Development of a Rotary Drilling Mechanism for Impregnated Diamond Bits

2014 ◽  
Vol 989-994 ◽  
pp. 3136-3139
Author(s):  
Zhan Tao Li ◽  
Yong Zheng Ma ◽  
Ken-ichi Itakura
Keyword(s):  
Diamond Particle ◽  
State Theory ◽  
Mechanical Parameters ◽  
Rotary Drilling ◽  
Core Drilling ◽  
Geological Surveys ◽  
Proposed Model ◽  
Optimal Value ◽  
Operation Parameters ◽  
Impregnated Diamond Bits

Impregnated diamond core bits are often used in core drilling for geological surveys. A tri-state theory is proposed to describe the three states in drilling processes for a diamond particle or a bit. These states are contacting state, cutting state, and ploughing state. Furthermore, the relations among thrust and other mechanical parameters are also summarized. The optimal value of the specific energy is in the cutting state. Several experiment results verified the proposed model. This mechanism is useful for selecting operation parameters in core drilling using impregnated diamond core bits.

scholarly journals An Analysis of the Retention of a Diamond Particle in a Metallic Matrix after Hot Pressing

2017 ◽  
Vol 17 (1) ◽  
pp. 17-20 ◽  
Author(s):  
J. Borowiecka-Jamrozek ◽  
J. Lachowski
Keyword(s):  
Elastic Energy ◽  
Synthetic Diamond ◽  
Computer Modelling ◽  
Diamond Particle ◽  
Metallic Matrix ◽  
Mechanical Parameters ◽  
Powder Mixtures ◽  
The Matrix ◽  
Calculation Results ◽  
Abaqus Software

Abstract This paper deals with computer modelling of the retention of a synthetic diamond particle in a metallic matrix produced by powder metallurgy. The analyzed sintered powders can be used as matrices for diamond impregnated tools. First, the behaviour of sintered cobalt powder was analyzed. The model of a diamond particle embedded in a metallic matrix was created using Abaqus software. The preliminary analysis was performed to determine the mechanical parameters that are independent of the shape of the crystal. The calculation results were compared with the experimental data. Next, sintered specimens obtained from two commercially available powder mixtures were studied. The aim of the investigations was to determine the influence of the mechanical and thermal parameters of the matrix materials on their retentive properties. The analysis indicated the mechanical parameters that are responsible for the retention of diamond particles in a matrix. These mechanical variables have been: the elastic energy of particle, the elastic energy of matrix and the radius of plastic zone around particle.

Kinetic Model with Effect of Water Content for Enzyme-Catalyzed Citronellyl Laurate Esterification Process

2013 ◽  
Vol 284-287 ◽  
pp. 423-428 ◽  
Author(s):  
Siti Asyura Zulkeflee ◽  
Suhairi Abd Sata ◽  
Norashid Aziz
Keyword(s):  
Experimental Data ◽  
Kinetic Model ◽  
Water Content ◽  
Model Development ◽  
Initial Water Content ◽  
Initial Water ◽  
Effect Of Water ◽  
Proposed Model ◽  
Optimal Value ◽  
Influence Of Water

A kinetic model with effect of water content for enzyme-catalyzed citronellyl laurate was developed. These models incorporate the combined influences of established kinetics model with the function model on the effect of initial water content with kinetic parameters. The model development was carried out by performing a linear and nonlinear regression based on the behavior of the kinetic parameter profiles and validated with experimental data. Using the developed models, the influence of water content towards the enzyme-catalyzed initial rate of reaction was theoretically explained. It has been shown that the proposed model have good agreement between experimental data and intends to capture the effect of water content towards the conversion of ester. With this model, the optimal value of initial water content for this process could be estimated.

scholarly journals Viscosity model of deep eutectic solvents from group contribution method

2022 ◽  
Author(s):  
Liuying Yu ◽  
Xiaojing Hou ◽  
Gao-Peng Ren ◽  
Kejun Wu ◽  
Chao-Hong He
Keyword(s):  
Deep Eutectic Solvents ◽  
State Theory ◽  
Group Contribution ◽  
Rate Theory ◽  
Model Parameters ◽  
Training Set ◽  
Free Volume Theory ◽  
Relative Deviation ◽  
Proposed Model ◽  
Very High

