True Breaking Research Articles

Are supersymmetric models with minimal particle content under tension for testing at LHC?

Abstract In supersymmetric models with minimal particle content and without large left-right squarks mixing, the conventional knowledge is that the Higgs Boson mass around 125 GeV leads to top squark masses O ( 10 ) TeV , far beyond the reach of colliders. Here, we pointed out that this conclusion is subject to several theoretical uncertainties. We find that electroweak symmetry breaking and evaluation of Higgs mass at a scale far away from the true electroweak symmetry breaking scale introduce a large uncertainty in Higgs mass calculation. We show that the electroweak symmetry breaking at the scale near the true vacuum expectation value of Higgs field can increase the Higgs Boson mass about 4–5 GeV and can lower the bounds on squarks and slepton masses to 1 TeV. Here we pointed out that the Higgs mass even with inclusion of radiative corrections can vary with electroweak symmetry breaking scale. We calculate it at two loop level and show that it varies substantially. We argue that Higgs mass like other coupling parameters can vary with energy scale and the Higgs potential with all orders loop corrections is scale invariant. This uncertainty to the Higgs mass calculation due to electroweak symmetry breaking around the supersymmetry breaking scale, normally taken as m t ˜ L m t ˜ R , to minimize the 1-loop radiative corrections can be removed if one considers all significant radiative contributions to make Higgs potential renormalization group evolution scale invariant and evaluates electroweak symmetry breaking at the scale near the electroweak symmetry breaking scale. A large parameter space becomes allowed when one considers electroweak symmetry breaking at its true scale not only for producing correct values of the Higgs masses, but also for providing successful breaking of this symmetry in more parameter spaces.

A new lower limit for the bond breaking strains of defect-free carbon nanotubes: Tight binding MD simulation study

The Order(N) Tight Binding Molecular Dynamics (TBMD) algorithms applied to simulate the tensile elongations of short (2–2.5nm) armchair and zigzag Single Walled Carbon Nanotubes (SWCNTs) without bond breakings or defect formation. Simulations are repeated at high temperatures. We fix the lower limit of breaking strains to short SWCNTs without bond breaking or 5–7 defects formation. At room temperature, the simulated (4,4) SWCNT is able to carry the strain up to 130% of the relaxed tube length without bond breaking or 5–7 defects formation. This value is 127% for (11,0) SWCNT, 125% for (17,0) SWCNT, 123% for (10,10) SWCNT. Bond breakings occur at lower strain values in defect-free, short nanotubes as the radii of the nanotubes increase, regardless of their chirality. This is true even when we heat the tubes to higher temperatures. Bond breaking strain values, tensile strength, Young’s moduli of the SWCNTs are obtained as functions of temperature. In general, defect-free zigzag nanotubes exhibit higher tensile strength than armchaired ones. Young’s moduli of defect-free individual single-wall nanotubes are found to be in the range of 0.400TPa within the elastic limit. At room temperature and experimentally realizable strain values, thinner tubes are more resistant to bond breaking and zigzag tubes over armchair ones. The same trend still holds at high temperatures although the resistance to strain gets lowered. We observe a slight decrease of the tensile strength with increasing temperatures. A similar behavior is also observed in Young’s moduli. These results are important in determining the true breaking strains of SWCNTs.

Diagram of fatigue limit states with high asymmetry

Hardening of structural elements and plasticity loss are observed for reactor elements which operate for a long time. In some cases, this results in a change of the asymmetry of multi-cycle loading of structures and a reduction of their service life. The diagram of limit states in the presence of fatigue with high asymmetry is confirmed experimentally for samples made of 08Kh18N10T austenitic steel, for which the true breaking strength is adopted as the average limit stress in a cycle.

On the problem of the maximum strength of metals and alloys in crystalline, amorphous, and nanocrystalline states

The true breaking stresses and the ultimate tensile strengths of 11 metals with various structures are calculated. Moreover, the fracture strengths of these metals at 0 and 298 K are calculated in the amorphous (σf, a) and nanocrystalline (σf,nanomax) states formed upon severe plastic deformation. The temperature dependences of these properties are also determined. These properties are obtained for a number of alloys (TiNi, NiNb, Pd80Si20, Ni60Nb40). The values of σf, a are shown to correlate with yield strength σy, nano of nanocrystalline substances, and a hypothesis of a deviation from the Hall-Petch relation is advanced. This hypothesis is supported by the calculation of the properties and diffusion characteristics. The obtained numerical results agree satisfactorily with the experimental data and the results of other approaches to estimating these properties.

