Failure mechanism and infrared radiation characteristic of hard siltstone induced by stratification effect

The deformation in sedimentary rock induced by train loads has potential threat to the safe operation of tunnels. This study investigated the influence of stratification structure on the infrared radiation and temporal damage mechanism of hard siltstone. The uniaxial compression tests, coupled with acoustic emission(AE) and infrared radiation temperature(IRT) were conducted on siltstones with different stratification effects. The results revealed that the stratigraphic structure significantly affects the stress-strain response and strength degradation characteristics. The mechanical parameters exhibit anisotropy characteristics, and the stratification effect exhibits a negative correlation with the cracking stress and peak stress. The failure modes caused by the stratification effect show remarkable anisotropic features, including splitting failure(Ⅰ: 0°-22.50°, Ⅱ: 90°), composite failure(45°), and shearing failure(67.50°). The AE temporal sequences demonstrate a stepwise response characteristic to the loading stress level. The AE intensity indicates that the stress sensitivity of shearing failure and composite failure is generally greater than that of splitting failure. The IRT field has spatiotemporal migration and progressive dissimilation with stress loading and its dissimilation degree increases under higher stress levels. The stronger the stratification effect, the greater the dissimilation degree of the IRT field. The abnormal characteristic points of average infrared radiation temperature(AIRT) variance at local stress drop and peak stress can be used as early and late precursors to identify fracture instability. Theoretical analysis shows that the competitive relationship between compaction strengthening and fracturing damage intensifies the dissimilation of the infrared thermal field for an increasing stress level. The present study provides a theoretical reference for disaster warnings in hard sedimentary rock mass.

Effects of microwave radiation on brain energy metabolism and related mechanisms

With the rapid development of electronic technologies, anxiety regarding the potential health hazards induced by microwave radiation(MW) has been growing in recent years. The brain is one of the most sensitive target organs for microwave radiation, where mitochondrial injury occurs earlier and more severely than in other organs. Energy metabolism disorders do play an important role during the process of microwave radiation-induced brain damage. In this paper, we will review the biological effects of microwave radiation, the features of brain energy supply and consumption and the effects of microwave radiation on mitochondrial energy metabolism and potential related mechanisms.

Hawking effect and quantum nonthermal radiation of an arbitrarily accelerating charged black hole using a new tortoise coordinate transformation

Using a new tortoise coordinate transformation, this paper investigates the Hawking effect from an arbitrarily accelerating charged black hole by the improved Damour-Ruffini method. After the tortoise coordinate transformation, the Klein-Gordon equation can be written as the standard form at the event horizon. Then extending the outgoing wave from outside to inside of the horizon analytically, the surface gravity and Hawking temperature can be obtained automatically. It is found that the Hawking temperatures of different points on the surface are different. The quantum nonthermal radiation characteristics of a black hole near the event horizon is also discussed by studying the Hamilton-Jacobi equation in curved spacetime and the maximum overlap of the positive and negative energy levels near the event horizon is given. There is a dimensional problem in the standard tortoise coordinate and the present results may be more reasonable.

Medical Radiation Exposure and Human Carcinogenesis-Genetic and Epigenetic Mechanisms

Ionizing radiation （IR） is a potential carcinogen. Evidence for the carcinogenic effect of IR radiation has been shown after long-term animal investigations and observations on survivors of the atom bombs in Hiroshima and Nagasaki. However, IR has been widely used in a controlled manner in the medical imaging for diagnosis and monitoring of various diseases and also in cancer therapy. The collective radiation dose from medical imagings has increased six times in the last two decades, and grow continuously day to day. A large number of evidence has revealed the increased cancer risk in the people who had frequently exposed to x-rays, especially in childhood. It has also been shown that secondary malignancy may develop within the five years in cancer survivors who have received radiotherapv, because of IR-mediated damage to healthy cells. In this article, we review the current knowledge about the role of medical x-ray exposure in cancer development in humans, and recently recognized epigenetic mechanisms in IR-induced carcinogenesis.

