Biodiesel production from fryer grease

Biodiesel is a renewable, biodegradable, environmentally benign fuel for use in the diesel engines. It can be produced from renewable sources such as vegetable oils or animal fats. Although this fuel has gained worldwide recognition for many years, it is not being widely commercialized mainly because it is more expensive than petroleum diesel. A cheaper feedstock, such as fryer grease, may be used to improve the economics of biodiesel. Methanol is the most common alcohol used in the transesterification process due to its low cost. However, recently, ethanol has been promoted as an alcohol for use in transesterification since it can be produced from renewable resources such as switchgrass, corn and wood, thereby reducing the dependency on petroleum sources (Pimentel and Patzek, 2005). A mixture of methanol and ethanol is hypothesized to take the advantages of both methanol and ethanol. The present work is focused on the production of biodiesel from fryer grease via transesterification with various mixtures of methanol and ethanol. Also, the kinetics of transesterification from fryer grease was studied. Since fryer grease contains a high concentration of free fatty acids (FFA) (5.6 wt. %) and water (7.3 wt. %), a two-step acid/alkaline transesterification process was used to produce the esters. Sulfuric acid and potassium hydroxide were used as acid and alkaline catalysts, respectively. The methanol to ethanol molar ratio was varied from 3:3 to 5:1, whereas alcohol to oil molar ratio was maintained at 6:1. After the fryer grease was transesterified, all esters met ASTM standard D-6751. The viscosity of these esters ranged from 4.7 to 5.9 mm2/s. The heating value of the esters was approximately 10% less than that of petroleum diesel. The cloud point and pour point were in the range of 1 to -1 oC and -3 to -6 oC, respectively. When the mixed alcohol was used ethyl esters were also formed at a lower concentration along with methyl esters. The dominant fatty acid in fryer grease esters was found to be oleic acid. The lubricity of kerosene fuel was improved by as much as 33 % through the addition of these esters at rates as low as 1 %. For the kinetic study of alkali-catalyzed transesterification of fryer grease, the alcohol to oil molar ratio, the reaction temperature, and the catalyst loading were varied as 6:1, 9:1, 12:1; 30, 40, 50 oC; and 0.5, 1.0, 1.5 %, respectively. The ester concentration was found to rise with an increase in the catalyst loading or the reaction temperature and with a decrease in the alcohol to oil molar ratio. The overall forward and backward reaction orders were assumed to follow first and second order kinetics, respectively. The kinetic parameters were calculated using MATLAB. The conversion of triglyceride to diglyceride was found to be the rate determining step (RDS) of the overall reaction, with an activation energy of 36.9 kJ/mol

