Dry Plate Research Articles

Compaction control of secondary materials used in earthworks

AbstractCompaction control is a fundamental part of quality assurance for earthworks and essential to ensuring the long‐term stability and serviceability of earth structures. As the testing of relative compaction for coarse‐grained materials is time‐consuming, plate load tests are typically used for this purpose. Practical experience shows that the compaction control of secondary materials using plate load tests is not as straightforward as suggested in earthwork specifications. Unfortunately, these subtleties are not widely known and typically lead to rejection of the compacted layers, despite the material having been compacted thoroughly. This paper summarizes the findings of compaction field tests on several secondary materials that were field‐compacted to varying dry densities. Field testing of the compacted layers included the determination of dry density and plate load tests (static and dynamic). The results of these field tests are presented and discussed here and show that the parameters provided by plate load tests do not relate to the dry densities of the materials tested in the same way as they do for natural materials. Suggestions are provided concerning the most viable way of conducting compaction control of secondary materials within the earthwork specifications of Germany and Austria.

Numerical Simulation and Topological optimization of the dry clutch pressure plate

The common dry clutch pressure plate was prone to produce high temperature and axial thermal deformation due to the frictional heat generated during engagement. The overheated and overdeformed pressure plate decreases the torque transmission capacity of the clutch system and causes some kind of clutch malfunction including clutch slip and fracture. In this paper, the clutch pressure plate was firstly optimized by the topological optimization. Inspired by the topological optimized result, an improved design of the pressure plate was brought out, where the specific radial cooling channels and axial cooling holes were introduced in the new improved design in order to improve heat transfer and reduce the mass and thermal deformation as well. The performance of the new improved design is simulated and further optimized by the FE method. It is indicated that the mass of the optimum pressure plate was greatly reduced from the original design, with a mass reduction of 3.1 kg. The axial thermal deformation is also significantly decreased from the original pressure plate, decreasing from the original 0.35mm to the present 0.28mm while keeping the maximum temperature of pressure plate unchanged. These comparisons show that thermal-mechanical performance of the new pressure plate is improved effectively.

Dry, wet depositions for ambient air nitrate, sulfate, and chloride ionic species at mixed (traffic, commercial, and residential) sampling sites in Central Taiwan

This research was focused on the measurements of ambient air pollutants species (Cl−, NO3−, and SO42−) concentrations of wet and dry depositions by using PS-1 (TSP), dry depositions plate and wet depositions tub at mixed (traffic, commercial, and residential) sampling sites. Lu-Liao, characterized by traffic, commercial and residential sites, was selected as the dry deposition measurement site. Hungkuang University, characterized by a traffic site, was selected as the wet deposition collection site. At the Luliao site, the results indicated that the average ionic species (Cl−, NO3−, and SO42−) concentrations were 12.86, 25.58, and 18.37 μg/m3, respectively, in winter and 2.94, 11.37, and 14.09 μg/m3, respectively in spring. The average ionic species (Cl−, NO3−, and SO42−) dry depositions were 284.43, 1808.50, and 412.93 μg/m2 min, respectively, in winter and 147.66, 109.59, and 415.44 μg/m2 min, respectively, in spring. As for the monthly Cl−, NO3−, and SO42− volume weighted mean (VWM) concentrations at the Hungkuang site, the results for January were 5.64, 4.41, and 10.13 mg/L, for May were 0.45, 1.98, and 2.09 mg/L, for June were 0.76, 1.39, and 2.46 mg/L, and for July were 1.83, 2.97, and 5.84 mg/L. The monthly Cl−, NO3−, and SO42− Fw (Fluxwet deposition) at the same site were 355.41, 277.63, and 638.15 mg/m2 month, respectively, for January; 17.01, 99.03, and 362.05 mg/m2 month, respectively, for May; 99.03, 181.18, and 319.45 mg/m2 month, respectively, for June; and 362.05, 587.86, and 1156.49 mg/m2 month, respectively, for July. SO42− had the highest VWM and Fw values when compared with the other ionic species, Cl− and NO3−. The highest VWM values for all ionic species (Cl−, NO3−, and SO42−) all occurred in winter.

