Millisecond Delays Research Articles

Methodology of designing blasting works in open pit mining in terms of their impact on construction objects

The firing of explosive charges with (millisecond) time delay gives a wide range of possibilities in designing multi-row blasting patterns and, at the same time, contributes positively to the minimization of the impact of blasting works on building infrastructure in the vicinity of mines. Selection of the appropriate millisecond delay should be based primarily on seismograms of vibrations induced during the firing of single explosive charges and analysis of the frequency structure of these vibrations. Using this type of data, the article presents a procedure for optimizing millisecond delays with the use of a computer programme dedicated to modern, electronic initiating systems that are currently applied towards obtaining a favourable vibration structure in terms of the assessment of the impact on buildings in accordance with the standard regulations applicable in Poland.

Design of a high speed rat whiskers tracking and symmetry analysis system based on FPGA.

This paper presents a high-speed rat whisker tracking and symmetry analysis system based on FPGA. The system utilizes high-speed image sensors recording rat face videos at 120 and 1000 fps. The Xilinx Ultra96 single computer board is chosen as the platform to implement the system's processing system (PS) and the programmable logic (PL) part. The PL part is responsible for high-speed image processing and whisker tracking, while the PS part analyzes the symmetry of rat face using the tracking results from the PL part. With a processing speed FoM of 118.5 fps/GHz on the Xilinx Ultra96 single computer board and 275.47 fps/GHz on a laptop with Intel Core i5-11500T@1.5GHz, the presented system achieves excellent performance. The proposed whisker detection method has a precision of 98.2% when a threshold with a 4-degree error is selected, with an average error angle of 0.98 degrees across more than 10,000 video frames. Moreover, the proposed system is capable of local video processing within millisecond delays. These results demonstrate the feasibility of developing a high-speed, accurate, and efficient whisker tracking and symmetry analysis system for rat behavior research.

Numerical Study of Rock Damage Mechanism Induced by Blasting Excavation Using Finite Discrete Element Method

In this paper, the mechanism of rock damage induced by blasting excavation is numerically studied by using an FDEM-based multiphysics fracture analysis software, MultiFracS. Based on the drainage channel project of Guanggu 1st Road to Gaoxin 4th Road, a numerical model considering the near-field fracture process is established to study the influence of a millisecond delay and construction technology on the blasting excavation. Firstly, the double side drift method model is established to analyze the influence of different millisecond delays on the peak blasting vibration velocity. Then, the rock fracture process of the surrounding rock around the blast holes under the blasting excavation construction technology of the double side drift method, the reserved core soil method, and the CRD method is studied, respectively. The numerical simulation results show that the mainshock phases of the blasting vibration velocity waveform generated by different bores overlap when the millisecond delay is small. With the increase in the millisecond delay, the mainshock phase is gradually separated, and the superposition effect of the blasting vibration is weakened. When the millisecond delay is greater than 40 ms, the peak blasting vibration velocity is not affected by the millisecond delay. In the three kinds of blasting excavation construction technologies, the double side drift method has a better effect on the deformation and the fracture control of the surrounding rock. The optimal millisecond delay and the rock fracture evolution process of the surrounding rock around blast holes with different blasting excavation construction technologies are obtained.

Digital Triggering Device and Generator of Starting Pulses for Ignition of Spark Gaps of REB Accelerator “TEMP”

To ensure the controllability and high noise immunity while measuring the characteristics of the accelerators of relativistic electron beams (REB) “TEMP”, and parameters of the processes in them, triggering devices with galvanic isolation of input and output circuits, allowing to set up the pulse delays in the range from 1 μs to tens of milliseconds, have been developed. When they are used, the effect of loop currents, which flow in the common ground circuits and affect the operation of the measuring equipment, is eliminated. To synchronize the operation of the REB accelerator “TEMP” a triggering device was developed and assembled. It was assembled from blocks produced on the up-to-date elemental base and is a complete functional product. The triggering device comprises a trigger block and delay units. The trigger block is developed on the basis of an AND - NOT chip and a multivibrator. The delay units are built on single-shot vibrators K155AG1 and differ in the value of adjustable delays, which are determined by the external elements R and C, connected to the multivibrator. Unfortunately, in case the millisecond delays are set up, the pulse drop on the multivibrator is not stable. Therefore, a digital triggering device was developed. The digital triggering device is built on the basis of digital microcircuits and consists of the following blocks: binary-decimal counters, decoders, and one oscillator with quartz frequency stabilization, which is common to all four channels. It contains four identical channels with delay adjustment from one microsecond to one hundred milliseconds. Such a pattern of the circuit allows, if necessary, adding channels for starting other units. Pulse signals of the triggering device are fed to the ignitor unit of the spark-gaps. A pulse generator for igniting the spark-gaps of the REB accelerator “TEMP” has been developed. A generator, designed to control the spark gaps ignition in the High Voltage Pulse Generator (HVPG) and spark gaps ignition in the magnetic systems, which are used in switching systems of the capacitor banks with the energy of 60 ¸ 150 kJ, has been described. The generator provides voltage pulses with the amplitude of up to 20 kV, at the current in the short circuit mode of 5 A, the pulse duration of the first half wave of 12 μs, and the pulse repetition frequency (PRF) of not more than 10 Hz.

