Effect of W on the Impact-Induced Energy Release Behavior of Al–Ni Energetic Structural Materials

Energetic structural materials (ESMs) are an important class of military materials due to their good structural and energy-releasing characteristics. To improve the damage effect of metal–metal ESMs with good mechanical properties, W was added to the 48Al–52Ni composites, and the effect of W on the impact-induced energy release behaviors was investigated. The results showed that the hot-press process and the addition of W did not change the microstructure and surface state of the constituent particles, leading to a stable onset temperature of the Al–Ni intermetallic reaction in (48Al–52Ni)100-xWx composites. Meanwhile, the decrease in the contact area between Al and Ni in the composites with increased W content resulted in the decrease in reaction heat. During the impact process, the intermetallic reaction of W caused by the Al–Ni intermetallic reaction, as well as the oxidation reaction of Al and Ni caused by the brittle fracture along the weak interface, caused the released energy of (48Al–52Ni)40W60 to reach 2.04 kJ/g.

A cable supporting test under impact loading based on 5G-IoT

Reliable supporting effect is of utmost important for the deep mining roadway to prevent the hazards during deep mining activities. Traditional supporting equipment are not satisfying in the absence of the energy-absorbing capacity, whereas the Constant-Resistance-Large-Deformation (CRLD) cable, which can endure a large deformation of 2 m and provide a constant resistance in the meantime, would be a reasonable choice. To verify the CRLD performance of the new cable and highlight its energy-absorbing capacity under impact loading, this paper designed an in situ blasting test in a discarded deep roadway, which is divided into four sections and reinforced by the traditional and CRLD cables, respectively. Firstly, a numerical study of the blasting testis is carried out, the CRLD cable element is proposed, based on the existing one of the FLAC3D software, and a static pullout test is simulated to verify the new element, the adapted impact loading is estimated and the dynamic calculation is performed. Furthermore, under the blasting, which releases the energy of the 1st seismic magnitude, the monitored axial forces of the cables are transmitted in real time using 5G-IoT, and the supporting effects of the two types of cables are compared. According to the numerical and experimental results, the CRLD cable is proven reliable to support the deep roadway, at least shocked by the released energy corresponding to the 1st seismic magnitude.

Focused Ultrasound in Neuroscience. State of the Art and Future Perspectives

Transcranial MR-guided Focused ultrasound (tcMRgFUS) is a surgical procedure that adopts focused ultrasounds beam towards a specific therapeutic target through the intact skull. The convergence of focused ultrasound beams onto the target produces tissue effects through released energy. Regarding neurosurgical applications, tcMRgFUS has been successfully adopted as a non-invasive procedure for ablative purposes such as thalamotomy, pallidotomy, and subthalamotomy for movement disorders. Several studies confirmed the effectiveness of tcMRgFUS in the treatment of several neurological conditions, ranging from motor disorders to psychiatric disorders. Moreover, using low-frequencies tcMRgFUS systems temporarily disrupts the blood–brain barrier, making this procedure suitable in neuro-oncology and neurodegenerative disease for controlled drug delivery. Nowadays, tcMRgFUS represents one of the most promising and fascinating technologies in neuroscience. Since it is an emerging technology, tcMRgFUS is still the subject of countless disparate studies, even if its effectiveness has been already proven in many experimental and therapeutic fields. Therefore, although many studies have been carried out, many others are still needed to increase the degree of knowledge of the innumerable potentials of tcMRgFUS and thus expand the future fields of application of this technology.

Energy Reserves and Industrial Development in Northeast India

The northeast of India is rich have abundant natural resources and has superior energy reserves, but the economic development of the region is backward which is difficult to forming industrial effects. Based on the energy conditions and economic endowment of northeast of India, this paper examines the development dilemma of this region and analyzes the policies adopted by India to promote the economic and industrial development of the region, so that the local economic potential can be released, energy development can be enhanced, and the industrial layout can be more reasonable.

