Pile Material Research Articles

Effects of depth- and composition-dependent thermal conductivity and the compositional viscosity ratio on the long-term evolution of large thermochemical piles of primordial material in the lower mantle of the Earth: Insights from 2-D numerical modeling

Effects of depth- and composition-dependent thermal conductivity and the compositional viscosity ratio on the long-term evolution of large thermochemical piles of primordial material in the lower mantle of the Earth: Insights from 2-D numerical modeling

Mapping Abandoned Uranium Mine Features Using Worldview-3 Imagery in Portions of Karnes, Atascosa and Live Oak Counties, Texas

Worldview-3 (WV3) 16-band multispectral data were used to map exposed bedrock and mine waste piles associated with legacy open-pit mining of sandstone-hosted roll-front uranium deposits along the South Texas Coastal Plain. We used the “spectral hourglass” approach to extract spectral endmembers representative of these features from the image. This approach first requires calibrating the imagery to reflectance, then masking for vegetation, followed by spatial and spectral data reduction using a principal component analysis-based procedure that reduces noise and identifies homogeneous targets which are “pure” enough to be considered spectral endmembers. In this case, we used a single WV3 image which covered an ~11.5 km by ~19.5 km area of Karnes, Atascosa and Live Oak Counties, underlain by mined rocks from the Jackson Group and Catahoula Formation. Up to 58 spectral endmembers were identified using a further multi-dimensional class segregation method and were used as inputs for spectral angle mapper (SAM) classification. SAM classification resulted in the identification of at least 117 mine- and mine waste-related features, most of which were previously unknown. Class similarity was further evaluated, and the dominant minerals in each class were identified by comparison to spectral libraries and measured samples of actual Jackson Group uranium host rocks. Redundant classes were eliminated, and SAM was run a second time using a reduced set of 23 endmembers, which were found to map these same features as effectively as using the full 58 set of endmembers, but with significantly reduced noise and spectral outliers. Our classification results were validated by evaluating detailed scale mapping of three known mine sites (Esse-Spoonamore, Wright-McCrady and Garbysch-Thane) with published ground truth information about the vegetation cover, extent of erosion and exposure of waste pile materials and/or geologic information about host lithology and mineralization. Despite successful demonstration of the utility of WV3 data for inventorying mine features, additional landscape features such as bare agricultural fields and oil and gas drill pads were also identified. The elimination of such features will require combining the spectral classification maps presented in this study with high-quality topographic data. Also, the spectral endmembers identified during the course of this study could be useful for larger-scale mapping efforts using additional well-calibrated WV3 images beyond the coverage of our initial study area.

Time-Varying Tool-Chip Contact in the Cutting Mechanics of Shear Localization

Abstract Shear localization is the dominant chip formation mechanism in machining of high performance metallic components, such as those made of titanium and nickel-based alloys. This paper presents an analytical thermo-mechanical model considering a new tool-chip contact mechanism due to shear localization. First, it is experimentally shown that the sticking and sliding contact lengths fluctuate with the frequency of shear localization. Second, a cutting mechanics model is developed considering the shear band formation, its rolling on the tool’s rake face, and the time-varying tool-chip contact length with experimental validation. Finally, the transient temperature at the tool-chip interface is predicted by taking the rolling phenomenon and the time-varying heat sources at the tool-chip interface into account. The proposed model shows that at the beginning of each segmentation cycle, the entire tool-chip contact length is dominated by sliding condition with negligible sticking length. When the tool advances, new workpiece material piles up in its front with an increase in the sticking length. Meanwhile, the sliding length decreases due to the drop in the load-bearing capacity of the shear band. When enough material piles up in front of the tool, a new shear band forms, and the entire contact length returns to the sliding condition. This process repeats each time a shear band occurs, causing the cyclic formation of shear bands and time-varying nature of the tool-chip contact length, therefore influencing the temperature and stress evolution at the tool-chip interface.

