Discrete Joint Research Articles

Roof deflections and sag in jointed, horizontally bedded strata ? A numerical study

A nonlinear finite element model with discrete joint modelling capability is developed. A semi-empirical equation introduced for determining the maximum deflections of clamped and vertically jointed roof beam is verified using a nonlinear finite element model. The mechanism of stability is also investigated numerically and concluded that the formation of Voussoir arch (Parobolic compressive zone) plays a major role in the overall stability of beam roofs over underground openings. Approximate linear equations are obtained for three joint spacings of 800, 400 and 200 mm, relating the maximum deflection of the beam and joint width for a given joint spacing.

Operant control of precentral neurons in monkeys: Evidence against open loop control

Four normal monkeys were operantly conditioned to change the firing pattern of 111 precentral neurons from phasic to tonic using an operant paradigm which quantifies the control of single neurons. Two monkeys then had their contralateral pyramidal tract (PT) sectioned and one monkey had C5-7 ventral rhizotomies. Postlesion data were: (1) contralateral C1-2PT lesions did not encumber the monkeys' control of precentral PTNs: (2) contralateral C5-7 ventral rhizotomies completely abolished accurate control of precentral neurons which received proprioceptive feedback from flaccid arm regions. These results indicate that precentral neurons are operantly controlled through proprioceptive feedback from peripheral mechanoreceptors. The output of the mechanoreceptors is probably dependent upon discrete joint angles and/or muscle tension which is maintained through non-PT pathways. These data do not support the concept that precentral neurons are operantly controlled directly from a central; 'open loop', pathway.

A low cost reliability test specification : Jacques de Corlieu. Microelectron. Reliab.19, 11 (1979)

The objective of this paper is to develop a methodology to construct and compute in a Bayesian setting, point and interval predictions based on general progressive Type-II censored data from Weibull model. Prediction bounds for the future observations (2-sample prediction) based on this type of censored will be derived. Bayesian predictions are obtained based on a continuous–discrete joint prior for the unknown two parameters. We have examined point predictions under symmetric and asymmetric loss functions. As application, the total duration time in a life test and the failure time of a k-out-of-m system may be predicted. An illustrative example consisting of various types of real data from an accelerated test on insulating fluid reported by Nelson (1982) [17] is presented. Finally, some numerical results using simulation study concerning different sample sizes, and different progressive censoring schemes were reported. A study of 10 000 randomly generated future samples from the same distribution shows that the actual prediction levels are satisfactory.

A New Random Data Description and Its Use in Transferring Road Roughness to Vehicle Response

The initial portion of the paper discusses the more conventional method of obtaining a vehicle transfer function where phase and magnitude are determined by dividing the cross spectral density of the input/output by the power spectral density (PSD) of the input. The authors needed a more descriptive analysis (over PSD) and developed a new signal description called Amplitude Frequency Distribution (AFD); a discrete joint probability of amplitude and frequency with the advantage of retaining amplitude distribution as well as frequency distribution. A better understanding was obtained, and transfer matrix functions were developed using AFD.

Projections to the cat's cerebral cortex from low threshold joint afferents.

AbstractThe projections to the cerebral cortex from the contralateral low threshold afferents of the musculocutaneous branch to the elbow joint (Ejt) and the posterior knee joint nerve (Kjt) were investigated in cats anesthetized with chloralose. Graded electrical stimulation of the nerves was used to evoke the cortical potentials. Three discrete joint projection areas were found in the cytoarchitectonic area 3 of the posterior sigmoid gyrus, i.e. one Ejt and two Kjt loci. These loci overlapped with the projections from group I muscle afferents. One Ejt and one or two Kjt loci were observed in positions corresponding to cytoarchitectonic areas 1 and 2. They did not receive input from group I muscle afferents. A separate locus with overlap between forelimb joint and muscle afferents was located in area 4 y. Components 1 and II of the joint nerve volley evoked short latency potentials in all cortical loci. Low threshold cutaneous afferents evoked responses in all joint loci. The spinal course of the ascending Ejt path was mainly located in the dorsal column. Kjt component I afferents travelled mainly in the dorsal columns and component I and II afferents in the dorsolateral fascicle. The Kjt path in the dorsolateral fascicle ascended uncrossed to the level of Ci.