Aging in the ferroic random-field Ising model system strontium-barium niobate

Large aging effects, investigated via temporal dependences of the dielectric response, are found to be inherent in the uniaxial ferroelectric relaxor systems $\mathrm{SBN}:\mathrm{Cr}$ and $\mathrm{SBN}:\mathrm{Ce}$. The results are discussed on the basis of domain coarsening and domain-wall pinning effects. Owing to the different charge disorder induced by the ${\mathrm{Cr}}^{3+}$ and ${\mathrm{Ce}}^{3+}$ dopants, a fundamental difference between both systems is established. While $\mathrm{SBN}:\mathrm{Ce}$ shows only a weak breaking of ergodicity, the $\mathrm{SBN}:\mathrm{Cr}$ system experiences true ergodicity breaking.

Dynamics within metastable states in a mean-field spin glass

In this letter we present a dynamical study of the structure of metastable states (corresponding to TAP solutions) in a mean-field spin-glass model. After reviewing known results of the statical approach, we use dynamics: starting from an initial condition thermalized at a temperature between the statical and the dynamical transition temperatures, we are able to study the relaxational dynamics within metastable states and we show that they are characterized by a true breaking of ergodicity and exponential relaxation.

Efficiency of Wire Rope Terminations

Nine wire rope terminations were evaluated with respect to true efficiency, service life, and sensitivity to poor workmanship in a comprehensive laboratory test program. The portion of the program concerned with true efficiency, as determined by pull tests to destruction, is reported here. Five diameter values of Lang and Regular construction ropes of the 6 × 19 and 6 × 37 class were used on the following wire rope terminations: Flemish Loop with Steel Sleeve and Thimble, Flemish Loop with Steel Sleeve, Wedge Socket, Swaged Socket, Turn Back Loop with Aluminum Sleeve and Thimble, Thimble Splice with Four Tucks, U-Bolt Clips with Thimble, Zinc Poured Socket, and Resin Poured Socket. The true efficiency was shown to be affected by termination type, rope type, and the interaction of these factors. The efficiency values measured in this test program are less than those reported in the literature which are based on the catalog breaking load rather than on the true breaking load. From a graphic and statistical analysis of the data it was possible to present a selection procedure for optimizing the efficiency.

Effect of technological factors on the true breaking stress of heat-resistant materials in rapid air streams

Effect of technological factors on the true breaking stress of heat-resistant materials in rapid air streams

Effects of Strain-Rate and Temperature on Stress-Strain Behavior of Some Solid Polymers

The effect of deep freezing on the fracture behaviors of solid polymers has been investigated experimentally as a fundamental study of industrial cryogenic crushing operation.The mechanical properties of polymethyl methacrylate (PMMA) and polyvinyl chloride (PVC) are found to be critically dependent on the temperature (-180∼+120°C) at which they are deformed, as shown by the following equations (1)∼(3), but are independent of the strain-rate at which they are deformed, in the range of crosshead speed about 0.5 to 500mm/min. The values of true breaking stress σBc, and breaking strain εBc at the ductile-brittle fracture transition temperature Tc are the material-constants.σB/σBc={1-e-(Tc/T)2}/(1-e-1) (1)εBc/εB={1-e-(Tc/T)3}/(1-e-1) (2)εy=εB0=(1-e-1)·εBc=0.6321εBc (3)

鋼の繰返引張荷重に対する時間強度について

The time-strength of steel and cast iron under repeated tension was reported previously by the authers. In the present paper the similar experiments made on the specimens with U-shaped annular notches are reported. Summary of the results is as follows:(1) The S-N diagram of a steel for the specimens with or without notches, if both axes are shown in logarithmic scale, consists of three straight lines, i. e., a horizontal line which represents the endurance limit, another horizontal line which represents the tensile strength, and a sloped straight line, the extent of which at N=1 is equal to the true breaking strength.(2) The S-N curves of a steel for the specimens with and without notches intersect at N=103-105, and so the time-strength of a steel for the specimens with notches at N less than the value at the intersecting point, is larger than the time-strength for without notches.