Problems Faced by University Teachers and Students in the Semester System

A semester is a period of six months. This system is very effective in higher education. It is considered more innovative, appropriate, and cooperative than the annual system. It provides the students with an opportunity for continuous learning, assessment, and feedback. However, many teachers and students criticize that they always miss the deadline for course completion so that students cannot engage in extracurricular activities. In this regard, the present study aims to explore the problems faced by university teachers and students in the semester system. To accomplish the objective, the researcher adopted a phenomenological research design under the qualitative method. It is based on the lived experiences of University-level English teachers and students about the semester system at TU. The total population of this study consisted of university EFL teachers and students in Nepal, out of which, the researcher selected only five university EFL teachers and ten students from Tribhuvan multiple campus, Palpa using a purposive sampling procedure. Similarly, the researcher made an interview guideline and then took the interview with the sampled teachers and students to obtain in-depth information. The results revealed that the most of the teachers and students paid more attention to their course contents than to extracurricular activities. Similarly, there are piles of materials in the syllabus; however, most of the important materials are not available in the market. There is no extra facility for economically backward students.

Analytical Solution of Horizontal Dynamic Response of a Floating Pile Embedded in an Elastic–Poroelasitc-Layered Soil

The horizontal dynamic interaction problems of a floating pile with soil have received little attention from scholars in recent years. This paper first proposed an analytical solution for the dynamic characteristics of the floating pile subjected to horizontal steady-state excitation embedded in soil containing the groundwater table level. Based on Biot’s elastodynamic theory, the governing equations of the soil around the pile are obtained. By virtue of the Hankel transform technique and variable separation method, the shaft reactions and base resistances transferred from the soil are calculated and substituted into the dynamic equation of the floating pile derived by the Euler beam model. The dynamic impedance coefficient of the pile head in the frequency domain is obtained by using the transfer matrix method. Comparisons with the previous studies are performed to validate the accuracy of the presented approach. The effects of the thickness of the pile end soil, the slenderness ratio of the pile, the groundwater table level and the relative modulus of pile material on the pile dynamic response are investigated through several numerical analyses. The results show that there is an “active soil thickness” for the horizontal dynamic forced floating piles due to the reflection and refraction of the stand waves. Meanwhile, the effect of the groundwater table level should not be neglected to ensure the safety of pile foundation under service life.

Quality evaluation of ground improvement by deep cement mixing piles via ground-penetrating radar

Deep cement mixing piles are a key technology for treating settlement distress of soft soil subgrade. However, it is very challenging to accurately evaluate the quality of pile construction due to the limitations of pile material, large number of piles and small pile spacing. Here, we propose the idea of transforming defect detection of piles into quality evaluation of ground improvement. Geological models of pile group reinforced subgrade are constructed and their ground-penetrating radar response characteristics are revealed. We have also developed ground-penetrating radar attribute analysis technology and established ground-penetrating radar technical system for evaluating the quality of ground improvement. We further prove that the ground-penetrating radar results integrating single-channel waveform, multi-channel section and attributes can effectively detect the defects and stratum structure after ground improvement. Our research results provide a rapid, efficient and economic technical solution for the quality evaluation of ground improvement in soft soil subgrade reinforcement engineering.

A technological advancement in artificial refuges for an endangered marsupial predator