Development of Biodiesel Production Processes from Various Vegetable Oils

Biodiesel is an alternative fuel to petroleum diesel that is renewable and creates less harmful emissions than conventional diesel thus the use of this fuel is a shift toward “sustainable energy”. Biodiesel can be produced from vegetable oil, animal fat, and organisms such as algae or cyanobacteria. Since vegetable oils are the major source for current commercial biodiesel, they are the focus of this thesis. The main objective of this Ph.D. research is to develop processes suitable to produce biodiesel from various vegetable oils especially for those of non-edible oils such as used cooking oil, canola oil from greenseed, and mustard oil. An additional objective is to understand the relationship between the parent vegetable oils and the corresponding biodiesel properties. Used cooking oil was the first vegetable oil investigated in this research. Initially, oil degradation behavior was monitored closely during frying. During 72 hours of frying, acid value and viscosity of the oil increased from 0.2 to 1.5 mgKOH•g-1 and from 38.2 to 50.6 cP, respectively. It was found that ester yield was improved by addition of canola oil to used cooking oil, i.e. addition of 20% canola oil to used cooking oil increased methyl ester yield and ethyl ester yield by 0.5% and 12.2%, respectively. At least 60% canola oil addition is needed to produce ASTM grade ethyl ester biodiesel. The optimum reaction conditions to produce biodiesel are 1% KOH loading, 6:1 alcohol to oil ratio, 600 rpm stirring speed, and either 50°C reaction temperature for 2 hr or 60°C reaction temperature for 1.5 hr for methanolysis and 60°C reaction temperature for 2 hr for ethanolysis. Among non-edible vegetable oils, greenseed canola oil can be used in the most simple biodiesel production process. In this case, an addition of fresh vegetable oil is not required, because chlorophyll contained in this oil did not play a crucial role in the reaction activity. Methyl ester yields derived from greenseed canola oil without and with 94.1 ppm chlorophyll content are 95.7% and 94.8%, respectively. In contrast, erucic acid contained in mustard oil created difficulties in the production process. Ester yield derived from mustard oil using the conditions mentioned above was only 66% due to the present of unconverted monoglyceride. To obtain a deeper understanding on mustard oil transesterification, its reaction kinetics was studied. In the kinetic study, transesterification kinetics of palm oil was also investigated to study the effect of fatty acid chain length and degree of saturation on the rates of the reactions. It is shown in this research that the rates of mustard monoglyceride transesterification (rate constant = 0.2-0.6 L•mol-1•min-1) were slower that those of palm monoglyceride transesterification (rate constant = 1.2-4.2 L•mol-1•min-1) due to its lower molecular polarity resulting from the longer chain of erucic acid. The activation energy of the rate determining step (in this case, conversion of triglyceride to diglyceride reaction step) of mustard transesterification was, however, 26.8 kJ•mol-1, which is similar to those of other vegetable oils as reported in literature. Despite the presence of unconverted monoglyceride, distillation can be used to obtain a high purity ester. Several ester properties are determined by characteristics of the parent oil and choice of alcohol used in transesterification. Chlorophyll contained in greenseed canola oil, for example, has an adverse effect on biodiesel oxidative stability. The induction time for methyl ester derived from treated greenseed canola oil (pigment content = 1 ppm) was enhanced by 12 minutes compared to that derived from crude greenseed canola oil (pigment content = 34 ppm). The optimum bleaching process involves the use of 7.5 wt.% montmorillonite K10 at 60°C and stirring speed of 600 rpm for 30 minutes. In addition, it was found that induction time of treated greenseed canola ethyl ester (1.8 hr) was higher than that of methyl ester (0.7 hr), which suggests a better oxidative stability of esters of higher alcohols. Furthermore, the use of higher alcohols instead of methanol produced materials with improved low temperature properties. For example, the crystallization temperatures of monounsaturated methyl, ethyl, propyl, and butyl esters prepared from mustard oil were -42.5°C, -51.0°C, -51.9°C, and -58.2°C, respectively. In contrast, the lubricity of biodiesel is mainly provided by its functional group which is COOCH3 for methyl ester. The use of higher alcohols in transesterification results in a less polar functional group in the corresponding ester molecule, which leads to reduction in ester lubricity. Methyl ester provided the highest lubricity among all esters produced, i.e. wear reduction at 1% treat rate of methyl ester, ethyl ester, propyl ester, and butyl ester are 43.7%, 23.2%, 30.7% and 30.2%, respectively. The outcomes of this research have been published in several scientific journals and presented at national and international conferences. The published articles and conference presentations are listed at the beginning of each chapter in this thesis

Clinical characteristics of oral chronic graft-versus-host disease according to the 2014 National Institutes of Health (USA) consensus criteria

