Single Spring Gravity Compensator For A Multi Degree Of Freedom Manipulator Arm,
2023
Faculty of Engineering
Single Spring Gravity Compensator For A Multi Degree Of Freedom Manipulator Arm, Krittanai Sajjapongse
Chulalongkorn University Theses and Dissertations (Chula ETD)
Designing industrial robots requires utmost attention to power consumption and safety, especially in today's environment where humans work closely with robots. However, due to their robust and weighty structures, most robotic manipulators are typically engineered with high-power systems to handle payloads and counteract gravity. This research develops a novel gravity compensator system that employs a single spring to counterbalance a multi-DOF manipulator. This system combines cam follower systems with a square root mechanism. We provide a general equation that applies to multiple degrees of freedom. Additionally, we designed and built a 3-DOF manipulator prototype. The experiment shows that our gravity …
The High Temperature Degradation Of Ferritic Stainless Steel In Solid Carbon Atmospheres,
2023
Chulalongkorn University
The High Temperature Degradation Of Ferritic Stainless Steel In Solid Carbon Atmospheres, Prakeaw Ngamsri, Suwijak Pokwitidkul, Paweena Treewiriyakitja, Penpisuth Thongyoug, Ratchapon Nilprapa, Jennarong Tungtrongpairoj
Journal of Metals, Materials and Minerals
Stainless steel is widely used for many components and parts in coal-fired thermal power plants. AISI 430 ferritic stainless steel (FSS) is one common grade to combat the degradation at high temperatures in coal combustion atmospheres containing flue gas, coal ash, and soot (impure solid carbon particles). However, the effect of the solid carbon particles on the degradation of FSS needs to be clarified. Graphite powder was used to simulate solid carbon atmospheres for investigating the degradation of AISI 430 at high temperatures of 1150℃ to 1350℃ in coal-fired boilers. After the carbothermic reduction, the mass gain of a pre-oxidized …
Recovery Of Pure Silver From Spent Silver Electroplating Solutions Via Electrochemical Process And Zinc Cementation,
2023
Chulalongkorn University
Recovery Of Pure Silver From Spent Silver Electroplating Solutions Via Electrochemical Process And Zinc Cementation, Tapany Patcharawit, Chatisa Kansomket, Woranittha Kritsarikun, Ketmanee Taseela, Chonthicha Paernaphan, Thiwavan Laphosin, Teerawut Tannukit, Sakhob Khumkoa
Journal of Metals, Materials and Minerals
Recycling of spent silver electroplating solutions has been investigated via electrowinning and electrorefining in comparison to zinc cementation technique in this research. Two different compositions of transparent and dark waste solutions were used having the remaining silver contents of 17.71 g⸳L-1 and 33.36 g⸳L-1 respectively. The waste solutions were used as an electrolyte in the first step of electrowinning at low current density of 0.015 A⸳cm-2. It was found that increasing electrowinning time from 4 h to 24 h increased the recovery of silver cathode for both types of waste solutions. The optimum electrowinning time was higher than 8 h, …
Effects Of Indium And Gallium Ratio On Tarnish Resistance, Corrosion And Mechanical Properties Of 950 Silver Alloy,
2023
Chulalongkorn University
Effects Of Indium And Gallium Ratio On Tarnish Resistance, Corrosion And Mechanical Properties Of 950 Silver Alloy, Aumphol Yanil, Patama Visuttipitukul, Ekasit Nisaratanaporn, Charasphat Preuksarattanawut
Journal of Metals, Materials and Minerals
The effects of Indium (In) and Gallium (Ga) ratio on tarnish resistance, corrosion and mechanical properties of 950 silver alloy were studied. 950 Silver alloy with aluminium (Al), silica (Si) and germanium (Ge) were added with In and Ga at the range of 0.44 to 1.90 weight percent. The increment of secondary structure with Ge-Si rich phase in Ag-Al alloy increases hardness, but reduces ultimate tensile strength. The addition of In and Ga improves tarnish and corrosion resistance. The color differences as indicated by Delta E tolerances (DE*) of Ag-Al alloys are in the range of 8.64 to 11.40 while …
