Simultaneous Blasting Research Articles

Structural response of steel-concrete composite panels to near field simultaneous blast and fragmentation loading

Steel-concrete composite sandwich panels are used in blast doors or blast walls to protect personnel and equipment in explosive environments due to their superior performance against blast effects. In the design of such panels, most design methods treat blast and fragment loading independently for far-field explosions. However, the synergistic effects of combined blast and fragments loading should be accounted for in close-in explosion scenarios. In this study, a field test program was conducted to assess the damage of the steel-concrete composite panels subjected to close-in explosion of cased charges at various scaled distance between 0.39 and 0.78 m/kg1/3. Characterization test of cased charge detonation was performed to explore the combined loading effect. The analysis includes the pressure-time history from the cased charge detonation, distribution of the fragment masses and velocities over the test panels. The structural damage and response of the composite panels against the combined loading effects was measured. The results indicated that in addition to the damage from the blast wave, the panel was remarkably damaged by the fragment impact. Despite the significant structural damage, the panels maintained its structural integrity after the tests. Additionally, quasi-static load tests were conducted on the panels to quantify their load resistant differences in pristine condition and various damaged conditions due to the explosive effects.

Dynamic response characteristics of backfill under blasting disturbance simulated through a three-dimensional model

During mining operations, the backfill body is subject to significant disturbance due to large-volume blasting, resulting in stress concentration and vibration response within the backfill. This alters energy distribution, leading to the continuous development, expansion, and accumulation of damage, potentially culminating in instability and collapse. Blasting disturbance in stopes is the main cause of filling instability and ore dilution. It is crucial to study the failure mechanism of filling bodies under blasting load to guide actual mine production. In this study, a custom mold was created to establish an innovative three-dimensional model of an ore-backfill system subject to explosion loading. Simultaneous detonation was selected as the control group and delayed detonation was selected as the experimental group. Monitoring and analysis methods, such as a high-speed camera system, MATLAB software, and vibration monitors, were utilized to investigate the impact of delay time on the dynamic response characteristics of the backfill. The results show that the dynamic fracture process of the backfill is mainly divided into four stages: initial crack initiation stage, crack development stage, crack expansion stage, and backfill collapse stage. The difference in delay time on the dynamic fracture process of the backfill is mainly reflected in two aspects: time effect and crack distribution. The surface flatness after delayed detonation is higher by 20.5 % as compared with that after simultaneous detonation. The average damping rate during delayed detonation decreases by 19.7 % as compared with that after simultaneous detonation, the frequency distribution of the single stage is more uniform, and the instantaneous peak energy during delayed detonation is 0.76 times that during simultaneous detonation. The maximum crushing size, average crushing size, and bulk crushing size after delayed detonation are reduced by 25 %, 15.26 %, and 9.23 %, respectively, compared with that after simultaneous blasting. Thus, delayed detonation effectively improves the crushing effect while reducing the degree of damage to the backfill.

A novel method for simulating nuclear explosion with chemical explosion to form an approximate plane wave: Field test and numerical simulation

A nuclear explosion in the rock mass medium can produce strong shock waves, seismic shocks, and other destructive effects, which can cause extreme damage to the underground protection infrastructures. With the increase in nuclear explosion power, underground protection engineering enabled by explosion-proof impact theory and technology ushered in a new challenge. This paper proposes to simulate nuclear explosion tests with on-site chemical explosion tests in the form of multi-hole explosions. First, the mechanism of using multi-hole simultaneous blasting to simulate a nuclear explosion to generate approximate plane waves was analyzed. The plane pressure curve at the vault of the underground protective tunnel under the action of the multi-hole simultaneous blasting was then obtained using the impact test in the rock mass at the site. According to the peak pressure at the vault plane, it was divided into three regions: the stress superposition region, the superposition region after surface reflection, and the approximate plane stress wave zone. A numerical simulation approach was developed using PFC and FLAC to study the peak particle velocity in the surrounding rock of the underground protective cave under the action of multi-hole blasting. The time-history curves of pressure and peak pressure partition obtained by the on-site multi-hole simultaneous blasting test and numerical simulation were compared and analyzed, to verify the correctness and rationality of the formation of an approximate plane wave in the simulated nuclear explosion. This comparison and analysis also provided a theoretical foundation and some research ideas for the ensuing study on the impact of a nuclear explosion.