Findings from previous research of artificial refuges constructed for northern quolls, as well as collaboration with species experts, engineers, designers, and industry, have led to an advanced design for northern quoll habitat creation. With ongoing habitat destruction, conservationists and land managers are increasingly looking to human-made alternatives to provide shelter to wildlife (Cowan et al., 2021, Watchorn et al., 2022). In the Pilbara region of Western Australia, mining companies are required to offset habitat destruction that affects species of conservation significance. These offsets are often in the form of compensation approaches—including the creation of artificial habitat—so it is critical that compensation measures are effective. One such species of conservation significance is the northern quoll (Dasyurus hallucatus), which is impacted by the destruction of rugged and rocky denning habitat during mining (Moore et al., 2022). In many cases, mining companies have looked to artificial refuges as a potential offset tool to provide denning habitat for quolls—historically created as large piles of rocky material with internal crevices formed by the variation in material used. Cowan et al. (2020) investigated the ability of these artificial refuge designs to imitate natural northern quoll dens and published their findings in Conservation Science and Practice. Artificial refuges had internal microclimates reflective of those inside natural dens but were much shallower and had less complex surrounding habitat. Artificial refuges also had higher visitations of feral cats (Felis catus), a predator of northern quolls. Northern quoll visitation was extremely low at artificial refuges, while feral cats were observed raising young within one artificial refuge, highlighting the potentially negative impacts of these structures if not designed appropriately. These findings had important conservation implications and sparked much activity in this space. Collaboration among industry, government, engineers, designers, consultants, and species experts has led to at least one project aimed at advancing the development of artificial refuges for northern quolls. Habitat Innovation and Management—experts in artificial habitat design and manufacture—in collaboration with industry partner Fortescue Metals Group and northern quoll experts, developed a reproducible artificial refuge for northern quolls (Figure 1). The artificial refuge considers the internal denning requirements of northern quolls (e.g., depth), as described by Cowan et al. (2020), as well as environmental threats such as extreme temperatures, fire, and heavy rain that are common in the Pilbara. The artificial refuge is constructed using linear low-density polyethylene (LLDPE) to which a flame-retardant additive is applied to increase fire resistance. Manufacture of the refuge is achieved using rotational molding which involves rotating a heated mold filled with LLDPE, where the softened material spreads around the walls of the mold, forming the required shape. The artificial refuge incorporates features critical to the ecological needs of northern quolls, including an air-circulating vent, an escape shelf, and an entrance which can be configured with natural or artificial materials to exclude larger predators such as feral cats. The refuge is designed to be easily deployed in the field and covered with layers of soil and rocks to assist in thermal buffering, fire protection, and habitat complexity (Figure 2). Future research will include field testing of the refuges alongside management techniques such as invasive predator control and vegetation restoration. This will help to determine if these artificial refuges can support breeding populations of northern quolls long term. All authors conceived the idea for the manuscript and contributed to writing, editing, and approved final submission. Writing was led by Mitchell A. Cowan. The concept and design of the artificial refuge was led by Michael N. Callan and Carl Tippler at Habitat Innovation and Management with input from Mitchell A. Cowan and Dale G. Nimmo. We thank the editor and reviewers for their thoughtful reviews on this manuscript. Michael N. Callan and Carl Tippler are Directors of Habitat Innovation and Management. No data were used in this manuscript.

CALCULATION OF THE MAXIMUM ALLOWABLE LOAD ON A REINFORCED CONCRETE PILE IN THE PROCESS OF DRIVING IT INTO THE SOIL

Due to the lack of technical standards (DSTU) in Ukraine for the technology and quality control of the installation of driven piles, the conditions for high-quality performance of pile driving are often violated, for example, the driving force exceeds the strength of the pile material. This leads to the destruction of piles, which is most characteristic of sandy soils. In the project documentation for the installation of driven piles, with rare exceptions, there are no restrictions on the value of the driving force based on the strength of the pile based on the material, mainly due to the difficulties that arise when calculating the maximum permissible load on the pile when it is deepened by driving the pile.According to amendment No. 1 to DBN V.2.1-10-2009 [2] the amount of Rstv. is determined by calculating the strength of the material in accordance with the requirements of DBN B.2.6-98; 2009 [3], while considering the pile as a rod rigidly clamped in the soil in a section located at a distance ℓ1 from the point of application of the compressive force (see Fig. 1 and dependencies (2), (3)).According to DBN B.2.6-98; 2009 [ 3 ], the amount of compressive load allowed for the pile material is determined by calculating the pile as an eccentrically compressed reinforced concrete element under the action of a longitudinal force, while taking into account the random eccentricity eo, which in any case must take at least 1/600 of the distance between its cross-sections, fixed from displacement and 1/3 - from the height of the cross-section. In addition, it is also necessary to take into account the influence of longitudinal deflection by multiplying the value of the random eccentricity eо by the coefficient η according to dependence (5).The specified recommendations of the DBN on determining the value of the compressive load allowed for the pile material refer to the pile as an eccentrically compressed reinforced concrete element in a static state, which does not take into account the influence of technological factors in the process of pile compression.Our experience of sinking piles at dozens of sites has shown that the impact of the pressing technology on the permissible load on a reinforced concrete pile during its sinking is manifested in the form of an increase in eccentricity due to technological factors. In table 2, the reasons affecting the eccentricity of the load on the pile in the process of its immersion are considered in various ways of creating a compressive force: due to the weight of the structures of buildings and structures; due to the weight of equipment or anchor loads; due to anchor devices.The article draws the following conclusions.1. When calculating the maximum permissible load on a reinforced concrete pile in the process of pressing it into the ground, it is necessary to take into account, in addition to the recommended DBN B.2.6-98:2009 [ 3 ] random eccentricity and eccentricity from longitudinal deflection, as well as technological eccentricity by multiplying the value of random eccentricity by the coefficient of working conditions piles when pressed.2. We proposed the values of the coefficients of pile operating conditions for determining the calculated technological eccentricity for different ways of creating a compressive force and different ways of transferring the compressive load to the pile (through the head or through the side faces) (see Table 3). These values are empirical, they will be adjusted as experience is gained in the application of the pile driving method.

