underground excavation instability mechanisms
Underground excavation in jointed rocks
... UNDERGROUND EXCAVATION IN JOINTED ROCKS JIAO XUGUANG (B.Eng.(Hons.),NUS) A THESIS SUBMITTED FOR THE DEGREE ... block define the magnitude of rock support and reinforcement required in the design of underground rock excavations Variation in rock parameters may result in uncertainties on the identification ... design with probability of failure is adopted to evaluate the stability of rock block in underground excavations The effects of scatter of various rock parameters are examined in detail using...
Ngày tải lên: 30/09/2015, 10:12
Unraveling genomic instability in multiple myeloma mechanisms, biological and clinical implications
... instability, the mechanism underlying this is unclear Genomic instability in cancer is broadly categorized into mutational instability, e.g., microsatellite instability (MIN) and chromosome instability ... a major mechanism of chromosome instability in MM Rationale and Hypothesis MM is characterized by chromosomal abnormalities that are hallmarks of chromosomal instability Abnormalities in the ... proposed as a mechanism leading to chromosome instability in solid tumors We therefore hypothesized that similar abnormalities may underlie chromosome instability in MM Furthermore, such abnormalities...
Ngày tải lên: 11/09/2015, 09:58
An embedded improved soil berm in an excavation mechanisms and capacity
... berm at m excavation depth for excavations 15 m halfwide 254 Figure 7.23 Soil heave at m below the initial ground level for different length of berm at m excavation depth for excavations ... stages of excavation O’Rourke et al (1998) reported an excavation stabilised by deep mixing method (DMM) and jet grouting in deep marine clay with excavation depth from 13.9 m to 19.4 m The excavation ... displacement for an excavation of 25 m half-wide at m excavation depth (FEM) 253 Figure 7.21 Horizontal movement at the top of the wall with different length of the berm at m excavation depth...
Ngày tải lên: 15/09/2015, 21:57
Mechanisms and Mechanical Devices Sourcebook - Chapter 3
... feed mechanisms Sclater Chapter 5/3/01 10:20 AM Page 63 63 Sclater Chapter 64 5/3/01 10:20 AM Page 64 Sclater Chapter 5/3/01 10:20 AM Page 65 SEVEN LINKAGES FOR TRANSPORT MECHANISMS Transport mechanisms ... a chucking lever 61 Sclater Chapter 5/3/01 10:20 AM Page 62 SEVEN AUTOMATIC-FEED MECHANISMS The design of feed mechanisms for automatic or semiautomatic machines depends largely upon such factors ... their relative positions 72 Sclater Chapter 5/3/01 10:20 AM Page 73 TRAVERSING MECHANISMS FOR WINDING MACHINES The seven mechanisms shown are parts of different yarn- and coil-winding machines Their...
Ngày tải lên: 22/10/2012, 14:26
Mechanisms and Mechanical Devices Sourcebook - Chapter 4
... motion is popular for mechanisms in feeders and automatic machines Two identical hypocycloid mechanisms guide the point of the bar along the triangularly shaped path The mechanisms are useful ... motion of the summing gear 110 Sclater Chapter 5/3/01 10:45 AM Page 111 HYPOCYCLOID MECHANISMS The appeal of cycloidal mechanisms is that they can be tailored to provide one of these three common motions: ... gear that rolls on a stationary external gear All the cycloidal mechanisms shown here are general This results in compact positive mechanisms capable of operating at Coupling the output pin to...
Ngày tải lên: 22/10/2012, 14:26
Mechanisms and Mechanical Devices Sourcebook - Chapter 5
... prior mechanisms Some of those included single-point drives that were subject to backlash (with consequent slight tilting and uncertainty in the distance between the plates) Other prior mechanisms ... 180º 153 Sclater Chapter 5/3/01 11:46 AM Page 154 STROKE-AMPLIFYING MECHANISMS When the pressure angles of strokeamplifying mechanisms are too high to satisfy the design requirements, and it is ... with the plate for the bevel cut Sclater Chapter 5/3/01 11:46 AM Page 159 COMPUTING MECHANISMS Analog computing mechanisms are capable of almost instantaneous response to minute variations in input...
Ngày tải lên: 22/10/2012, 14:26
Mechanisms and Mechanical Devices Sourcebook - Chapter 6
... longer life 178 Sclater Chapter 5/3/01 12:24 PM Page 179 OVERRIDING SPRING MECHANISMS FOR LOW-TORQUE DRIVES Overriding spring mechanisms are widely used in the design of instruments and controls All ... Page 181 SPRING MOTORS AND TYPICAL ASSOCIATED MECHANISMS Many applications of spring motors in clocks, motion picture cameras, game machines, and other mechanisms offer practical ideas for adaptation ... dirt and contamination 185 Sclater Chapter 5/3/01 12:24 PM Page 186 AIR SPRING MECHANISMS EIGHT WAYS TO ACTUATE MECHANISMS WITH AIR SPRINGS Linear force link: A one- or twoconvolution air spring...
