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Articles 1441 - 1470 of 3173

Full-Text Articles in Mechanical Engineering

Energy And Exergy Efficiency Of Double Slope Passive Solar Still, Jandri Fan Ht Saragi, Wawan Septiawan Damanik Nov 2020

Energy And Exergy Efficiency Of Double Slope Passive Solar Still, Jandri Fan Ht Saragi, Wawan Septiawan Damanik

Journal of Mechanical Engineering Science and Technology (JMEST)

Solar desalination functions to filter water, both sea water and brackish water, to produce clean water that is fit for consumption with energy from the sun. Solar energy is a renewable energy source that has been widely studied for its use. One of its uses is in a double slope passive solar still where the sun is the main source. Energy and exergy obtained from solar energy are not all used to evaporate water in the desalination system, so it is necessary to calculate efficiency energy and exergy in the system. This study aims to obtain data on the amount …


Characteristics Biolubricant Enriched With Nanoparticle Additives: A Review, Zhahra Hanif Sholiha, Gaguk Jatisukamto Nov 2020

Characteristics Biolubricant Enriched With Nanoparticle Additives: A Review, Zhahra Hanif Sholiha, Gaguk Jatisukamto

Journal of Mechanical Engineering Science and Technology (JMEST)

The engine movement mechanism is a system composed of machine elements that contact or rub against each other between these surfaces. Surfaces that rub against each other will cause a friction force that causes wear on the surface, so it requires energy to fight the friction force. Lubricants are needed to reduce friction and reduce wear rates, where lubricants are generally made of mineral materials. Lubricants made from synthetic materials are non-renewable and cause environmental problems. The development of biolubricants as lubricating materials based on animal fats or vegetable oils is continuously being carried out. This study aims to observe …


Optimization Of Stir Casting Of Aluminum Matrix Composites (Amcs) With Filler Of Recycled Glass Powder (Rgp) For The Mechanical Properties, Yusup Hendronursito, Tumpal Ojahan, Anang Anshori, Asep Yunanto Nov 2020

Optimization Of Stir Casting Of Aluminum Matrix Composites (Amcs) With Filler Of Recycled Glass Powder (Rgp) For The Mechanical Properties, Yusup Hendronursito, Tumpal Ojahan, Anang Anshori, Asep Yunanto

Journal of Mechanical Engineering Science and Technology (JMEST)

A study of making Aluminum Matrix Composites (AMCs) uses recycled glass powder (RGP) as a filler has been carried out through the stir casting process. The experimental design uses the Taguchi method of 3^3 orthogonal array L9 with the parameters of powder size (20>x> 80, 80>y> 200, 200>z> 325), percentage of filler vs matrix (2%, 7%, 12%), and stirring time (30 Seconds, 3 Minutes, 12 Minutes). The optimum conditions for the hardness of Al-GRp composites were obtained from specimens with Mesh powder size parameters 200> z> 325, the percentage of glass vs aluminum powder was 12% wt, …


Surface Properties And Adsorption Capacities Of Rice Bran-Activated Carbon, Dewa Ngakan Ketut Putra Negara, Tjokorda Gde Tirta Nindhia, Wayan Nata Septiadi Nov 2020

Surface Properties And Adsorption Capacities Of Rice Bran-Activated Carbon, Dewa Ngakan Ketut Putra Negara, Tjokorda Gde Tirta Nindhia, Wayan Nata Septiadi

Journal of Mechanical Engineering Science and Technology (JMEST)

The growing need for activated carbon requires alternative raw materials to replace non-renewable raw materials whose existence is decreasing. Biomass is a very promising precursor, one of which is from rice bran. This research concerns the development of activated carbon derived from rice bran. Carbonization was carried out at 600 OC and physically activated with nitrogen flow rates of 150 mL/min for 40, 80, and 120 minutes. The activated carbons produced (AC-D40, AC-D80, and AC-D120) were characterized to determine the surface properties, surface morphology, and adsorption capacity for nitrogen and blue methylene adsorptions. The results showed that activated carbon that …


Design Of Savonius Vertical Axis Wind Turbine For Vehicle, Filian Arbiyani, Fernando Pranata Lasut Nov 2020

Design Of Savonius Vertical Axis Wind Turbine For Vehicle, Filian Arbiyani, Fernando Pranata Lasut