Experimental and Numerical Study on the Effect of Three-Hole Simultaneous Blasting Technology on Open-Pit Mine Bench Blasting

Blasting technology is widely applied in various engineering applications due to its cost-effectiveness and high efficiency, such as in mining, transport infrastructure construction, and building demolition. However, the occurrence of cracking in the rear row has always been a major problem that disrupts mining bench blasting. To address this issue, a three-hole simultaneous blasting technology is proposed in this study. Both numerical simulations and onsite blasting experimental testing were conducted. To aid this endeavor, the three-hole simultaneous blasting and the hole-by-hole blasting methods were adopted to comparatively analyze the severity of the damage caused to the original rock and the effect of rock fragmentation in the rear row. The obtained results highlighted that the outcome of the blast produced by the three-hole simultaneous blasting method is satisfactory, with fewer flying stones and concentrated blasting piles required. Additionally, the original rock in the rear row showed no obvious sign of tensile damage and had uniform fragmentation. It was also found that a block size of less than 60 cm accounts for 100%, while a block size of less than 50 cm accounts for 98.7% of the whole blocks, with no large blocks reported. Moreover, a penetrating horizontal crack occurred in the direction of the connection of the blast hole center when the three-hole simultaneous blasting method was adopted. This resulted in a smooth and flat rear part of the rocks at the interface. Compared to the hole-by-hole blasting method, the three-hole simultaneous blasting method improved the effective stress and displacement at each measurement point. At the measurement point directly at the front of the borehole, the maximum effective stress attained 67.9 GPa, and the maximum displacement reported was 31.9 cm. Overall, it was shown that the three-hole simultaneous blasting technology is applicable in similar applications of mine bench blasting, which is conducive to addressing the rear row original rock strain for onsite bench blasting.

A 3D nearfield vibration model for simultaneous blasting of multiple holes in the sedimentary rock formation.

Blasting is the most common excavation techniques for sedimentary rocks especially for sandstone. However, blasting process leads to unwanted breakage in the rock beyond the desired perimeter of excavation and such breakage is called blast-induced rock damage or ‘backbreak’. In surface blasting, ‘backbreak’ impacts on bench stability, excavator operation and drilling in the new face. However, prior estimation of extent of rock breakage zone can provide an idea to formulate the blast design to control the backbreak. In the estimation of blast-induced damage zones, vibration-based prediction techniques are one of the popular choices due to their easy applicability in varying geotechnical conditions. The existing vibration-based models are mostly one dimensional and estimate the damage zone only for the single blasthole. However, practically more than one blast holes are blasted to match the production requirement. Sometimes due to improper delay sequence or by using detonating fuse as surface connection, more than one blastholes are blasted simultaneously. Thus, in this study, a damage estimation model is developed based on vibration theory, which can estimate the damage zone generated due to the blasting of multiple holes simultaneously. This model is a three-dimensional model, which considers the position of the blast holes, charges and point of damage in a 3D space. The model is tested in sandstone rock through four numbers of single row multiple holes blastrounds. It is found that the model is predicting damage zone with an accuracy of ± 12%.

Study on rock mass failure characteristics of double-hole delayed blasting in interbedding based on particle expansion algorithm

The existence of the interface between soft and hard rock often makes it difficult to control the blasting effect. Studying the influence of structural plane and delayed initiation time on rock blasting characteristics can make the blasting effect more controllable. In this paper, by using the Particle Flow Code (PFC2D) and particle expansion algorithm, the double-hole delayed blasting experiments of soft-hard rock are carried out, and the results are analyzed from the perspectives of fragment gradation, micro contact force and energy field. Results show that: 1) When blasting in hard rock, if the distance between structural plane and blasthole is about two times the radius of crushing area, it will easier to form large area fragments, and the fragments tend to be crushed with the increase of the distance. When the distance is 2–4 times the radius of crushing area, with the increase of delay time, the overall fragment area value increases first and then decreases, and reaches the maximum when the delay time is 4 ms. 2) When the structural plane existing in the rock mass, the delayed initiation will make the contact force become relatively uniform within a certain range. The main direction of contact force will appear in the uneven state of contact force generated by simultaneous or delayed initiation, which is close to the parallel or vertical direction of blasthole connection. 3) When blasting in hard rock, if the distance between the structural plane and the blasthole is greater than about two times the radius of the crushing area, compared with simultaneous blasting, the peak kinetic energy and peak strain energy of delayed blasting will be reduced by about 33% and 46% respectively.