Date Palm Tree’s Defense Mechanisms from Viral Infection and Solar Ultraviolet Radiation

A comprehensive review of scientific literature has uncovered no reported cases of date palm trees infected by a virus and no viral infections have been reported by farmers. In spite of the hot and humid environment they inhabit, the abundance of viral infestations in the soil, other plants and organisms surrounding the trees and the frequency of importation and transplantation of these trees into the region. Such conditions should cause the date palms to also be infected. Notably, other palm trees do not exhibit the same level of innate viral immunity that is found in date palms. The date palm tree’s innate viral immunity is a virgin area in botanical research. The biological segment in date palm tree DNA that enables survival under genotoxic radiation also deserves further investigation. This field of study may enable the breeding of other economically important plants to improve desert ecology and economy, land management, agriculture and horticulture.

The quantum nonthermal radiation and horizon surface gravity of an arbitrarily accelerating black hole with electric charge and magnetic charge

Using a new tortoise coordinate transformation,we discuss the quantum nonthermal radiation characteristics near an event horizon by studying the Hamilton-Jacobi equation of a scalar particle in curved space-time,and obtain the event horizon surface gravity and the Hawking temperature on that event horizon.The results show that there is a crossing of particle energy near the event horizon.We derive the maximum overlap of the positive and negative energy levels.It is also found that the Hawking temperature of a black hole depends not only on the time,but also on the angle.There is a problem of dimension in the usual tortoise coordinate,so the present results obtained by using a correct-dimension new tortoise coordinate transformation may be more reasonable.

Study on the discharge mechanism and EM radiation characteristics of Trichel pulse discharge in air

The Trichel pulse stage is an unstable stage of negative corona discharge that can also involve electromagnetic(EM) radiation signals. In this paper, the discharge mechanism and radiation characteristics of the Trichel pulse are studied in the needle-plate electrode configuration. The Trichel pulse current and its EM radiation signals are measured at different applied voltages.The results show that Trichel pulse discharge changes from the random pulse stage to the continuous pulse stage as the applied voltage increases. During these different stages, the normalized shape of the Trichel pulses remains unchanged, while the frequency of the EM radiation generated by the discharge remains unchanged. The discharge mechanism and EM radiation characteristics of the Trichel pulse are theoretically analyzed in the different stages.Both the positive ion sheath and the negative ion cloud play key roles in the formation of the Trichel pulse. The EM radiation signal is generated by the rapidly changing Trichel pulse current, and the Trichel pulse current waveform determines the characteristics of the EM radiation signal.

Impaired swallowing mechanics of post radiation therapy head and neck cancer patients: A retrospective videofluoroscopic study

AIM: To determine swallowing outcomes and hyolaryngeal mechanics associated with post radiation therapy head and neck cancer(rt HNC) patients using videofluoroscopic swallow studies. METHODS: In this retrospective cohort study, video-fluoroscopic images of rt HNC patients(n = 21) were compared with age and gender matched controls(n = 21). Penetration-aspiration of the bolus and bolus residue were measured as swallowing outcome variables. Timing and displacement measurements of the anterior and posterior muscular slings elevating the hyolaryngeal complex were acquired. Coordinate data of anatomical landmarks mapping the action of the anterior muscles(suprahyoid muscles) and posterior muscles(long pharyngeal muscles) were used to calculate the distance measurements, and slice numbers were used to calculate time intervals. Canonical variate analysis with post-hoc discriminant function analysis was performed on coordinate data to determine multivariate mechanics of swallowing associated with treatment. Pharyngeal constriction ratio(PCR) was also measured to determine if weak pharyngeal constriction is associated with post radiation therapy.RESULTS: The rt HNC group was characterized by poor swallowing outcomes compared to the control group in regards to: Penetration-aspiration scale(P < 0.0001), normalized residue ratio scale(NRRS) for the valleculae(P = 0.002) and NRRS for the piriform sinuses(P = 0.003). Timing and distance measurements of the anterior muscular sling were not significantly different in the two groups, whereas for the PMS time of displacement was abbreviated(P = 0.002) and distance of excursion was reduced(P = 0.02) in the rt HNC group. A canonical variate analysis shows a significant reduction in pharyngeal mechanics in the rt HNC group(P < 0.0001). The PCR was significantly higher in the test group than the control group(P = 0.0001) indicating reduced efficiency in pharyngeal clearance. CONCLUSION: Using videofluoroscopy, this study shows rt HNC patients have worse swallowing outcomes associated with reduced hyolaryngeal mechanics and pharyngeal constriction compared with controls.