Journal of Mechanical Engineering Science and Technology (JMEST)

The use of cellular phones is increasing in society, but due to the limited battery capacity of cell phones, it is necessary to charge the battery when travelling in the long distances. The Savonius type wind turbine has a potential as an energy source harvesting the wind energy flowing around the car. However, due to the available space on the car, careful design of Savonius vertical axis wind turbine for vehicle is necessary. The research is conducted numerically using MATLAB software. The wind speed, Reynolds number, and electric power output are numerically simulated to obtain the swept area design. Innovative …


New Design Of Aluminum 6061 Welding Joining Using Friction Stir Welding Method, Widia Setiawan, Nugroho Santoso, Surojo Surojo Nov 2020

New Design Of Aluminum 6061 Welding Joining Using Friction Stir Welding Method, Widia Setiawan, Nugroho Santoso, Surojo Surojo

Journal of Mechanical Engineering Science and Technology (JMEST)

Parallel, lap, corner, and T joints are commonly used in fusion welding and solid welding. Other joints made are lap and butt joint. This study aims to evaluate a new design of fitting model single U and double U for friction stirr welding of Aluminum. Aluminum sheet 6061with a thickness of 10 mm, will be cut to a length of 150 mm and a width of 100 mm, then a locking groove will be made with an inner size of 5 mm and a length of 150 mm The flow is used to be paired in the FSW process. This …


Tool Life Prediction Of Ti [C,N] Mixed Alumina Ceramic Cutting Tool Using Gradient Descent Algorithm On Machining Martensitic Stainless Steel, Joseph Daniel S, Senthil Kumar A Nov 2020

Tool Life Prediction Of Ti [C,N] Mixed Alumina Ceramic Cutting Tool Using Gradient Descent Algorithm On Machining Martensitic Stainless Steel, Joseph Daniel S, Senthil Kumar A

Journal of Mechanical Engineering Science and Technology (JMEST)

In automated manufacturing systems, most of the manufacturing processes, including machining, are automated. Automatic tool change is one of the important parameters for reducing manufacturing lead time. Machining studies on Martensitic Stainless Steel was conducted using Ti[C,N] mixed alumina ceramic cutting tool. Tool life was evaluated using flank wear criterion. The tool life obtained from experimental machining process was taken as training dataset and test dataset for machine learning. Tool life model was developed using Gradient Descent Algorithm. The accuracy of the machine learning model was tested using the test data, and 99.83% accuracy was obtained.


Moisture Reduction Of Honey In Dehumidification And Evaporation Processes, Anang Lastriyanto, Sasongko Aji Wibowo, Erwan Erwan, Firman Jaya, Jati Batoro, Dewi Masyithoh, J.S.A Lamerkabel Nov 2020

Moisture Reduction Of Honey In Dehumidification And Evaporation Processes, Anang Lastriyanto, Sasongko Aji Wibowo, Erwan Erwan, Firman Jaya, Jati Batoro, Dewi Masyithoh, J.S.A Lamerkabel

Journal of Mechanical Engineering Science and Technology (JMEST)

The high water content of honey can lead to fermentation and accelerate the deterioration of honey. One way to prevent fermentation in honey is to reduce the water content of honey. There are several ways to reduce the water content of honey, namely through a dehumidifier and evaporation. This study aimed to examine the relationship of reduced water content towards time in between dehumidifier and evaporation processes. The research method uses an exponential equation model to determine the value of the constant (K). The constant value (K) is used to predict the rate of reduction in moisture content between the …


Review Of Γ’ Rafting Behavior In Nickel-Based Superalloys: Crystal Plasticity And Phase-Field Simulation, Zhiyuan Yu, Xinmei Wang, Fuqian Yang, Zhufeng Yue, James C. M. Li Nov 2020

Review Of Γ’ Rafting Behavior In Nickel-Based Superalloys: Crystal Plasticity And Phase-Field Simulation, Zhiyuan Yu, Xinmei Wang, Fuqian Yang, Zhufeng Yue, James C. M. Li

