Nux Vomica 200 CH reduced acute hypnotic effect of alcohol in young toads

Potentized Nux Vomica has been reported to produce antialcoholic effect in mice, rats and toads. The effect relates to consumption of alcohol and alcohol-induced loss of righting reflex (RR). RR’s maintain normal erect posture of an animal and are centrally controlled in the midbrain. In the present study young toads, Duttaphrynus melanostictus were first treated with Nux vomica 200 CH and then partially immersed in 209 mM ethanol solution in such a way that their head remained above the level of ethanol solution. Toadlets were removed from the ethanol solution every 10 min, tested for the loss of RR and returned to the ethanol solution. Toadlets were placed in a supine position on a dry flat surface. Failure to right within 60 sec was considered as the loss of RR. The experiment was repeated 10 times. Control toadlets were pretreated with 90% ethanol instead of Nux Vomica 200 CH. The percentages of toadlets showing loss of RR, both in the control as well as in the Nux-treated groups, were shown in graphs against the duration of exposure to ethanol solution. Differences in the percentage distribution between the control and the treatment groups losing RR were tested by χ2 test. All the experiments were conducted at room temperature. The percentage of toadlets losing RR increased with time of exposure to ethanol solution. The increase was significantly higher with the control than with the Nux-treated group. Nux Vomica 200 CH might have influenced the mid-brain of toadlets thereby countering the hypnotic effect of ethanol in the toadlets.

Simulation Calculation on the Failure Mode of the Big-size Sandbag Cofferdam on Soft Foundation

The offshore engineering develop fast in recent years, a new method named “big-size sandbag cofferdam” is applied to many practical projects in China. The sandbag is made of geotextile with large sizes in length and width. Sandbags are filled with pumped sea sand and stacked together layer by layer. Many theoretical obstacles remain unsolved, which has restricted the application of this advanced technology. Based on an instability project located in Bohai Bay, the failure mode of the big-size sandbag cofferdam on soft foundation was studied. The results show that the deformation of cofferdam was concentrated on the bottom sandbag, under the action of insufficient foundation bearing capacity and overburden load, the stress of the geotextile at the bottom layer increase sharply during the fast filling, then exceed its ultimate tensile strength, and the cofferdam would be pulled apart from the bottom to top, lead to a continuous penetrating sliding surface failure of big-size sandbag cofferdam.

Effects of temperature and loads on hardness and surface failure modes of cemented carbide

Cemented carbide is a common cutting material with a hardness that significantly affects its usability. A Vickers indentation test was performed to analyse changes in the hardness of cemented carbide cutters with temperature and loads to understand its variation law. Moreover, indentation-induced surface damage was observed, and its elements were analysed. Crack distributions on the indentation surface were detected and analysed through an etching method. The results demonstrate that the hardness of cemented carbide decreases with greater temperatures and loads. At room temperature, the hardness of cemented carbide decreased from 1321 to 996 MPa when the loads increased from 300 to 800 N. When the external load was fixed at 500 N, the hardness of the cemented carbide decreased from 1113 to 939 MPa as the temperature increased from 25 to 350 °C. Moreover, the density of the indentation-induced surface damages increased with a reduction of the Vickers hardness. In addition, the mean free path of the binding phase for the cemented carbide with large grain sizes was relatively high. Therefore, it is difficult to generate diagonal cracks under large loads and high temperatures, which are beneficial to prevent cutter flaking.

Research on Surface Failure Law of Working Faces in Large Mining Height and Shallow Buried Coal Seam

In the process of high-intensity and large-space mining in Shendong mining area, various surface cracks are generated on the surface, resulting in serious damage to the surface buildings and the local ecological environment. To study the influence of overlying rock movement on surface failure of near-field single key strata of near-shallow buried and large mining height working face, the relationship between overburden movement, strata pressure appearance, and surface failure at working face 52307 in Daliuta mining area was analyzed by field measurement and numerical simulation. The results show the following: (1) there is only one thick and hard key stratum in the overburden of large mining height and near-shallow buried working face. Under the condition of presplitting roof blasting, the first weighting step is still as high as 95 m, and the periodic breaking step of roof is 20–30 m. During the weighting, the working resistance of support is still close to the rated resistance. (2) The single key stratum plays an obvious role in controlling overburden movement. After the first weighting of the working face, a stepped subsidence crack appears on the surface within a short time, and the crack lags behind the working face for about 5 m. (3) During each periodic weighting process, the breaking and subsidence of key blocks are accompanied by surface cracks.

Experimental Investigation on Hard Rock Breaking with Fiber Laser: Surface Failure Characteristics and Perforating Mechanism

The rock-breaking characteristics and the influence factors of laser perforation are investigated in this study. A series of fiber laser perforation experiments on basalt, sandstone, and granite were conducted. Experimental measurements of rock failure morphologies and composition tests showed that the main surface features are thermal cracks and glazed layer formed by the melting and condensing of rock in laser perforation. It is also found that higher quartz content could help reduce the glazed degree of rock. Comprehensive results showed that the laser rock perforation is mainly formed by thermal fractures, the decline of molten pool, and the evaporating and splashing of the special melted rock components. The depth of rock perforation and SE usually increase with the laser irradiation time, while the ROP gradually decreases. With the increase of laser power, the perforation depth and ROP gradually increase, while the SE initially decreases and then increases indicating that there is an optimal power that maximizes perforation efficiency. It is believed that the strength of rock is the main factor affecting laser perforation efficiency, and the lower rock strength resulted in deeper perforation depth, higher ROP, and lower SE.

Evaluating the effects of lateral control surfaces failure on the generic transport model: a case study

ABSTRACTExtensive research in recent years has focused on improving the current loss-of-control prevention systems and developing new strategies for safe path planning of the impaired aircraft. Success in developing such systems requires a comprehensive perception of the influence of damage on the aircraft’s dynamic behaviour and performance, and the effect of various failure degrees on the flight envelope confinement and the remaining safe maneuvers. This paper comprehensively describes the effects of lateral control surface failure on the NASA Generic Transport Model (GTM) flight envelope, defined by a set of attainable steady-state maneuvers herein referred to as trim points. The study utilises a large database of high-fidelity maneuvering flight envelopes computed for the unimpaired case and wide ranges of the aileron and rudder failure cases at different flight conditions. Flight envelope boundary is rigorously investigated, and the key parameters confining the trim points at different boundary sections are identified. Trend analyses of the impaired flight envelopes and the corresponding limiting factors demonstrate the effect of various failure degrees on the remaining feasible trim points. Results can be employed in emergency path planning with potential uses in the development of aircraft resilient control and upset recovery systems.