions. In this manner, electronic malfunctions which could cause blade angle to send the propeller into overspeed conditions and high negative thrust can be avoided.
In currently available electronic propeller control systems, with mechanical backups, the overall system size and complexity can be problematic with regard to important weight and cost considerations.
There exists a need, therefore, for an electronic propeller control system with a mechanical backup which is reliable and provides due consideration to weight and complexity for increasing flight efficiency and decreased costs, respectively.

Counterweighted propeller control system