The Time-strength of Steel and Cast Iron under Repeated Tension

In designing machine parts and structures, the time-strength often comes into question. The authors made many fatigue tests on specimens of steel and cast iron under repeated tension, and obtained their S-N diagrams. Then the authors came to the conclusion, that (1) the S-N diagram of cast iron, both in logarithmic scale, consists of the two straight lines, i.e., a horizontal line which represents the endurance limit and a straight line, the value of which at N=1 is equal to the tensile strength, (2) the S-N diagram of steel, both in lograrithmic scale, consists of three straight lines, i.e., a horizontal line which represents the endurance limit, another straight line which represents the tensile strength, and a sloped straight line, the extent of which at N=1 is equal to the true breaking strength.

On the Tensile Strength of the Circular Bar with a Rectangular Notch

Properties of the circular bar with a rectangular notch are researched, with special reference to tension, intending to clarify the influence produced by the depth and breadth of the notch upon the breaking stress of the several test pieces. In the experiments, steel bar test pieces of 1.5cm dia., having the following 36 types of rectangular notch are stretched out by Olsen-type universal testing machine. Breadth of notch=0.1, 0.2 and 0.3cm. Depth of notch=0.1, 0.2, 0.3, 0.4, 0.5 and 0.6cm. Consequently, the relations between the ultimate strength and the sectional area of notch are obtained, and true breaking stresses are the same with all the test pieces except for circular bar with no notch or with a deep notch.

滲炭鋼の破損機構について

I succeeded in extending Woodvine's fatigue theory over the tensile properties of case hardened steel (mild carburized), technical cohesion strength was induced. I concluded that case hardened layer prevented the inner layer to slip (or to yield), and made three stages of tensile properties with case depth; 1 st; true breaking strengthe's lowering, 2 nd; the technical cohesion strength of inner layer, 3 rd; the tensile strength increase only by the case hardened layer. (Carbon and chrom steels were used). The value of technical cohesion strength by this method is lower than that of the notch method by Kuntze, this depends on the residual stress. Why case hardened layer in my calculation has an assumed higher tensile strength than solid high carbon steel depends on the residual stress. Then, I measured the residual stress of the test pieces and made clear that these were founded on the tension residual stress in the inner layer and the compression residual stress in the case hardened laver. Next, I tried to extend the Woodvine's fatigue theory to the tensile test pieces with various notch radius. Without the case hardened layer it coincided with the experimental results of low carbon steal by Kuntze, while with case hardened layer it approached the value of the calculated result by Neuber, but their case depths are sufficiently deep to increase their tensile strength only by the case hardened layer.

Wire Cables

High tensile steel wire has many uses in connection with aircraft. A single wire has the advantage of a high breaking stress, greater than that of the bulk material from which it is made, because, as Goodman has pointed out, the drawing produces an elongated stricture of the steel, and the wire strength approximates to the true breaking stress of a larger specimen, which is the tension the latter resists at the moment of fracture divided by the reduced area. The British Engineering Standards Association's specification, 2wi., requires a minimum breaking stress of 80 tons per sq. in. up to 0.160in. diameter, 90 to 0.116, and 100 to 0.064. These stresses can safely be exceeded when required particularly with wire of small diameter.

The relation between breaking stress and extension in tensile tests of steel

A large number of the tensile tests of steel are now made with test-pieces, which are only a few diameters long (fig. 1). When such a test-piece is broken by tension, it has a profile, as shown in fig. 2. The usual records, made when the tests are carried out, include, among other things, “breaking stress” and “extension per cent.” “Breaking stress” here means the maximum tension applied divided by the original area of the test-piece; and extension per cent, is taken as the percentage increase due to the strain, in the distance between two marks, one at either end of the test-piece, whose unstrained distance is known. The use of the term “breaking stress” in the above sense is convenient, from an engineer’s point of view, as showing what force a bar, etc., of given sectional area will stand before giving way. The true breaking stress of a material, however, is the actual intensity of the stress at the broken surface, and is, of course, greater than the nominal breaking stress, because of the reduced area of the broken surface. To avoid con­fusion, I will call the true breaking stress the “intrinsic strength” of the material.