In this work, based on mathematical model inspired by transition state theory, the group contribution (GC) method is used to predict the viscosity of DESs. The model is constrained by Eyring rate theory and hard sphere free volume theory. A dataset of 2229 experimental measurements of the viscosity of 183 DESs from literature is used for determining the model parameters and subsequent verification of the model. The rules introduced by this model are simple and easy to understand. The results show that the proposed model is able to predict the DESs viscosity with very high accuracy, i.e., with an average absolute relative deviation of 8.12% over the training set and 8.64% over the test set, using only temperature and composition as inputs. The maximum absolute relative deviation is 34.63%. Therefore, the as-proposed model can be considered a highly reliable tool for predicting DESs viscosity when experimental data are absent.

scholarly journals Theoretical and Case Studies of Interval Nonprobabilistic Reliability for Tailing Dam Stability

Geofluids ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Longjun Dong ◽  
Daoyuan Sun ◽  
Xibing Li
Keyword(s):  
Mechanical Parameters ◽  
Analysis Model ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
Proposed Model ◽  
Tailing Dam ◽  
Calculation Results ◽  
Tailing Dams ◽  
Dam Stability ◽  
The Stability

The stability of the operation of a tailing dam is affected by reservoir water level, phreatic line, and mechanical parameters of tailings. The values of these factors are not a definite value in different situations. Meanwhile, the existence of the phreatic line makes it a more complex issue to analyze the stability of the tailing dam. Additionally, it is very hard to give a definite limit to the state of tailing dam from security to failure. To consider the uncertainty when calculating the stability of the tailing dams, interval values are used to indicate the physical and mechanical parameters of tailings. An interval nonprobabilistic reliability model of the tailing dam, which can be used when the data is scarce, is developed to evaluate the stability of the tailing dam. The interval nonprobabilistic reliability analysis model of tailing dam is established in two cases, including with and without considering phreatic line conditions. The proposed model was applied to analyze the stability of two tailing dams in China and the calculation results of the interval nonprobabilistic reliability are found to be in agreement with actual situations. Thus, the interval nonprobabilistic reliability is a beneficial complement to the traditional analysis method of random reliability.

scholarly journals A Conceptual Model for a Safety-Based Theory of Lean Construction

Buildings ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 23 ◽  
Author(s):  
Soheila Moaveni ◽  
Seyed Banihashemi ◽  
Mohammad Mojtahedi
Keyword(s):  
Conceptual Model ◽  
Construction Projects ◽  
Project Managers ◽  
Lean Construction ◽  
Project Delivery ◽  
New Approach ◽  
Factors Affecting ◽  
Work Related ◽  
Proposed Model ◽  
Optimal Value

The construction industry is one of the most fatal industries, so it is important to pay more attention to safety solutions. Even though work-related accidents are known as a major waste in construction projects, little attention has been paid so far to incorporating safety into the lean construction framework. In this research, lean construction theory is reviewed through the lens of safety. That being so, the identified challenges in previous research on improving safety in construction projects are categorized, and those related to the concept of lean project delivery are introduced. Then, the principles of the lean construction framework are explained, and the relevant changes for incorporating safety into the framework are introduced and discussed. The proposed model includes a new approach to the Transformation-Flow-Value framework, in order to pay particular attention to safety in construction projects as one of the factors affecting the success of projects, and achieving optimal value for stakeholders. It is expected that this hybrid model would further enrich the lean construction framework. The careful attention of project executives to this model may improve the safety situation in construction projects. The conceptual model presented in this study can be used in the decision making process for project managers as well as research into optimization of safety costs, and eliminating waste (including models for optimizing the movement of machinery, controlling and reducing rework, and designing the site layout).

scholarly journals Precise Identification of Coal Thickness by Channel Wave Based on a Hybrid Algorithm

2019 ◽  
Vol 9 (7) ◽  
pp. 1493 ◽  
Author(s):  
Changfang Guo ◽  
Zhen Yang ◽  
Shuai Chang ◽  
Ting Ren ◽  
Wenli Yao
Keyword(s):  
Hybrid Approach ◽  
Propagation Distance ◽  
Inversion Result ◽  
Proposed Model ◽  
Optimal Value ◽  
Channel Wave ◽  
Precise Prediction ◽  
Value Effect ◽  
Reconstructive Techniques ◽  
Search Capability

