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Articles 1501 - 1530 of 3655
Full-Text Articles in Engineering
New Views On The Ingenious Applications Of Ag Nanoparticles As A Sensor For Antibiotic Detection And As A Potent Antimicrobial Agent, Keyur Bhatt, Anita Kongor, Mohd Atharb, Vinod Jain
New Views On The Ingenious Applications Of Ag Nanoparticles As A Sensor For Antibiotic Detection And As A Potent Antimicrobial Agent, Keyur Bhatt, Anita Kongor, Mohd Atharb, Vinod Jain
Journal of Metals, Materials and Minerals
Nanotechnology uses exceptional approaches for the control of bacterial infections which uncovers the potential function of bio-systems at nano-scale level. Compared to silver ions, silver nanoparticles possess enhanced physicochemical stability and low bio-toxicity properties. The intrinsic chemical framework of silver nanoparticles is prone to exhibit a significant chemistry when used as sensor and as therapeutic. Nowadays, silver is used in (nano-) medicine, in the form of nanoparticles to optimize its therapeutic property for controlling infections caused by multidrug-resistant bacteria. Exclusive use of antibiotics as medicines and its discharge from the body of the infected person or animals into the sewage …
Investigations On Phase Coexistence And Functional Properties Of Bczt Lead-Free Piezoceramic, Jirapa Tangsritrakul, Thiyanee Sonkami, Chumpon Wichittanakom, Chotiros Dokkhan, Panithi Wiroonpochit
Investigations On Phase Coexistence And Functional Properties Of Bczt Lead-Free Piezoceramic, Jirapa Tangsritrakul, Thiyanee Sonkami, Chumpon Wichittanakom, Chotiros Dokkhan, Panithi Wiroonpochit
Journal of Metals, Materials and Minerals
Large piezoelectric properties was observed in (1-x)BZT-(x)BCT where x=0.5 or Ba0.85Ca0.15Ti0.9Zr0.1O3 (denoted as BCZT), leading to a promising candidate for lead-free piezoelectric materials. However, phase formation of the BCZT is controversial and still unclear since various phase coexistences were identified in the literatures, for instances, the mixed phases of rhombohedral-tetragonal (R-T), ortho-rhombic-tetragonal (O-T) or rhombohedral-orthorhombic-tetragonal (R-O-T). Additionally, it is well known that the crystal structure plays a crucial role on the occurrence of polarization in the piezoceramics. Therefore, this work aims to investigate the coexistence of phase formation at room temperature for the BCZT powder and ceramic. Moreover, the electrical …
Influence Of Precursor Preparation On The Synthesis Of Boron Carbide From Glutinous Rice Flour, Kannigar Dateraksa, Sujarinee Sinchai
Influence Of Precursor Preparation On The Synthesis Of Boron Carbide From Glutinous Rice Flour, Kannigar Dateraksa, Sujarinee Sinchai
Journal of Metals, Materials and Minerals
Boron carbide is a promising candidate for a variety of applications, including blasting nozzles, neutron moderators, and lightweight armor. Using of inexpensive and readily available starting materials which can react with boric acid to form B-O-C bonds, e.g., glutinous rice flour, is one of alternative means to produce high purity boron carbide powder at low temperature. In this study, boric acid and glutinous rice flour, boron and carbon sources, were used for synthesizing B4C powder by the carbothermic reduction. The mole ratios of boric acid to glutinous rice flour ranging from 1:1 to 2.5:1 were formulated and mixed by continuous …
Effect Of Zinc-Hydroxo Species On The Growth Of One-Dimensional Zno Nanostructures, Nontakoch Siriphongsapak, Somyod Denchitcharoen
Effect Of Zinc-Hydroxo Species On The Growth Of One-Dimensional Zno Nanostructures, Nontakoch Siriphongsapak, Somyod Denchitcharoen
Journal of Metals, Materials and Minerals
One-dimensional ZnO nanostructures were grown on ZnO seed layer by hydrothermal method using zinc nitrate (Zn(NO3)2) and sodium hydroxide (NaOH) as precursors. The concentrations of NaOH and Zn(NO3)2 were varied from 40 mM to 680 mM and kept constant, respectively. Effects of increasing the hydroxide ions on the concentration of zinc-hydroxo species in the solution were studied using thermodynamic simulation software. The simulated results showed that Zn(OH)2 and Zn(OH)3- concentrations tended to decrease but Zn(OH)42- was non-linearly increased when the concentration of NaOH at room temperature was increased. After the growth of ZnO, the samples were characterized by FESEM and …