Dynamic response of rock mass induced by the transient release of in-situ stress

During the excavation of rock mass with the method of drill and blast, the release of in-situ stress, also known as excavation load on boundary, is traditionally assumed as a quasi-static process, so the inertia and all other dynamic responses induced by the release of in-situ stress can be ignored. After analyzing the process of release of in-situ stress induced by rock mass excavation with the method of drill and blast and determining the duration of the release of in-situ stress, it is found that the release of in-situ stress induced strain rate can reach a magnitude of 10−1–101/s or higher if the initial in-situ stress has a level of 20–50MPa, it implies that the release of in-situ stress is a transient process, and the transient character of the release of in-situ stress and correspondingly induced dynamic response of surrounding rock should be taken into account together with excavation. Problems such as the determination of redistributed in-situ stress corresponding to initiation sequences of millisecond delays, the way and path of the transient release of in-situ stress, transient release of in-situ stress induced vibration and comparison with blasting induced vibration are also discussed in this paper. Finally, a case of in-situ stress release induced vibration in Pubugou hydropower projects are presented as verifications.

Successful Introduction of Cloud Computing into your Organization: A Six-Step Conceptual Model

LITERATURE SURVEY: THE LANDSCAPE OF CLOUD COMPUTING A recent survey on the status, applications, versatilities, popularities, and opportunities gained by using cloud computing platforms reveals interesting facts as follows: Many banks including ING are testing cloud computing for integrating it into their operations. In a survey of 186 banking technology professionals interested in cloud computing 73 percent of the participants indicated that cloud computing will enable them to meet user demands quickly and achieve scale (Crosman, 2010). Morgan Stanley is another major bank that is planning to integrate cloud computing into its operations. However, security and privacy in cloud computing are among the major concerns (Cohen, 2008). Department of Defense (DoD) is exploring the use of cloud computing in one of the following four categories (Anonymous, 2010): * Use commercially provided cloud services * Deploy cloud computing within DoD networks * Develop a multi-agency cloud computing network for data processing and storage * Develop a combined DoD/commercial provider system Key decision makers believe cloud computing will provide greater agility and flexibility for the DoD, today and in the future. Cloud computing will also increase efficiencies and incur marked cost savings during their life-cycles to alleviate some of the pressure of budget reductions. Once again, security and privacy are major concerns for this deployment (Forbes, 2011, Anonymous, 2011). In addition, experts believe that, the department of defense could run more effectively using cloud technologies. DoD could become a model and show other large organizations how cloud computing applications could be used (Linthicum, 2010d). According to experts it makes no sense for smaller enterprises to operate their own data centers. Cloud computing will be both cost effective and also environmentally safer and cleaner for such organizations (Krill, 2010). Cloud computing platforms clearly support the growing phenomenal of computing and could help organization to achieve their green goals. An executive at global consultancy CSC predicts that half of all IT workloads will become cloud services by 2016 (Knorr, 2011). Despite millisecond delays cross-ocean cloud applications are gaining in popularity because of major cost saving and other advantages (Thibodeau, 2011c). President Barack Obama relies heavily on cloud computing and data center consolidation to keep IT costs under control (Thibodeau, 2011b). The Obama administration aims to cut costs by embracing the cloud in place of in-house, proprietary technology (Samson, 2010). A report published in Techland.time.com in February 2011 indicates that YouTube uses cloud computing infrastructure to split video processing between hundreds of thousands of machines, allowing them to process video seven times faster than in 2008 (and even four times faster than just six months ago) (McMillan, 2011). Tata Communications will offer cloud computing that includes services for computing, data transfer, and storage (Ribeiro, 2010). Joining Microsoft, Oracle, Google and others, IBM plans to offer a cloud-based office suite (Jackson, 2011). IBM also puts Notes and collaboration in the cloud (Knorr, 2010). China is building a city-sized cloud computing and office complex that will include a mega data center. Cloud computing is among the projects supporting that country's double-digit growth in IT spending (Thibodeau, 2011a). BACKGROUND As reviewed in the previous section, cloud computing is one of the fastest area of application within the information systems field. Most computer and networking companies are trying to either enter into this area or increase their existing market share. Even during the economic down turn, cloud computing related jobs have been in high demand (Linthicum, 2010b). …