Ngày tải lên: 22/10/2012, 14:26
Mechanisms and Mechanical Devices Sourcebook - Chapter 7
... 5/3/01 12:32 PM Page 201 CAM-CURVE GENERATING MECHANISMS It usually doesn’t pay to design a complex cam curve if it can’t be easily machined—so check these mechanisms before starting your cam design ... 216 Fig Over-centering mechanisms find many applications in electrical switches Considerable design ingenuity has been applied to fit this principle into many different mechanisms It is the basis ... on the spring itself 218 Fig Gravity-tips, although slower acting than most snap mechanisms, can be called snap mechanisms because they require an accumulation of energy to trigger an automatic...
Ngày tải lên: 22/10/2012, 14:26
Mechanisms and Mechanical Devices Sourcebook - Chapter 8
... which all ball axes project To prevent slippage under starting or shock load, torque responsive mechanisms are located on the input and output sides of the drive The axial pressure created is ... all speed ratings above zero The pulsations of this drive are damped by several parallel sets of mechanisms between the input and output shafts (Figure 22 shows only one of these sets.) At zero ... change in angular velocity of the driven member is required, as in quick-return drives, intermittent mechanisms in such machines as printing presses, planers, shears, winding machines, and automatic-feed...
Ngày tải lên: 22/10/2012, 14:26
Mechanisms and Mechanical Devices Sourcebook - Chapter 9
... within safe limits For example, if the throttle accidentally opens when the driving wheels or driven mechanisms are locked, the clutch will stop The clutch can be fitted with sprockets, sheaves, or ... phenolic laminate clutch plates B and the large gear 323 Sclater Chapter 5/3/01 12:57 PM Page 324 MECHANISMS FOR STATION CLUTCHES Innumerable variations of these station clutches can be designed ... advantages of efficiency and controllability over older clutches and brakes As in other roller-locking mechanisms, lock is achieved in this mechanism by jamming rollers between a precise surface on one...
Ngày tải lên: 22/10/2012, 14:26
Mechanisms and Mechanical Devices Sourcebook - Chapter 10
... fingers, and pinned members form the basis of these ingenious mechanisms Mechanical stops are often required in automatic machinery and servomechanisms to limit shaft rotation to a given number of ... together by the material being processed is positive speed synchronization of the individual driving mechanisms Typical examples of such a system are steel mill strip FIG 1—PRIMARY INDICATORS FIG 2—SECONDARY ... calls for primary indicators like the contact rolls shown Their movements actuate conveyor control mechanisms atively low; thus it limits this controller to applications where the indicator has sufficient...
Ngày tải lên: 22/10/2012, 14:26
Mechanisms and Mechanical Devices Sourcebook - Chapter 11
... DRIVEN HAMMER MECHANISMS The application of controlled impact forces can be as practical in specialized stationary machinery as in the portable electric hammers shown here These mechanisms have ... required The striker mechanisms illustrated are operated by springs, cams, magnetic force, air and vacuum chambers, and centrifugal force The drawings show only the striking mechanisms Fig This ... (B) Many other forms are possible 386 Sclater Chapter 11 5/3/01 1:16 PM Page 387 PERMANENT MAGNET MECHANISMS Fig A suspension Fig Tension devices Fig An instrument coupling Fig A reel brake Fig...
Ngày tải lên: 22/10/2012, 14:26
Mechanisms and Mechanical Devices Sourcebook - Chapter 13
... FIVE-BAR MECHANISMS Geared five-bar mechanisms offer excellent force-transmission characteristics and can produce more complex output motions—including dwells—than conventional four-bar mechanisms ... Page 455 FEEDER MECHANISMS FOR ANGULAR MOTIONS How to use four-bar linkages to generate continuous or intermittent angular motions required by feeder mechanisms In putting feeder mechanisms to ... dimensions to maximize snap-action Over-centering toggle mechanisms, as shown in Fig 1, are widely used in mechanical and electrical switches, latch mechanisms and mechanical overload controls These...
Ngày tải lên: 22/10/2012, 14:26
Mechanisms and Mechanical Devices Sourcebook - Chapter 14
... making parts from a variety of polymer materials, and it has also been used to make preassembled mechanisms, both in polymer and ceramic materials Fig 11 Mold Shape Deposition Manufacturing (MSDM): ... two-level process, but a three-level process with two mechanical layers permits micromachining mechanisms such as gears that rotate on hubs or movable optical mirror arrays A four-level process ... of multispeed transmissions for minimotors In addition, it should be possible to integrate these mechanisms with sensors, such as tachometers and load cells, as well as circuits, to create integrated...