Experimental And Numerical Characterization Of Fatigue Crack Propagation In High-Speed Railway Wheel Er8 Steel, Chaichayo Suetrong, Vitoon Uthaisangsuk
Experimental And Numerical Characterization Of Fatigue Crack Propagation In High-Speed Railway Wheel Er8 Steel, Chaichayo Suetrong, Vitoon Uthaisangsuk
Journal of Metals, Materials and Minerals
In this work, characteristics of fatigue crack growth in the Paris regime of the rail wheel steel grade ER8 were investigated. Experimental crack growth tests under different cyclic loads of a compact tension (CT) specimen and corresponding FE simulations were carried out. The extended FE method (XFEM) coupled with damage evolution based on the strain energy release rate or the Paris law was applied to describe the crack propagation mechanism in the tested CT samples. Hereby, the fatigue fracture model parameters were firstly determined from the experimental data. It was found that the predicted crack growth rates agreed well with …
Effect Of Cladding Of Stellite-6 Filler Wire On The Surface Of Ss316l Alloy Through Cold Metal Arc Transfer Process, Thinesh Babu Thiagarajan, Sengottuvel Ponnusamy
Effect Of Cladding Of Stellite-6 Filler Wire On The Surface Of Ss316l Alloy Through Cold Metal Arc Transfer Process, Thinesh Babu Thiagarajan, Sengottuvel Ponnusamy
Journal of Metals, Materials and Minerals
In this work, Cladding was done on SS316L alloy through the CMT process using Stellite-6 filler wire. 31 experiments were done at different welding conditions as per CCD matrix. The cladding specimens were characterized by macro and micro-study, Vickers microhardness evaluation and corrosion resistance analysis. An optical microscope, SEM-EDAX, and XRD were used to predict the structural characterizations, presence and the distributions of the elements. Based on the study higher voltage & welding speed showed appreciable hardness at the interface & cladding regions. The thickness of the interface was noted at a maximum of 190 μm. The EDS spectra showed …
Development And Characterization Of Sic Fiber Reinforced B4c Composite, Jitendra Kumar Sonber, Sanjib Majumdar, Vivekanand Kain
Development And Characterization Of Sic Fiber Reinforced B4c Composite, Jitendra Kumar Sonber, Sanjib Majumdar, Vivekanand Kain
Journal of Metals, Materials and Minerals
This study is conducted to investigate the effects of silicon carbide short fiber (SiCf) reinforcement on processing and properties of boron carbide ceramic. Studies have been carried out on the hot pressing, mechanical property measurement, microstructure evolution and oxidation study of SiCf reinforced B4C composite. B4C-SiCf composites have been prepared by hot pressing at 1950℃ with varying SiCf content in the range of 10 vol% to 30 vol%. All the composites are densified to near theoretical density. It is noticed that hardness of composite is decreased and fracture toughness of composite is increased by addition of SiC fiber. Hardness of …
Facile Purification Of Locally Mined Gypsum And Its Use For Preparing Nano-Hemihydrates, Luqman Ayodeji Adams, Enobong Essien, Taiwo Aiyeloro, Stella Oseyomon, John Makanjuola
Facile Purification Of Locally Mined Gypsum And Its Use For Preparing Nano-Hemihydrates, Luqman Ayodeji Adams, Enobong Essien, Taiwo Aiyeloro, Stella Oseyomon, John Makanjuola
Journal of Metals, Materials and Minerals
Gypsum has a wide range of applications, in interior decorations, building construction, supplements or implants in orthopaedics to mention a few. However, in many developing countries including Nigeria, there is still a large-scale importation despite huge available natural deposits. In this study, a facile method to purify locally-mined gypsum has been explored based on the mineral retrograde solubility in water. The purified gypsum was investigated for its elemental composition in comparison to the crude sample and a commercially obtained medical-grade gypsum using X-ray fluorescence (XRF). The results showed that the purified gypsum contained 94.05% CaSO4 compared with the crude which …