Correction: Coherence Potentials: Loss-Less, All-or-None Network Events in the Cortex

There was an error in the third sentence of the second paragraph of the section Correlated nLFPs Are Temporally Clustered with Millisecond Delays. It should read: Note that the maximal average fraction of correlated sites as a function of trigger amplitude is achieved when there are >50% available sites on the array, and thus the upper part of the sigmoidal function cannot be explained by a ceiling effect due to limited array size.

Experience is required for the maintenance and refinement of FM sweep selectivity in the developing auditory cortex

Frequency modulated (FM) sweeps are common components of vocalizations, including human speech. How developmental experience shapes neuronal selectivity for these important signals is not well understood. Here, we show that altered developmental experience with FM sweeps used in echolocation by the pallid bat leads to either a loss of sideband inhibition or millisecond delays in the timing of inhibitory inputs, both of which lead to a reduction in rate and direction selectivity in auditory cortex. FM rate selectivity develops in an experience-independent manner, but requires experience for subsequent maintenance. Direction selectivity depends on experience for both development and maintenance. Rate and direction selectivity are affected by experience over different time periods during development. Altered inhibition may be a general mechanism of experience-dependent plasticity of selectivity for vocalizations.

Canadian Liquefaction Experiment (CANLEX): Blast-Induced Ground Motion and Pore Pressure Experiments

Abstract As part of the Canadian Liquefaction Experiment (CANLEX), single and multiple explosive charges were detonated in a level deposit of loose, saturated, sand-size mine tailings. Empirical equations were developed from pore pressure and ground motion recorded at several locations. A condition of zero effective stress was induced at a depth of 6 m when peak particle velocity exceeded 0.65 m/s for single detonations and 0.13 m/s for twelve detonations having millisecond delays. Little or no excess pore pressure was induced from single or multiple detonations when peak particle velocity or peak compressive strain was less than 0.01 m/s or 0.001 %, respectively. The blasting experiments were conducted and analyzed to determine blast-induced ground motion and pore pressure response in a level deposit and to determine the possibility of using explosives to trigger flow-liquefaction in tailings located below an embankment, while keeping peak particle velocities within limits set by Syncrude Canada, Ltd.

Application of a damage model for rock fragmentation to the millisecond blasting for ditching deep blast-holes

A modified elastic-plastic model yielded good agreement between the calculated fragmented regions and excavated ditch profiles for blasting in limestone. The numerical simulation was conducted using millisecond delays on a ditching program using deep blast-holes. Both rock movement during ditching and the mechanism of millisecond blasting were analyzed. The results show that the numerical simulation based on the chosen damage model can predict the dynamic event of rock fragmentation and should prove to be useful in blasting design.

Combination-sensitive neurons in the ventroanterior area of the auditory cortex of the mustached bat.