Dynamic response of UHMWPE plates under combined shock and fragment loading

Ultra-high molecular weight polyethylene (UHMWPE) fiber composite has been extensively used to construct lightweight protective structures against ballistic impacts, yet little is known about its performance when subjected to combined blast and fragment impacts. Built upon a recently developed laboratory-scale experimental technique to generate simulated combined loading through the impact of a fragment-foam composite projectile launched from a light gas gun, the dynamic responses of fully-clamped UHMWPE plates subjected to combined loading were characterized experimentally, with corresponding deformation and failure modes compared with those measured with simulated blast loading alone. Subsequently, to explore the underlying physical mechanisms, three-dimensional (3D) numerical simulations with the method of finite elements (FE) were systematically carried out. Numerical predictions compared favorably well with experimental measurements, thus validating the feasibility of the established FE model. Relative to the case of blast loading alone, combined blast and fragment loading led to larger maximum deflections of clamped UHMWPE plates. The position of the FSP in the foam sabot affected significantly the performance of a UHMWPE target, either enhancing or decreasing its ballistic resistance. When the blast loading and fragment impact arrived simultaneously at the target, its ballistic resistance was superior to that achieved when subjected to fragment impact alone, and benefited from the accelerated movement of the target due to simultaneous blast loading.

Cytofluorimetric assay to investigate variability in blinatumomab in vitro response.

The T-cell engager antibody blinatumomab (BlincytoT⁢M) represents a promising rescue therapy for relapsed/refractory CD19+ acute lymphoblastic leukemia (B-ALL), although ~20-30% of patients still do not respond to treatment. Blinatumomab creates a tight synapsis between CD3+ T-lymphocytes and leukemic CD19+ B-cells, resulting in a granzyme B (GzB)-mediated specific lysis of leukemic cells. Aim of the study was to provide evidence that variability in blinatumomab response could have a genetic basis in PAX5, one of the most often mutated genes in B-ALL, affecting the CD19 surface expression on lymphoblasts, and could be explored in vitro by means of a cytofluorimetric assay, staining both surface antigens (CD45, CD19 and CD3) and intracytoplasmic markers (7AAD, Syto16). Two human immortalized B-ALL cell lines (NALM6 and REH) were chosen for their different PAX5 and CD19 protein levels, as verified by western blot and flow cytometry, respectively. In contrast to NALM6, REH cells do not express the full-length PAX5 protein and show less CD19 on the cell surface (fluorescence peak median intensity: 9155 versus 28895). Co-cultures of CD3+ T-lymphocytes from healthy donors and B-ALL cell lines were seeded at an effector-to-target cell ratio of 1:10 for simulating the condition existing in the bone marrow due to the malignant invasion of blast cells. Co-cultures were exposed in vitro to blinatumomab and the simultaneous increase in blast mortality and T-lymphocytes activation induced by the drug was observed at day +7 (both effects: p < 0.0001 versus untreated, two-way ANOVA, Bonferroni post-test), and was particularly pronounced in REH compared to NALM6 co-cultures (p < 0.05). Surprisingly, daily release of GzB in supernatants, measured by an ELISA assay, was significantly lower in drug-exposed REH co-cultures compared to NALM6 at early time-points (days +3 and +4, p-value < 0.0001, three-way ANOVA), reaching a comparable plateau only towards the end of the incubation period (at day +5). Only 2 out of 5 primary co-cultures of leukemic and mononuclear cells isolated from bone marrow aspirates of B-ALL patients (age: median 10.7 years, interquartile range (IQR) 3.4; males: 60%) responded to the drug in vitro (simultaneous blast mortality and T-lymphocyte activation: both effects: p < 0.0001 versus untreated) and at different drug concentrations. Results were unrelated to the percentages of immature CD19+ B-cells in the diagnostic samples. In conclusion, cytofluorimetric analysis can highlight the different response induced by blinatumomab among co-cultures. Whether and how this difference is affected by PAX5-regulated CD19 expression is unclear and whether it is predictive of in vivo response to therapy remains to be established. Further dedicated studies are required to investigate these issues in detail.

Study on Optimization of Delay Method of Wedge Cut Blasting in Tunnel

Relying on the entrance section of a high-speed railway tunnel blasting project, the fluid-solid coupling algorithm based on ANSYS/LS-DYNA was used to optimize the parameters of wedge cut blasting, and the vibration could be reduced on the basis of ensuring the blasting effect. Through the combination of visual numerical simulation results and rock-breaking mechanism of wedge cut blasting, the maximum vibration velocity of different monitoring points in the model under different segmented time delay was analyzed. The results show that the best method for detonation is dividing the blastholes into three segments from upper to lower and dividing the left and right symmetrical blastholes into one segment. When the delay time is 10 ms, the average vibration reduction ratio is the best, which is reduced by 18% compared with the six-hole simultaneous blasting. In addition, the actual surrounding rock stress has a clamping effect on the cut blasting area. The wedge cut blasting footage obtained by numerical simulation was basically consistent with the field results, which proved that the model is reasonable and effective. This study intuitively and accurately demonstrated the process of cut blasting, the superposition curve of vibration velocity and the vibration reduction results under different delay times, and the effect of cut blasting. The results can be directly applied to similar projects, and the optimal blasting parameters and related issues can be solved more accurately with the help of this engineering analysis method.

Calculation of equivalent charge weight per delay and vibration velocity prediction for millisecond delay blasting

Drilling and blasting is the most economical rock fracture technology in water conservancy, transportation, mining and tunnel engineering. And the application of nonel detonator network in rock blasting is still the most widely used initiation method in engineering blasting practice. Due to the detonator delay error, there is a deviation between the actual initiation time and designed initiation time in the Nonel detonation network, which will cause the change of blasting time sequence and the overlapping of blast-holes. There are detonator dispersion phenomenon with the same delay time and superposition effect for seismic waves with different delay time, which brings great trouble to the value of charge weight per delay and the prediction of particle peak vibration velocity. In order to the predict particle peak vibration velocity more accurately and efficiently, the millisecond delay blasting test was conducted, and the calculation model of vibration velocity for group blast-hole simultaneous blasting with dispersed charge was established. The influence of the blast-hole number on the equivalent charge weight for simultaneous blasting and its value selection method were studied and constructed. The modified particle peak vibration velocity scaled distance formula and the particle peak vibration velocity prediction method were proposed based on the results of regression analysis of single-hole blasting. The results show that the equivalent charge weight of group blast-hole simultaneous blasting is smaller than the nominal charge weight per delay, and the equivalent charge weight of simultaneous blasting can be calculated by converting through the reduction coefficient, which decreases exponentially with the increase of the blast-hole number. The superposition effect of seismic waves with different delay time can be considered by introducing vibration wave superposition factor into the modified particle peak vibration velocity scaled distance formula. The average absolute error, average relative error and root mean square error between the actual and the predicted particle peak vibration velocity values are 0.05 cm/s, 9.52% and 0.059 cm/s, respectively. It is feasible to apply the modified particle peak vibration velocity proportional distance regression analysis method to the prediction and control of blasting vibration velocity in the field.

Procedural framework for explosion classification by the seismic load criterion

For the first time the quantitative classification of blasting operations as sources of blasting vibrations is constructed. According to the classification, all sources are divided into the sources of increased, normal and reduced action. The classification is based on the rectilinear dependences of the PPV attenuation factor on the logarithm of the seismicity coefficient, which are included in Sadovsky’s formula to predict the peak particle velocity under the seismic action of explosions. The classification is based on the statistical analysis of 76 seismicity coefficient—PPV attenuation factor couples reflective of the wide geography of blasting operations carried out in solid minerals mining and in civil engineering. The reliability of the statistical analysis result is proved using the Fisher criterion and Student statistics. The classification boundaries of seismic sources are verified. The sources of increased seismic activity are compared by the conditions of blasting in watered and in very strong rocks, the use of largediameter blast holes, the choice of explosive mass for simultaneous blasting and the influence of the initiation method on the seismic effect produced. The sources of normal and reduced seismic activity were compared by the conditions of blasting in underground mines, at quarries of building materials with ground surface recording, blasting in civil construction and with preliminary borehole slotting. The classification allows the quantitative comparison of blasting operations by the level of seismic action in the intervals of 6–2700 and 0.6–2.8 by the seismicity coefficient and PPV attenuation factor, respectively, for PPV in cm/s. The classification is representative of the current technology of blasting in the world practice.