Chronic graft-versus-host disease (cGVHD) is a serious and common complication of allogeneic hematopoietic cell transplantation (alloHCT). The oral cavity is the second most common site affected by cGVHD. In 2014, the 2005 National Institutes of Health (NIH) consensus criteria were revised to address areas of controversy. The aim of this study was to evaluate the clinical characteristics of oral cGVHD using the 2014 NIH consensus criteria. The baseline data of oral manifestation of patients, who were diagnosed with oral cGVHD, in the first dental visit were analyzed (n=22). The oral mucosal disease was evaluated by NIH modified Oral Mucosa Rating Scale (OMRS) and Thongprasom sign score. The salivary gland disease and sclerotic disease were determined by the presence of signs and symptoms. The functional impact was assessed by the organ-specific severity score. The median time from transplant to oral cGVHD diagnosis was 11.9 months. White striae with an erosive area was found in 72.7% of the patients. The mean ± SD of NIH modified OMRS was 6.1 ± 3.0. The most common and severely affected site of lichen planus-like features was buccal mucosa. Xerostomia, superficial mucocele and limited mouth opening were found in 18.2%, 9.1%, and 9.1%, respectively, of the patients. Almost all patients (90.9%) had partial limitation of oral intake. There were no significant differences in NIH modified OMRS or organ-specific severity score among the patient characteristic groups. Moreover, there was no association between the oral manifestations of cGVHD and the patient characteristics. The most common oral manifestation of cGVHD was white striae with an erosive area of oral mucosal disease, followed by xerostomia, superficial mucocele, and limited mouth opening. The 2014 NIH consensus criteria for diagnostic and severity assessment are informative and feasible in real-world practice

EVALUATION OF ITERATIVE INTERPOLATION METHODS FOR METAL ARTEFACTS REDUCTION OF PELVIC COMPUTED TOMOGRAPHYIMAGES: A PHANTOM STUDY

Metal artefacts obscure the organs as shown on a computed tomography (CT) image. The effect of the artefact can be reduced by using sinogram completion techniques. The aim of this study is to evaluate interpolation methods - linear interpolation (LI), total variation in painting (TV), high order total variation inpainting (HTV) for reducing the effect of the artefact. In this study, the sinogram completion technique applied on the simulated pelvic CT image of a hip prosthesis. Algorithms consist of four steps: 1) segment the metal region on the image, 2) transform the image into a sinogram and find the boundary of the metal sinogram, 3) estimate the new value of the missing data using three different methods 4) reconstruct the modified sinogram and add back the metal region into the reconstructed image. The percentages of the difference of intensity value between the artefact image and the nonartefact image of three techniques were computed. The percentages of artefact reduction were evaluated to compare the effectiveness of algorithms. The HTV method can provide the lowest difference of intensity value amongst three interpolation algorithms. The artefact reduction of the HTV method reduced 89.43%. The HTV technique could be used for solving the metal artefact problem effectively on CT images

The Stability Diagram of a Single-Electron Transistor

A single-electron transistor (SET) is a promising technology, superseding a traditional transistor. This device needs to be accurately controlled by external voltage sources because this sophisticated structure is operated in the submicron scale. Quantum phenomena control a single-electron flow through the SET framework andkeep the electron in this framework. The number of excess electrons is important since it indicates the state of the device. The external potential change can disturb the state constant. To forecast and specify the state, a mathematical model of the state transition was built. The model was then plotted as a stability diagram. The electrostatic energy was considered and analytically solved for the model. In this way, the complicated mathematics involved in this quantum phenomena could be simplified. In the result, the stability diagram is plotted by using the capacitance parameters that is reported by Hofheinz et al. (2006) and it strongly correlates with stability diagrams that were previously reported, however, the approach was different. With simplicity method, it may be applied to the type of complex single-electron devices such as single electron pump

Inverted L-Shaped CP Patch Antenna with Corner-Truncated Partial Ground Plane Diagonally Adjoined with Square Branch for L-Band Applications

This research proposes an inverted L-shaped patch antenna with a corner-truncated partial ground plane diagonally adjoined to a square branch for L-band applications. The adjoining square branch was used to perturb linear polarization for circular polarization, and the corner-truncated partial ground plane was utilized to enhance the axial ratio bandwidth (ARBW). Simulations were performed, an antenna prototype was fabricated, and experiments were carried out. The simulation and measured results were in good agreement. The proposed antenna could achieve an ARBW of 77.87% (1.09–2.48 GHz). The novelty of this research lies in the concurrent use of a square branch and a corner-truncated partial ground plane to realize wide ARBW in an L-band, rendering the technology suitable for satellite communication and navigation applications

