Kabini Karanja | Jomo Kenyatta University of Agriculture and Technology (original) (raw)
Papers by Kabini Karanja
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Fuel Cells, Sep 30, 2023
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Engineering Reports
Short carbon fiber‐reinforced polymer composites are desirable for many additive manufacturing (A... more Short carbon fiber‐reinforced polymer composites are desirable for many additive manufacturing (AM) applications as they are light and structurally strong. The process parameters in fused filament fabrication (FFF) significantly affect the mechanical properties of SFRP parts. In this work, three‐point bending tests are carried out to investigate the flexural behavior of 3D‐printed polyamide 12 carbon fiber (PA12‐CF) specimens. An L18 Taguchi design of experiments with Gray relational analysis is applied to optimize the FFF parameters. It is shown that build orientation has the most influence on flexural properties and the distribution of short fibers has an additional effect. For a rectilinear infill pattern, the maximum flexural strength of the part was realized at the printing speed, layer thickness, and extrusion temperature of 30 mm/s, 0.15 mm, and 270°C, respectively. With these parameters, the flexural strength of the part is 119.9 MPa and the flexural modulus is 3038 MPa. For...
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World Journal of Engineering and Technology
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Metal Matrix Composites(MMC) are composites with at least one metallic constituent material. Thes... more Metal Matrix Composites(MMC) are composites with at least one metallic constituent material. These materials generally have desirable qualities such as high strength-to-weight ratio, high toughness, lowvalue of coefficient of thermal expansion, high wear resistance, and thermal stability. They are therefore increasingly finding applications in areas that require these qualities such as in aerospace, automotive, millitary, biological and nuclear energy fields. The application of these materials usually require them to be machined to a high accuracy and to have a good surface finish. These materials are hard and abrasive, making it difficult to machine using conventional processes such as drilling and grinding. To address these challenges, electrical discharge machining(EDM)can be used. This paper investigates the effect of low frequency vibration in EDM machining of aluminium silicon carbide (AlSiC) MMC using oil and deionised water as the dielectric fluids. Experiments were carried ...
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Sustainable Research and Innovation Proceedings, May 25, 2011
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The maturity method has been successfully used to predict the strength of concrete prepared accor... more The maturity method has been successfully used to predict the strength of concrete prepared according to American standards (ASTM). This study investigated the applicability of the method to concrete prepared according to British standards (BS), and also assessed the effect of a plasticizer on the strength and maturity of concrete. Three mixes were prepared, one according to American standards (mix A) and two according to British standards (mixes B and C). Modified lignosulphonate (Sika Plastiment BV-40) was used to increase the workability of mix C. Although concrete mix proportioning according to British standards resulted in a denser mix (2400 kg/m3) than American standards (2342 kg/m3), a water-cement (w/c) ratio of 0.5 was used for all mixes. Cylindrical specimens (each measuring 150 mm in diameter by 300 mm deep) and beam specimens (each measuring 150 mm wide by 530 mm long by 150 mm deep) were made andcured at 23 oC. The compressive and splitting tensile strengths of the cyli...
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JOURNAL OF SUSTAINABLE RESEARCH IN ENGINEERING, Sep 30, 2021
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PROCEEDINGS OF THE 13TH AUN/SEED-NET REGIONAL CONFERENCE ON MATERIALS (RCM 2020) AND THE 1ST INTERNATIONAL CONFERENCE ON MATERIALS ENGINEERING AND MANUFACTURING (ICMEM 2020), 2021
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PROCEEDINGS OF THE 13TH AUN/SEED-NET REGIONAL CONFERENCE ON MATERIALS (RCM 2020) AND THE 1ST INTERNATIONAL CONFERENCE ON MATERIALS ENGINEERING AND MANUFACTURING (ICMEM 2020)
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The Electrical Discharge Machining (EDM) Process is complex in nature partly due to the mechanism... more The Electrical Discharge Machining (EDM) Process is complex in nature partly due to the mechanism of material removal, and, partly due to the presence of many machining parameters. This complexity of the EDM process has undermined its full potential drastically reducing its efficiency. In turn, this has led to relatively higher consumption of electrical energy, longer machining periods, higher rate of electrode wear and lower surface quality of the finished product. Various researchers have used varied approaches with the aim of optimizing the process. However, most of these researches have focused on optimization of one or at most two parameters and have used either fuzzy logic control techniques or modeling approaches. Others have used purely predictive and non-realtime approaches. All of these do not offer the advantage of realtime control of the process. This paper focuses on experimental work carried out to establish the performance of Resistance-Capacitance (RC) pulse generati...