Temperature and solar radiation utilization of rice for yield formation with different mechanized planting methods in the lower reaches of the Yangtze River,China

Several studies have demonstrated the effect of planting methods on rice yield, but information on the climate resources is limited. This study aims to reveal the effects of planting methods on climate resources associated with rice yield in a rice-wheat rotation system in the lower reaches of the Yangtze River, China. Field experiments were conducted in 2014 and 2015 with two japonica, two indica hybrid, and two japonica-indica hybrid varieties grown under three mechanized planting methods： carpet seedling of mechanical transplanting（CT）, mechanical direct seeding（DS）, and pot-hole seedling of mechanical transplanting（PT）. The rice yield and total dry matter under PT were greater than those under CT and DS methods. Besides, the entire growth duration and daily production showed significant positive relations with rice yield. Compared with CT and DS, the effective accumulated temperature and cumulative solar radiation of rice under PT were higher in phenological phases. In addition, the dry matter/effective accumulated temperature and solar energy utilization of rice under CT and DS were higher during vegetative phase and lower during reproductive and grain filling phases in contrast to PT. The mean daily temperature and mean daily solar radiation in the entire growth duration showed significant positive correlation with rice yield, total dry matter, and harvest index. This study demonstrated that when the mean daily temperature is 〈25.1°C in vegetative phase and 〉20.1°C in grain filling phase, rice yield could be increased by selecting mechanized planting methods. Most varieties under PT method exhibited high yield and climate resources use efficiency compared with CT and DS. In conclusion, the PT method could be a better cultivation measure for high rice yield, accompanied with high temperature and solar radiation use efficiency in a rice-wheat rotation system in the lower reaches of the Yangtze River, China.

Flexibility potential of Cs_(2)BX_(6)(B=Hf,Sn,Pt,Zr,Ti;X=I,Br,Cl)with application in photovoltaic devices and radiation detectors

As interest in double perovskites is growing,especially in applications like photovoltaic devices,understanding their mechanical properties is vital for device durability.Despite extensive exploration of structure and optical properties,research on mechanical aspects is limited.This article builds a vacancyordered double perovskite model,employing first-principles calculations to analyze mechanical,bonding,electronic,and optical properties.Results show Cs_(2)Hfl_(6),Cs_(2)SnBr_(6),Cs_(2)SnI_(6),and Cs_(2)PtBr_(6)have Young's moduli below 13 GPa,indicating flexibility.Geometric parameters explain flexibility variations with the changes of B and X site composition.Bonding characteristic exploration reveals the influence of B and X site electronegativity on mechanical strength.Cs_(2)SnBr_(6)and Cs_(2)PtBr_(6)are suitable for solar cells,while Cs_(2)HfI_(6)and Cs_(2)TiCl_(6)show potential for semi-transparent solar cells.Optical property calculations highlight the high light absorption coefficients of up to 3.5×10^(5) cm^(-1)for Cs_(2)HfI_(6)and Cs_(2)TiCl_(6).Solar cell simulation shows Cs_(2)PtBr_(6)achieves 22.4%of conversion effciency.Cs_(2)ZrCl_(6)holds promise for ionizing radiation detection with its 3.68 eV bandgap and high absorption coefficient.Vacancy-ordered double perovskites offer superior flexibility,providing valuable insights for designing stable and flexible devices.This understanding enhances the development of functional devices based on these perovskites,especially for applications requiring high stability and flexibility.

