Simulated Experiment on Wind Erosion Resistance of Salix Residual in the Agro-Pastoral Ecotone

Plant residual is of great importance in retarding soil wind erosion in the agro-pastoral ecotone. However, few studies have determined the effects of sand plant residual on wind erosion resistance. Based on field surveys, the influences of Salix residual biomass of 200, 400, 600, and 800 g m−2, soil incorporated with a residual thickness of 0.5, 1.0, and 2.0 cm, and typical proportion of residual branches and leaves (2:1, 1:1, and 1:2) on wind erosion resistance were investigated using a simulated wind tunnel. The results showed the following: 1) The soil loss amount ranged from 1.56 to 40.8 kg m−2 as Salix residual biomass decreased from 800 to 0 g m−2, with a critical residual biomass value of 400 g m−2. 2) As the thickness of soil-incorporated residual increased, the soil loss amount reduced rapidly, especially for 0–9 cm above the surface accounting for 84.6% of the total. 3) Salix branch residual is more important in resisting soil wind erosion as compared with its leaves. This kind of study may provide theoretical explanations for the optimal reconstruction of sandy vegetation in the northern wind-sand regions.

Crushing of Double-Walled Corrugated Board and Its Influence on the Load Capacity of Various Boxes

As long as non-contact digital printing remains an uncommon standard in the corrugated packaging industry, corrugated board crushing remains a real issue that affects the load capacity of boxes. Crushing mainly occurs during the converting of corrugated board (e.g., analog flexographic printing or laminating) and is a process that cannot be avoided. However, as this study shows, it can be controlled. In this work, extended laboratory tests were carried out on the crushing of double-walled corrugated board. The influence of fully controlled crushing (with a precision of ±10 μm) in the range from 10 to 70% on different laboratory measurements was checked. The typical mechanical tests—i.e., edge crush test, four-point bending test, shear stiffness test, torsional stiffness test, etc.—were performed on reference and crushed specimens. The residual thickness reduction of the crushed samples was also controlled. All empirical observations and performed measurements were the basis for building an analytical model of crushed corrugated board. The proven and verified model was then used to study the crushing effect of the selected corrugated board on the efficiency of simple packages with various dimensions. The proposed measurement technique was successfully used to precisely estimate and thus control the crushing of corrugated board, while the proposed numerical and analytical techniques was used to estimate the load capacity of corrugated board packaging. A good correlation between the measured reduced stiffness of the corrugated cardboard and the proposed analytical predictive models was obtained.

Intraoperative Spinal Cord Remote Monitoring with a Modified US A-Scope

Materials and Methods: The motivation for this feasibility study were: (i) to modify the ultrasonic A-scope in order to monitor remotely, intraoperatively and in real-time tumor’s depth and size, before cutting its dura and to control tumor’s residual thickness while its resection and (ii) to demonstrate these abilities during several spinal-cord surgeries. Results: The ultrasonic A-scope was modified for these purposes, to a noncontact, intraoperative and real-time device. It was successfully applied during several human spinal cord clinical trials. Its data were compared with those of a pre-operative MRI (of the same person), where a good similarity was obtained between them, with a difference less than 1mm, in most cases. Conclusions: The modified A-Scope advantages: (i) remote, intraoperative and real-time monitoring; (ii) accurate and objective data was obtained; (iii) there is no direct contact between the US transducer and the monitored tissue, as the ultrasound propagates through a free stream of normal saline; (iv) the length of the free stream is few mm, at least; (v) the handpiece enables to monitor in a confined area, as it has a small foot-print; (vi) it is simple to operate the device; (vii) it enables to define intraoperatively tumor edges, before cutting and opening the dura. Consequently, this modified device seems to be a valuable and useful tool to define intraoperatively tumor’s location and its complete removal and reducing potential damages to healthy tissues surrounding it.

Crushing of Single-Walled Corrugated Board during Converting: Experimental and Numerical Study

Corrugated cardboard is an ecological material, mainly because, in addition to virgin cellulose fibers also the fibers recovered during recycling process are used in its production. However, the use of recycled fibers causes slight deterioration of the mechanical properties of the corrugated board. In addition, converting processes such as printing, die-cutting, lamination, etc. cause micro-damage in the corrugated cardboard layers. In this work, the focus is precisely on the crushing of corrugated cardboard. A series of laboratory experiments were conducted, in which the different types of single-walled corrugated cardboards were pressed in a fully controlled manner to check the impact of the crush on the basic material parameters. The amount of crushing (with a precision of 10 micrometers) was controlled by a precise FEMat device, for crushing the corrugated board in the range from 10 to 70% of its original thickness. In this study, the influence of crushing on bending, twisting and shear stiffness as well as a residual thickness and edge crush resistance of corrugated board was investigated. Then, a procedure based on a numerical homogenization, taking into account a partial delamination in the corrugated layers to determine the degraded material stiffness was proposed. Finally, using the empirical-numerical method, a simplified calculation model of corrugated cardboard was derived, which satisfactorily reflects the experimental results.

Crushing of Double-Walled Corrugated Board and Its Influence on the Load Capacity of Various Boxes

As long as the non-contact digital printing is not a common standard in the corrugated packaging industry, corrugated board crushing is a real issue that affects the load capacity of the boxes. Crushing mainly occurs during the converting of corrugated board (e.g. analog flexographic printing or laminating) and is a process that cannot be avoided. However, as show in this study, it can be controlled. In this work, extended laboratory tests were carried out on the crushing of double-walled corrugated board. The influence of fully controlled crushing (with a precision: ±10 μm) in the range from 10 to 70 % on different laboratory measurements was checked. Most of the typical mechanical tests were performed e.g. edge crush test, four-point bending test, shear stiffness test, torsional stiffness test, etc. on reference and crushed specimens. The residual thickness reduction of the crushed samples was also controlled. All empirical observations and performed measurements were the basis for building an analytical model of crushed corrugated board. The proven and verified model was then used to study the crushing effect of the selected corrugated board on the efficiency of simple packages with various dimensions.

Crushing of Single-Walled Corrugated Board During Converting: Experimental and Numerical Study

Corrugated cardboard is an ecological material, mainly because, in addition to virgin cellulose fibers also the fibers recovered during recycling process are used in its production. However, the use of recycled fibers causes slight deterioration of the mechanical properties of the corrugated board. In addition, converting processes such as printing, die-cutting, lamination, etc. cause micro-damage in the corrugated cardboard layers. In this work, the focus is precisely on the crushing of corrugated cardboard. A series of laboratory experiments were conducted, in which the different types of single-walled corrugated cardboards were pressed in a fully controlled manner to check the impact of the crush on the basic material parameters. The amount of crushing (with a precision of 10 micrometers) was controlled by a precise FEMat device, for crushing the corrugated board in the range from 10 to 70 % of its original thickness. In this study, the influence of crushing on bending, twisting and shear stiffness as well as a residual thickness and edge crush resistance of corrugated board was investigated. Then, a procedure based on a numerical homogenization, taking into account a partial delamination in the corrugated layers to determine the degraded material stiffness was proposed. Finally, using the empirical-numerical method, a simplified calculation model of corrugated cardboard was derived, which satisfactorily reflects the experimental results.

Effect of vibration treatment on increasing the durability of tillage equipment working bodies

This paper reports a study into the durability of tillage equipment working bodies. It has been established that the quality of surface layers during plastic deformation depends on a series of factors. These factors include the degree of hardening, the thickness of the hardened layer, the size and nature of the distribution of residual stresses. The study has shown that the technology to restore working bodies that involves vibration oscillations provides for higher durability. Investigation of deformed samples demonstrates that when exposed to vibration treatment, the microstructure is more fine-grained and even; the hardness of the treated surface of a ploughshare blade increases by 22‒35 %. This contributes to hardening the machined surface. It has been established that the tillage equipment working body wear is a random process, which is predetermined by changes in the structural dimensions and shape of cutting elements. An analysis of the wear distribution density of cutting elements has revealed its compliance with the law of normal distribution. It should be noted that the most influential geometric parameter of a working body affecting the part’s resource is the wear depth. This parameter determines the residual thickness of the ploughshare wall. Data from surface-layer studies at hardening make it possible to note a decrease in the limiting state of the examined parameters. In particular, the wear of a ploughshare tip was 17 % less than the limiting state. The study of durability has shown that the amount of tillage equipment working body wear is 1.28 times less when using vibrational plastic deformation. Accordingly, when restoring ploughshares, in order to increase the working bodies’ resource, it is more expedient to use a method that implies the welding of tires made from steel 45 involving sormite surfacing and vibration treatment