Stability and hysteresis of Faraday waves in Hele-Shaw cells

The instability of Faraday waves in Hele-Shaw cells is investigated experimentally and theoretically. A novel hydrodynamic model involving capillary action is proposed to capture the variation of the dynamic contact line between two close walls of narrow containers. The amplitude equations are derived from the gap-averaged model. By means of Lyapunov’s first method, a good prediction of the onset threshold of forcing acceleration is obtained, which shows the model’s validity for addressing the stability problem for Faraday waves in Hele-Shaw cells. It is found that the effect of the dynamic contact line is much greater than that of Poiseuille assumption of velocity profile for the cases under investigation. A new dispersion relation is obtained, which agrees well with experimental data. However, we highly recommend the conventional dispersion relation for gravity–capillary waves, which can generally meet common needs. Surface tension is found to be a key factor of interface flows in Hele-Shaw cells. According to our experimental observations, a liquid film is found on the front wall of the Hele-Shaw cell when the wave is falling. As a property of the friction coefficient from molecular kinetics, wet and dry plates show different wetting procedures. Unlike some authors of previous publications, we attribute the hysteresis to the out-of-plane interface shape rather than to detuning, i.e. the difference between natural frequency and response frequency.

Evaluation of preserving the viability of sheep's teeth PDL cells according to the different times and storage medias

Introdution: Vitality of periodontal ligament (PDL) cells is very critical for replantation of complete avulsion teeth due to traumatic injuries. This is important for transferring an avulsed tooth to clinic for replantation that which Medias used for storage.This study aimed to compare the vitality of PDL cells of sheep teeth cultured in different storage medias including α-Minimum Essential Medium (αMEM), Dulbecco’s Modified Eagle’s Medium (DMEM), Hank’s Balanced Salt Solution (HBSS), and mint extract
 Methods: In this lab trial study, PDL cells were obtained from 124 healthy anterior and posterior sheep teeth and cultured in αMEM, DMEM, HBSS, and mint extract for periods of 2, 6, 24, 48, 72, or 96 hours (24 groups). For each solution, positive control group were PDL cells without incubation in any storage media. For each group, there was a negative control considered cells growing in dry plate with no medium. After exposure of PDL cells to scheduled solution for scheduled incubation time, centrifuge was performed for 10 minutes at rate of 2000G. Then cell percipitates were added into the solution of collagenase (3mgr/ml) and Dispase (4mgr/ml to cell precipitates, which were incubated at 37° C for 60 minutes. After washing cellular suspension in PBS, vitality of the cells was assessed by Trypan blue exclusion, on a neobar slide by magnification of 200X. The data were analyzed statistically using 2-way ANOVA test by SPSS version 15.
 Results: Statistically significant differences in efficacy of different medias were obtained at least between two media (P=0.0001). PDL cells cultured in αMEM and mint extract showed 90% and 52.22% vitality representing, respectively, the best and the weakest storage media.
 Conclusion: αMEM can be a suitable transport medium up to 96 hours to preserve the vitality of the PDL cells of avulsed teeth. There is a reverse correlation between the viability of PDL cells and incubation time, increasing the time decreases the viability.

Experimental Investigation of Hydrodynamic Characteristic of a New Rotating Stream Tray

The hydrodynamic characteristic of a new rotating stream tray (NRST) was investigated. The tests were carried out using an air–water/oxygen experimental system in a column with a diameter of 500 mm. The hydrodynamic parameters studied were dry plate pressure drop, wet plate pressure drop, weeping, entrainment, and Murphree liquid efficiency. The results showed that the NRST has excellent performance in terms of high operational flexibility. The pressure drop, weeping rate, and entrainment rate remained low even under a high-capacity operation. Correlations of pressure drop, weeping, and entrainment for the NRST were obtained by regression analysis. The results can provide some important theoretical guidance for the development of this type of trays.