Efficiency Of 2-Dodecylaminopyridine For The Liquid-Liquid Extraction Of Gold(Iii) From Succinic Acid Medium, Umrao Shep, Rucha Pawar, Balasaheb Arbad
Efficiency Of 2-Dodecylaminopyridine For The Liquid-Liquid Extraction Of Gold(Iii) From Succinic Acid Medium, Umrao Shep, Rucha Pawar, Balasaheb Arbad
Journal of Metals, Materials and Minerals
Extractive recovery of gold(III) from succinic acid solution with high molecular weight amine: 2-dodecylaminopyridine (2-DDAP) as a new extractant in xylene has been investigated. Extraction data indicates that 5 × 10-4 mol⋅L-1 2-DDAP is a very efficient and fast extractant. Gold(III) can be effectively extracted (D = 414.16) with 2-DDAP from 0.04 M succinic acid solution. The equilibrium of gold(III) from aqueous phase of succinic acid with 2-DDAP is achieved within 60 sec. The extraction of gold(III) with 2-DDAP proceed at the interface according to ion pair formation mechanism. The best stripping solution from among the studied ones is the …
Effect Of Dc Power On The Thickness, Hardness And Adhesion Strength Of Ti-51 At% Ni Coated Ti/Tin, Ishiaka Shaibu Arudi, Esah Hamzah, Muhammad Azizi Mat Yajid, Bushroa Abdul Razak
Effect Of Dc Power On The Thickness, Hardness And Adhesion Strength Of Ti-51 At% Ni Coated Ti/Tin, Ishiaka Shaibu Arudi, Esah Hamzah, Muhammad Azizi Mat Yajid, Bushroa Abdul Razak
Journal of Metals, Materials and Minerals
The coating of Ti/TiN was successfully deposited on Ti-51 at% Ni substrates by using direct current (DC) magnetron sputtering technique and the effect of different sputtering power on the thickness, surface hardness and adhesion strength of the coatings were studied. The microstructural characterization was carried out using scanning electron microscope (SEM), energy-dispersive X-ray (EDX) and X-ray diffractometer (XRD). The coating thicknesses were detected and measured using SEM. The surface hardness test was performed using microhardness tester, and the adhesion strength was carried out by scratch testing. The results showed that the TiN crystallites growth orientation, thickness, surface hardness and adhesion …
Developments Of Biodegradable Polymer Based On Polylactic Acid (Pla) With Natural Color Extracts For Packaging Film Applications, Worraphol Nansu, Passarawan Chaiwut, Sukunya Ross, Gareth Ross, Nungruthai Suphrom, Sararat Mahasaranon
Developments Of Biodegradable Polymer Based On Polylactic Acid (Pla) With Natural Color Extracts For Packaging Film Applications, Worraphol Nansu, Passarawan Chaiwut, Sukunya Ross, Gareth Ross, Nungruthai Suphrom, Sararat Mahasaranon
Journal of Metals, Materials and Minerals
This research was interested in the use of natural colorants to replace hazardous synthetic pigments in the plastic polymer industry. The natural colors were selected from local plants indigenous to southeast Asia, which were Hibiscus sabdariffa roselle calyx (RS) and Caesapinia sappan Linn heartwood (SP). Natural colorant extracts were used as additives in poly(lactic acid ) (PLA). These were manufactured using a twin screws extruder and blow film extruder to obtain biodegradable thin films for use as packaging materials. Biodegradable films were characterized by color index, light barrier properties, water vapor transmission (WVTR), morphology, mechanical and chemical properties. The results …
Effects Of Delay Time And Curing Temperature On Compressive Strength And Porosity Of Ground Bottom Ash Geopolymer Mortar, Nattapong Makaratat, Sumrerng Rukzon, Prinya Chindaprasirt
Effects Of Delay Time And Curing Temperature On Compressive Strength And Porosity Of Ground Bottom Ash Geopolymer Mortar, Nattapong Makaratat, Sumrerng Rukzon, Prinya Chindaprasirt
Journal of Metals, Materials and Minerals
