Mechanization and Import Substitution in Zimbabwean Farmers' Equipment: A Case Study of the Revitalization of an Abandoned Tractor Trailer
Drill String Vibrational Analysis and Parametric Optimization for a Portable Water Well Rig Development
An Efficient Deep Neural Network with Amplifying Sine Unit for Nonlinear Oscillatory Systems
The Occupational Directness of Nanorobots in Medical Surgeries
Recent Trends in Solar Thermal Cooling Technologies
Design of Oil-Ammonia Separator for Refrigeration Systems
A Review on Mechanical and Tribological Characteristics of Hybrid Composites
Design and Experimental Investigation of a Natural Draft Improved Biomass Cookstove
Progressive Development of Various Production and Refining Process of Biodiesel
Optimization of Wire-ED Turning Process Parameters by Taguchi-Grey Relational Analysis
Evaluation Of Mechanical Behavior Of Al-Alloy/SiC Metal Matrix Composites With Respect To Their Constituents Using Taguchi Techniques
Multistage Extractive Desulfurization of Liquid Fuel by Ionic Liquids
Isomorphism Identification of Compound Kinematic Chain and Their Mechanism
Development of Electroplating Setup for Plating Abs Plastics
A Comprehensive Review of Biodiesel Application in IDI Engines with Property Improving Additives
This paper provides an analysis of one of the dysfunctions in borehole drill strings, which is torsional vibration. Additionally, an analysis of mitigation through systematic adjustment of the key parameters of Weight on the Bit (WOB) and Rotations per Minute (RPM) is conducted. One of the key forms of dysfunction is undesired vibration and shocks on the drill strings. The vibration and shock experienced by drill strings have a detrimental impact on equipment life, resulting from damage to the drill bit and the drill string components. This paper studies a generalized lumped-parameter model of the drill-string system to provide a fundamental understanding of the torsional stick-slip vibrations during drilling operations. The impact of various parameters such as the weight on the bit, rotational speed, and damping on the severity of vibration, in particular, stick-lip vibration, is analyzed. Various passive, active, and semi-active control strategies to mitigate the torsional vibrations have been studied and implemented with varying degrees of success, subject to continual development. From the simulation, the WOB, the drive torque, and rotational velocity determine the stick-slip onset and severity. This paper focuses on active control of the rotational speed and the weight on the bit by systematic adjustment to eliminate stick-slip while avoiding other undesirable effects and thus achieving optimum performance. Further study will be on multi-stability analysis to define the optimum operation zones and the design of vibration reduction tools and control strategies.
This paper presents the design and dynamic response of a proposed non- Micro-Electro Mechanical Systems (MEMS) 1D torsional spring resonant scanner. The torsional spring was selected as the compliant structure of the device, and it was fabricated using aluminum with dimensions of 49 x 3.50 x 0.18 mm (L x W x T). An Analysis of Variance (ANOVA) test was performed to determine the difference in mean between the operating resonant frequency and the three types of materials, which are aluminum, stainless steel, and carbon steel. The device operates at a resonant frequency of 80.65 Hz, yielding a maximum scanning angle of 58.06 ˚. Hysteresis was observed from the frequency response chart of the system. By comparing the resonant frequency of the experimental results with the dynamic analysis of this device, the percentage error of the resonant frequency and optical scanning angle was found to be 6.67% and 16.84%, respectively.
An investigation was carried out on the effects of unsafe ergonomics practices by tractor operators in industrial companies in Zimbabwe. The survey was conducted in companies that manufacture tiles and bricks, collect waste litter using trailer-towed tractors, and construction companies. The investigation used a questionnaire to survey 15 operators in these different companies. Among other complications, Low Back Pain (LBP) affected all operators in the abovementioned industries. Other general complications noted were hand and leg pain, headaches, and chest pains. The Quality Function Deployment (QDF) important matrix indicated that investigating ergonomic effects is crucial. This paper concludes that reducing vibration and weight will provide a safer working environment for tractor operators and reduce the ergonomic effects investigated. Present ergonomic inventions and modifications must focus on producing a minitractor that dampens vibrations and improves the comfort of operator/tractor drivers.
The extent of gas production from shale reservoirs depends heavily on the stress-strain impact on the reservoir. The reservoir's developed stress allows the rocks to fracture naturally. The developed fractures across the reservoir blocks enhance the gas flow from the reservoir towards the wellbore. This review paper provides a comprehensive overview of the technologies and engineering of shale formation permeability behavior and the impact of induced stress and strain. The impacts of stress and strain on the permeability of shale are also studied. This paper presents the effect of stress-strain analysis on gas recovery due to various gas injections, the dependence of gas shale fracture permeability on effective stress and reservoir pressure, analyzing the consequences of various gas injection rates on stress and strain, and the result of stress-strain elongation or variation on hydrocarbon recovery.
Early hybrid drilling concepts date back to the 1930s, but the development of a viable drilling tool has only become feasible with recent advances in Polycrystalline Diamond Compact (PDC) cutter technology. This paper describes a new generation of hybrid bits based on proven PDC bit designs with roll cutters on the bit periphery. Laboratory and field results will be presented, comparing the performance of hybrid bits with that of conventional PDC and roller bits. A hybrid bit can drill shale and other plastically behaving formations two to four times faster than a roller cone because it is more aggressive and efficient. The penetration rate of a hybrid bit responds linearly to Revolutions Per Minute (RPM), unlike roller taper bits that exhibit an exponential response with an exponent less than one. In other words, a hybrid drill will drill significantly faster than a comparable roller drill in motor applications. Another advantage is the influence of rolling mills on bit dynamics. Compared to conventional PDC bits, torsional oscillations are up to 50% lower, and low-speed slip/slip and high-speed swirl are reduced. This gives the hybrid drill a wider operating window and greatly improves tool face control in directional drilling. The Hybrid Drill is a highly specific drill aimed at traditional cylindrical taper applications limited by the Rate of Penetration (ROP), large-diameter PDC-bit and roller-cone-bit applications limited by torque or Weight on Bit (WOB). Highly interconnected formations with high torque fluctuations can cause premature C3 failure and limit mean operating value torque, and motor and/or P applications where higher ROP and better build speed and tool face control are desired.