Chemical and Materials Engineering Faculty Publications

Rafting is an important phenomenon of the microstructure evolution in nickel-based single crystal superalloys at elevated temperature. Understanding the rafting mechanism and its effect on the microstructure evolution is of great importance in determining the structural stability and applications of the single crystal superalloys. Phase-field method, which is an excellent tool to analyze the microstructure evolution at mesoscale, has been gradually used to investigate the rafting behavior. In this work, we review the crystal plasticity theory and phase-field method and discuss the application of the crystal plasticity theory and phase-field method in the analysis of the creep deformation and microstructure …


The Economics Of Classroom 3-D Printing Of Open-Source Digital Designs Of Learning Aids, Nicole Gallup, Joshua M. Pearce Nov 2020

The Economics Of Classroom 3-D Printing Of Open-Source Digital Designs Of Learning Aids, Nicole Gallup, Joshua M. Pearce

Michigan Tech Publications, Part 1

While schools struggle financially, capital for purchasing physical learning aids is often cut. To determine if costs could be reduced for learning aids, this study analyzed classroom-based distributed digital manufacturing using 3-D printing of open-source learning aid designs. Learning aid designs are analyzed in detail for their economic viability considering printing and assembly costs with purchased components and compared to equivalent or inferior commercial products available on Amazon. The results show current open-source 3-D printers are capable of manufacturing useful learning aids and that doing so provides high economic savings in the classroom. Overall, the average learning aid would save …


Machine Learning Augmentation Micro-Sensors For Smart Device Applications, Mohammad H. Hasan Nov 2020

Machine Learning Augmentation Micro-Sensors For Smart Device Applications, Mohammad H. Hasan

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Novel smart technologies such as wearable devices and unconventional robotics have been enabled by advancements in semiconductor technologies, which have miniaturized the sizes of transistors and sensors. These technologies promise great improvements to public health. However, current computational paradigms are ill-suited for use in novel smart technologies as they fail to meet their strict power and size requirements. In this dissertation, we present two bio-inspired colocalized sensing-and-computing schemes performed at the sensor level: continuous-time recurrent neural networks (CTRNNs) and reservoir computers (RCs). These schemes arise from the nonlinear dynamics of micro-electro-mechanical systems (MEMS), which facilitates computing, and the inherent ability …


Laser Powder Bed Fusion Of Nitihf High-Temperature Shape Memory Alloy: Effect Of Process Parameters On The Thermomechanical Behavior, Mohammadreza Nematollahi, Guher P. Toker, Keyvan Safaei, Alejandro Hinojos, S. Ehsan Saghaian, Othmane Benafan, Michael J. Mills, Haluk E. Karaca, Mohammad Elahinia Nov 2020

Laser Powder Bed Fusion Of Nitihf High-Temperature Shape Memory Alloy: Effect Of Process Parameters On The Thermomechanical Behavior, Mohammadreza Nematollahi, Guher P. Toker, Keyvan Safaei, Alejandro Hinojos, S. Ehsan Saghaian, Othmane Benafan, Michael J. Mills, Haluk E. Karaca, Mohammad Elahinia

Mechanical Engineering Faculty Publications

Laser powder bed fusion has been widely investigated for shape memory alloys, primarily NiTi alloys, with the goal of tailoring microstructures and producing complex geometries. However, processing high temperature shape memory alloys (HTSMAs) remains unknown. In our previous study, we showed that it is possible to manufacture NiTiHf HTSMA, as one of the most viable alloys in the aerospace industry, using SLM and investigated the effect of parameters on defect formation. The current study elucidates the effect of process parameters (PPs) on the functionality of this alloy. Shape memory properties and the microstructure of additively manufactured Ni-rich NiTiHf alloys were …


Prefilling Mylar Capacitor Edge Margins To Improve Capacitor Reliability And Size, Chase Kayser Nov 2020

Prefilling Mylar Capacitor Edge Margins To Improve Capacitor Reliability And Size, Chase Kayser

Mechanical Engineering ETDs

Typical high-voltage, wound film-foil capacitors have large edge margins filled with air to prevent breakdown between foil electrodes. This arrangement is inefficient for energy density and leaves a volume where particulates may settle in an uncontrolled atmosphere. The reliability and size of high-voltage, wound film-foil capacitors could be improved by adding a material with higher breakdown strength into the edge margins. This will not only improve reliability and size but also act as a barrier to prevent foreign object debris (FOD), volatile organic compounds (VOCs), and water from damaging the capacitor’s performance. This paper will discuss the process of determining …