Radiation Spectral Analysis of 3D Dust Molecular Clusters(PAHs)and Peptoids under Ionization and Electric Field in ISM

Polycyclic aromatic hydrocarbons(PAHs),PANHs,and peptoids dust spectral calculations from the interstellar medium(ISM)are important for dust observations and theory.Our goal is to calculate the radiation spectrum of spherical PAHs dust clusters in a vacuum containing ionized and applied in the presence of an electric field.We propose a new simple computational model to calculate the size of three-dimensional spherical dust clusters formed by different initial dust structures.By the Vienna Ab-initio Simulation Package code,the density functional theory with the generalized approximation was used to calculate the electron density gradient and obtain the radiation spectrum of dust.When the radius of spherical dust clusters is~[0.009-0.042]μm,the dust radiation spectrum agrees well with the Z=0.02 mMMP stellar spectra,and the PAHs radiation spectrum of NGC 4676 at wavelengths of(0-5]μm and(5-10]μm,respectively.In the ionized state,the N-PAH,C_(10)H_(9)N,2(C_(4)H_(4))^(1+),and peptoids 4(CHON),(C_(8)H_(10)N_(2)O_(5))^(1+)dust clusters at 3.3μm,while the 2(C_(22)H_(21)N_(3)O_(2))^(1+),4(CHON)dust clusters at 5.2μm have obvious peaks.There is a characteristic of part of PAHs and peptoids clusters radiation at the nearinfrared wavelength of 2μm.However,especially after applying an electric field to the dust,the emission spectrum of the dust increases significantly in the radiation wavelength range[3-10]μm.Consequently,the dust clusters of PAHs,PANHs,and peptoids of the radius size~[0.009-0.042]μm are likely to exist in the ISM.

Effect of rock mechanical properties on electromagnetic radiation mechanism of rock fracturing

The influence of rock mechanical properties on the electromagnetic radiation(EMR)mechanism of rock fracturing is an important research topic in solid mechanics and earthquake prediction.In this study,an EMR model of rock fracturing considering the fracture factor,elastic modulus,Poisson’s ratio,radiation distance and crack length is derived based on the Hertz oscillator array assumption.An experimental system,including an electromagnetic shielding module,an EMR signal induction and transmission module,a signal recording module and a loading module,is developed to understand the EMR characteristics of four different rocks.The validity of the EMR theoretical model is verified and the relationships between the rock cracking morphology and the EMR waveform,amplitude and frequency are revealed.It is found that rock mechanical properties have obvious influences on the EMR waveform,amplitude and frequency during rock fracturing.This study provides a better understanding on the EMR mechanism of rock fracturing and can help to improve the accuracy of rock disaster prediction based on EMR.

Estimation of fracturing mechanisms by the ratio of radiated energy between S and P waves of microseismic events during mining in metal mines

In the mining process of deep metal mines,diff erent types of rock mass instability failures are caused by strong mining disturbance.It is beneficial to master the fracture mechanism of rock mass in time to effectively prevent and control the ground pressure disasters.Microseismic signals are generated by the propagation and expansion of cracks inside the rock mass that contain plentiful information about the structural changes of rock mass.The ratio of the radiated energy of S and P waves(Es/Ep)of microseismic events can fast and eff ectively calculate the rock fracture mechanism,which is widely used for ground pressure hazard risk assessment.In this paper,this method was used to analyze the fracture mechanism of rock mass around deep stope in Hongtoushan copper mine and Ashele copper mine.Furthermore,the spatial distribution characteristics and proportion changes of microseismic events with diff erent fracture mechanisms along with the mining process were studied.The results show that tensile cracks play a dominant role,accounting for 62%of the total events,during non-shear fracturing of the rock mass caused by the stoping unloading eff ect,while shear cracks occupy 68%of the total events during orebody slip failure.When the physical and mechanical properties of the orebody and rock mass are signifi cantly diff erent,slip failure along their contact zone is prone to occur under blasting disturbance.During deep mining,it is necessary to control the exposed area of the roof by each stoping,especially during the earlier mining stage,to avoid tensile stress concentration.The temporal and spatial variation of tension cracks and shear cracks induced by roof damage obtained in this paper can guide the prevention and control of ground pressure disasters in deep mining eff ectively.