This research investigated development of ground bottom ash (GBA) for a new geopolymer material. The compressive strength and porosity of the geopolymer mortar containing GBA were tested. The GBA-based geopolymer mortar mixtures were designed by control liquid to GBA ratio for all tests. Extra water was also used to maintain the workability of geopolymer mortar. The sodium hydroxide (NaOH) concentrations of 10 M and 15 M were used. Furthermore, sodium silicate (Na2SiO3) to sodium hydroxide (NaOH) ratios by mass such as 0.50, 1.50 and 2.50 were also used as alkali activator solutions. Effects of delay time and no-delay time, heat …
A Review Of Rice Husk Silica As A Heterogeneous Catalyst Support, Izzati Nasir, Nadiah Ameram, Arlina Ali, Siti Roshayu Hassan, Nurul Akmar Che Zaudin, Jamil Mohamed Sapari
A Review Of Rice Husk Silica As A Heterogeneous Catalyst Support, Izzati Nasir, Nadiah Ameram, Arlina Ali, Siti Roshayu Hassan, Nurul Akmar Che Zaudin, Jamil Mohamed Sapari
Journal of Metals, Materials and Minerals
The yield of amorphous silica has less residue of mineral content in rice husk (RH) and a high specific surface area through the simple alkaline extraction process at first, then acid precipitation of RH. At this time, the leaching process using alkali and calcination of RH is the best method to acquire amorphous silica with a high surface area. The different temperatures were used for the calcination of RH and continue with sodium hydroxide (NaOH) treatment by using different concentration. The sample titrated using hydrochloric acid (HCl) to extract silica. Pretreatment with acid leaching for the RH was also conducted …
Enhanced Mechanical And Thermal Properties Of Fly Ash-Based Geopolymer Composites By Wollastonite Reinforcement, Khanthima Hemra, Takaomi Kobayashi, Pavadee Aungkavattana, Sirithan Jiemsirilers
Enhanced Mechanical And Thermal Properties Of Fly Ash-Based Geopolymer Composites By Wollastonite Reinforcement, Khanthima Hemra, Takaomi Kobayashi, Pavadee Aungkavattana, Sirithan Jiemsirilers
Journal of Metals, Materials and Minerals
The present study investigated the mechanical and thermal properties of geopolymer composite. The geopolymer composite was prepared by mixing fly ash and wollastonite with the alkaline activator, which was 6 M KOH:K2SiO3 in a mass ratio of 1:1 and a solid:liquid mass ratio of 3:2. The compressive strength at 28 days of geopolymer was 33.3 MPa and possessed the highest strength of 38.3 MPa when 30 wt% wollastonite was added. The flexural strength presented differently whereby it increased from 2.1 MPa to 6.8 MPa. It increased remarkably up to 200% with the addition of 50 wt% wollastonite. The geopolymer composites …
Raman Signal Enhancement Of Low-Cost Metal Sheet Sers With Gold Decoration, Nampueng Pangpaiboon, Kawinphob Phetnam, Sukon Kalasung, Chanunthorn Chananonawathorn, Viyapol Patthanasettakul, Mati Horprathum, Pitak Eiamchai, Noppadon Nuntawong, Saksorn Limwichean
Raman Signal Enhancement Of Low-Cost Metal Sheet Sers With Gold Decoration, Nampueng Pangpaiboon, Kawinphob Phetnam, Sukon Kalasung, Chanunthorn Chananonawathorn, Viyapol Patthanasettakul, Mati Horprathum, Pitak Eiamchai, Noppadon Nuntawong, Saksorn Limwichean
Journal of Metals, Materials and Minerals
Surface Enhance Raman Spectroscopy (SERS) is a sensitive surface creating plasmonic resonance for the Raman scattering. SERS is considered as a powerful technique to enhance the Raman signal, when quantity of sample is limited. Recently, our lab team has discovered a low-cost SERS template fabrication, laser-engraving method, which is suitable with gold nanoparticles decoration. In this work, two different materials, zinc and copper, are used as metal sheet SERS substrate. Gold nanoparticles sputtered with 270 s of sputtering time are used as decorated noble metal. FE-SEM images illustrate the nano-in-microstructure of the engraved metal sheets. The decorated Au nanoparticles are …
Oxidation Behavior Of Sn-1 Wt% Bi Alloy In Air And Deionized Water At Room Temperature, Tanavut Naravuthichai, Patama Visuttipitukul, Sirichai Leelachao, Tachai Luangvaranunt
Oxidation Behavior Of Sn-1 Wt% Bi Alloy In Air And Deionized Water At Room Temperature, Tanavut Naravuthichai, Patama Visuttipitukul, Sirichai Leelachao, Tachai Luangvaranunt
Journal of Metals, Materials and Minerals
Formation of tin oxides on surface Sn-1 wt% Bi alloy lapping plates causes interactions with protrusions of embedded diamond grits, and reduces the efficiency of the lapping process. The rate and type of oxide formation were investigated to understand the problem. Electrochemical analysis was performed to characterize the oxide film thickness, and x-ray photoelectron spectroscopy was performed to characterize the tin oxide species. Oxidation in air at room temperature reaches a thickness of 23 Å after 72 h. Oxidation in deionized water at room temperature has a faster growth rate, and reaches a thickness of 33 Å after 72 h. …
Mechanical Performance Of Woven Carbon Reinforced Epoxy Composites With Varied Orientation Angle, Sweety Ashish Agrawal, Someshwar Bhattacharya
Mechanical Performance Of Woven Carbon Reinforced Epoxy Composites With Varied Orientation Angle, Sweety Ashish Agrawal, Someshwar Bhattacharya
Journal of Metals, Materials and Minerals
The mechanical properties of woven carbon fibre reinforced epoxy composites laminated with different orientation angle in stacking sequence were investigated. Woven fabric layers with different linear density carbon tow have been produced on modified rigid rapier sample loom and impregnated with epoxy by hand lay-up technique for composite preparation. Curing of composite was carried out at room temperature for 2 h. Five different laminar composites were prepared with different orientation angles [(0/0/0/0), 0/+30/-30/0, 0/+45/-45/0, 0/+60/-60/0 and 0/+90/-90/0]. The mechanical properties like tensile, flexural, and impact test) were analysed in both longitudinal and transverse directions. Physical properties such as density and …
Investigation Of Optimum Parameters For Rotary Friction Welding Of Aluminum Round Bars Using Three-Level Factorial Design Methodology, Tanakorn Jantarasricha, Siridech Kunhirunbawon, Montri Wimol
Investigation Of Optimum Parameters For Rotary Friction Welding Of Aluminum Round Bars Using Three-Level Factorial Design Methodology, Tanakorn Jantarasricha, Siridech Kunhirunbawon, Montri Wimol
Journal of Metals, Materials and Minerals
The welding process has been essential to increasing productivity in numerous industries across Thailand. There are several welding processes to choose from, and the welding process to use will be determined by the suitability of the production in that industry. Another important consideration in welding is to keep the mechanical properties of the joint area as close to the parent material workpiece as possible. This research aims to select the optimum parameter for rotary friction welding aluminum round bar AA6063-T5. That is according to the DIN 50125 type B standard test. The optimal condition consists of welding rotational speed, welding …
Synthesis And Optical Properties Of Forsterite Ceramic Pigments Using Mirror Wastes As A Flux, Niti Yongvanich, Natchaya Lithira, Nitchakarn Nuniead, Wanchalerm Chauyarsa
Synthesis And Optical Properties Of Forsterite Ceramic Pigments Using Mirror Wastes As A Flux, Niti Yongvanich, Natchaya Lithira, Nitchakarn Nuniead, Wanchalerm Chauyarsa
Journal of Metals, Materials and Minerals
Cobalt-doped forsterite ceramic pigments based on the formula (Mg2-2xCo2x)SiO4 (x = 0, 0.05, 0.1, 0.2) were synthesized using mirror wastes as a flux. Addition of this flux enhanced forsterite phase formation at lower temperature by as much as 200℃. The resulting pigment particles were in a micron range which is suitable for use in a ceramic glaze. The host structure (Mg2SiO4) could accommodate cobalt cations up to 20 at%. Investigation on the chemical distribution revealed that no chemical species from the flux reacted with pigment grains. Optical properties were examined by UV-vis spectroscopy and colorimetry. Technical performance of the obtained …
Optimal Multi-Reservoir System Operations Under Inflow Scenarios In Nam Ngum River Basin, Lao Pdr, Bounhome Kimmany
Optimal Multi-Reservoir System Operations Under Inflow Scenarios In Nam Ngum River Basin, Lao Pdr, Bounhome Kimmany
Chulalongkorn University Theses and Dissertations (Chula ETD)
The Nam Ngum River is one of the main rivers in Lao PDR. Many hydropower projects are currently operated, under construction, and in the planning stage within the Nam Ngum River Basin (NNRB). These hydropower projects are managed by different organizations which could lead to conflict in operation and hinder the achievement of national developments. The main objective of this research is therefore to develop an optimization model for maximizing hydropower production in the NNRB through optimal reservoir operation under the impact of climate change. The potential consequence of maximizing hydropower production that could lead to flooding was also considered …
การใช้ของเสียกระจกแผงพลังงานแสงอาทิตย์ทดแทนการใช้ปูนซีเมนต์บางส่วนในการผลิตมอร์ตาร์, ครองขวัญ ข่วงบุญ
การใช้ของเสียกระจกแผงพลังงานแสงอาทิตย์ทดแทนการใช้ปูนซีเมนต์บางส่วนในการผลิตมอร์ตาร์, ครองขวัญ ข่วงบุญ
Chulalongkorn University Theses and Dissertations (Chula ETD)
จากปริมาณของเสียแผงพลังงานแสงอาทิตย์ที่กำลังจะเกิดขึ้นภายในระยะเวลา 20-30 ปีจากการติดตั้งในช่วงพ.ศ. 2545-2558 อาจจะเป็นน้ำหนักได้ถึง 235,954 ตัน โดยส่วนใหญ่ประเทศไทยนิยมใช้แผงพลังงานแสงอาทิตย์ชนิดผลึกซิลิกอน ซึ่งแผงประเภทนี้มีปริมาณกระจกมากถึงร้อยละ 70-80 โดยน้ำหนักขององค์ประกอบแผง การจัดการของเสียแผงพลังงานแสงอาทิตย์ในประเทศไทยในขณะนี้มีการกำจัดด้วยการนำไปทิ้งที่หลุมฝังกลบอุตสาหกรรม ซึ่งเป็นการจัดการที่ไม่ยั่งยืนเพราะเป็นการสูญเสียทรัพยากรอย่างไร้ประโยชน์ ในงานวิจัยนี้มุ่งเน้นในการนำกระจกแผงพลังงานแสงอาทิตย์ชนิดผลึกซิลิกอนนำกลับมาใช้ประโยชน์ใหม่ โดยทำการศึกษาผลกระทบต่อสมบัติต่างๆของมอร์ตาร์ที่มีการแทนที่บางส่วนของปูนซีเมนต์ด้วยกระจกแผงพลังงานแสงอาทิตย์บดละเอียดขนาด d50 ที่ 4.97 ไมโครเมตร ที่ร้อยละ 0, 10, 20 และ 30 โดยน้ำหนัก จากผลการศึกษาพบว่าเมื่อเพิ่มปริมาณผงกระจกจะทำให้ ค่าการขยายตัวของซีเมนต์เพสต์มีค่าเพิ่มขึ้น ค่าการก่อตัวระยะต้นและระยะปลายของซีเมนต์เพสต์สั้นลง ค่าการไหลแผ่ของมอร์ตาร์มีค่าลดลง การซึมผ่านของคลอไรด์ในมอร์ตาร์ลดลง สำหรับกำลังรับแรงอัดมอร์ตาร์ช่วงอายุต้น พบว่ามอร์ตาร์ที่มีปูนซีเมนต์ที่มีการแทนที่ด้วยผงกระจกร้อยละ 0 ให้กำลังรับแรงอัดสูงที่สุด แต่ที่อายุ 90 วัน มอร์ตาร์ที่มีการแทนที่ปูนซีเมนต์ด้วยผงกระจกร้อยละ 10 ให้กำลังรับแรงอัดที่สูงที่สุด เนื่องจากการเกิดปฏิกิริยาปอซโซลานิกใช้เวลานานกว่าจะเกิดปฏิกิริยา
การปรับปรุงสถานีงานตรวจสอบถังแก๊สคลอรีนโดยใช้การประเมินทางสรีรวิทยาในการทำงาน และชีวกลศาสตร์, ภาณุพงศ์ ภาวิไล
การปรับปรุงสถานีงานตรวจสอบถังแก๊สคลอรีนโดยใช้การประเมินทางสรีรวิทยาในการทำงาน และชีวกลศาสตร์, ภาณุพงศ์ ภาวิไล
Chulalongkorn University Theses and Dissertations (Chula ETD)
สารคลอรีนที่มีความชื้นสูงสามารถกัดกร่อนถังโลหะบรรจุสารคลอรีนจนเกิดการรั่วไหล การนำถังมาบรรจุสารคลอรรีนใหม่จึงต้องมีการตรวจสอบและระบายน้ำออกจากถังโดยการยกถังคลอรีนคว่ำลง แต่การยกถังหนัก 50 กิโลกรัม จำนวน 100 ถังต่อคนต่อวัน และท่าทางการยกที่ไม่เหมาะสม ทำให้เกิดปัญหาการปวดหลังของพนักงาน ผลจากการประเมินภาระงานของพนักงานเพศชายทั้ง 10 คน พบว่าค่าแรงกดอัดสูงสุดที่กระดูกสันหลังส่วนล่างเฉลี่ยตลอดการยกอยู่ที่ 5,673.4 นิวตัน และ ผลจากการประเมินภาระความเหนื่อยล้าของงาน โดยวิเคราะห์อัตราการเต้นของหัวใจอยู่ในเกณฑ์ที่ไม่ปลอดภัย ซึ่งอาจเกิดอันตรายต่อผู้ปฏิบัติงานในอนาคต จากการปรับปรุงการทำงานทั้ง 3 แนวทางพบว่า แนวทางการใช้อุปกรณ์ช่วยยกคลอรีนและการใช้กล้องงูสามารถลดค่าแรงกดอัดสูงสุดที่กระทำต่อกระดูกหลังส่วนล่างเหลือน้อยกว่า 1,224.8 นิวตัน และผลประเมินภาระความเหนื่อยล้าของงานอยู่ในเกณฑ์ปลอดภัยกลายเป็นงานภาระเบา แต่แนวทางการใช้พนักงาน 2 คนยกถังคลอรีนสามารถลดค่าแรงกดอัดสูงสุดที่กระทำต่อกระดูกสันหลังส่วนล่างได้น้อยกว่า 3,992.4 นิวตัน และผลประเมินภาระความเหนื่อยล้าของงานอยู่ในเกณฑ์ปลอดภัยเพียง 4 คนจากพนักงานทั้ง 10 คน ตามแนวทางประเมินของ Brouha ดังนั้นทางหน่วยงานกรณีศึกษาจึงได้เลือกแนวทางการใช้อุปกรณ์ช่วยยกและพลิกถังคลอรีน เนื่องจากมีความคุ้มค่าในการลงทุนเทียบกับระดับความปลอดภัยที่ได้รับ
Key Success Factors Identification For Logistics Outsourcing In Myanmar, Pyae Sone Htoon
Key Success Factors Identification For Logistics Outsourcing In Myanmar, Pyae Sone Htoon
Chulalongkorn University Theses and Dissertations (Chula ETD)