Study On The Viability Of Preparing Plaster Molds For Rapid Prototyping Of Complex Ceramic Parts Using The Lost Pla Method, Shelton F. Fowler Iv Nov 2020

Study On The Viability Of Preparing Plaster Molds For Rapid Prototyping Of Complex Ceramic Parts Using The Lost Pla Method, Shelton F. Fowler Iv

Honors College Theses

In the field of metal casting, cast parts often require an internal cavity to be made to meet design requirements. Frequently, these interior surfaces are not manufacturable through standard machining processes, and even when possible, they would most likely involve expensive and time-consuming operations. In order to avoid these machining costs, expendable ceramic or sand cores are manufactured and placed into the mold to allow the direct casting of complex internal geometries. This research seeks to use relatively inexpensive plastic 3D printing technology and the lost PLA casting process for the production of low-cost and rapidly producible ceramic cores. A …


Effect Of Landfill Leachates On Some Water Quality Indicators Of Selected Surface Water And Groundwater At Ilokun, Ado-Ekiti, Nigeria, Olorunwa Omofunmi, Adesola Satimehin, Abraham Oloye, Okwunna Umego Nov 2020

Effect Of Landfill Leachates On Some Water Quality Indicators Of Selected Surface Water And Groundwater At Ilokun, Ado-Ekiti, Nigeria, Olorunwa Omofunmi, Adesola Satimehin, Abraham Oloye, Okwunna Umego

Makara Journal of Technology

This study was conducted to examine the impact of dumpsites on the quality of groundwater and surface water. The water samples and leachates were collected from dumpsites in respective zones. The physicochemical properties of the samples were examined and determined in accordance with the standards of the American Public Health Association. Results indicated that the groundwater and surface water that are close to the dumpsites have an electrical conductivity of 385 and 245 Sd/cm, total dissolved solids of 168 and 128 mg/L, a turbidity of 4.6 and 22 NTU, a total alkalinity of 103 and 50 mg/L, a total hardness …


Microstrip Filters: A Review Of Different Filter Designs Used In Ultrawide Band Technology, Hussain Bohra, Giriraj Prajapati Nov 2020

Microstrip Filters: A Review Of Different Filter Designs Used In Ultrawide Band Technology, Hussain Bohra, Giriraj Prajapati

Makara Journal of Technology

In this study, optimization techniques applied in designing microstrip bandpass ultra-wideband (UWB) filters are presented. Optimization based on various defected ground structure techniques, resonator designs, and type of dielectric materials is discussed. Microstrip bandpass filters implemented at UWB frequency bands used in wireless communication systems have key features to control frequency response in passband and stopband. Optimization techniques are studied to attain optimum performance of bandpass microstrip filters to ensure minimum insertion loss, high selectivity, compactness, sharp transitions at cut-off frequencies, high return loss, and excellent linearity. Extensive study shows that proper selection of fabrication techniques and type of material …


Effect Of Catholyte Concentration On Current Production During Chocolate Industry Wastewater Treatment By A Microbial Fuel Cell, Diana Rahayuning Wulan, Suprihanto Notodarmojo Nov 2020

Effect Of Catholyte Concentration On Current Production During Chocolate Industry Wastewater Treatment By A Microbial Fuel Cell, Diana Rahayuning Wulan, Suprihanto Notodarmojo

Makara Journal of Technology

Microbial fuel cells (MFCs) use bacteria as a catalyst to oxidize organic and/or inorganic substrates and produce electric currents. Wastewater could function as an electron donor in the anode chamber and, thus, represents a very promising energy source. Catholytes, as electron acceptors, influence power production in MFCs by increasing the availability of electrons. The present research aims to determine the influence of catholyte concentration on current production in an aerobic two-chamber MFC. Aerobic treatment was carried out in the two-chamber MFC operated in an incubator at 37  1 °C with and without aeration in the cathode chamber. Wastewater from …


Evaluation Of Il-17a And Il-17f Gene Expression In Peripheral Blood Mononuclear Cells In Different Clinical Stages Of Chronic Hepatitis B Infection In An Iranian Population, Tannaz Akbari Kolagar, Seyed Reza Mohebbi, Fatemeh Ashrafi, Shahrzad Shoraka, Hamid Asadzadeh Aghdaei, Mohammad Reza Zali Nov 2020