Construction and Calculation Analysis of Mechanical Model of Crushed Rock Pile Treatment of Foundation Earthquake

In recent years, earthquakes have occurred frequently at home and abroad, causing huge losses to the local society. Therefore, it is important to study the mechanical response of foundations under earthquakes. In this paper, firstly, gravel piles are selected as soft ground improvement materials, and A single bulk material pile section and a peripile soil section within the influence of a single pile are considered as a study unit, and the pore water discharge from the consolidation process is equal to the volume reduction of the unit, considering the consolidation deformation of the pile body, the composite foundation consolidation equation is derived, and the consolidation equation is solved by the separation variable method through the isostrain assumption and initial boundary conditions, and the average superporous water pressure of the soil between the body and the pile is obtained. Then, a more realistic non-uniform ground motion input method is adopted, and the seismic fluctuations are converted into equivalent loads on artificial boundary nodes through the Matlab program, and the equivalent loads are applied to the established viscoelastic artificial boundary by OpenSees software to realize ground motion input. Finally, a mechanical analysis model is established by hypothesis, and with the help of mode orthogonal theory and Hilbert yellow transform, the calculation method of ground seismic mechanical response based on non-uniform ground motion input is obtained. The results show that the effect of gravel pile encryption can reduce the accumulation rate and peak of super-static pore pressure during vibration, and the surface settlement of the site is reduced by 40–50% and the surface lateral shift is reduced by 30–50% after encryption; the drainage effect has a significant effect on reducing the accumulation rate of super-static pore pressure and the post-earthquake dissipation time of the soil during vibration, and the surface settlement is reduced by about 10–20% and the lateral shift is reduced by about 30–40% after increasing the drainage effect.

INCREASING THE PRODUCTIVITY OF PILE DIVING IN ORCHARDS AND VINEYARDS BY USING HYDROJET TECHNOLOGY

The need to solve the problem of reducing labor intensity, reducing the volume of earthworks, as well as reducing the time of the process of sinking piles in orchards and vineyards. Currently, the theoretical issues of the dynamics of piles when they are immersed in the soil have not been developed to the extent required by practice. The primary task here is to study the process of sinking the pile into the soil in order to achieve the required depth of immersion with minimal damage to the structure of the pile itself, and for it to perform the work that is set before it. Naturally, in the process of sinking piles into the soil, not only elastic, but also viscous, plastic properties of the soil are manifested and its destruction occurs. The theoretical tasks of sinking the pile into the soil, taking into account the viscous, plastic properties of the soil environment and the deformation characteristics of the pile material, have not been investigated. Nowadays, in connection with the circumstances that are currently happening in Krane, in the Vinnytsia region, the percentage of people's involvement in agricultural affairs is growing significantly, namely: in the planting of new garden and grape plantations and lands. There is a demand for immersion equipment that can quickly and efficiently perform the assigned tasks. Therefore, increasing the productivity of the process of sinking piles in orchards and vineyards through the use of hydrojet technology is an extremely relevant topic. The purpose of the article is to increase the productivity of the process of sinking piles in orchards and vineyards by using hydrojet technology. Creation of favorable conditions for the intensification of the production process and the application of effective methods of action on its object; continuous implementation of technological movement; reduction and general elimination of the use of unproductive labor; in particular, when performing auxiliary operations; management of the dynamic state of the system in which technological action takes place; the multifunctionality of the technological process and the harmonious combination of its main structural components are, for the most part, trends in the development of technical progress in the implementation of pile sinking.