Investigating The Effect Of Temperature And Nacl Concentration On Corrosion Behavior Using Commercial Food Cans,
2023
Chulalongkorn University
Investigating The Effect Of Temperature And Nacl Concentration On Corrosion Behavior Using Commercial Food Cans, Samar S. Hussein, Abeer A. Radhi, Wafaa K. Mahmood
Journal of Metals, Materials and Minerals
In the present work, commercial tin-plate used as storage cans for three different products (salmon fish, green peas, and corn) are used to investigate the corrosion to storage temperature and salt concentration. The corrosion process was electrochemically monitored using the potentiodynamic polarization method and the structure and concentrations of the corrosion products were investigated using X-ray diffraction (XRD). To characterize the resulting sample morphology, emission scanning electron microscopy (FESEM) was used. The results showed that the corrosion resistance of the tin-coating, was important constant and by changing the NaCl concentration and operation temperature, the corrosion resistance was lower. It is …
Optimized Conditions For Cobalt Diffusion In Sri Lankan Colorless Topaz And Coloration Mechanism Elucidation Through Spectro-Chemical Investigation,
2023
Chulalongkorn University
Optimized Conditions For Cobalt Diffusion In Sri Lankan Colorless Topaz And Coloration Mechanism Elucidation Through Spectro-Chemical Investigation, Chandana P. Udawatte, Sunil Abeyweera, L. R. K. Perera, Sandun Illangasinghe, Chirath Weerasooriya, Chakkaphan Sutthirat, Naleen Jayasinghe, Tilak Dharmaratne, Saranga Diyabalanage
Journal of Metals, Materials and Minerals
Most of natural topaz is colorless; thus, methods of color enhancement are widely used for coloring this mineral. Currently, blue color is obtained by cobalt diffusion due to drawbacks in existing coloration methods. In this study, optimum conditions suitable for Cobalt diffusion in Sri Lankan colorless topaz were investigated and coloration mechanism was elucidated. The diffusion agent was prepared by mixing CoCO3 with Na2CO3, CaCO3 and carbon powder and diffusion was carried-out by varying the temperature and soaking time. Chemical analysis, UV-Vis absorption spectrum, infrared absorption spectra, and Raman peaks of diffused and non-diffused topaz were tested. The results clearly …
Fabrication Of Glass-Ceramics Composite By Infiltration Of Lithium Tetraborate Glass Into Porous Magnesium Aluminate Spinel Ceramic,
2023
Chulalongkorn University
Fabrication Of Glass-Ceramics Composite By Infiltration Of Lithium Tetraborate Glass Into Porous Magnesium Aluminate Spinel Ceramic, Nattawat Kulrat, Chumphol Busabok, Saweat Intarasiri, Somsak Dangtip, Wasana Khongwong
Journal of Metals, Materials and Minerals
Magnesium aluminate spinel (MAS) glass-ceramics composite has excellent mechanical and optical properties. It can be obtained from porous ceramic by infiltrating the proper choice of glass. In this study, porous MAS ceramic was prepared by conventional sintering from MAS powder to reach a bulk density of 2.48 g∙cm-3 (70.1% of relative density). The porous MAS ceramic was then infiltrated with molten lithium tetraborate glass (Li2B4O7; LTB) at 950℃ for 30 (IF30) and 60 (IF60) min. They were left to cool down to 700℃ inside the furnace before being taken out to quench in ambient. The glass-ceramics composite was obtained with …
Ph-Responsive Polymeric Nanostructures For Cancer Theranostics,
2023
Chulalongkorn University
Ph-Responsive Polymeric Nanostructures For Cancer Theranostics, Devadass Jessy Mercy, Karthick Harini, Swaminathan Madhumitha, Chinnadurai Anitha, Jayakumar Iswariya, Koyeli Girigoswami, Agnishwar Girigoswami
Journal of Metals, Materials and Minerals
Responsive polymeric nanostructures are being designed to improve the efficiency of existing treatment techniques by delivering therapeutics in precise locations. The properties of the particles can be altered to act as a probe for imaging applications also. Hence, an effective theranostic agent can be tailor-made to meet the requirements. The pH variability has aroused considerable interest in nano-responsive-stimulus production since the mild acidic condition is a hallmark of the tumor microenvironment. The cargo sealed inside the carrier will be released either by swelling or disassembly of the carrier as they meet a pH drop. The modification strategy for the synthesis …