Evaluation Of Il-17a And Il-17f Gene Expression In Peripheral Blood Mononuclear Cells In Different Clinical Stages Of Chronic Hepatitis B Infection In An Iranian Population, Tannaz Akbari Kolagar, Seyed Reza Mohebbi, Fatemeh Ashrafi, Shahrzad Shoraka, Hamid Asadzadeh Aghdaei, Mohammad Reza Zali

Makara Journal of Technology

Hepatitis B virus (HBV) infection is one of the main causes of liver damage, which can also lead to chronic hepatitis B (CHB) infection. More than 240 million individuals worldwide are chronic carriers of HBV. Among individuals with CHB who are untreated, approximately 15% – 40% will progress to liver cirrhosis or cancer. The interactions between HBV and host immune response play significant roles in the progression of CHB. CHB can be generally divided into four different clinical phases: immune tolerance (IT), immune clearance, inactive carrier, and Hepatitis B surface antigen (HBsAg)-negative reactivation phase (ENEG). Many studies showed that interleukins …


Redesign Of Product Packaging With Kansei Engineering: Empirical Study On Small-Medium Enterprises In Indonesia, Amalia Suzianti, A. Aldianto Nov 2020

Redesign Of Product Packaging With Kansei Engineering: Empirical Study On Small-Medium Enterprises In Indonesia, Amalia Suzianti, A. Aldianto

Makara Journal of Technology

Small-medium enterprises (SMEs) in Indonesia have been proven to be one of the important pillars of the national economy. Unfortunately, some problems hinder their development, and one of the critical problems is the quality of product packaging. The packages of SME products are considered poor, dirty, and unattractive. Packaging problem is one of the factors why consumers are less interested in buying and why SME products always lose in the competition with other products. This study discusses how to employ Kansei engineering to design better SME product packaging with a focus on psychological (affective) aspects. This research concludes that there …


Effect Of Pvdf-Ca Ratio On Electrospun Membrane For Water–Oil Filtration Application, Mohamad Haziq Alias, Izan Izwan Misnon, Rajan Jose Nov 2020

Effect Of Pvdf-Ca Ratio On Electrospun Membrane For Water–Oil Filtration Application, Mohamad Haziq Alias, Izan Izwan Misnon, Rajan Jose

Makara Journal of Technology

Oil spillage and generation of industrial water–oil wastewater mixture ignite a focus on filtration technology. Electrospinning technique provides a versatile route in producing tunable diameter and pores in nanofiber filtration membrane development. In this work, polyvinylidene difluoride (PVDF) and cellulose acetate (CA) electrospun membrane at different concentration ratios were synthesized for water–oil filtration application. The polymeric solutions were characterized using viscometer and conductivity testing, whereas the membranes were analyzed using contact angle, tensile test, scanning electron microscopy (SEM), and filtration testing of oil (dichloromethane). Conductivity test showed a decreased conductivity along with decrement of CA ratio in the polymeric solution. …


Performance-Shaping Factors Of Personnel Performing Evacuation And Escape On Offshore Installations In Tropical, Norafneeza Norazahar, Nur Azizah Arryanie Morshidi, Arshad Ahmad, Wijayanuddin Mohd Ali Nov 2020

Performance-Shaping Factors Of Personnel Performing Evacuation And Escape On Offshore Installations In Tropical, Norafneeza Norazahar, Nur Azizah Arryanie Morshidi, Arshad Ahmad, Wijayanuddin Mohd Ali

Makara Journal of Technology

Performance-shaping factors (PSFs) are used to address the strengths and weaknesses of workers performing escape and evacuation activities. These PSFs are time, environmental factors as stressors, complexity of activities, experiences and training, interaction between workers and emergency equipment, workers’ physical conditions, and procedures. This paper presents a survey work on fitness for the duty of workers performing basic offshore survival and emergency response training. The training provides credible scenarios of escape and evacuation in case of an emergency of offshore installations in tropical waters. The survey is conducted among participants of the tropical basic offshore safety induction & emergency training …


Fabrication And Characterisation Of Highly Aligned Fibrous Assemblies, Tan Chin Joo Nov 2020

Fabrication And Characterisation Of Highly Aligned Fibrous Assemblies, Tan Chin Joo

Student Works (2020-2029)