EVALUATION OF APPROXIMATIONS IN REACTOR PULSE

An evaluation of validity of theoretical pulse models (Fuchs-Hansen and Nordheim-Fuchs model) in reactor pulse modelling was performed by developing so called Improved Pulse Model. The effect of each of the five assumptions on the most important pulse physical parameters, maximal power, total released energy and full width at half maximum was studied. In the Improved Pulse Model the assumptions are disposed out with the improvements, where to account the delayed neutrons the six point kinetic equations are solved, the temperature dependences of the temperature reactivity coefficient of fuel and specific heat are taken into account, also the final ejected time of transient control rod from reactor core, whose value of reactivity varies in height and the heat dissipation from the fuel are considered. It is found that the theoretical models predict a higher maximum power, lower total released energy and full width at half maximum than the Improved Pulse Model.

Constraining the transient high-energy activity of FRB 180916.J0158+65 with Insight–HXMT follow-up observations

Context. A link has finally been established between magnetars and fast radio burst (FRB) sources. Within this context, a major issue that remains unresolved pertains to whether sources of extragalactic FRBs exhibit X/γ-ray outbursts and whether this is correlated with radio activity. If so, the subsequent goal is to identify these sources. Aims. We aim to constrain possible X/γ-ray burst activity from one of the nearest extragalactic FRB sources currently known. This is to be done over a broad energy range by looking for bursts over a range of timescales and energies that are compatible with those of powerful flares from extragalactic magnetars. Methods. We followed up on the observation of the as-yet nearest extragalactic FRB source, located at a mere 149 Mpc distance, namely, the periodic repeater FRB 180916.J0158+65. This took place during the active phase between 4 and 7 February 2020, using the Insight–Hard X-ray Modulation Telescope (Insight–HXMT). By taking advantage of the combination of broad-band wavelengths, a large effective area, and several independent detectors at our disposal, we searched for bursts over a set of timescales from 1 ms to 1.024 s with a sensitive algorithm that had been previously characterised and optimised. Moreover, through simulations, we studied the sensitivity of our technique in the released energy-duration phase space for a set of synthetic flares and assuming a range of different energy spectra. Results. We constrain the possible occurrence of flares in the 1−100 keV energy band to E < 1046 erg for durations Δ t < 0.1 s over several tens of ks exposure. Conclusions. We can rule out the occurrence of giant flares similar to the ones that were observed in the few cases of Galactic magnetars. The absence of reported radio activity during our observations prevents us from making any determinations regarding the possibility of simultaneous high-energy emission.

Bridging Macro and Micro Cosmos by a New Sight on “Photon Aging” – A Simple Approach for Explaining Diracs Large Numbers

The energy loss of photons due to the cosmological red shift is interpreted, here, as a periodical process of transferring electromagnetic field energy into the space. The transferred energy portions are independent on photon energy if this transfer occurs with their frequency. The amounts of periodically released energy are so small that the related ultra-long wave length photons have to be understood as perfectly delocalized. Thus, the described point of view bridges the quantum micro cosmos with the macro cosmos. It is proposed to regard this energy exchange as a typical property of universal time arrow and to interpret the &ldquo;large numbers&rdquo;, in particular the dimensionless reciprocal of product of Hubbles constant and Planck time as the fundamental parameter describing cosmic evolution.

Investigating the Width of Isolated Coal Pillars in Deep Hard-Strata Mines for Prevention of Mine Seismicity and Rockburst

In deep mines, a reasonable design of the widths of isolated coal pillars (ICPs) is critically important, particularly for hard-strata mines. This is because the frequent occurrence of mine seismicity (MS) and rockburst in deep mines often arises from the inappropriate widths of the remnant ICPs. To address this problem, this paper takes the ICP of Yingpanhao Coal Mine in Inner Mongolia in China as the engineering case study and then presents a mechanical model to illuminate the occurrence mechanism of MS induced by the mining on both sides of ICPs. The results indicate that, after the mining on both sides of ICPs, the ICPs will produce a vertical compressive deformation, and the overlying high main key stratum (MKS) will experience a flexure deformation. When the limited deflection of MKS is less than the compression of ICPs, the MKS will be fractured, and the released energy may lead to MS. Based on the mechanism model, a design criterion is proposed for ICP widths; this criterion can effectively reduce the risk of the induced rockburst and MS. Then the occurrence mechanism of MS and the design basis for ICP width are verified by numerical simulation and field microseismic monitoring. The results in this paper may be used as a theoretical guidance for rational ICP design in deep mines and may help mitigate the risk of rockburst and MS from early mining stages.