Ngày tải lên: 22/10/2012, 14:26
Mechanisms and Mechanical Devices Sourcebook - Chapter 15
... Cataloging-in-Publication Data Sclater, Neil Mechanisms and mechanical devices sourcebook / Neil Sclater, Nicholas P Chironis.— 3rd ed p cm Rev ed of: Mechanisms & mechanical devices sourcebook ... and edited the Second Edition of Mechanisms and Mechanical Devices Sourcebook after the death of Mr Chironis The late Nicholas P Chironis developed the concept for Mechanisms and Mechanical Devices ... Chironis, Neil Sclater 2nd ed 1996 ISBN 0-07-136169-3 Mechanical movements I Chironis, Nicholas P II Mechanisms & mechanical devices sourcebook III Title TJ181.S28 2001 621.8—dc21 2001030297 Copyright...
Ngày tải lên: 22/10/2012, 14:26
Mechanisms and Mechanical Devices Sourcebook - Chapter 12
... removal is identical except that the motions are reversed QUICK-RELEASE MECHANISMS QUICK-RELEASE MECHANISM Quick release mechanisms have many applications Although the design shown here operates ... the panel assembly The concept is also adaptable to hydraulic, pneumatic, and mechanical systems Mechanisms of this type can simplify the manual installation and removal of modular equipment where ... devices for load-carrying carts or trucks, hooks or pick-up attachments for cranes, and quick-release mechanisms for remotely controlled manipulators This quick-release mechanism is shown locking a...
Ngày tải lên: 22/10/2012, 14:26
Mechanisms and Mechanical Devices Sourcebook - Chapter 16
... belleville bowed cantilever coil compression flat, in mechanisms helix, Hunter’s leaf motors overriding mechanisms pop-up ring return, in mechanisms rubber, molded stem, DeHaviland’s tapered-pitch ... ceramic clutches designing with permanent detent mechanisms permanent, (PM) rare-earth Manipulators (see Robots industrial) Maltese cross, six-sided Mechanisms adjustable output adjustable stroke ... rotation-to-translation scotch-yoke screw self-locking simple feeding snap-action sorting speed control for mechanisms tension control Links 170 167 399 417 417 416 417 94 417 115 115 115 196 319 402 56 56...
Ngày tải lên: 22/10/2012, 14:27
Mechanisms and Mechanical Devices Sourcebook - Chapter 17
... material considered to be obsolete and unsuitable for new designs was deleted For example, clockwork mechanisms for timing, control, and display have almost universally been replaced in contemporary ... who may want to further research on any patents now or once held by those individuals Many of the mechanisms illustrated in this book were invented by anonymous artisans, millwrights, instrument ... were invented by self-trained engineers, scientists, and technicians By themselves, many of the mechanisms and devices described in this book are just mechanical curiosities, but when integrated...
Ngày tải lên: 22/10/2012, 14:27
Mechanisms and Mechanical Devices Sourcebook - Chapter 18
... Parallel-Link Mechanisms Stroke Multiplier Force and Stroke Multipliers Stroke-Amplifying Mechanisms Adjustable-Stroke Mechanisms Adjustable-Output Mechanisms Reversing Mechanisms Computing Mechanisms ... Sclater FM 5/3/01 9:50 AM Page xi Permanent Magnet Mechanisms Electrically Driven Hammer Mechanisms Thermostatic Mechanisms Temperature-Regulating Mechanisms Photoelectric Controls Liquid Level Indicators ... Flat Springs in Mechanisms Pop-Up Springs Get New Backbone Twelve Ways to Put Springs to Work Overriding Spring Mechanisms for Low-Torque Drives Spring Motors and Typical Associated Mechanisms Flexures...
Ngày tải lên: 22/10/2012, 14:27
Mechanisms and Mechanical Devices Sourcebook - Chapter 1
... computer science Other technical specialties that have contributed to robot development include servomechanisms, hydraulics, and machine design The latest and most advanced industrial robots include ... Space Flight Center, Greenbelt, Maryland The figure schematically illustrates three manipulator mechanisms for positioning an end effector (a robot hand or other object) in a plane (which would ... actuators incorporated into a linkage that is classified as “P4R” in the discipline of kinematics of mechanisms because it includes one prismatic (P) joint and four revolute (R) joints The improved...
Ngày tải lên: 22/10/2012, 14:27