Adhesion Of Thermal Oxide Scale Formed On Silicon-Containing Hot-Rolled Steel Oxidised In Oxygen,
2023
Chulalongkorn University
Adhesion Of Thermal Oxide Scale Formed On Silicon-Containing Hot-Rolled Steel Oxidised In Oxygen, Wannapha Issaard, Thanasak Nilsonthi
Journal of Metals, Materials and Minerals
Defects can be caused by the thermal oxide scale that forms on the surface of steel during the hot rolling process. The oxidation and adhesion of scale on silicon-containing hot-rolled steel were investigated in a flowing 20% O2-N2 gas mixture at 900°C. Scale spallation was observed using a tensile testing machine equipped with a CCD camera. The thickness of the scale was 3.45 μm for the higher silicon steel and 4.86 μm for the lower silicon steel. The oxide scale consists of hematite, magnetite, wustite, and iron. The strain that caused the first spallation was used to calculate the mechanical …
Oxidation Behaviour Of Mn-Co Spinel Coating On Aisi 430 Ferritic Stainless Steel With And Without Cu In Ar-Co -H O Atmosphere,
2023
Chulalongkorn University
Oxidation Behaviour Of Mn-Co Spinel Coating On Aisi 430 Ferritic Stainless Steel With And Without Cu In Ar-Co -H O Atmosphere, Thammaporn Thublaor, Padungaut Srihathai, Panya Wiman, Angkana Muengjai, Somrerk Chandra-Ambhorn
Journal of Metals, Materials and Minerals
AISI 430 ferritic stainless steel is a promising candidate for utilising as interconnects of solid oxide fuel cells due to its cost effectiveness and durability. Many methods for applying coating on steel substrates have been developed in order to decrease the degradation of steel due to oxidation rate and chromium volatile problems. Manganese-cobalt spinel exhibits high conductivity, thermal expansion compatible with ferritic stainless steels, and forms a barrier to inhibit chromium migration during oxidation. Copper can be added to manganese-cobalt spinel to improve electrical conductivity of the spinel coating. This work investigated oxide scale formation and oxidation rate of Mn-Co …
Production Of Autoclaved Lightweight Concretes Using Pottery Stone And Bagasse Ash,
2023
Chulalongkorn University
Production Of Autoclaved Lightweight Concretes Using Pottery Stone And Bagasse Ash, Sutthima Sriprasertsuk, Saijit Daosukho
Journal of Metals, Materials and Minerals
This study investigated the influence of pottery stone and bagasse ash on the mechanical features of autoclaved lightweight concrete. Pottery stone is a natural resource of igneous rock weathering commonly exists with white clay, feldspar and limestone. This raw material is mainly composed of quartz and mica that has been used for the production of ceramic products. Bagasse ash is a waste product of the sugar refining process that causes serious environmental pollution. Pottery stone and bagasse ash waste were physically characterized and partially substituted by the weight of cement in lightweight concrete with the addition of aluminium powder at …
Paper-Based Colorimetric Sensor For Mercury Ion Detection Using Smartphone Digital Imaging,
2023
Chulalongkorn University
Paper-Based Colorimetric Sensor For Mercury Ion Detection Using Smartphone Digital Imaging, Pakorn Preechaburana, Somsak Sangnuy, Supaluck Amloy
Journal of Metals, Materials and Minerals
In this research, we have developed a colorimetric paper-based sensing platform for the determination of mercury ion (Hg2+) using gold nanoparticles (AuNPs). To evaluate the selectivity in the response to a special target, urea is used as recognizing ligands on AuNPs for selective sensing Hg2+. Colorimetric readings in the presence of various environmentally relevant metal ions, such as Na+, K+, Zn2+, Pb2+, and Hg2+, were also studied. The results show that amongst all the tested metal ions, the SPR peaks are located at 525 nm except in the case of the present of Hg2+, in which is red shifted to …
Dielectric Properties And Electrochemical Behavior Of Graphene Oxide Derived From Myanmar Coal Minerals,
2023
Chulalongkorn University