Experimental and Numerical Investigation of Blast‐Induced Vibration for Short‐Delay Cut Blasting in Underground Mining

It is essential to control the damage to the surrounding rock and engineering structures in the process of cut blasting with a single free surface in underground mining. To reduce vibration induced by cut blasting, this paper proposes short‐delay cut blasting, in which blast holes that are near each other are sequentially initiated with short‐delay times. Experimental tests of cut blasting were conducted in a roadway in the Shaxi copper mine to compare the peak particle velocity (PPV) and frequency characteristics of simultaneous blasting and short‐delay blasting. Numerical modelling was then developed to study the influence of short‐delay times on blast vibration. The accuracy of the numerical simulation was verified by the comparison of the test and simulated data of single‐hole blasting. The results show that the amplitude reduction ratio (ARR) value increases gradually with the increase in delay intervals, and the vibration reduction for delay intervals smaller than 6 ms is very limited, particularly in the near field. The principal frequencies (PFs) for short‐delay blasting are similar to those for simultaneous blasting, which implies that the frequencies do not increase directly with the decrease of the delay intervals. The experimental tests also show that the mean frequencies (MFs) for the 8 ms delay are slightly higher than those for the 0 ms delay blast. In the case of ensuring the rock breaking of cut blasting, longer delay intervals of 8∼10 ms are beneficial to further reduce PPV in practical blasting.

Short-delay blasting with single free surface: Results of experimental tests

Delay blasting with relatively long-delay intervals is widely used in mining engineering since the former detonated blast-holes can produce new free surfaces for the later detonated blast-holes. With the application of electronic detonators, which have a minimum delay and a delay accuracy of 1 ms, a new blasting pattern using short-delay intervals is proposed in the present study in order to improve rock breaking and control blast-induced vibrations in cutting blasting with single free surface in underground mines. Theoretical analyses are firstly conducted to investigate the mechanisms of blasting crater formation and vibration reduction of short-delay blasting. Then a series of blasting crater tests with different delay intervals are performed to compare the characteristics of blasting craters and blast-induced vibrations produced by short-delay and simultaneous blastings. The results of crater sizes show that it is possible to form a common blasting crater only when the delay intervals are shorter than the formation time of a new free surface. It is also found that the short-delay blasting can effectively reduce PPV compared with the simultaneous blasting, particularly in the near-field. Spectral analysis indicates that there is less energy in the low-frequency content in short-delay blasting than simultaneous blasting. The possibility and feasibility of reducing vibration via short-delay blasting in underground mines are also discussed in this study.

Measurement of the higher-order anisotropic flow coefficients for identified hadrons in Au + Au collisions atsNN=200GeV

New PHENIX measurements of the anisotropic flow coefficients $v_2\{\Psi_2\}$, $v_3\{\Psi_3\}$, $v_4\{\Psi_4\}$ and $v_4\{\Psi_2\}$ for identified particles ($\pi^{\pm}$, $K^{\pm}$, and $p+\bar{p}$) obtained relative to the event planes $\Psi_n$ in Au$+$Au collisions at $\sqrt{s_{_{NN}}}$ = 200 GeV are presented as functions of collision centrality and particle transverse momenta $p_T$. The $v_n$ coefficients show characteristic patterns consistent with hydrodynamical expansion of the matter produced in the collisions. For each harmonic $n$, a modified valence quark number $n_q$ scaling plotting $v_n/(n_q)^{n/2}$ versus ${\rm KE}_T/n_q$ is observed to yield a single curve for all the measured particle species for a broad range of transverse kinetic energies ${\rm KE}_T$. A simultaneous blast wave model fit to the observed particle spectra and $v_n(p_T)$ coefficients identifies spatial eccentricities $s_n$ at freeze-out, which are much smaller than the initial-state geometric values.