Adhesion characteristics of geopolymer mortar to concrete and rebars

In recent years, geopolymers have gained a wide attention as highly ecological-friendly building materials, having a capability to cut down 70% of CO2 emissions in comparison to the ordinary cement concrete. In this study, geopolymer mortars are proposed as repair materials for reinforced concrete structures, due to their superior acid resistance, heat resistance and high strength in comparison to the existing repair materials. The objective of this study is to investigate the adhesion properties of geopolymer mortars to concrete substrates with different surface treatments, steel plates and rebars. As a result, the geopolymer mortars are found to have excellent adhesion properties to dry concrete substrates, steel plates and rebars. Concrete substrates treated with grinder, further enhanced the adhesion properties of geopolymer mortars. On the other hand, poor adhesion of geopolymer mortars to wet concrete substrates was observed due to the presence of water on the interfacial zone, which decreased the alkali concentration of the geopolymer, resulting in lower adhesion strength. In general, geopolymer mortars are found to have suitable adhesion properties to the concrete substrates, steel plates and rebars and can be applied as repair materials for reinforced concrete structures.

Rewetting and boiling in jet impingement on high temperature steel surface

Interface topologies and boiling phenomena are observed within the water jet impingement zone during quenching of a high temperature (300 °C–900 °C) steel plate by direct optical observations. Stable film boiling may occur, but surface asperities may easily penetrate the vapor film and interact with the flowing liquid. By cooling down more rapidly than the remaining solid surface, such asperities act as a kind of micro-fin. Rather surprisingly, non-coalescing bubbles on top of the thin vapor film have been observed, probably formed on top of penetrating surface asperities. After establishing contact between water and solid, so after rewetting, an intense bubble activity is normally seen of bubbles that are footed on a dry plate area with a contact line reflecting the light-emitting diode lights and condensing at later times. These are vapor bubbles. A high surface roughness promotes rewetting that may be initiated at several places simultaneously. For an initial plate temperature of 300 °C and a total height roughness of 5 μm, rewetting took place without the occurrence of a vapor film; surfaces at or above 450 °C exhibited vapor film formation, even for a high jet subcooling of 80 °C. Temperature and time of rewetting are strongly affected by the initial surface temperature and jet subcooling and less by the jet velocity. New correlations are provided to predict these dependencies.

Bioremoval of Different Heavy Metals by the Resistant Fungal Strain Aspergillus niger.

The objective of this work was to study the resistance and removal capacity of heavy metals by the fungus Aspergillus niger. We analyzed the resistance to some heavy metals by dry weight and plate: the fungus grew in 2000 ppm of zinc, lead, and mercury, 1200 and 1000 ppm of arsenic (III) and (VI), 800 ppm of fluor and cobalt, and least in cadmium (400 ppm). With respect to their potential of removal of heavy metals, this removal was achieved for zinc (100%), mercury (83.2%), fluor (83%), cobalt (71.4%), fairly silver (48%), and copper (37%). The ideal conditions for the removal of 100 mg/L of the heavy metals were 28°C, pH between 4.0 and 5.5, 100 ppm of heavy metal, and 1 g of fungal biomass.

Experimental study on molten metal spreading and deposition behaviors

In this paper, experimental investigation of the molten metal spreading behavior that was carried out at Hokkaido University using high frequency inductive heater is presented to address the fundamental behavior of the molten metal spreading and deposition behaviors on dry flat plate. Molten copper was utilized as a test sample, and dataset was obtained for the falling molten metal on dry stainless-steel plate at various elevations, nozzle sizes and initial temperatures. During the spreading transient, high-speed thermo-camera was utilized to measure the molten metal’s surface temperature. Immediately after the solidification, solidified molten metal’s spread area and deposition thickness were measured. Based on the database obtained, dimensional analysis was conducted to identify the key parameters responsible for the molten metal spreading. From the obtained database, new experimental correlation was developed which is capable of predicting the spreading area at reasonable accuracy. Present analysis provides characteristic information of molten metal spreading and deposition behaviors which will be useful for the corium relocation problem in severe accident analysis.