Precise prediction of coal thickness is of the utmost importance in realizing intelligent and unmanned mining. As the channel wave is characterized by an easily recognizable waveform, a long propagation distance, and strong energy, it is widely used for coal thickness inversion. However, most traditional inversion methods are local in nature, and the inversion result is probably not optimal in the global scope. This paper introduces the GA-SIRT hybrid approach, which combines Genetic Algorithms (GA) and Simultaneous Iterative Reconstructive Techniques (SIRT) in order to deal with the above problem and to improve the accuracy of coal thickness inversion. The proposed model takes full advantage of the strong global search capability of GA and of the fast local convergence rate of the SIRT. Moreover, it inhibits the poor local search ability and the local optimal value effect of the GA and the SIRT respectively. The application of the GA-SIRT in the Guoerzhuang coal mine has significantly enhanced its accuracy, stability, and overall computational efficiency. Hence, the introduced novel hybrid model can precisely resolve and identify the coal thickness according to the channel wave. It can also be extended to other geophysical tomographic inversion problems towards the reduction of potential local optimal solutions.

Financial conflict resolution model in BOT contracts using bargaining game theory

2019 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Morteza Bayat ◽  
Mostafa Khanzadi ◽  
Farnad Nasirzadeh ◽  
Ali Chavoshian
Keyword(s):  
Capital Structure ◽  
Period Length ◽  
Financial Benefit ◽  
New Approach ◽  
Content Type ◽  
Proposed Model ◽  
Optimal Value ◽  
Financial Interests ◽  
Concession Period ◽  
The Government

Purpose This study aims to determine the optimal value of concession period length in combination with capital structure in build–operate–transfer (BOT) contracts, based on direct negotiation procurement and considering the conflicting financial interests of different parties involved in the project. Design/methodology/approach The financial model of a BOT project is developed considering all the influencing factors. Then, fuzzy set theory is used to take into account the existing risks and uncertainties. Bilateral bargaining game based on alternating-offers protocol is applied between the government and the sponsor to divide project financial benefit considering the lender’s requirements. Finally, concession period and equity level will be determined simultaneously according to the sponsor’s and government’s share of project financial benefit and the lender’s requirements. Findings The proposed model is implemented on a real case study, and a fair and efficient agreement on concession period length and capital structure is achieved between the government and the sponsor considering the lender’s requirements. It is revealed that being the first proposer in the bargaining process will affect the concession period length; however, it will not affect the equity level. Moreover, it is shown that considering income tax as a part of government’s financial benefit increases the length of concession period. Research limitations/implications The presented model concentrates on direct negotiation procurement in BOT projects where the sponsor and government bargain on dividing financial benefits of project. It is assumed that the product/service price is determined before according to market analysis or users’ affordability. All the revenue of project during concession period is assumed to belong to the sponsor. Practical implications The proposed model provides a practical tool to aid BOT participants to reach a fair and efficient agreement on concession period and capital structure. This could prevent failing or prolonging the negotiation and costly renegotiation. Originality/value By investigation of previous studies, it is revealed that none of them can determine the optimal value of concession period length and capital structure simultaneously considering the BOT negotiation process and different financial interests of parties involved in the project. The proposed model presents a new approach to determine the financial variables considering the conflicting interests of involved parties. The other novelty aspects of the presented model are as follows: introducing a new approach for calculating the sponsor and the government’s share of project financial benefit that will affect the determination of the concession period length and considering the effect of existing risks and uncertainties on final agreement between the involved parties using fuzzy set theory.

Wear Characteristics of Impregnated Diamond Bit in Drilling Armor Ceramic

2011 ◽  
Vol 179-180 ◽  
pp. 1150-1155
Author(s):  
Chao Gao ◽  
Jun Tang Yuan ◽  
Hao Jin ◽  
Zhong Quan Song
Keyword(s):  
Crystal Shape ◽  
Wear Characteristics ◽  
Comprehensive Properties ◽  
Impregnated Diamond Bit ◽  
Optimal Value ◽  
Abrasion Rate ◽  
Diamond Grain ◽  
Diamond Bit ◽  
Impregnated Diamond Bits ◽  
Diamond Abrasive

This paper describes the wear characteristics of impregnated diamond bits when drilling in Al2O3 armor ceramic. With different bits being developed, drilling experiments and scanning electron microscope (SEM) examinations were conducted, and the results show that diamond wear types consist of complete crystal shape, micro fragmentation, whole fragmentation, wearing flat and falling off of diamond; abrasive wear, impact abrasion and erosion exist in the wear of diamond and bond; diamond grain size and concentration have their optimal value under fixed machining conditions; diamonds of high quality could increase bit drilling efficiency and serving life; the bit whose abrasion rate of bond matches that of diamonds presents the best comprehensive properties.

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