Influence law of multipoint vibration load on slope stability in Xiaolongtan open pit mine in Yunnan, China

The purpose of this work was to explore the influence law of vibration load on rock mass structure and slope stability. Based on the type and transmission way of vibration stress wave, the main stress in the horizontal and vertical directions was analyzed and the superposition effect of the stress wave was revealed. After the mechanical analysis of the sliding mass, the calculation formulas of the anti-sliding force and the sliding force were derived and the damage mechanism of blasting vibration to the structural plane was defined. In addition, according to the structure and lithologic parameter of the slope as well as the vibration monitoring data, the west slope stability of Xiaolongtan open pit mine was analyzed. The results show that the time-dependent stability factor is proportional to the vibration speed and the peak values appear at the same time. Vibration load promotes the breakage of the structural plane leading to the drop of the west slope stability factor by 0.23%. Under the multipoint simultaneous blasting, the fluctuating laws of the stability factors are consistent. The more the start-up points are, the higher the weakening degree to the slope stability is. Under the multipoint allochronic blasting, the stability factor depends on the synthetic waveform structure of all vibration waves. The greater the blasting time difference is, the lower the weakening degree to the slope stability is. Selecting the reasonable quantity of start-up points and time difference could fully reduce the adverse influence of vibration load to slope stability.

Evaluation of the structural integrity of the CPR1000 PWR containment under steam explosion accidents

Detailed three-dimensional finite element models were set up to study the dynamic response and the possible damage of the CPR1000 PWR containment under steam explosion accidents with a full consideration of the complex geometric structures, the complex mechanical behavior of materials and the complex blast loadings. The structural integrity of the containment and the internal structures was evaluated under five typical steam explosion scenarios. In addition, the influence of the thermal loading was investigated by setting up a thermal-mechanical coupling finite element model. It is found that under steam explosions, only a small portion of energy is transferred to the concrete containment and therefore, the influence of the explosions on the containment is insignificant. Although the internal facilities and the structures are damaged severely by the blast loadings, the damage to the containment is negligible and the structural integrity is ensured. The thermal loading has a noticeable influence on the loading-capability of the containment structure. It is shown even a pure thermal load, i.e., a 150°C temperature variation across the containment wall, can cause some damage to the concrete containment. The damage is further deepened by a simultaneous blast loading due to a steam explosion. However, the maximum depth of the damage is small compared with the thickness of the wall and the integrity of the concrete containment is still ensured.