Dielectric Properties And Electrochemical Behavior Of Graphene Oxide Derived From Myanmar Coal Minerals, Min Maung Maung, Chan Nyein Aung, Gasidit Panomsuwan, Khin Khin Win
Journal of Metals, Materials and Minerals
Graphene Oxide (GO) metal nanocomposites make up an emerging class of advanced materials and enhance material functionality to obtain multifunctional properties and working towards superior performance of energy storage devices. GO was derived from Myanmar coal minerals using Modified Hummer method. The silver and nickel nanoparticles were used as metal ions or metal nanoparticles to form GO nanocomposites. Their characteristics were identified by XRD, SEM and Raman Spectroscopy. The energy gap of GO and GO composites was also investigated by the aid of UV-Vis spectroscopy. The dielectric constant is measures of the amount of electrical energy that can be stored …
A Review On New Cobalt-Free Cathode Materials For Reversible Solid Oxide Fuel Cells,
2023
Chulalongkorn University
A Review On New Cobalt-Free Cathode Materials For Reversible Solid Oxide Fuel Cells, Sedat Akkurt, Can Sindiraç, Tuğçe Özmen Egesoy, Emre Erğen
Journal of Metals, Materials and Minerals
The exponential growth in the requirement of fuel cells and batteries leads to increased demand for cobalt due to its common use in high-performance Li-ion batteries and high-temperature fuel cells/electrolyzers. This sharp increment in demand raises concern about the availability of limited reserves of cobalt which can impact the price of cobalt. Moreover, the geographic limitations of cobalt resources may endanger the whole supply chain. In addition to all those, huge moral issues of cobalt mining are also another problem. Hence, leading battery, fuel cells and electrolyzer manufacturers are looking for sustainable alternatives to reduce cobalt dependency. A more specific …
High-Temperature Oxidation Resistance Of Craln Thin Films Prepared By Dc Reactive Magnetron Sputtering,
2023
Chulalongkorn University
High-Temperature Oxidation Resistance Of Craln Thin Films Prepared By Dc Reactive Magnetron Sputtering, Nirun Witit-Anun, Adisorn Buranawong
Journal of Metals, Materials and Minerals
CrAlN thin films were prepared by using the reactive DC unbalanced magnetron sputtering method from the single alloy target on a silicon substrate. The effect of annealing temperature in the air which ranges from 500℃ to 900℃ for 1 h on phase structure, film composition, surface morphology, microstructure, and hardness was investigated by XRD, EDS, FE-SEM, and Nanoindentation techniques, respectively. The high-temperature (up to 900℃) oxidation resistance of the thin film was also evaluated. The result shows that solid solutions of (Cr,Al)N with (111), (200), and (220) planes for the as-deposited film and no oxide phase were found after annealing …
Effect Of Annealing Temperature On The Tio Anodized Films Properties For Dental Implant Application,
2023
Chulalongkorn University
Effect Of Annealing Temperature On The Tio Anodized Films Properties For Dental Implant Application, Phanawan Whangdee, Wittawat Saenrang, Nampueng Pangpaiboon, Pristanuch Masakul, Dujreutai Pongkao Kashima
Journal of Metals, Materials and Minerals
The TiO2 anodized films generated at low current density after annealing are good candidates for surface coating, as a hydrophilicity is a crucial characteristic that determines dental implant applications. In this study, the hydrophilicity of TiO2 anodized films annealed at various temperatures was examined. It was found that increasing the annealing temperature during the anodization procedure improves the hydrophilicity of the TiO2 anodized films. This is related to the evolution of the TiO2 anodized film structure produced by raising the annealing temperature, which converts the TiO2 anodized amorphous phase to rutile phases. Moreover, increased annealing temperature results in more oxygen …
Structure And Properties Of The Contact Wire Obtained By Ecap With Forming,
2023
Chulalongkorn University
Structure And Properties Of The Contact Wire Obtained By Ecap With Forming, Denis Alekseevich Aksenov, Rashid Nailevich Asfandiyarov, Georgy Iosifovich Raab, Yulia Ramilevna Sementeeva