Burial history and the evolution of hydrocarbon generation in Carboniferous-Permian coal measures within the Jiyang super-depression, China

In the Jiyang Sub-basin, Carboniferous-Permian (C-P) coal-measure source rocks have experienced complex multi-stage tectonics and therefore have a complex history of hydrocarbon generation. Because these coal measures underwent multi-stage burial and exhumation, they are characterized by various burial depths. In this study, we used the basin modeling technique to analyze the relationship between burial history and hydrocarbon generation evolution. The burial, thermal and maturity histories of C-P coals were reconstructed, including primary hydrocarbon generation, stagnation, re-initiation, and peak secondary hydrocarbon generation. The secondary hydrocarbon generation stage within this reconstruction was characterized by discontinuous generation and geographical differences in maturity due to the coupled effects of depth and a delay of hydrocarbon generation. According to the maturity history and the delay effect on secondary hydrocarbon generation, we concluded that the threshold depth of secondary hydrocarbon generation in the Jiyang Sub-basin occurred at 2,100 m during the Yanshan epoch (from 205 Ma to 65 Ma) and at 3,200 m during the Himalayan period (from 65 Ma to present). Based on depth, residual thickness, maturity, and hydrocarbon-generating intensity, five favorable areas of secondary hydrocarbon generation in the Jiyang Sub-basin were identified, including the Chexi areas, Gubei-Luojia areas, Yangxin areas, the southern slope of the Huimin depression and southwest of the Dongying depression. The maximum VRo/burial depth (%/km) occurred in the Indosinian epoch as the maximum VRo/time (%/100Ma) happened in the Himalayan period, indicating that the coupling controls of temperature and subsidence rate on maturation evolution play a significant role in the hydrocarbon generation evolution. A higher temperature and subsidence rate can both enhance the hydrocarbon generation evolution.

Measurement of erosion state and refractory lining thickness of blast furnace hearth by using three-dimensional laser scanning method

The three-dimensional (3D) model of erosion state of blast furnace (BF) hearth was obtained by using 3D laser scanning method. The thickness of refractory lining can be measured anywhere and the erosion curves were extracted both in the circumferential and height directions to analyze the erosion characteristics. The results show that the most eroded positions located below 20# tuyere with an elevation of 7700 mm and below 24#–25# tuyere with an elevation of 8100 mm, the residual thickness here is only 295 mm. In the circumferential directions, the serious eroded areas located between every two tapholes while the taphole areas were protected well by the bonding material. In the height directions, the severe erosion areas located between the elevation of 7600 mm to 8200 mm. According to the calculation, the minimum depth to ensure the deadman floats in the hearth is 2581 mm, corresponding to the elevation of 7619 mm. It can be considered that during the blast furnace production process, the deadman has been sinking to the bottom of BF hearth and the erosion areas gradually formed at the root of deadman.

Studies on Key Effect Factors of Natural Circulation Characteristics for Advanced PWR Reactor Cavity Flooding System

In order to enhance the ability of severe accident mitigation for Pressurised Water Reactor (PWR), different kinds of severe accident mitigation strategies have been proposed. In-Vessel Retention (IVR) is one of the important severe accident management means by External Reactor Vessel Cooling. Reactor cavity would be submerged to cool the molten corium when a severe accident happens. The success criterion of IVR strategy is that the heat flux which transfers from the corium pool must be lower than the local critical heat flux (CHF) of the reactor pressure vessel (RPV) outside wall and the residual thickness of the RPV wall can maintain the integrity. The residual thickness of RPV is determined by the heat flux transfer from the corium pool and the cooling capability of outer wall of the RPV. There are various factors which would influence the CHF and the cooling capability of outer wall of the RPV. In order to verify the optimized design which is beneficial to the heat transfer and the natural circulation outside the actual reactor vessel, a large-scale Reactor Vessel External Cooling Test (REVECT) facility has been built. A large number of sensitivity tests were carried out, to study how these sensitivity factors affect CHF value and natural circulation. Based on the test results, the structure of the test section flow channel has an obvious effect on the CHF distribution. The flow channel optimized can effectively enhance the CHF value, especially to enhance the CHF value near the “heat focus” region of the molten pool. The water level in the reactor pit has also a great impact on the natural circulation flow. Although natural circulation can be maintained with a low water level, it will lead to a decrease of the cooling capacity. Meanwhile, some noteworthy test phenomena have been found, which are also essential for the design of the reactor pit flooding system.