Introduction: Popular Entertainment and American Theater Prior to 1900

Although Col. George A. Custer's defeat at Little Big Horn on 25 June 1876 was anything but theatrical event, it certainly became one very soon after. By middle of August, theatergoers in New York City were flocking to Wood's Theatre for Harry Seymour's blood-and-thunder re-enactment Sitting Bull; or, Custer's Last Charge. (1) Meanwhile, out on Plains scout and part-time actor and playwright named William F. Buffalo Bill accidentally found himself on 17 July face to face with Cheyenne warrior named Yellow Hair. The two exchanged single, simultaneous blast of gunfire, which only survived. Taking his opponent's scalp in hand, almost immediately began to weave brief skirmish into larger and more complex battle of deliberately taken revenge for Custer, with as hero. Moreover, according to most reports, fought while decked out in a stage costume of black velvet slashed with scarlet and trimmed with silver buttons (2) Although he was at this particular moment in employ of U.S. Fifth Cavalry, had by this time become something of celebrity on East Coast for his highly stylized (some might say cliche-riddled) touring stage reenactments of his own exploits. Thus, his wearing of stage costume both arises from his ongoing interest in performing frontier persona and inflects event with theatrical note. And in autumn of 1876, further embellished importance of skirmish, and hence his reputation, by starring in New York in play he had commissioned about his killing of Yellow Hair called The Red Right Hand, or The First Scalp for Custer. The printed programs for this show reportedly included poetry and news releases about [the Little Big Horn battle], by which Cody and his managers traded on audience's belief that were transmitting news from front, representing events actually unfolding on plains even as spectators sat watching them in Boston, New York, or Omaha. (3) The transmutation of current events into theater represents but one ingredient in United States' long history of imbuing popular modes of entertainment with matters of cultural or national consideration. As further example of this phenomenon, consider Royall Tyler's The Contrast (1787), where character Jonathan goes out in search of circus-like place he had heard of where a hocus pocus man ... could eat case knife only to find himself in proper playhouse watching Sheridan's School for Scandal The joke is that when they lifted up great green cloth Jonathan naively believed he and rest of audience were merely looking right into next neighbor's house (4) The Contrast is generally credited as the first comedy written by an American to be produced professionally and character of Jonathan as first instance of now-familiar Yankee rube character type. (5) Jonathan's misapprehension of nature of space in which he finds himself one evening once again points to relationship between popular theatrical entertainment and crafting of very frameworks within which knowledge of world could be organized or produced. Which is to say, Jonathan's search for performer of tricks leads him and, by extension, those who have come to theater to watch an actor perform this role to lesson in theatrical verisimilitude. In 1993 Gary A. Richardson observed that Whether out of religious, aesthetic, or ideological bias, nation's cultural arbiters have tradition ally been, at best, ambivalent about America's drama and its functions. This is especially true of drama before O'Neill, about which prevailing opinion seems to be that less said better. (6) Fortunately, this assessment is far less true than it may have been decade ago, for much admirable scholarship has in recent years given serious consideration to American theater prior to advent of literary Modernism. (7) Nevertheless, compelling and important questions still remain, among them questions about extent to which developments in American popular entertainment prior to 1900 contributed contemporaneously to culture's questions about such matters as high- and lowbrow art, popularity versus artistic quality, and representation of political and social events as entertainment. …

AgdbNet - antigen sequence database software for bacterial typing.

BackgroundBacterial typing schemes based on the sequences of genes encoding surface antigens require databases that provide a uniform, curated, and widely accepted nomenclature of the variants identified. Due to the differences in typing schemes, imposed by the diversity of genes targeted, creating these databases has typically required the writing of one-off code to link the database to a web interface. Here we describe agdbNet, widely applicable web database software that facilitates simultaneous BLAST querying of multiple loci using either nucleotide or peptide sequences.ResultsDatabases are described by XML files that are parsed by a Perl CGI script. Each database can have any number of loci, which may be defined by nucleotide and/or peptide sequences. The software is currently in use on at least five public databases for the typing of Neisseria meningitidis, Campylobacter jejuni and Streptococcus equi and can be set up to query internal isolate tables or suitably-configured external isolate databases, such as those used for multilocus sequence typing. The style of the resulting website can be fully configured by modifying stylesheets and through the use of customised header and footer files that surround the output of the script.ConclusionThe software provides a rapid means of setting up customised Internet antigen sequence databases. The flexible configuration options enable typing schemes with differing requirements to be accommodated.

WebACT—an online companion for the Artemis Comparison Tool

WebACT is an online resource which enables the rapid provision of simultaneous BLAST comparisons between up to five genomic sequences in a format amenable for visualization with the well-known Artemis Comparison Tool (ACT). Comparisons can be generated on-the-fly using sequences directly retrieved via EMBL database queries, or by entering or uploading user sequences. Furthermore, pre-computed comparisons are available between all publicly available, completed prokaryotic genomes and plasmids currently contained within the Genome Reviews database (372 sequences, representing 175 different species). The system is designed to minimize the volume of downloaded data and maximize performance. Genome sequences, annotation and pre-computed comparisons are stored in a relational database allowing flexible querying based on user-defined sequence regions, from whole genome to a defined region flanking a specified gene. Comparison and sequence files, whether computed online or retrieved from the database of pre-computed genome comparisons, can be viewed online using ACT and are available for download. Freely accessible at http://www.webact.org. User guide and worked examples are available at http://www.webact.org/WebACT/docs.

Effective methods of compaction of water-saturated soils by blasting

The writer demonstrates the effectiveness of compaction of water-saturated soils by the method of successive blasting of charges in comparison with the method of simultaneous blasting, as a result of rational application of the gravity wave formation phenomenon.