Continuum characterization of jointed rock masses: Part II—Significance of low shear modulus

Finite element analysis is used to compare the displacement fields given by an anisotropic continuum model of a jointed rock mass with that obtained from the discrete joint model. The models have been described in Part I of the paper. These computations reveal excellent agreement between the finite element predictions of the joint model and the continuum model, except in the region of steep stress gradients near the loaded area. The anisotropic continuum model predicts a stress distribution that is significantly different from Flamant's solution for a strip load on a semi-infinite rock mass. Stresses are transmitted to a considerably greater depth along joints and to some extent across joints. This tendency is more pronounced in a medium of very low shear modulus, which corresponds to a joint set of low shear stiffness. Three case histories have been analyzed to evaluate the elastic behaviour of rock masses. These investigations suggest that actual rock masses may behave as a medium of low shear modulus. In this paper, attention is focused on the ddverse effects of low shear modulus on the stability of rock masses.

A Truncated Maximin Approach to Farm Planning under Uncertainty with Discrete Probability Distributions

AbstractA method is presented for solving linear programming problems under the assumption that input‐output, restraint, and functional coefficients follow a discrete joint probability distribution. This may be a rather plausible assumption in some uncertain farm planning contexts. The objective function is formulated in terms of variance and/or expectation. Special attention is given to the most adverse outcomes with respect to both the functional value and side constraints. Parametric analysis can be used to determine trade‐offs among the functional value, the adversity level, the tolerance probability, and the probability of infeasibility. Finally, the proposed method is applied to a farm problem.

The Muddy Mountain Overthrust in Southeastern Nevada

Previous articleNext article FreeThe Muddy Mountain Overthrust in Southeastern NevadaChester R. LongwellChester R. Longwell Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The Journal of Geology Volume 30, Number 1Jan. - Feb., 1922 Article DOIhttps://doi.org/10.1086/622840 Views: 109Total views on this site Citations: 7Citations are reported from Crossref PDF download Crossref reports the following articles citing this article:Luisa F. Zuluaga, Haakon Fossen, Gregory Ballas, Atle Rotevatn Structural and petrophysical effects of overthrusting on highly porous sandstones: the Aztec Sandstone in the Buffington window, SE Nevada, USA, Geological Society, London, Special Publications 459, no.11 (Apr 2017): 59–77.https://doi.org/10.1144/SP459.8Atilla Aydin, Ghislain de Joussineau The relationship between normal and strike-slip faults in Valley of Fire State Park, Nevada, and its implications for stress rotation and partitioning of deformation in the east-central Basin and Range, Journal of Structural Geology 63 (Jun 2014): 12–26.https://doi.org/10.1016/j.jsg.2014.02.006W. Lansing Taylor, David D. Pollard, Atilla Aydin Fluid flow in discrete joint sets: Field observations and numerical simulations, Journal of Geophysical Research: Solid Earth 104, no.B12B12 (Dec 1999): 28983–29006.https://doi.org/10.1029/1999JB900179David J. Campagna, Atilla Aydin Basin genesis associated with strike-slip faulting in the Basin and Range, southeastern Nevada, Tectonics 13, no.22 (Jul 2010): 327–341.https://doi.org/10.1029/93TC02723Robert J. Fleck, Michael D. Carr The age of the Keystone Thrust: Laser-fusion 40 Ar/ 39 Ar dating of Foreland Basin Deposits, southern Spring Mountains, Nevada, Tectonics 9, no.33 (Jul 2010): 467–476.https://doi.org/10.1029/TC009i003p00467Richard W. Allmendinger Fold and thrust tectonics of the western United States exclusive of the accreted terranes, (): 583–608.https://doi.org/10.1130/DNAG-GNA-G3.583 REFERENCES, (Jan 1966): 165–172.https://doi.org/10.1016/B978-0-08-011275-6.50009-4