Applied Mechanics and Materials Vols. 477-478

Abstract: By describing the environmental requirements for food storage, puts forward the green air conditioning system to create a low-temperature environment for food of these creatures such as ice storage air-conditioning, ground source heat pumps, solar cooling and so on. Combined the related system diagram or schematic in the context of promoting green and healthy, pointed out the future direction of development of the low-temperature grain storage.

Abstract: Short circuit current density (J_sc) and photoelectric conversion efficiency (η) of the different material quantum dot intermediate band solar cells (QD-IBSCs) under full concentrated sunlight were compared in this work. The QD-IBSCs were designed with QDs formed from different excitonic Bohr radius semiconductors embedding in the different wide band gap materials. Modulation doping was used to realize partially filling the IB with electrons in QD, the influence of localized states from doping on IB was also considered. The performance of these SCs was numerically simulated based on the detailed balance principle. The J_sc and η in QD-IBSCs can be adjusted via tuning the position and density of states of IB due to varying the mean size (d) and doping level of QDs in absorption region. Under the same doping level in an identical host gap material with ΔE_G=2.0 eV, the J_sc and η of the Si QD-IBSCs can be optimized with 4.3 nm-QDs, however, those of CdTe devices raises while those of Ge cells drops with increasing the sizes of QD from 2 nm to 8 nm. With changing the host gap ΔE_G, variation of the IB energy level E_H with respect to valence band corresponding to the maximum η_m was explored, dependence of η on the operation voltage was analyzed, and the impurity effect on the η was taken into account. Present work indicates that an appropriate band gap material should be adopted to fabricate QDs to embed in suitable doped host gap one to obtain the high performance QD-IBSC.

Abstract: The radionuclides released from NPPs (Nuclear Power Plants) as a result of accidents will significantly affect human health by causing cancer, genetic diseases, or acute radiation sickness. To investigate and evaluate the influence of the airborne hazardous materials on human bodies in an indoor environment in urban areas near NPPs, it is necessary to calculate the inhalation dose. In this study, a method for the assessment of the inhalation dose of indoor radionuclides was proposed. This method consists of the combination of the basic equation of natural ventilation and the empirical equation for calculation of the inhalation dose. The method was applied in a modeled densely urban domain, and CFD simulations were conducted to obtain the wind pressure distribution on the building surfaces. Moreover, the impacts of certain important parameters, including the ventilation coefficient, the age group of humans, the wind velocity, the urban street width, and the building height, were discussed in this paper. The results show that all of these parameters affect the indoor inhalation dose. In most cases, the indoor dose obtained at the same floor was higher with a higher ventilation coefficient, breathing rate, wind velocity, and street width or a lower building height. Furthermore, people living in the middle floors will generally be exposed to a lower inhalation dose than those in other floors especially the top floor.

Abstract: The fracture distribution around circular cavities has been widely observed in experiments and well documented in literature from 1980. Most of the works are based on experiments’ results, which cost considerable time and money. With varied numerical methods developed more and more researcher employ numerical experiments on computers instead of physical experiments. Firstly, the nodal enrichment functions for Extended Finite Element Method in conjunction with additional degrees are presented. Moreover, we describe the cohesive segments method, which is followed by the damage initiation and evolution laws. In the last a borehole numerical model is built up and the simulation results of the primary fracture propagation are presented.

Abstract: The main causes and influencing factors of artificial side soil slope slide of soil-cutting in seasonal frozen area are analyzed and put forward, and a mechanical theoretical model form is also put forward. Based on checking computation of artificial side slope saturated soil stability in melting period, it provides effective measures by adopting drainage to stabilize side slope instead of cutting it to keep soil-cutting side slope stable in the seasonal frozen area. Then the comprehensive stability technology of side slope by introducing geotextile as lower levels drainage and by adopting net geotextile lattice to stabilize soil and planting Malian grass.

Abstract: In order to study the stability of rock-socketed piles in landslide control project, this paper took a practical engineering as example, employed the ANASYS software platform as the implementation tool to establish the finite element analysis model. In this analysis, the Drucker-Prager criterion was selected and several differentiated models were established to research the influence of different socketed depth on rock stability. The result indicates that when the embedding depth is constant, the deformation of rock is growing with the increasing of load. When entering into the plastic response, the crack eventually developed into plastic zone around the rock-socketed pile; the adverse effects of the bottom rock would be smaller complying with the deeper of the pillar embedding into the rock; the cost increases with depth of embedded part in practical engineering, according to this research, it is economical and reasonable to choose triple pile diameter as the embedded depth.

Abstract: The shear modulus and damping ratio of soil are important factors for soil layer seismic response analysis, people have done a lot of research. Currently, the method to measure soil shear modulus and damping ratio have bending element test method, resonant column test, dynamic triaxial test and so on. This article describes the British GDS company developed a new resonant column GDS-RCA's main features, technical indicators and working principle, compared the IEM original GZ-1 resonant column test results with GDS-RCA resonant column test results, the compared results are as follows: both damping ratio results in somewhat different, but in 10^-6-10^-4 low strain shear modulus ratio between the range of test results are consistent, GDS-RCA resonant column testing machine can by low-frequency torsional mode, expand the soil strain measurement extended to 10^-6-10^-2, and the small strain to large strain test results are in good connection.

Abstract: In the process of drilling and cast-in place pile, which usually produces a large amount of wasted mud. If the wasted mud had been mishandled, which may result in serious environmental problems. Combined with engineered examples, this paper mainly elaborates some common techniques related to the solidification treatment of wasted mud, the laboratory solidified test were done on the basis of the existed technical methods. The effect and cost of solidification treatment using different solidification agents were comparatively analyzed according to the result of test. Finally, in order to purpose of the optimal environmental and economic benefits, the suitable solidification treatment method and optimal mixture ratio are put forward to deal with the engineered problems.

Abstract: Taking one foundation pit engineering in Hangzhou for example, a numerical model of foundation pit under local load was established through the two-dimensional finite element software Plaxis. The influence on the displacements and bending moments of the retaining structure caused by construction process, the value and position of local load had been investigated. A simple discuss about local load' influence scope had been made. The results show that the displacements of row piles reach maximum after being excavated. As the values of local load increase or the distance between local load and foundation pit decrease, the status of the retaining structure becomes worse. Influence scope of load calculated in traditional method based on Rankine' theory may be rather small.

Abstract: Considering reinforcement zone and natural foundation as a whole, the displacement component formulas satisfy with the displacement boundary conditions were constructed based on some hypotheses. Considering friction influence under foundation, a approximate analytical algorithm of foundation deformation was established under embankment loads by the variational method of displacement, and the approximate analytical formula on the relationship between the load and the average settlement was derived. The static load model tests were carried out in laboratory to verify the feasibility of this method proposed in this paper. Key words: load-settlement relation; variational method of displacement; embankment load; composite foundation