The axial behaviour of piles driven in chalk

This paper describes research into the poorly understood axial behaviour of piles driven in chalk. Comprehensive dynamic and monotonic axial testing on 27, mostly instrumented, piles undertaken for the ALPACA joint industry projects is reported and interpreted covering: diameters between 139 mm and 1·8 m; lengths from 3 to 18 m; different pile material types; tip and groundwater conditions; and ages after driving. The experiments show the factors that influence resistance most strongly are: (a) pile end conditions; (b) slenderness ratio and flexibility; (c) shaft material; (d) age after driving; (e) relative water table depth; and (f) whether loading is compressive or tensile. Varying the factors systematically identified a remarkable average long-term shaft resistance range from below 11 kPa to more than 200 kPa for piles driven at the same low- to medium-density chalk test site in Kent (UK). Dynamic and static analyses demonstrate that soil resistances to driving were generally well predicted by the Chalk ICP-18 short-term formulation. Considering the piles’ long-term behaviour, the Chalk ICP-18 approach over-predicted capacity, while the widely used CIRIA approach proved over-conservative for most cases. The research enabled the development of a revised ‘ALPACA-SNW’ long-term capacity assessment method that matches the test outcomes far more faithfully.

Experimental study of the thermodynamic properties of high thermal conductivity energy pile

In this paper, high thermal conductivity concrete (containing 4% graphite and 0.6% steel fiber) was prepared as a pile material by a model test. A high thermal conductivity energy pile was produced. The temperature field distribution of the pile and soil, the additional stress of the pile, the soil pressure at the pile end, and the displacement of the pile top were analyzed. The results showed that compared with the thermal conductivity, compressive strength, and flexural strength of ordinary C30 concrete, those of the high thermal conductivity concrete were increased by 30%, 11%, and 9%, respectively. Under load, the additional stress of the pile was large in the middle and small at both ends. After three thermal cycles, the maximum additional tensile and compressive stresses of the pile were 0.48 MPa and −0.58 MPa, respectively. The maximum value of the soil pressure at the pile end decreased with an increase in the number of thermal cycles. Thermal cycles caused cumulative pile top settlement, with a final settlement of 0.26 mm. In practical engineering, the influence of long-term thermal cycles on the safety of buildings should be noted.

An automatic forage unloading method based on machine vision and material accumulation model

The traditional cooperative operation method of forage harvesters and trailers suffers from low hopper unloading rates and forage waste, which hinders the development of precision agriculture. To address these issues, this study proposed an automatic forage unloading method. First, the outline of the forage pile was extracted based on machine vision, and the pile's repose angle was determined by linearly fitting its profile. Next, we utilized the forage accumulation model to develop a prediction method for the forage drop point and the automatic unloading method. The reliability of the forage accumulation models and the feasibility of the automatic unloading method were then verified through DEM simulation. Finally, field forage harvests were conducted to validate the effectiveness of the automatic unloading method and the accuracy of the mass calculation model. The simulation showed that the average absolute errors of the simulation and model calculation results of the three material piles were less than 0.1 m3, respectively. The field experiment showed that the maximum absolute error between the predicted and actual drop points was 0.095 m. The average absolute errors of the mass calculation model and the weighing method were 21.37 kg, 37.68 kg, and 60.36 kg, respectively. This research improves harvesting efficiency, reduces forage waste, and promotes the automatic development of self-propelled forage harvesters.