Analytical and experimental investigation on the free vibration of a floating composite sandwich plate having viscoelastic core

This paper focuses on the free vibration analytical solution of a composite sandwich plate consisting of woven carbon laminated faces and a viscoelastic foam core. In addition to the dry condition, a case of floating on bounded water is considered for the sandwich plate not only in analytical work but also in verification experiments. The equations of motion for the first-order shear-deformation plate in contact with the fluid are derived by using Hamilton's principle, and analytically solved using Navier's procedure. Bounded water boundary conditions and velocity potential function are used to describe the fluid motion. The viscoelastic properties of a marine PVC foam core are extracted from dynamic mechanical analysis. Frequency response function (FRF) method is applied in modal testing for measuring the natural frequencies of the dry and wet sandwich plates. Experimental results demonstrate the validity of the analytical results. The effects of the foam core behavior, core thickness, plate dimension ratio, and the fluid density on the natural frequencies are examined and discussed. The decrease of the fundamental mode natural frequency with the presence of the viscoelastic foam core is more prominent for the dry sandwich plate with respect to the wet one already damped by water.

Nonlinear Cyclic Behaviour of Precast Concrete Frame Sub-Assemblies With “Dry” End Plate Connection

This paper presents in detail the design characteristics of dry and demountable end plate beam-column connection for an emulative jointed precast concrete frame system whose structural performance is similar to that of a wet jointed/monolithic concrete frame system. The load transfer mechanism as well as an analytical framework to calculate the ultimate capacity of the end plate connection is explained in detail. The hysteretic behaviour of the frame sub-assemblies with the end plate connection is experimentally evaluated under quasi-static cyclic loading. Accuracy of the developed analytical equations is assessed by comparing the predicted nominal lateral strength and stiffness with the test results. Also, structural performance of a frame sub-assembly with the end plate connection is evaluated by comparing the experimentally obtained hysteretic plot with the hysteretic plots of the frame systems with wet joints or ductile connectors reported in literature. Nonlinear cyclic behaviour of the tested frame sub-assemblies is numerically simulated by using the “pivot” and “IMK peak oriented” hysteresis models, and the accuracy of the developed numerical models is evaluated by comparing with the test results. The importance of a correct moment-rotation backbone curve to capture the capping point is highlighted through different case studies. Based on the evidences reported herein, it is concluded that the proposed end plate beam-column connection acts as a rigid moment connection, and a precast concrete frame system developed using end plate beam-column connections is demountable and it is able to structurally perform at par with (if not better than) a precast concrete frame system with wet joints.

Experimental simulation of downward molten material relocation by jet ablation of structures and fuel coolant interaction in a fast reactor

In the remote chance of a core melt-down accident in a fast reactor, the molten corium from the fuel subassembly can come out in the form of a liquid jet due to the prevailing transient pressure. This high temperature jet is capable of causing local breaches on horizontal solid structures such as the grid plate with which they come into contact inside the main vessel. After penetration through the plates, the molten jet undergoes fragmentation in the bulk coolant available below the grid plate, in the lower plenum and settles on the core catcher. Experimental investigation of molten material relocation in the downward direction is carried out with a wood's metal jet impinging on a pair of solid wood's metal plates. The wood's metal alloy is heated electrically to about 300 °C inside the melt chamber and released through a nozzle to impinge on the dry plates mounted on rigid supports and allowed to pierce through the plates. The jet then gets quenched in bulk water contained in the experimental vessel. The trajectory of vertical jet impinging on the set of two parallel horizontal plates is captured using a high speed camera. Thermocouples are placed on the top and bottom surface of the plates to assess the temperature evolution. The breach area formed on the plates by the hot molten jet is assessed from the experiments. The initial pressure of the liquid jet is varied from 0 bar to 2 bar gauge pressure. The mass of the debris collected on the breached wood's metal target plates and the stainless steel collector plate gives evidence that the entire molten mass of jet does not reach the bottom collector plate but gets distributed on all the plates. The particle size distribution is obtained for the fragmented wood's metal debris settled on the collector plate. It is observed that the mass median diameter of the fragmented particles and porosity of the debris bed decreases as the jet release pressure is increased. An empirical correlation between the particle size represented by the mass median diameter and the initial pressure of the jet is obtained.

Measurement of ambient air particulate pollutant concentrations and dry depositions for PS-1 combined with dry deposition plate at a wetland site

In this study, the concentrations of ambient total suspended particulates (TSP) and their dry deposition were measured using a PS-1 sampler with dry deposition plates at a wetland sampling site in central Taiwan during a sampling period from October 2016 to December 2016. The PS-1 sampler was fixed at set distances (1.5 and 2 m) from a dry deposition plate, and sampled particulate pollutants were sampled to determine their concentrations and dry deposition rates simultaneously. A dry deposition plate 3 m from the PS-1 sampler was also used to collect dry deposition particulate. This plate was also used to compare dry depositions from ambient air, collected from new device. The results thus obtained indicated that the average dry deposition rates on the dry deposition plates that were 1.5 and 2 m from the sampler were 103.15 and 103.94 µg/m2 min, respectively, in October, 83.36 and 100.18 µg/m2 min in November, and 171.2 and 157.5 µg/m2 min in December. These dry deposition rates were compared with that 3 m away from the PS-1 sampler. The statistical t test revealed no significant differences between the dry depositions on dry deposition plates at 1.5 and 2 m from the sampler. The dry deposition rates at 1.5 and 2 m from the sampler did not differ significantly from that at 3 m from the PS-1 sampler. This study proves that a PS-1 sampler can be combined with a dry deposition plate to measure TSP concentrations and dry depositions simultaneously using a single device.

Finite element analysis of thermal buckling characteristics of automotive 430 dry clutch pressure plate

The thermal buckling characteristics of the automotive dry clutch pressure plate under two typical thermal loads are comprehensively investigated by the finite element method based on the thermal buckling theory, respectively. The influence of the temperature distribution along the pressure plate thickness direction and the boundary constraints on the thermal buckling characteristics of the pressure plate is studied. The analysis results show that: 1) the temperature distribution on the thickness of the pressure plate has a negligible effect on its thermal buckling characteristics; 2) the boundary condition of the pressure plate has a significant effect on its thermal buckling mode; 3) the thermal buckling of the pressure plate is easier to occur in its cooling stage than in the heating stage. Since the critical buckling temperature far exceeds the actual possible temperature, the concave deformation of pressure plate is not induced by the thermal buckling mechanism.

International Relations of the Chinese Yogācāra School in the 8th Century: Focusing on Chongjun and Faqing (Faxiang)

According to his stūpa inscription (Tang Chanzhisi gu dade fashi Chongjun ta ming bing xu唐禅智寺故大徳法師崇俊塔銘并序; Based on the glass dry plates of Tokyo National Research Institute for Cultural Properties), Chongjun (696–760) of the Chanzhisi temple in Yang province learned Yogācāra, Buddhist logic, the Lotus sūtra and Nirvāna sūtra from Zhizhou 智周,and traveled to Tufan 吐蕃 or Tibet. Faqing (or Faxiang), his immediate disciple, a Buddhist layman, responded to a Tōketsu 唐決 (Questions to the Chinese Buddhists) brought by Japanese monk Tokushō 徳清,according to Zōshun’s 蔵俊 Inmyō daisho shō 因明大疏抄 and Gen’ei’s 玄叡 Daijō sanron daigishō 大乗三論大義鈔.Although it is said that there was no doctrinal development of Chinese Yogācāra after Zhizhou, we can see the international interactions between the Chinese Yogācāra school and the surrounding areas in the 8th century.

Влияние современных технологий на требования стандарта к качеству древесно-стружечных плит

The concept of quality in the minds of Soviet and Russian people is inextricably linked with the concept of GOST. Requirements, imposed by the standard to quality of production, does not remain constant, but change in accordance with the level of development of science, technology and best practices. The article considers dynamics of changes of requirements of GOST 10632 "Chipboards. Technical conditions" to the quality of chipboards in the last 40 years. The author analyzes the wording of this standard, approved in 1977, 1989, 2007 and 2014. For specified period of time the labeling of the plates P-A and P-B to P1, P2 has changed, which is related to the harmonization with foreign standards. In the last edition of the GOST 2014 plates have no restrictions on size, so as to replace presses periodic action, which have specific dimensions of the heating plates of the press, presses of continuous extrusion come. The same situation is with the densities of boards, the manufacturer sets its value, but the strength of the plates shall conform to the requirements of the standard. Although, strength characteristics (ultimate strength in tension perpendicular to the plate and the ultimate strength in static bending) are reduced with each new edition of GOST. Tightening of the requirements has occurred to the sanitary and hygienic indicators of chipboards. The content of free formaldehyde has decreased from 10 to 4 mg per 100 g of absolutely dry plate. To obtain competitive boards of E0 emission class Russian chemical industry needs to develop a large amount of resins with low content of free formaldehyde.

Hydrodynamics and mass transfer performance of flow-guided jet packing tray

A new flow-guided jet packing tray (FJPT) with high flux and efficiency has been designed in this paper. Hydrodynamics and mass transfer performance of FJPT, including tray pressure drop, weeping, entrainment, clear liquid height and tray efficiency, have been studied with cold-flow model experiments (using water, air and other system other simulation system for the test in the absence of chemical reaction conditions), using air-water-oxygen system in a 500mm diameter plexiglass column. According to the experimental data, the empirical formulas of the FJPT have been established in terms of dry pressure drop and wet pressure drop. Compared with New Vertical Sieve Tray(New VST), FJPT has lower pressure drop. The experimental result shows that dry plate pressure drop is independent of the size of the gap, while bigger cap bottom gap leads to lower wet plate pressure drop and weeping percent, smaller bottom gap leads to less entrainment and higher tray efficiency. These have provided a good theoretical basis for the research and development of the compound tray.

Hygroscopic effects on the penetration-resistance behavior of a specially-orthotropic CFRP composite plates

This paper addresses the impact responses of dry and wet specially-orthotropic cross-ply CFRP composite plates under low-velocity impact loading. Experimental tests were performed for five different moisture content conditions using anti-symmetric cross-ply composite plates. To analyze the hygroscopic effects, all plates were immersed in hot water for water absorption and then impacted by constant weight via an impactor. Absorbed water cause matrix swelling and leads to disbanding between the matrix and fiber at the interface, as observed in SEM images. The results showed that plates with a higher level of moisture content showed more undulation in the time-force curve and a relatively small change in the peak force for all plates. Moisture content does not have a substantial effect on the penetration-resistance of the plates. The flexural rigidity or stiffness of the plates decreases due to moisture content and large damage sizes were observed for wet specimens in the C-scan pictures as compared to dry plate.

Hydrodynamic characteristics of a three-stage dual-flow sieve plate scrubber

Experimental study has been carried out in a dual-flow sieve plate scrubber to study the flow characteristics such as dry plate and total tray pressure drop, average clear liquid height and fraction of holes passing gas. The flow characteristics were observed for air–water system at different gas liquid rates with 8.297 × 10−4 to 27.6 × 10−4 Nm3/s gas flow rates (QG) and liquid flow rates (QL) of 20.649 × 10−6 to 48.183 × 10−6 m3/s. The dry plate pressure drop values are measured experimentally and compared with the predicted values from the existing correlation in the literature. The experimental results of tray total pressure drop and average clear liquid height on tray are plotted against gas load factor (Fs) based on which the flow regimes on present dual-flow sieve plate are discussed. The fraction of holes passing gas values are calculated using correlations available in the literature using average plate pressure drop. The average clear liquid height values from experimental study are matched well with the predicted values of average clear liquid heights from the modified form of clear liquid height correlation.