Vascular grafting has been an effective remedy to vascular diseases for decades. Autografting by using the veins or arteries in the patient’s body is found to have patency rate for years. However, autografting may not be possible when compatible vessels are not available. In this case, synthetic vascular grafts are found to be effective replacements. Nevertheless, synthetic grafts with diameter less than 4 mm becomes challenging due to thrombogenicity and mismatch of mechanical properties with the native vessels. Along this line, the ability to develop new biostable synthetic materials suitable for smaller grafts and the ability to evaluate their resulting …


Dynamic Analysis Of Viscoelastic Circular Diaphragm Of A Mems Capacitive Pressure Sensor Using Modified Differential Transformation Method, Dr Olurotimi A. Adeleye, Muritala Yusuf, Oluwaseyi .. Balogun Oct 2020

Dynamic Analysis Of Viscoelastic Circular Diaphragm Of A Mems Capacitive Pressure Sensor Using Modified Differential Transformation Method, Dr Olurotimi A. Adeleye, Muritala Yusuf, Oluwaseyi .. Balogun

Karbala International Journal of Modern Science

In this paper, a dynamic analysis of the viscoelastic circular diaphragm of a Micro-Electro-Mechanical System (MEMS) capacitive pressure sensor using the Modified Differential Transformation Method (MDTM) is presented. The MEMS technology has been increasingly used to fabricate sensors and actuators and the MEMS capacitive pressure sensor is emerging in many high-performance applications. The deflection of these sensors diaphragm (plate) depends largely on the material of the diaphragm. In this study, a circular diaphragm of viscoelastic material is modeled using the classical plate theory. The governing differential equation is solved using Modified Differential Transformation Method (MDTM) and the result is validated …


Finite Element Analysis Investigation Of Hybrid Thin-Ply Composites For Improved Performance Of Aerospace Structures, Alana M. Zahn Oct 2020

Finite Element Analysis Investigation Of Hybrid Thin-Ply Composites For Improved Performance Of Aerospace Structures, Alana M. Zahn

Mechanical & Aerospace Engineering Theses & Dissertations

Commercial and private aircraft have a need for strong yet light materials in order to have the most ideal performance possible. This study looks at the use of thin-ply composite materials to improve the performance of aircraft structures by means of weight savings and/or strength increase when compared to laminates that are composed of exclusively standard-ply materials. In order to perform an investigation based solely on finite element analysis, validation efforts were performed using test data from open hole tension, open hole compression, notched tension, and notched compression specimens. Once the models were validated sufficiently, the same modeling practices were …


Open Source High-Temperature Reprap For 3-D Printing Heat-Sterilizable Ppe And Other Applications, Noah G. Skrzypczak, Nagendra G. Tanikella, Joshua M. Pearce Oct 2020

Open Source High-Temperature Reprap For 3-D Printing Heat-Sterilizable Ppe And Other Applications, Noah G. Skrzypczak, Nagendra G. Tanikella, Joshua M. Pearce

Michigan Tech Publications, Part 1

Thermal sterilization is generally avoided for 3-D printed components because of the relatively low deformation temperatures for common thermoplastics used for material extrusion-based additive manufacturing. 3-D printing materials required for high-temperature heat sterilizable components for COVID-19 and other applications demands 3-D printers with heated beds, hot ends that can reach higher temperatures than polytetrafluoroethylene (PTFE) hot ends and heated chambers to avoid part warping and delamination. There are several high temperature printers on the market, but their high costs make them inaccessible for full home-based distributed manufacturing required during pandemic lockdowns. To allow for all these requirements to be met …


Open-Source Grinding Machine For Compression Screw Manufacturing, Jacob Franz, Joshua M. Pearce Sep 2020

Open-Source Grinding Machine For Compression Screw Manufacturing, Jacob Franz, Joshua M. Pearce