ความต้องการระบบวัดทดสอบคุณลักษณะของสายอากาศสำหรับอุตสาหกรรมโทรคมนาคมของประเทศไทยNeed of Antenna Characteristic Measurement Systems for Thailand’s Telecommunication Industry

ในปัจจุบัน ระบบการสื่อสารไร้สายในประเทศไทย เช่น ระบบเครือข่ายโทรศัพท์มือถือ การสื่อสารผ่านดาวเทียมและระบบการสื่อสารไมโครเวฟ เป็นต้น มีความจำเป็นอย่างยิ่งในชีวิตประจำวันของสังคมไทยโดยเฉพาะอย่างยิ่งระบบเครือข่ายโทรศัพท์มือถือหรือระบบไร้สายรุ่นที่ 5 (5G) ที่กำลังจะใช้งานจริงในอนาคตอันใกล้นี้ในระบบการสื่อสารไร้สายนั้น สายอากาศ (Antenna) เป็นอุปกรณ์ที่มีความสำคัญเป็นอย่างมากเพื่อการสื่อสารที่มีประสิทธิภาพ จากการรายงานในหัวข้อการขยายโครงข่ายโทรศัพท์เคลื่อนที่ย่านความถี่ 2.1 กิกะเฮิรตซ์ นับตั้งแต่เปิดให้บริการจนถึง ณ สิ้นเดือนกันยายนปี พ.ศ. 2558 มีโครงข่ายที่เปิดให้บริการรวม 40,966 สถานีฐาน [1] ซึ่งทุกๆ สถานีฐานจะประกอบไปด้วยสายอากาศแถวลำดับ (Array Antenna) ที่มีขนาดใหญ่สำหรับสถานีฐานในระบบโทรศัพท์มือถือจำนวนอย่างน้อย 1–3 ตัวขึ้นไปต่อสถานีฐาน ดังนั้นจึงมีความต้องการสายอากาศเป็นจำนวนมาก โดยเฉพาะอย่างยิ่งระบบเครือข่ายโทรศัพท์มือถือในอนาคต สำหรับระบบการสื่อสารผ่านดาวเทียมและระบบการสื่อสารไมโครเวฟส่วนใหญ่แล้วจะใช้สายอากาศตัวสะท้อน (Reflector Antenna) ดังรูปที่ 1 เนื่องจากความต้องการที่จะรับสัญญาณจากดาวเทียมที่อยู่ไกลจากผิวโลกถึง 36,000 กิโลเมตร ซึ่งมีระดับความแรงน้อยมากๆ ดังนั้นจึงมีความจำเป็นต้องใช้สายอากาศที่มีโครงสร้างขนาดใหญ่ที่มีอัตราการขยายสูง เช่น สายอากาศตัวสะท้อนสายอากาศเลนส์ เป็นต้

A Low-Cost Audio Prescription Labeling System Using RFID for Thai Visually-Impaired People

<div><p>This research aims to develop a low-cost audio prescription labeling (APL) system for visually-impaired people by using the RFID system. The developed APL system includes the APL machine and APL software. The APL machine is for visually-impaired people while APL software allows caregivers to record all important information into the APL machine. The main objective of the development of the APL machine is to reduce costs and size by designing all of the electronic devices to fit into one print circuit board. Also, it is designed so that it is easy to use and can become an electronic aid for daily living. The developed APL software is based on Java and MySQL, both of which can operate on various operating platforms and are easy to develop as commercial software. The developed APL system was first evaluated by 5 experts. The APL system was also evaluated by 50 actual visually-impaired people (30 elders and 20 blind individuals) and 20 caregivers, pharmacists and nurses. After using the APL system, evaluations were carried out, and it can be concluded from the evaluation results that this proposed APL system can be effectively used for helping visually-impaired people in terms of self-medication.</p></div