The purpose of this paper is to identify the key success factors that have a profound effect on the service quality of outsourced logistics functions in the import/export sector of trade business in Myanmar and rank them accordingly to their importance when outsourcing logistics functions. The paper states the critical elements required for logistics service providers to compete for high customer satisfaction in Yangon, Myanmar. Fuzzy TOPSIS methodology with triangular fuzzy numbers is used to identify the key success factors and rank them in order of their relative closeness to the ideal solution. The findings suggest that soft factors such …
Effect Of Hydrogen Co-Feeding On Ethylene Polymerization With Ziegler-Natta Catalysts With Different Amounts Of Titanium, Santhakamol Kittibanpacha
Effect Of Hydrogen Co-Feeding On Ethylene Polymerization With Ziegler-Natta Catalysts With Different Amounts Of Titanium, Santhakamol Kittibanpacha
Chulalongkorn University Theses and Dissertations (Chula ETD)
Effect of hydrogen on the prepared TiCl4-MgCl2 catalysts having loading amounts of titanium was investigated via ethylene homopolymerization and ethylene/1-hexene copolymerization in slurry polymerization process. First, the catalysts were prepared to obtain different Ti loadings from 4.4 to 6.5 wt%. Then, all catalysts were characterized and tested in ethylene homopolymerization and ethylene/1-hexene copolymerization in the presence and absence of hydrogen during polymerization. It was found that hydrogen enhanced the catalyst activities on the catalyst with high Ti content (6.5 wt%) for 2.6 times and 1.9 times for ethylene homopolymerization and ethylene/1-hexene copolymerization, whereas it decreased the activity of the catalyst …
Simulation Of Flexural Performance Of Mill-Cut Steel Fiber Reinforced Concrete Beam Degraded By Mild Corrosion, Minh Khanh Vo
Simulation Of Flexural Performance Of Mill-Cut Steel Fiber Reinforced Concrete Beam Degraded By Mild Corrosion, Minh Khanh Vo
Chulalongkorn University Theses and Dissertations (Chula ETD)
The reinforced concrete structure is widely used for various applications structure due to its many advantages, so it is easily exposed to severe environments and corrosion of steel occurred shortening the life durable of the structure which may cause danger to humans and economic damage. Corrosion occurred as a significant factor leading to the further deterioration of performance and reduction of the loading resistance of reinforced concrete structures. Therefore, durable corroded structures should be dealt with to ensure user safety. In recent decades, steel fiber reinforced concrete is studied and applied cause of provides better durability. Nevertheless, there is a …
Surface Enhanced Raman Spectroscopy Analysis Of Thin-Smear-Contamination On Hdd Read-Write Head, Charin Seesomdee
Surface Enhanced Raman Spectroscopy Analysis Of Thin-Smear-Contamination On Hdd Read-Write Head, Charin Seesomdee
Chulalongkorn University Theses and Dissertations (Chula ETD)
Surface-enhanced Raman spectroscopy (SERS) is one of the most powerful analytical techniques for the identification of molecules in microelectronics industry for failure analysis protocol. In this work, a dry-processed gold nanoclusters were prepared by magnetron sputtering deposition to promote the enhancement of the Raman signal for the best intensity gain from selected common polymers found in hard disk drive as surface contamination. The optimized sputtering conditions was applied for SERS on polycarbonate (PC), polyethylene terephthalate (PET), polypropylene (PP), and high-density polyethylene (HDPE). The Raman spectrum showed the average Raman signal intensity gain at about 114%, 78%, 254%, and 226% respectively. …
Communities Of Nitrifying Microorganisms From Recirculating Aquaculture Systems (Rass) Under Different Ammonium Concentration And Salinity, Preeyaporn Pornkulwat
Communities Of Nitrifying Microorganisms From Recirculating Aquaculture Systems (Rass) Under Different Ammonium Concentration And Salinity, Preeyaporn Pornkulwat
Chulalongkorn University Theses and Dissertations (Chula ETD)