Michigan Tech Publications, Part 1

Some of the most promising distributed recycling and additive manufacturing (DRAM) technical systems use fused particle fabrication (FPF) or fused granular fabrication (FGF), where compression screws force post-consumer waste plastic through a heated nozzle for direct 3D printing. To assist the technical evolution of these systems, this study provided the details of an invention for a low-cost, easily replicable open-source grinding machine for compression screw manufacturing. The system itself can be largely fabricated using FPF/FGF following the self-replicating rapid prototyper (RepRap) methodology. This grinding machine can be made from a cordless cut-off grinder and < $155 in parts. The new invention is demonstrated to be able to cut custom screws with variable (i) channel depths, (ii) screw diameters, (iii) screw lengths, (iv) pitches, (v) abrasive disk thicknesses, (vi) handedness of the screws, (vii) and materials (three types of steel tested: 1045 steel, 1144 steel, and 416 stainless steel). The results show that the device is more than capable of replicating commercial screws as well as providing makers with a much greater flexibility to make custom screws. This invention enables the DRAM toolchain to become even more self-sufficient, which assists the goals of the circular economy.


Numerical Study Of Paraffin Wax Melting In A Cavity With A Gradient Of Hot Wall Inclination, Agus Dwi Korawan Aug 2020

Numerical Study Of Paraffin Wax Melting In A Cavity With A Gradient Of Hot Wall Inclination, Agus Dwi Korawan

Makara Journal of Technology

The melting of a phase change material (PCM) in a cavity with a gradient of hot wall inclination was simulated numerically using five models, namely, Model-A, Model-B, Model-C, Model-D, and Model-E with gradients of −2, −4, ∞, 4, and 2, respectively. The PCM was paraffin wax, which was melted using an enthalpy porosity technique with a pressure-based method. Model-A was found to be the best model. For the completion of the melting process, the models were assigned with the liquid fraction of 1. Model-A required the shortest time, followed by Model-B, Model-C, Model-E, and Model-D, respectively. Compared with Model-C, Model-A …


Homogenization Of Composite And Cellular Materials Incorporating Microstructure And Surface Energy Effects, Ahmad Gad Aug 2020

Homogenization Of Composite And Cellular Materials Incorporating Microstructure And Surface Energy Effects, Ahmad Gad

Mechanical Engineering Research Theses and Dissertations

In the last few decades, the popularity of composite and cellular materials has rapidly increased through their widespread applications in multiple engineering fields including aerospace, automotive, civil and biomedical. However, to a large extent, the success of their practical applications depends on our ability to predict their mechanical behavior by using high-fidelity mechanics models.

Micromechanical modeling of composite and cellular materials is a challenging task due to the heterogeneous nature of such materials and the interactions among various constituent phases at the microscopic level, which result in non-homogeneous deformation, strain and stress fields. Therefore, it is necessary to develop simple …


Mechanism Of Compaction With Wrinkle Formation During Automatic Stitching Of Dry Fabrics And The Size Effect Of Compression Molded Discontinuous Fiber-Reinforced Composites, Anibal Benjamin Beltran Laredo Aug 2020

Mechanism Of Compaction With Wrinkle Formation During Automatic Stitching Of Dry Fabrics And The Size Effect Of Compression Molded Discontinuous Fiber-Reinforced Composites, Anibal Benjamin Beltran Laredo

Mechanical & Aerospace Engineering Theses & Dissertations

With an ever-increasing demand for composites, more ways of manufacturing them are becoming popular and widely used. Stitching of dry fabrics is an efficient method for improving delamination resistance. Discontinuous fiber reinforced composites can be used as a lightweight alternative material for metals through a process of compression molding, which allows for complex shape manufacturing while offering structural grade mechanical properties.

This study demonstrates how the stitching of dry fabrics can be adapted to more complex surfaces. The consequences of stitching of curvilinear surfaces can result in defect formation. Therefore, to understand the physical formation of possible defects, experimental characterization …


Aqueous Redox Flow Batteries With Boron Doped Diamond As An Electrode., Alex M. Bates Aug 2020

Aqueous Redox Flow Batteries With Boron Doped Diamond As An Electrode., Alex M. Bates

Electronic Theses and Dissertations

As the interest and implementation of renewable energy accelerates, so does that of grid energy storage. It is widely believed that a cost-effective energy storage technology will bring about the proliferation of renewable energy. Redox flow battery (RFB) technology represents a promising solution to cost-effective grid energy storage. Compared to other technologies, RFBs have a long lifetime, high efficiency, are non-flammable, significantly reduce cost, and separately scale power and energy. The separation of power and energy enables increased energy capacity by simply adding electrolyte volume. Of the challenges facing RFB technology, one readily apparent is the cost of the active …