The Effect of Inorganic Nanoadditives on the Thermal, Mechanical and UV Radiation Barrier Properties of Polypropylene Fibres

The objective of this study of modified polypropylene (PP) fibres using nanoadditives (nano-CaCO3 and Cloisite 30B) was to determine the influence of these additives on thermal and mechanical properties, but especially on the barrier properties of the nanocomposite fibres against UV radiation. The DSC data obtained from measurements of PP/CaCO3 or PP/C30B nanocomposite fibres were used for determination of the constants n and K of the Avrami equation and in the estimation of other thermal properties of the fibres, such as their crystallization half-time t1/2, rate of crystallization t1/2, the necessary time for maximum crystallization tmax and free energy per unit area of surface in the lamella perpen-dicular to the axis of a high-molecular chain se. The nano-CaCO3 or Closite 30B fillers (pre-treated separately in three different solvents: glycerine, acetone and water) did not influence the melting temperatures but caused an increase in PP crystallization temperatures in comparison with the pure PP fibres. The pre-treatments of nanoadditives resulted in increase of n, K, t1/2 values and decrease of t1/2, tmax as well as the values of free surface energies per unit area of the modified PP fibres. There was also observed a decrease in the mechanical properties, however, there was an increase of barrier properties against UV radiation of nanocomposite PP fibres in comparison with neat PP fibres, which was one of the main objectives of the study.

Differential Proteomics Reveals the Potential Injury Mechanism Induced by Heavy Ion Radiation in Mice Ovaries

In the present study, we used a proteomics approach based on a two-dimensional electrophoresis （2-DE） reference map to investigate protein expression in the ovarian tissues of pubertal Swiss-Webster mice subjected to carbon ion radiation （CIR）. Among the identified proteins, ubiquitin carboxy-terminal hydrolase L1 （UCH-L1） is associated with the cell cycle[1] and that it influences proliferation in ovarian tissues. We analyzed the expression of UCH-L1 and the proliferation marker proliferation cell nuclear antigen （PCNA） following CIR using immunoblotting and immunofluorescence. The proteomics and biochemical results provide insight into the underlying mechanisms of CIR toxicity in ovarian tissues.

Effect of the Substitution of Sand by Rubber of Waste Tires on the Mechanical Properties of Hydraulic Concrete and Exposure to Gamma Radiation

For a long time and until now, rubber is the most used material for the manufacture of tires for motor vehicles. Unfortunately, once the tire meets its life cycle, the remaining rubber cannot be recycled, so the tires are discarded in collection centers and often in clandestine dumps. This represents a serious environmental problem because, in one case, these waste tires become breeding grounds for insects and wildlife that is harmful to humans. In the second case, the tires are burned, releasing highly damaging gases into the atmosphere. On the other hand, concrete is worldwide the construction material par excellence. It is basically composed of cement, gravel and sand. Mixing these three components in different proportions, their mechanical strength in compression can be increased. However, due to its fragile nature, concrete, once a crack is formed, it rapidly advances by fragmenting the material and producing its rapid collapse. In the present work, in order contribute to the care of the environment as well as to modify the fracture mode of the concrete, rubber particles obtained from waste tires were used as sand substitute in hydraulic concrete. In addition, rubber modified samples concrete were lately exposed to 70 kGy of gamma radiation in order to study the effects of this radiation on the mechanical deformation of concrete. The results showed a decrease in the mechanical properties of the concrete with rubber particles with respect to the traditional concrete itself. However, such decreases were offset by the fact that samples with rubber addition do not collapses as fast as the free rubber samples. The acquired data pave the way for research with great benefits, such as the use of recycled tires in concrete for its fracture mode modification in a beneficial way, as well as a possible decrease in the cost of concrete.