Journal of Metals, Materials and Minerals
This paper presents the results of the development of a promising method for manufacturing contact wires for high-speed railways. The developed method is based on the principles of severe plastic deformation and the combination of metal-forming processes. The solution obtained is a combination of equal-channel angular pressing with the forming of a shaped contact wire with a cross-sectional area of 120 mm2 in one tooling. A feature of the work is that with the help of a comprehensive study by the methods of finite element computer modeling and a physical experiment, not only the stress-strain state of the deformation zone …
Multipurpose Fluorescent Carbon Dots From Papaya Seed Waste As Sensing Materials For Cu2+ Detection And Diethyl Ether Vapor Sensor Via Electronic Nose System,
2023
Chulalongkorn University
Multipurpose Fluorescent Carbon Dots From Papaya Seed Waste As Sensing Materials For Cu2+ Detection And Diethyl Ether Vapor Sensor Via Electronic Nose System, Nichaphat Thongsai, Aphinya Chuiduang, Sumana Kladsomboon, Insik In, Peerasak Paoprasert
Journal of Metals, Materials and Minerals
Herein, carbon dots (CDs) as biocompatible, fluorescent carbon-based nanomaterials were synthesized from papaya seed waste as renewable carbon sources for the first time via a facile acid pyrolysis method. The papaya seed-derived CDs showed blue fluorescence emission under UV light (365 nm) with a quantum yield of 2.74%, and contained oxygen-, and nitrogen- containing functional groups. Due to their surface functionality, the CDs have a great potential for using as fluorescence sensing probe in metal ion sensing application. The CD solution exhibited the most selective detection to Cu2+ as presented the highest fluorescence quenching with the limit of detection (LOD) …
Synthesis And Characterization Of Electron Beam Irradiated Glutinous Rice Husk-Derived Biochar And Activated Carbon For Aqueous Electrochemical Capacitors,
2023
Chulalongkorn University
Synthesis And Characterization Of Electron Beam Irradiated Glutinous Rice Husk-Derived Biochar And Activated Carbon For Aqueous Electrochemical Capacitors, Kittapas Kitsanadecha, Charlita Sinmak, Patchanan Onchomchan, Kanit Hantanasirisakul, Tanagorn Kwamman, Suranan Anantachaisilp
Journal of Metals, Materials and Minerals
Glutinous rice husk, an abundant agricultural biowaste in Thailand, was pretreated with high energy electron beam irradiation (EBI) at doses of 500 kGy, 1000 kGy, and 1500 kGy prior to fabrication into biochar by carbonization at 500℃ under nitrogen atmosphere. The biochar was then treated with KOH and subsequently heated at 800℃, yielding activated carbon (GAC). The physical, chemical, and electrochemical properties of the as-received biochar (GB) and activated carbon (GAC) were investigated. Scanning electron microscopic images (SEM) suggested that biochar irradiated with 1500 kGy (GB-1500) has the highest porosity compared to the other samples. The electrochemical properties of GB …
Polyol Method And Surface Functionalization Of Silver Nanowires Using Bovine Serum Albumin For Surface-Enhanced Raman Scattering Application,
2023
Chulalongkorn University
Polyol Method And Surface Functionalization Of Silver Nanowires Using Bovine Serum Albumin For Surface-Enhanced Raman Scattering Application, Khoa Tien Cao, Khoi Khac Tran, Hue Thi Do
Journal of Metals, Materials and Minerals
Silver nanowires (AgNWs) with diverse applications are attracting the attention of many researchers around the world. In this study, we applied the polyol method to synthesize AgNWs based on Polyvinyl-pyrrolidone (PVP) average molecular weight of 360,000, ethylene glycol (EG), and AgNO3 precursor with a fresh AgCl preparation. To synthesize this material we first investigate optimal parameters through the influence of reaction temperature, time of creating AgNWs using plasmon absorption spectroscopy, and scanning electron microscope (SEM) images. The obtained AgNWs are high efficiency, large aspect ratio, and good dispersion in the solution. This sample continues to be conducted to surface functionalization …