1. Because the ventroanterior (VA) area is one of the target areas of the FM-FM area in the auditory cortex of the mustached bat, Pteronotus parnellii parnellii, response properties of combination-sensitive neurons in this area were studied with constant-frequency (CF) tones, frequency-modulated (FM) sounds, and sounds similar to the bat's biosonar signal (pulse), which consisted of long CF components (CF1-4) and short FM components (FM1-4). CF1-4 and FM1-4 are the components in the four harmonics (H1-4) of the pulse. 2. Combination-sensitive neurons are clustered in a small area immediately anteroventral to the Doppler-shifted CF processing (DSCF) area and posteroventral to the anterior division of the primary auditory cortex. Because this cluster in the VA area is small, it was difficult to record a sufficient number of combination-sensitive neurons to explore the functional organization of the cluster, but it was found that the response properties of these VA neurons were unique. 3. Combination-sensitive neurons in the VA area are tuned to particular combinations of signal elements similar to the first and second harmonics of the pulse and/or echo. Unlike neurons in the FM-FM, dorsal fringe (DF), and CF/CF areas, no neurons in the VA area are tuned to the signal elements in the first and third or fourth harmonics. 4. The great majority of combination-sensitive neurons in the VA area can not be easily classified into either FM-FM or CF/CF neurons, because they show facilitative responses to combinations of CF1/CF2, FM1-FM2, and FM1-CF2. Therefore, they are called H1-H2 neurons. In the FM-FM and CF/CF areas, all the neurons could be easily classified as FM-FM or CF/CF. This uniqueness of H1-H2 neurons is related to the fact that their best frequencies for facilitation are predominantly between 61.0 and 62.0 kHz, i.e., within the frequency range of stabilized Doppler-shifted echo CF2. 5. In addition to 27 H1-H2 neurons, 7 FM1-FM2 neurons were also recorded in the VA area. The best delays of these H1-H2 and FM1-FM2 neurons measured with FM1-FM2 pairs are between 1 and 10 ms. Unlike neurons in the FM-FM and DF areas, their delay-tuning curves are very broad, even if their best delays are short, and extend beyond zero delay to several millisecond "negative" delays of the FM2 from the FM1, i.e., several millisecond delays of the FM1 from the FM2.(ABSTRACT TRUNCATED AT 400 WORDS)

Initiation timing influence on ground vibration and airblast

ABSTRACT A major concern with blasting at surface mines is generation of ground vibrations and airb1ast and their effects on nearby residences. This Bureau of Mines report looks at the use of millisecond delays in blast design and their effect on the resulting ground vibrations and airb1ast. A total of 52 production blasts were instrumented and monitored at a surface coal mine in southern Indiana. Arrays of seismographs were used to gather time histories of vibrations and airblast. The data were analyzed for peak values of vibration and airblast and for frequency content. Various delay intervals were used within and between rows of b1astho1es.De1ay interva1s within rows were 17 and 42 ms, and those between rows ranged from 30 to 100 ms; these interva1s are equivaIent to 0.5 and 1.3 ms/ft within rows and 1.2 to 4.3 ms/ft between rows. Subsonic delay interva1s with in rows reduced airb1ast by 6 dB. Large delay interva1s between rows reduced the amp1itude of ground vibrations; their frequency depended primar...

A Laboratory Study of Blast Densification of Saturated Sand

Laboratory tests have been conducted to investigate the potential of millisecond delays in blast‐densification of saturated cohesionless sand. A large liquefaction tank was used to prepare and contain the sand. Commercially available blasting caps were used as the explosive. Cone penetration tests and sand surface elevation changes were measured. In addition to lowering the peak body wave ground motions, densification with millisecond delays was shown to be comparable to densification by a single large blast with a total charge weight equal to the sum of the delays. Increases in cone penetration resistance were measured 10–40 cm (4–16 in.) from the charges. A gradual increase in point resistance was observed with time after each blast. The increase in penetration resistance may be attributed to gradual improvement of intergranular bonds and dissipation of explosion created gases.

Velocity accuracy and performance characteristics of Janus acoustic Doppler navigator systems

The Janus radar Doppler navigator system has excellent velocity measuring accuracy which the analog underwater acoustic navigator system, using dual independent bottom and volume reverberation modes, cannot match. While considerable differences exist between aerospace and hydrospace vehicle dynamics, they can be largely mitigated using only millisecond delays in post time integration smoothing of the velocity-time history which results in small dynamic induced system errors. The transducer construction and installation errors are primarily random, small, and partially reducible in proportion to time and cost. The basic difference between the radar and acoustic system velocity accuracy is in the water reverberation mode which is necessary for the latter system in deep water. This error depends on ocean currents, upwelling, internal waves, etc., but most importantly on the water particle motion caused by the displacement of water as the hull moves. This paper is a review of the Janus acoustic system and the various intrinsic errors, including calculations of the limiting error due to water undergoing essentially incompressible flow around an ellipsoidal model of a submarine hull.