Mechanism of E' center induced by γ ray radiation in silica optical fiber material

The characteristics of the best known defect centers E' in silica optical fiber material irradiated with ray were investigated by ESR at room temperature.A mechanism model of production of the E' center defect was established.The production of E' center includes two processes creation and activation.The strained bonds(or oxygen replacement) in silica networks lead to the creation of new defects whose concentration increases linearly with the dose.The pre-existing defects produce the activation,which tends to saturation.According to this model,the relation of E' center concentration changing with irradiation dose was obtained theoretically.The results are in good agreement with the experimental results.

Active control of structural sound radiation in an acoustic enclosure consisting of flexible structure

The active control of structural sound radiation in an acoustic enclosure is studied by using distributed point force actuators as the secondary control force, and the control mechanisms for the radiated noise in the cavity are analyzed. A rectangular enclosure involving two simply supported flexible plates is created for this investigation. The characteristics of the primary and secondary sound field and the structural-acoustic coupled system are analyzed, and the optimal control objective for reducing the sound pressure level （SPL） in the cavity is derived. The response of the SPL in the cavity is analyzed and compared when the secondary point force actuators with different locations and parameters are applied to the two flexible plates. The results indicate that the noise in the cavity can be better controlled when some point force actuators are applied to two flexible plates for cooperative control rather than the point force actuators being only applied to the excited flexible plate.

Vibration and Acoustic Radiation from Orthogonally Stiffened Infinite Circular Cylindrical Shells in Water

Based on the motion differential equations of vibration and acoustic coupling system for thin elastic shells with ribs, by means of the Fourier integral transformation and the Fourier inverse transformation, as well as the stationary phase method, an analytic solution, which has satisfying computational effectiveness and precision, is derived for the solution to the vibration and acoustic radiation from a submerged stiffened infinite circular cylinder with both ring and axial ribs. It is easy to analyze the effect of stiffening supports in the acoustic radiation field by use of the formulas obtained by the presented method and corresponding numerical computation. It is shown that the axial-stiffeners can improve the mechanical and acoustical characteristics. Moreover, the present method can be used to study the acoustic radiation mechanism of the type of structure.

Synchrotron radiation investigations of the Sr_2MgSi_2O_7:Eu^(2+),R^(3+) persistent luminescence materials

The electronic and defect energy level structure of polyerystalline Sr2MgSi2OT：Eu^2＋,R^3＋ persistent luminescence materials were studied with thermoluminescence and different synchrotron radiation spectroscopies （UV-VUV emission and excitation, X-ray absorption near-edge spectroscopy （XANES） and extended X-ray absorption f＇me structure （EXAFS））. Special attention was paid on the effect of the R3＋ co-dopants on the persistent luminescence properties of the materials. Theoretical calculations using the density functional theory （DFT） were carried out simultaneously with the experimental work. The experimental band gap energy （Eg） value of ca. 7.1 eV agreed very well with the DFT value of 6.7 eV. The variation of the Eg value was attempted to relate with the trap structure as well as with the different properties of the R3＋ co-dopants. The trap level energy distribution depended strongly on the R3＋ co-dopant except for the shallowest trap energy above the room temperature remaining practically the same, however. The different processes in the mechanism of persistent luminescence from Sr2MgSi2OT：Eu^2＋,R^3＋ were assembled and their contributions discussed.