Dynamic compressive and splitting tensile characteristics of rubber-modified non-autoclaved concrete pipe piles

Non-autoclaved concrete pipe piles are gaining attention as an environmentally friendly alternative to autoclaved concrete pipe piles. The purpose of this study was to investigate the changes in the impact resistance of a non-autoclaved concrete pipe pile with the addition of rubber. To this end, various volume fractions of rubber particles were used to replace the fine sand in the non-autoclaved pipe pile concrete (0%, 5%, 10%, 15% and 20%). The dynamic and static mechanical responses of rubber-modified non-autoclaved pipe pile concrete were explored through quasi-static and dynamic compression and splitting tensile tests. The results showed that (1) The tensile-compression ratio of the rubber-modified non-autoclaved pipe pile concrete increased with the rubber content, and the brittleness of non-autoclaved concrete was improved by adding rubber. (2) When subjected to impact load, rubber particles could absorb some of the impact energy, reduce the impact load on the aggregate, and prevented the aggregate from being crushed. (3) The impact toughness index and energy consumption ratio of non-autoclaved pipe pile concrete increased with the increase of rubber content. When the rubber content was 10%, the impact toughness index and energy consumption ratio of non-autoclaved pipe pile concrete were 52.2% and 51.2% higher than those of non-autoclaved pipe pile concrete without rubber particles, respectively, and its impact resistance was the best. The impact resistance of rubber-modified non-autoclaved pipe pile concrete was better than that of traditional autoclaved pipe pile concrete, and met the mechanical performance requirements of prestressed high-strength concrete pipe pile. It could be used as a new prestressed high-strength concrete pile material, which helped to reduce energy consumption in the production process of piles. The study provided parameter basis for the subsequent drop hammer impact test and numerical simulation of pipe piles.

Evaluation of Spatial Characteristics of Corroded Situations in Service Steel Sheet Piles by Applying Geostatistics

The corrosion degradation of the steel sheet pile material accelerates in recent years. The extremely accelerated corrosion induces the thickness loss and decreases the mechanical characteristics. It is essential to evaluate the corroded situations for the design and maintenance of the infrastructures. In this study, the spatial characteristics of the corrosion loss in service steel sheet pile canals were evaluated by the geostatistics with the variogram and kriging. In experimental procedures, steel sheet pile thicknesses were measured in service drainage canals. The thickness sampling was conducted in the air, tidal, water, sludge and soil zones. In analytical procedures, the variogram analysis is conducted for modeling of the spatial structures of the corrosion loss distribution. The ordinary kriging based on the theoretical variogram interpolates the no-sampling area. As a result, the thickness profile shows the largest corrosion loss in the tidal zone. The kriging interpolation shows the acceleration of the corrosion in the flanges of the tidal zone.

A Systematic Review of the Geotechnical and Structural Behaviors of Fiber-Reinforced Polymer Composite Piles

Composite piles have emerged as a popular alternative to conventional piling materials for deep foundations and have gained significant traction as a specific type of pile due to their potential to mitigate durability issues often associated with standard piling materials. A new type of composite piles can improve structural behavior and extend service life. This research uses an inclusive review methodology to evaluate the geotechnical and structural behaviors of fiber-reinforced polymer (FRP) composite piles. Scopus was utilized to address the relevant keywords and state-of-the-art documents, and VSOviewer software was adopted to spot recurring patterns in the data using scientometric maps. Low-stiffness composite materials are a concern, according to the research work. Thus, researchers are working on confined concrete-filled FRP piles to improve the structural and geotechnical properties used in various load-bearing conditions. However, more research is required to comprehensively understand the behaviors of the studied types of composite piles. Indeed, there is a need for large-scale lab and field studies to determine how axial and lateral loads influence composite piles. This could help create guidelines for constructing the reviewed types of composite piles.