Bioaugmentation of nitrifying cultures can accelerate nitrification during startup and transition periods of recirculating aquaculture systems (RASs) operations. To formulate nitrifying cultures for RASs, impacts of ammonia and salinity (NaCl) on culturing nitrifying microorganisms were comprehensively investigated by including currently known groups of nitrifying microorganisms (ammonia-oxidizing archaea (AOA), ammonia oxidizing bacteria (AOB), comammox, Nitrospira, and Nitrobacter). Initially, community structure of nitrifying microorganisms was observed in biofilters from water recirculation units of shrimp holding tanks operated at two different salinities of 2 and 15 g/L. Unique patterns of nitrifying communities consisting of AOA, comammox, and Nitrospira (without AOB and Nitrobacter) were …
การจัดสมดุลสายการประกอบผลิตภัณฑ์ผสมแบบขนานหลายวัตถุประสงค์ที่ทำงานโดยคนงานและหุ่นยนต์, สุพิชชา งามพานิช
การจัดสมดุลสายการประกอบผลิตภัณฑ์ผสมแบบขนานหลายวัตถุประสงค์ที่ทำงานโดยคนงานและหุ่นยนต์, สุพิชชา งามพานิช
Chulalongkorn University Theses and Dissertations (Chula ETD)
ในงานวิจัยนี้ได้เสนอวิธีแก้ปัญหาของการจัดสมดุลสายการประกอบผลิตภัณฑ์ผสมลักษณะขนาน ที่มีการดำเดินงานการประกอบผลิตภัณฑ์โดยหุ่นยนต์, คนงาน และคนงานผู้พิการ สำหรับสายการประกอบแบบขนาน เป็นระบบการประกอบที่ประกอบด้วยสายการประกอบเส้นตรงตั้งแต่ 2 สายการประกอบขึ้นไป ถูกนำมาจัดเรียงในแนวขนานกัน มีข้อดีคือ ทำให้สามารถลดรอบเวลาของสายการประกอบลงได้ โดยเฉพาะอย่างยิ่งในกรณีที่เวลาดำเนินงานของบางขั้นงานมีค่าสูงกว่ารอบเวลาที่ต้องการของสายการประกอบ ในงานวิจัยนี้มีวัตถุประสงค์ในการแก้ปัญหาของจัดสมดุลสายการประกอบ 5 วัตถุประสงค์ ได้แก่ 1) ประสิทธิภาพของสายการประกอบมากที่สุด 2) ปริมาณการปล่อยฝุ่น PM2.5 จากหุ่นยนต์เฉลี่ยมีค่าน้อยที่สุด 3) ความแตกต่างของภาระงานเฉลี่ยระหว่างสถานีงานน้อยที่สุด 4) ค่าความแปรปรวนจากการใช้พลังงานของพนักงานน้อยที่สุด 5) มูลค่าภาษีที่สามารถประหยัดได้จากการจ้างงานคนพิการมากที่สุด ซึ่งถือเป็นปัญหาแบบเอ็นพีแบบยาก (NP-hard) ทำให้เป็นไปได้ยากที่จะได้คำตอบที่ดีที่สุด (Optimal Solution) ในระยะเวลาที่จำกัด ดังนั้นจึงจะประยุกต์ใช้อัลกอริทึมวิธีการเชิงวิวัฒนาการแบบมากวัตถุประสงค์ ที่ถูกจัดว่าเป็นเมตาฮิวริสติก (Metaheuristic) ในการแก้ปัญหา, พัฒนาคำตอบ และค้นหาค่าที่ดีที่สุดพร้อมๆกันไปของแต่ละวัตถุประสงค์ โดยอัลกอริทึมที่จะศึกษาและทำการเปรียบเทียบประสิทธิภาพในการแก้ปัญหาของงานวิจัยนี้คือ วิธีการเชิงวิวัฒนาการแบบหลายวัตถุประสงค์โดยยึดหลักการจำแนก (MOEA/D) และ วิธีเชิงพันธุกรรมแบบการจัดลำดับที่ไม่ถูกครอบงำ III (NSGA-III) จากผลการเปรีบยเทียบตัวชี้วัดสมรรถนะของงานวิจัยแสดงให้เห็นว่า NSGA-III มีสมรรถนะที่ดีเหนือกว่า MOEA/D ในเกือบทุกโจทย์ปัญหา
Treatment Of Cutting Oil Via Fe0/Air And Al0/Air Using Waste From Auto Parts Manufacturing, Warangkana Srimoke
Treatment Of Cutting Oil Via Fe0/Air And Al0/Air Using Waste From Auto Parts Manufacturing, Warangkana Srimoke
Chulalongkorn University Theses and Dissertations (Chula ETD)
Used shot blast and aluminium dross wastes generated from auto part manufacturing were applied as catalysts under the modified-air Fenton (MAF) system to treat synthetic cutting oil wastewater. Experimental designs were applied to find optimum conditions in terms of size and amount of catalyst, initial pH, initial cutting oil concentration, air flow rate, and mixing speed. Fe0 and Al0 forms were found in used shot blast and aluminum dross, respectively, according to XRD and XRF results, and the element contents of Fe and Al were found to be 96.37 % and 37.13 %, respectively. For used shot blast under the …
On The Mechanical Properties Of Al/Cu-Grid/Al Intermetallic Composite, Hamza Essoussi, Said Ettaqi
On The Mechanical Properties Of Al/Cu-Grid/Al Intermetallic Composite, Hamza Essoussi, Said Ettaqi
Journal of Metals, Materials and Minerals
The present paper deals with the experimental investigation of new process combining static compression with high temperature as a simple way to prepare new Al/Cu-grid/Al metallic composite (MC) that consists of Aluminum matrix and Copper grid acting as ductile reinforcement stacked between the Al sheets. At the stage of composite fabrication, two different thermal cycles were tested to highlight the effect of processing temperature on the layers’ adherence and the mechanical properties of the prepared composites. Consequently, the microstructural and mechanical results revealed that the compression at 630℃ for 30 min, then furnace cooled to 450℃ followed by air cooling …