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This paper presents results of tests that were done to evaluate the performance of a transistoris... more This paper presents results of tests that were done to evaluate the performance of a transistorised pulse generation circuit that was developed. From the results obtained, the transistorised pulse generation circuit provides smooth and independent control of machining parameters allowing for fine adjustment of each of machining parameters. The experimental work carried out demonstrated the capability of the pulse generator to perform as per expected behaviour of an EDM machine's pulse generator.
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A Pulse generation circuit is a key component of an Electrical Discharge Machine (EDM) as it regu... more A Pulse generation circuit is a key component of an Electrical Discharge Machine (EDM) as it regulates and controls the machining process. Machining parameters such as frequency, duty cycle, machining time, voltage and their execution instructions are set through the Graphics User Interface (GUI) and executed by the pulse generator. Coupled to the pulse generation circuit is the motor driver circuit which controls the vertical motion of the tool based on the prevailing machining conditions, normally measured by a voltage sensor connected between the tool electrode and the workpiece. This paper presents a new approach in the development of a pulse generation and affiliated circuits for EDM machine developed at JKUAT. The current pulse generation circuit is based on resistor capacitor technology. Keywords—Electrical discharge machining, pulse generation cir-cuit, machining
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This text provides readers with a step by step guide on how to design an ANFIS based controller f... more This text provides readers with a step by step guide on how to design an ANFIS based controller for the control of machining vibrations. It puts emphasis on the design process with a view to enhancing the understanding of the topic under study. Once familiar with the design process, the readers can apply the acquired knowledge in the design of controllers for optimization of any machining processes.
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Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Fuel Cells, Sep 30, 2023
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Engineering Reports
Short carbon fiber‐reinforced polymer composites are desirable for many additive manufacturing (A... more Short carbon fiber‐reinforced polymer composites are desirable for many additive manufacturing (AM) applications as they are light and structurally strong. The process parameters in fused filament fabrication (FFF) significantly affect the mechanical properties of SFRP parts. In this work, three‐point bending tests are carried out to investigate the flexural behavior of 3D‐printed polyamide 12 carbon fiber (PA12‐CF) specimens. An L18 Taguchi design of experiments with Gray relational analysis is applied to optimize the FFF parameters. It is shown that build orientation has the most influence on flexural properties and the distribution of short fibers has an additional effect. For a rectilinear infill pattern, the maximum flexural strength of the part was realized at the printing speed, layer thickness, and extrusion temperature of 30 mm/s, 0.15 mm, and 270°C, respectively. With these parameters, the flexural strength of the part is 119.9 MPa and the flexural modulus is 3038 MPa. For...
Bookmarks Related papers MentionsView impact
World Journal of Engineering and Technology
Bookmarks Related papers MentionsView impact
Metal Matrix Composites(MMC) are composites with at least one metallic constituent material. Thes... more Metal Matrix Composites(MMC) are composites with at least one metallic constituent material. These materials generally have desirable qualities such as high strength-to-weight ratio, high toughness, lowvalue of coefficient of thermal expansion, high wear resistance, and thermal stability. They are therefore increasingly finding applications in areas that require these qualities such as in aerospace, automotive, millitary, biological and nuclear energy fields. The application of these materials usually require them to be machined to a high accuracy and to have a good surface finish. These materials are hard and abrasive, making it difficult to machine using conventional processes such as drilling and grinding. To address these challenges, electrical discharge machining(EDM)can be used. This paper investigates the effect of low frequency vibration in EDM machining of aluminium silicon carbide (AlSiC) MMC using oil and deionised water as the dielectric fluids. Experiments were carried ...