Lateral buckling capacity of steel H-piles supporting integral abutment bridges (IABs)

Integral abutment bridges (IABs) have been gaining wide popularity in the United States and neighboring countries due to the rapid increase in maintenance costs associated with conventional bridges. The elimination of expansion joints in IABs allows the thermally induced lateral demand in the superstructure to be transferred to the supporting piles. This paper aims to study the behavior of steel H-piles supporting IABs through a detailed nonlinear finite element analysis that was calibrated and validated against available experimental data. A total of 30 models were established to examine the effect of various parameters (pile size, pile orientation, pile material yield strength, pile equivalent cantilever length, and axial compressive load) on piles supporting jointless bridges subjected to a combined axial load and lateral cyclic displacement amplitude. Local buckling was the dominant failure mode for all the specimens. Furthermore, this paper reiterates the various parameters and assesses their influence through a statistical regression analysis to develop an empirical formula for calculating the lateral buckling capacity. The rationality of the developed formula was examined and tested with existing experimental data, which testified the reliability to be used for future design considerations.

Innovations in designing microwave electro-technological units with hybrid chambers

Aim of study: Microwave (MW) electro-technological units based on electromagnetic radiation of ultrahigh-frequency can involve thermal MW modification of dielectrics and non-thermal MW modification of polymers. Area of study: Russian Federation. Material and methods: The paper considers a method for making a unit with a hybrid chamber, where thermal and non-thermal MW modifications were carried out simultaneously, and the remaining energy after non-thermal MW modification of polymers was used for heating the dielectric. Main results: A microwave electro-technological unit with a hybrid chamber replaced two separate devices that implemented these MW modifications. It was cheaper and required one MW generator. The unit took up less space than two separate apparatuses, and upgraded the existing microwave dryer to perform thermal MW modification of a lumber pile and non-thermal MW modification of polymer materials. The existing microwave dryer was redeveloped by solving the boundary value problem in electrodynamics and heat and mass transfer. Research highlights: The research presents a microwave electro-technological unit with a hybrid chamber, combining thermal and non-thermal MW modifications of dielectric and polymer materials. As a result of upgrading the existing microwave dryer, it was possible to carry out both thermal and non-thermal MW modifications, namely, microwave drying of timber and microwave drying of up to seven different polymer objects.

Prediction of cutting forces in flexible micro milling processes by considering the change of instantaneous cutting direction

The characteristic of low stiffness of the micro mills usually leads to instantaneously changeable tool deflections, and as a result, actual in-process cutting parameters such as the instantaneous cutting directions and trajectories of the cutting edges will deviate from their designed values. Existing works seldom studied the influence of this fact on the cutting forces. This article presents a theoretical method to predict the micro milling forces by introducing the effects of the tool’s deflections on the process. Analytical formulae for determining the actual in-process cutting edge position and instantaneous cutting direction are originally derived based on the tool deflections, which are calculated by using the cantilever beam theory. At the same time, other actual in-process parameters such as rake angle, shearing angle and uncut chip thickness are subsequently formulated to detect their influences on the cutting. Based on the obtained actual in-process parameters and tool deflections, the shearing and ploughing forces, which constitute the total micro milling forces, are then formulated separately. An iterative algorithm, which integrates the above derivations with the material piling up effect, is developed to capture the coupling effect between the cutting forces and tool deflections during the micro milling process. A series of experimental tests are conducted, and the results prove that the accuracies of cutting forces and the cutting edge’s moving trajectories predicted by the proposed method are better than those obtained from the classic models without including the changes of cutting directions caused by the tool deflections.

Optimization Of Production Capacity In Manufacturing Multi Plate 424 Products Using Promodel Simulation At Pt CMP

A good production system is one of the important factors to determine the success of production. The integration of every process in production requires that every element in the system work properly. If one of the elements in the production process is jammed, this can cause big problems in the production process, such as a lot of idle time, inappropriate production targets, and so on. One alternative to overcome this is by simulating alternative solutions that have been proposed in a visual form with Promodel student version 7.5 software. The production process of making Multi Plate 424 at PT CMP occurs an imbalance in the machines used, which results in idle time and the length of the process of making the multi plate 424. This problem occurs because there are many piles of material on each of the machines used, so that it has an impact on the length of time for the multi plate. The proposed alternative solution is to reduce the bottleneck on each machine. Based on the simulation carried out between the existing system simulation and the proposed simulation model, there are several results including the schedule time, which is 21037.28 minutes, while the proposed simulation model is 18390,22 minutes with the total entries that enter the finished goods warehouse is 630 pcs