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Sustainable Research and Innovation Proceedings, May 25, 2011
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The maturity method has been successfully used to predict the strength of concrete prepared accor... more The maturity method has been successfully used to predict the strength of concrete prepared according to American standards (ASTM). This study investigated the applicability of the method to concrete prepared according to British standards (BS), and also assessed the effect of a plasticizer on the strength and maturity of concrete. Three mixes were prepared, one according to American standards (mix A) and two according to British standards (mixes B and C). Modified lignosulphonate (Sika Plastiment BV-40) was used to increase the workability of mix C. Although concrete mix proportioning according to British standards resulted in a denser mix (2400 kg/m3) than American standards (2342 kg/m3), a water-cement (w/c) ratio of 0.5 was used for all mixes. Cylindrical specimens (each measuring 150 mm in diameter by 300 mm deep) and beam specimens (each measuring 150 mm wide by 530 mm long by 150 mm deep) were made andcured at 23 oC. The compressive and splitting tensile strengths of the cyli...
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
JOURNAL OF SUSTAINABLE RESEARCH IN ENGINEERING, Sep 30, 2021
Bookmarks Related papers MentionsView impact
PROCEEDINGS OF THE 13TH AUN/SEED-NET REGIONAL CONFERENCE ON MATERIALS (RCM 2020) AND THE 1ST INTERNATIONAL CONFERENCE ON MATERIALS ENGINEERING AND MANUFACTURING (ICMEM 2020), 2021
Bookmarks Related papers MentionsView impact
PROCEEDINGS OF THE 13TH AUN/SEED-NET REGIONAL CONFERENCE ON MATERIALS (RCM 2020) AND THE 1ST INTERNATIONAL CONFERENCE ON MATERIALS ENGINEERING AND MANUFACTURING (ICMEM 2020)
Bookmarks Related papers MentionsView impact
The Electrical Discharge Machining (EDM) Process is complex in nature partly due to the mechanism... more The Electrical Discharge Machining (EDM) Process is complex in nature partly due to the mechanism of material removal, and, partly due to the presence of many machining parameters. This complexity of the EDM process has undermined its full potential drastically reducing its efficiency. In turn, this has led to relatively higher consumption of electrical energy, longer machining periods, higher rate of electrode wear and lower surface quality of the finished product. Various researchers have used varied approaches with the aim of optimizing the process. However, most of these researches have focused on optimization of one or at most two parameters and have used either fuzzy logic control techniques or modeling approaches. Others have used purely predictive and non-realtime approaches. All of these do not offer the advantage of realtime control of the process. This paper focuses on experimental work carried out to establish the performance of Resistance-Capacitance (RC) pulse generati...
Bookmarks Related papers MentionsView impact
This paper presents results of tests that were done to evaluate the performance of a transistoris... more This paper presents results of tests that were done to evaluate the performance of a transistorised pulse generation circuit that was developed. From the results obtained, the transistorised pulse generation circuit provides smooth and independent control of machining parameters allowing for fine adjustment of each of machining parameters. The experimental work carried out demonstrated the capability of the pulse generator to perform as per expected behaviour of an EDM machine's pulse generator.
Bookmarks Related papers MentionsView impact
A Pulse generation circuit is a key component of an Electrical Discharge Machine (EDM) as it regu... more A Pulse generation circuit is a key component of an Electrical Discharge Machine (EDM) as it regulates and controls the machining process. Machining parameters such as frequency, duty cycle, machining time, voltage and their execution instructions are set through the Graphics User Interface (GUI) and executed by the pulse generator. Coupled to the pulse generation circuit is the motor driver circuit which controls the vertical motion of the tool based on the prevailing machining conditions, normally measured by a voltage sensor connected between the tool electrode and the workpiece. This paper presents a new approach in the development of a pulse generation and affiliated circuits for EDM machine developed at JKUAT. The current pulse generation circuit is based on resistor capacitor technology. Keywords—Electrical discharge machining, pulse generation cir-cuit, machining
Bookmarks Related papers MentionsView impact
This text provides readers with a step by step guide on how to design an ANFIS based controller f... more This text provides readers with a step by step guide on how to design an ANFIS based controller for the control of machining vibrations. It puts emphasis on the design process with a view to enhancing the understanding of the topic under study. Once familiar with the design process, the readers can apply the acquired knowledge in the design of controllers for optimization of any machining processes.
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact