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2018

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Articles 661 - 690 of 703

Full-Text Articles in Chemical Engineering

Investigation Of Proppant Static Settling Velocity In Hydraulic Fractures Using Viscoelastic Linear Gel, Vismay Manishbhai Shah Jan 2018

Investigation Of Proppant Static Settling Velocity In Hydraulic Fractures Using Viscoelastic Linear Gel, Vismay Manishbhai Shah

Masters Theses

"Few studies have quantified proppant transport in static conditions using actual proppant and validated previously established correlation. The objective of this study is to investigate the rheological properties of the linear gel, and determine the effect of size, shape and specific gravity of the proppant, fracture walls and rheological properties of the fluid on the proppant settling velocity in static condition and validate the previously established correlation.

Shear viscosity and dynamic frequency sweep tests were performed to investigate the viscous and viscoelastic behaviour of the HPG linear gel with five different concentrations. Proppant settling experiments were conducted with different proppant …


Hydraulic Fracture Design Optimization For Nubian Sandstone Formation In Libya, Housameddin Mohamed Sherif Jan 2018

Hydraulic Fracture Design Optimization For Nubian Sandstone Formation In Libya, Housameddin Mohamed Sherif

Masters Theses

There is growing interest in developing unconventional oil and gas reserves in Libya, such as the tight portions of the Nubian sandstone.

Well-X7 is a development well drilled to a TD of 13,005' penetrating the Upper Nubain Sandstone (UNSS) at 12,122'-12,207' and the Lower Nubain Sandstone (LNSS) at 12,524'-12,880' KB. Based on open hole logs, the UNSS has 71 ft of net pay and the LNSS was found to have 295 ft of net pay. Openhole logs also showed low permeabilities of 2.5 and 3 md for the UNSS and LNSS, respectively. The well was initially perforated in both zones …


Synthesis And Comprehensive Studies Of Nanogels For Enhanced Oil Recovery, Jiaming Geng Jan 2018

Synthesis And Comprehensive Studies Of Nanogels For Enhanced Oil Recovery, Jiaming Geng

Doctoral Dissertations

“Nanomaterials have been developed and applied for enhanced oil recovery (EOR) in oil industry. Among the developed nanomaterials, nano-sized crosslinked polymeric gel particles (nanogels) have shown the potential in improving both the macro- and micro-displacing efficiency. This dissertation focuses on the synthesis and the potential EOR mechanisms of nanogels. Nanogels with positive, negative, and neutral charges were synthesized through suspension polymerization. The morphology, size distribution, and zeta potential of nanogels were elucidated by corresponding technologies, such as scanning electron microscopy and dynamic light scattering. The ability of nanogels in oil-water interfacial tension (IFT) reduction and oil-in-water (o/w) emulsion stabilization was …


Effects Of Co-Product Uses On Environmental And Economic Sustainability Of Hydrocarbon Biofuel From One- And Two-Step Pyrolysis Of Poplar, Daniel G. Kulas Jan 2018

Effects Of Co-Product Uses On Environmental And Economic Sustainability Of Hydrocarbon Biofuel From One- And Two-Step Pyrolysis Of Poplar, Daniel G. Kulas

Dissertations, Master's Theses and Master's Reports

This study investigated the environmental and economic sustainability of liquid hydrocarbon biofuel production via fast pyrolysis of poplar biomass through two pathways: a one-step pathway that converted poplar via fast pyrolysis only, and a twostep pathway that includes a torrefaction step prior to fast pyrolysis. Optimization of these fast pyrolysis-based biofuel processes were investigated through heat integration and alternative uses of the co-product biochar, which can be sold as an energy source to displace coal, soil amendment or processed into activated carbon. The impacts of optimization on the cost of hydrocarbon biofuel production as well as the environmental impacts were …


Molecular Biogeochemistry Of A Poor Fen, Zhimin Song Jan 2018

Molecular Biogeochemistry Of A Poor Fen, Zhimin Song

Dissertations, Master's Theses and Master's Reports

Variations in climate may rapidly change the carbon balance of peatlands and increase greenhouse gas emissions through accelerated decomposition of peat and dissolved organic matter (DOM). In this study, porewater samples were collected monthly from May to October in 2017 to study the effects of plant functional groups (PFGs) on DOM, dissolved inorganic and organic nitrogen through the season in a poor fen with replicate plots dominated by different PFGs in Nestoria, Michigan, USA (46.34˚N 88.16˚W). The composition of the peat porewater showed strong statistical significance with plot type and season.The observed PFG and season impact on the composition of …


Reverse Insulator Dielectrophoresis: Utilizing Droplet Microenvironments For Discerning Molecular Expressions On Cell Surfaces, Jeana Collins Jan 2018

Reverse Insulator Dielectrophoresis: Utilizing Droplet Microenvironments For Discerning Molecular Expressions On Cell Surfaces, Jeana Collins

Dissertations, Master's Theses and Master's Reports

Lab-on-a-chip (LOC) technologies enable the development of portable analysis devices that use small sample and reagent volumes, allow for multiple unit operations, and couple with detectors to achieve high resolution and sensitivity, while having small footprints, low cost, short analysis times, and portability. Droplet microfluidics is a subset of LOCs with the unique benefit of enabling parallel analysis since each droplet can be utilized as an isolated microenvironment. This work explored adaptation of droplet microfluidics into a unique, previously unexplored application where the water/oil interface was harnessed to bend electric field lines within individual droplets for insulator dielectrophoretic (iDEP) characterizations. …


Investigation Of Mechanical, Electrical, And Thermal Properties Of Particulate/Fiber/Polymer Composites, Julie Tomasi Jan 2018

Investigation Of Mechanical, Electrical, And Thermal Properties Of Particulate/Fiber/Polymer Composites, Julie Tomasi

Dissertations, Master's Theses and Master's Reports

Composites have many applications due to their high strength to weight ratio, chemical resistance, and the ability to tune properties like electrical resistivity (ER). In this work, polyetheretherketone (PEEK) and cycloaliphatic epoxy (CE) composites with different fillers were studied. PEEK composites contained up to 10 wt% Akzo Nobel Ketjenblack carbon black (CB), up to 15 wt% Asbury Carbons TC307 graphene nanoplatelets (GNP), up to 30 wt% Solvay carbon fiber (CF), and combinations of the three carbons. Formulations were developed for electrostatic dissipative and electrically conductive applications. The most conductive formulation was 7.5 wt% CB/30 wt% CF/PEEK, which had an electrical …


Limiting Key Drilling Parameters To Control Mud Losses In Basra's Oil Fields, Iraq, Abo Taleb Tuama Al-Hameedi Jan 2018

Limiting Key Drilling Parameters To Control Mud Losses In Basra's Oil Fields, Iraq, Abo Taleb Tuama Al-Hameedi

Doctoral Dissertations

"Wells in Basra's oil fields are highly susceptible to lost circulation problems when drilling through the Dammam, Hartha, and Shuaiba formations. Drilling engineers are challenged to select the optimum value for key drilling parameters such as ECD, Yp, MW, WOB, ROP, and RPM to mitigate mud losses in these formations. Many of these drilling parameters are inter-related and the overall impact of changing key parameters require extensive drilling experience and study. A multi-regression analysis was performed on mud loss event data for more than 300 wells drilled in Basra's oil fields. From this analysis, a model was developed to predict …


Hydrodynamics Related Performance Evaluation Of Upflow Moving Bed Hydrotreater Reactor (Mbr) Using Developed Experimental Methods And Cfd Simulation, Vineet Alexander Jan 2018

Hydrodynamics Related Performance Evaluation Of Upflow Moving Bed Hydrotreater Reactor (Mbr) Using Developed Experimental Methods And Cfd Simulation, Vineet Alexander

Doctoral Dissertations

"Upflow Moving Bed Hydrotreater (MBR) reactor is used for hydrotreating resid crude oil. It is a two-phase upflow reactor having a catalyst bed with conical bottom, and plena. At industrial conditions the reactor is not performing at its best and encountering issues such as hot spots, catalyst agglomeration inside the catalyst bed leading to frequent shutdown of the reactor. The root cause of these problems are linked to the improper hydrodynamics inside the catalyst bed. To investigate this, the industrial scale MBR is scaled down to a pilot scale and indicative and key hydrodynamic parameters are investigated using developed experimental …


Process Simulation And Experimental Investigation Of Biofuel Production In A High Rate Anaerobic Digestion Process, Haider Al-Rubaye Jan 2018

Process Simulation And Experimental Investigation Of Biofuel Production In A High Rate Anaerobic Digestion Process, Haider Al-Rubaye

Doctoral Dissertations

"The non-hazardous waste management hierarchy of the US EPA calls for “Reduce, Reuse, and Recycle” (or the three R’s) of wastes. The anaerobic digestion process is one of the most important methods that used to treat the wastes and at the same time generate energy out of it. The anaerobic digestion process generates a mixture of methane and carbon dioxide gases which is known as biogas.

The biogas composition is about 50-70% methane and 10-30% of carbon dioxide and trace amount of other gases like hydrogen and hydrogen sulfide. This biogas can be used in power generation, heating systems and …


Experimental And Numerical Investigation On Tar Production And Recycling In Fixed Bed Biomass Gasifiers, Jia Yu Jan 2018

Experimental And Numerical Investigation On Tar Production And Recycling In Fixed Bed Biomass Gasifiers, Jia Yu

Doctoral Dissertations

"Bioenergy has been utilized for domestic purposes since pre-recorded history and it catches the highlight in the recent decades because it naturally benefits the world climate and energy security. Gasification is one of the key technologies to efficiently and economically convert biomass into syngas and further into biofuels. Despite these outstanding advantages, biomass gasification suffers from the formation of unfavorable byproduct tar and the consequential tar elimination. Moreover, the collected tar is toxic and thus requires storage and strict deposit method to avoid environmental pollution.

To understand the mechanisms of biomass gasification and tar production, simulations with Aspen Plus were …


Computational Design And Numerical Analyses Of Thermal-Hydraulics In A Pwr-Type Small Modular Nuclear Reactor, Vivek Murlidhar Rao Jan 2018

Computational Design And Numerical Analyses Of Thermal-Hydraulics In A Pwr-Type Small Modular Nuclear Reactor, Vivek Murlidhar Rao

Doctoral Dissertations

"This dissertation focuses on computational design of a PWR-type small modular nuclear reactor (SMR), and analysis of coolant thermal-hydraulics during steady-state operation. Physical design of the SMR is based on the existing AP-1000 and Small Modular Reactor designs by Westinghouse Nuclear.

The first paper discusses a two-stage simulation of turbulent flow in the lower plenum of the RPV. In the first stage, four time-dependent Reynolds-Averaged Navier-Stokes (RANS) based turbulence models were used to simulate turbulent flow, compare predictions and identify an appropriate turbulence model. In the second stage, the selected turbulence model was once again used to simulate flow on …


The Significance Of Grouping And Missed Bubbles On Interfacial Area Concentration And Void Fraction, Chandller Stephen-Leslie Mills Jan 2018

The Significance Of Grouping And Missed Bubbles On Interfacial Area Concentration And Void Fraction, Chandller Stephen-Leslie Mills

Doctoral Dissertations

"The two-fluid model is used in nuclear reactor safety codes. Two of the important constitutive relations will be discussed in this study, the interfacial area concentration and void fraction. The Interfacial area concentration is directly affected by the number of bubbles and how these bubbles are categorized into groups. In this study, a new algorithm was implemented to account for trailing bubbles, bubbles with short response times, and the categorization of bubbles based upon diameter for all group 1 bubbles. The optical and conductivity probes were used to determine the void fraction and interfacial area concentration in a bubble column. …


Engineering Polymeric Hollow Fiber Membrane Reactors For Sustainable Chemical Transformation Reactions, Yingxin He Jan 2018

Engineering Polymeric Hollow Fiber Membrane Reactors For Sustainable Chemical Transformation Reactions, Yingxin He

Doctoral Dissertations

“Over the past decade, laboratory-scale continuous-flow processes have witnessed explosive developments and have attracted a great deal of interest with respect to the significance of the economic and environmentally-sustainable production of pharmaceuticals, fine chemicals, and agrochemicals, as well as upgrading of biomass feedstocks. Immobilization of organocatalysts and metal nanoparticles on continuous-flow microreactors offers an efficient catalytic system that exploits and enhances the advantages of both nanocatalysis and flow chemistry, the so-called flow nanocatalysis approach. Various approaches have been developed for the development of continuous-flow reactions including immobilization and subsequent anchoring of organocatalysts and metal nanoparticles within microfluidic reactors. However, many …


Enhancement Of Heat Transfer Coefficient Using Nanofluids For Multi-Stage Flash Desalination (Msf) Plant, Nasser Zouli Jan 2018

Enhancement Of Heat Transfer Coefficient Using Nanofluids For Multi-Stage Flash Desalination (Msf) Plant, Nasser Zouli

Doctoral Dissertations

“The enhancement of thermal conductivity and local heat transfer coefficient, under laminar and turbulent flow regimes, of water-based spherical Al2O3, CuO, and Fe2O3 nanofluids have been experimentally investigated for the improvement of the thermal desalination processes using a newly developed sophisticated noninvasive heat transfer coefficient probe that is flush mounted on the inner wall surface of the test section. The nanoparticles have been selected because of their superior thermal conductivity and low cost, as well as the magnetic characteristic of Fe2O3 nanoparticle since a magnet can collect it and reuse. …


Dehydration And Dehydrogenation Of Ethanol Over Smectite Catalysts, Chadaporn Krutpijit Jan 2018

Dehydration And Dehydrogenation Of Ethanol Over Smectite Catalysts, Chadaporn Krutpijit

Chulalongkorn University Theses and Dissertations (Chula ETD)

The research aimed to investigate the characteristics and catalytic properties of acid-activated montmorillonite catalyst and AgLi-modified montmorillonite catalyst. In the first part, the catalytic dehydration of ethanol to obtain ethylene over Al-pillared montmorillonite clays (MMT) with mineral acid activation including H2SO4 (SA-MMT), HCl (HA-MMT) and HNO3 (NA-MMT) was investigated. It revealed that HA-MMT exhibited the highest catalytic activity which can be attributed to an increase of weak acid sites and acid density by the activation of MMT with HCl. Upon the stability test for 72 h during the reaction, the MMT and HA-MMT showed only slight deactivation due to carbon …


Activated Carbon Derived From Bacterial Cellulose And Applications As Adsorbent And Solid Acid Catalyst, Arnon Khamkeaw Jan 2018

Activated Carbon Derived From Bacterial Cellulose And Applications As Adsorbent And Solid Acid Catalyst, Arnon Khamkeaw

Chulalongkorn University Theses and Dissertations (Chula ETD)

The aim of this research was to investigate the synthesis and characterization of activated carbon from bacterial cellulose (BC-AC) and its applications. The research was divided into three parts. The first part was the preparation of BC-AC and application of BC-AC as an adsorbent in methylene blue (MB) adsorption. Bacterial cellulose (BC) was carbonized with a chemical activation using phosphoric acid as an activating agent. It was found that BC-AC possesses mesoporous structures, high pore volume, high surface area, and high thermal stability. In MB adsorption application, BC-AC was a high effective adsorbent with a fast adsorption rate and high …


Deposition Of Rust Particles On Stainless Steel Surface, Taweechai Watcharapiboon Jan 2018

Deposition Of Rust Particles On Stainless Steel Surface, Taweechai Watcharapiboon

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research investigates deposition behavior of rust particles in ethylene glycol solution onto surface of stainless steel. The study includes effects of contact time of the solution on the surface, flow velocity, particles size and particle concentration in the solution, on the thickness of rust particle film on the surface. According to results, thickness of rust particle film increases as the immersing is prolonged. The film thickness becomes constant at about 100 day. The increased solution velocity, the decreased size of rust particles and the reduce in the particle concentration, cause the adhesion of the particles on the surface is …


ผลของปริมาณเยื่ออะรามิดและเส้นใยคาร์บอน ต่อสมบัติไทรโบโลยีในวัสดุพอลิเบนซอกซาซีนคอมพอสิทเสริมแรงด้วยเส้นใย, วิชชุกร เลิศวาสนา Jan 2018

ผลของปริมาณเยื่ออะรามิดและเส้นใยคาร์บอน ต่อสมบัติไทรโบโลยีในวัสดุพอลิเบนซอกซาซีนคอมพอสิทเสริมแรงด้วยเส้นใย, วิชชุกร เลิศวาสนา

Chulalongkorn University Theses and Dissertations (Chula ETD)

งานวิจัยนี้มีวัตถุประสงค์เพื่อพัฒนาวัสดุพอลิเบนซอกซาซีนคอมพอสิทที่เสริมแรงด้วยเยื่ออะรามิดและเส้นใยคาร์บอน เพื่อใช้เป็นวัสดุเสียดทานผ้าเบรกรถยนต์แทนการใช้แร่ใยหิน เนื่องจากแร่ใยหินส่งผลกระทบต่อสุขภาพในเชิงลบเมื่อมีการเข้าสู่ร่างกายผ่านระบบทางเดินหายใจ ดังนั้นงานวิจัยฉบับนี้จึงทำการศึกษาและนำเสนอการใช้เยื่ออะรามิดและเส้นใยคาร์บอน ทดแทนการใช้แร่ใยหิน อีกทั้งศึกษาผลของปริมาณเยื่ออะรามิดและเส้นใยคาร์บอนที่สัดส่วนเยื่ออะรามิดต่อเส้นใยคาร์บอนต่างๆ ดังนี้ 100:0 75:25 50:50 25:75 และ 0:100 เปอร์เซ็นต์โดยน้ำหนัก ต่อสมบัติทางความร้อน สมบัติทางกลและสมบัติทางไทรโบโลยีของวัสดุพอลิเบนซอกซาซีนคอมพอสิท จากการศึกษาพบว่า วัสดุพอลิเบนซอกซาซีนคอมพอสิทเสริมแรงด้วยเยื่ออะรามิดและเส้นใยคาร์บอน ที่สัดส่วน 75:25 โดยน้ำหนัก มีค่าสัมประสิทธิ์ความเสียดทานอยู่ในช่วง 0.34−0.44 ซึ่งเป็นไปตามมาตรฐานผลิตภัณฑ์อุตสาหกรรมผ้าเบรกสำหรับยานยนต์ (มอก. 97-2557) รวมทั้งมีอัตราการสึกหรอจากการใช้งานมีค่าต่ำอยู่ในช่วง 0.13x10-7 − 1.12x10-7 ลูกบาศก์เซนติเมตรต่อนิวตันเมตร ในช่วงอุณหภูมิ 100−350 องศาเซลเซียส ส่งผลให้วัสดุพอลิเบนซอกซาซีนคอมพอสิทนี้สามารถทนแรงเสียดทานและการสึกหรอได้ดีขึ้น นอกจากนี้วัสดุพอลิเบนซอกซาซีนคอมพอสิทยังมีเสถียรภาพทางความร้อนและทางกลที่โดดเด่น โดยมีอุณหภูมิการสลายตัวทางความร้อนที่การสูญเสีย 5 เปอร์เซ็นต์โดยน้ำหนัก เท่ากับ 420 องศาเซลเซียส มีอุณหภูมิเปลี่ยนสถานะคล้ายแก้ว มีค่าเท่ากับ 219 องศาเซลเซียส และค่าความแข็งแรงภายใต้แรงดัดโค้งสูงถึง 68.5 เมกกะปาสคาล ดังนั้นจากสมบัติทางไทรโบโลยีและความเสถียรภาพทางความร้อนและทางกลที่ดีจึงมีความเป็นไปได้อย่างยิ่งที่จะนำวัสดุพอลิเบนซอกซาซีนคอมพอสิทที่เสริมแรงด้วยเยื่ออะรามิดและเส้นใยคาร์บอน ที่สัดส่วน 75:25 โดยน้ำหนัก มาประยุกต์ใช้เป็นวัสดุเสียดทานผ้าเบรกรถยนต์ได้


แบตเตอรี่อะลูมิเนียม-อากาศแบบอิเล็กโทรไลต์คู่ไหลโดยใช้สารละลายเอทานอล/เอทิลีนไกลคอลเป็นอะโนไลต์, ธนวัฒน์ ภูษิตธนานันท์ Jan 2018

แบตเตอรี่อะลูมิเนียม-อากาศแบบอิเล็กโทรไลต์คู่ไหลโดยใช้สารละลายเอทานอล/เอทิลีนไกลคอลเป็นอะโนไลต์, ธนวัฒน์ ภูษิตธนานันท์

Chulalongkorn University Theses and Dissertations (Chula ETD)

แบตเตอรี่อะลูมิเนียม-อากาศได้รับความสนใจอย่างมากในปัจจุบัน เนื่องจากมีความจุจำเพาะตามทฤษฎีสูงถึง 2,980 mAh/g ต้นทุนต่ำ เป็นมิตรกับสิ่งแวดล้อม และมีปริมาณมากบนโลก แต่อย่างไรก็ตาม การกัดกร่อนตัวเองของอะลูมิเนียมในสารละลายแอลคาไลน์เป็นปัญหาสำคัญที่มีผลต่อข้อกำจัดในการนำไปประยุกต์ใช้งาน สารละลายเอทานอลสามารถยับยั้งการเกิดแก๊สไฮโดรเจนได้ เนื่องจากความว่องไวในการทำปฏิกิริยาของโปรตอนในเอทานอลมีค่าน้อยกว่าของน้ำ แต่ความว่องไวในการทำปฏิกิริยาของสารละลายเอทานอลยังต่ำเกินกว่าจะใช้งานในแบตเตอรี่อะลูมิเนียม-อากาศ สำหรับงานวิจัยนิ้ได้ศึกษาสารละลายอิเล็กโทรไลต์ของเอทิลีนไกลคอลต่อเอทานอลที่อัตราส่วนร้อยละ 0, 5, 10, 20 และ 30 โดยปริมาตร โดยมีโพแทสเซียมไฮดรอกไซด์เข้มข้น 3 โมลาร์ ตลอดจนศึกษาการประยุกต์ใช้งานสารละลายอิเล็กโทรไลต์ในแบตเตอรี่อะลูมิเนียม-อากาศแบบอิเล็กโทรไลต์คู่ไหล การทดลองดำเนินการโดยใช้ระบบอิเล็กโทรไลต์คู่ที่มีการไหลของสารละลายแอโนไลต์ ซึ่งโครงสร้างของแบตเตอรี่ประกอบไปด้วย อะลูมิเนียมแอโนด | แอโนไลต์ || เยื่อแลกเปลี่ยนไอออน || แคโทไลต์ | ขั้วอากาศแคโทด จากผลการศึกษาพบว่าอัตราส่วนของเอทิลีนไกลคอลเป็นตัวกำหนดการกัดกร่อนตัวเองของอะลูมิเนียม เอทิลีนไกลคอลส่งผลดีต่อระบบแบตเตอรี่โดยลดการเกิดชั้นฟิล์มระหว่างอลูมิเนียมกับสารละลายแอโนไลต์ พร้อมกับลดค่าศักย์ไฟฟ้าส่วนเกินของขั้วแอโนด อย่างไรก็ตาม เอทิลีนไกลคอลเพิ่มการกัดกร่อนตัวเองของอะลูมิเนียม และเพิ่มการเกิดแก๊สไฮโดรเจน นอกจากนี้แบตเตอรี่อะลูมิเนียม-อากาศที่ประกอบด้วยเอทิลีนไกลคอลร้อยละศูยน์โดยปริมาตร มีอัตราการไหลของแอโนไลต์ 160 มิลลิลิตรต่อนาที ที่การคายประจุคงที่ 5 มิลลิแอมป์ต่อตารางเซนติเมตร ให้ค่าความจุจำเพาะสูงสุดอยู่ที่ 2,100 มิลลิแอมป์ชั่วโมงต่อกรัม คิดเป็นร้อยละการใช้อะลูมิเนียมที่ 70.5 อย่างไรก็ตาม ค่าศักย์ไฟฟ้าของแบตเตอรี่มีค่าต่ำ เนื่องจาการเกิดชั้นออกไซด์ฟิล์มบนผิวหน้าของอะลูมิเนียม ค่าความจุจำเพาะของแบตเตอรี่ลดลงเมื่อเพิ่มปริมาณของเอทิลีนไกลคอล แต่ค่าศักย์ไฟฟ้าของแบตเตอรี่นั้นเพิ่มสูงขึ้น นอกจากนี้ค่าศักย์ไฟฟ้าของแบตเตอรี่เพิ่มขึ้น เมื่ออัตราการไหลของแอโนไลต์เพิ่มขึ้นอีกด้วย


Characterization Of Pyrolysis Products From Fast Pyrolysis Of Live And Dead Vegetation Native To The Southern United States, Mohammad-Saeed Safdari, Mahmood Rahmati, Elham Amini, Joel E. Howarth, Jansen P. Berryhill, Mark Dietenberger, David R. Weise, Thomas H. Fletcher Jan 2018

Characterization Of Pyrolysis Products From Fast Pyrolysis Of Live And Dead Vegetation Native To The Southern United States, Mohammad-Saeed Safdari, Mahmood Rahmati, Elham Amini, Joel E. Howarth, Jansen P. Berryhill, Mark Dietenberger, David R. Weise, Thomas H. Fletcher

Faculty Publications

Prescribed burning (controlled burning) is used to decrease accumulation of combustible materials and reduce impact of uncontrolled wildland fires. Prescribed fires are often used to burn undergrowth in Southern forests of the United States. In order to improve prescribed fire application, accomplish desired fire effects, and limit potential runaway fires, an improved understanding of the fundamental processes related to combustion of heterogeneous fuel beds of live and dead fuels is needed. The initial processes of combustion involve pyrolysis and ignition. During this research, fast pyrolysis of 14 live and dead (biomass) plant species which are native to the Southern United …


Fire Behavior In Chaparral–Evaluating Flame Models With Laboratory Data, David R. Weise, Thomas H. Fletcher, Wesley Cole, Shankar Mahalingam, Xiangyang Zhou, Lulu Sun, Jing Li Jan 2018

Fire Behavior In Chaparral–Evaluating Flame Models With Laboratory Data, David R. Weise, Thomas H. Fletcher, Wesley Cole, Shankar Mahalingam, Xiangyang Zhou, Lulu Sun, Jing Li

Faculty Publications

Flame and mass loss data for chaparral, a mixture of shrub plants from the Mediterranean climate zone of southwestern North America, from five previously reported experiments were used to evaluate several published models relating flame characteristics to mass loss and heat release rates. These data are unique with fuel moisture content ranging from 0.36 to 0.94 (dry basis); the study used mass loss rates which included water loss. Fit of the data to Froude number correlations developed by Albini, Byram, Nelson and Thomas and heat release rate—flame length correlations by Heskestad, Zukoski, and Yuan/Cox for axisymmetric and line fires were …


Lab-Scale Observations Of Flame Attachment On Slopes With Implications For Firefighter Safety Zones, Jonathan R. Gallacher, Brad Ripa, Bret W. Butler, Thomas H. Fletcher Jan 2018

Lab-Scale Observations Of Flame Attachment On Slopes With Implications For Firefighter Safety Zones, Jonathan R. Gallacher, Brad Ripa, Bret W. Butler, Thomas H. Fletcher

Faculty Publications

The Coanda effect is the phenomenon in which a jet entering quiescent fluid attaches to a nearby solid object due to inhibited entrainment of ambient fluid near the solid. Little is known about the influence of the Coanda effect on wildland fire behavior. Specifically, there is a lack of knowledge regarding how the flame attachment on slopes influences firefighter safety zone considerations in rugged terrain. This paper presents results for small-scale n-heptane pool fire experiments near a slope, showing how flame shape and heat flux are influenced by slope angle, slope boundary condition and distance from flame base. Flames near …


Effect Of Different Alumina Supports On Performance Of Cobalt Fischer-Tropsch Catalysts, Thomas H. Fletcher Jan 2018

Effect Of Different Alumina Supports On Performance Of Cobalt Fischer-Tropsch Catalysts, Thomas H. Fletcher

Faculty Publications

Four identically-prepared 20 wt% cobalt/0.15 wt% ruthenium Fischer-Tropsch catalysts, supported on different aluminas, were synthesized by incipient wetness impregnation, characterized, and compared based on their performance under standard Fischer-Tropsch synthesis conditions. Three alumina supports were obtained from commercial sources (Sasol, St. Gobain, and Alfa Aesar), while the fourth was made using a published technique that included 5 wt% silica. The silica-stabilized alumina catalyst produced superior Fischer-Tropsch rates of 49 mmol CO/gcat h, compared to the other catalysts on the commercial supports with rates of 26–39 mmol CO/gcat h. The improved performance of the silica-stabilized alumina support compared to the commercially …


Development Of Bioreactors For Comparative Study Of Naturalattenuation, Biostimulation, And Bioaugmentation Ofpetroleum-Hydrocarbon Contaminated Soil, Mohammad-Saeed Safdari, Hamid-Reza Kariminia, Mahmood Rahmati, Farhad Fazlollahi, Alexandra Polasko, Shaily Mahendra, W Vincent Wilding, Thomas H. Fletcher Jan 2018

Development Of Bioreactors For Comparative Study Of Naturalattenuation, Biostimulation, And Bioaugmentation Ofpetroleum-Hydrocarbon Contaminated Soil, Mohammad-Saeed Safdari, Hamid-Reza Kariminia, Mahmood Rahmati, Farhad Fazlollahi, Alexandra Polasko, Shaily Mahendra, W Vincent Wilding, Thomas H. Fletcher

Faculty Publications

Bioremediation of soil and groundwater sites contaminated by petroleum hydrocarbons is known as a technically viable, cost-effective, and environmentally sustainable technology. The purpose of this study is to investigate laboratory-scale bioremediation of petroleum-hydrocarbon contaminated soil through development of eight bioreactors, two bioreactors for each bioremediation mode. The modes were: (1)natural attenuation (NA); (2) biostimulation (BS) with oxygen and nutrients; (3) bioaugmentation (BA)with hydrocarbon degrading isolates; (4) a combination of biostimulation and bioaugmentation (BS-BA). Total petroleum hydrocarbons (TPH) mass balance over the bioreactors showed about 2% of initial20,000 mg kg-soil−1TPH was removed by advection due to synthetic groundwater which was flow-ing …


The Surface Modification Of Zeolite Y In Composite Selective Layer Of Hollow Fiber Membrane For Separation Of Co2/Ch4 Mixture, Thakorn Wichaidit Jan 2018

The Surface Modification Of Zeolite Y In Composite Selective Layer Of Hollow Fiber Membrane For Separation Of Co2/Ch4 Mixture, Thakorn Wichaidit

Chulalongkorn University Theses and Dissertations (Chula ETD)

This work focused on the fabrication and evaluation of composing hollow fiber mixed matrix membranes (MMMs) incorporated by zeolite Y for CO2/CH4 separation. The effects of surface modification of zeolite Y to improve compatibility of filler and polymer dispersibility of the filler in the polymer matrix on properties and separation performance of the membrane were investigated. A polysulfone (PSF) was used as a support hollow fiber and a selective layer composing of polyether-block-amide (Pebax) and zeolite Y (ZeY) and surface modification of zeolite Y (mo-ZeY) was coated on support. A [3-(2-Aminoethylamino)propyl]trimethoxysilane (AEAPTMS) was used to grafted on surface of pristine …


The Effect Of Mcm-41 Addition To Pva/Pan/Pvp Polymer Electrolyte For Zinc-Air Batteries, Sirinuch Nanthapong Jan 2018

The Effect Of Mcm-41 Addition To Pva/Pan/Pvp Polymer Electrolyte For Zinc-Air Batteries, Sirinuch Nanthapong

Chulalongkorn University Theses and Dissertations (Chula ETD)

A membrane separator is one of the main components in zinc-air batteries playing an important role in controlling the mass transfer for the electrochemical reaction in the battery which determines the battery performance. This work aimed to develop a new membrane separator for the zinc-air battery. Polyvinyl alcohol (PVA), polyacrylonitrile (PAN), polyvinylpyrrolidone (PVP), and their blends were used for the fabrication of separator in this work. In addition, an inorganic nanoparticle with high hydroxide content such as MCM-41 was also applied as the filler for the polymers. The results revealed that the addition of PAN in PVA enhanced the electrolyte …


The Surface Modification Of Zeolite Y In Composite Selective Layer Of Hollow Fiber Membrane For Separation Of Co2/Ch4 Mixture, Thakorn Wichaidit Jan 2018

The Surface Modification Of Zeolite Y In Composite Selective Layer Of Hollow Fiber Membrane For Separation Of Co2/Ch4 Mixture, Thakorn Wichaidit

Chulalongkorn University Theses and Dissertations (Chula ETD)

This work focused on the fabrication and evaluation of composing hollow fiber mixed matrix membranes (MMMs) incorporated by zeolite Y for CO2/CH4 separation. The effects of surface modification of zeolite Y to improve compatibility of filler and polymer dispersibility of the filler in the polymer matrix on properties and separation performance of the membrane were investigated. A polysulfone (PSF) was used as a support hollow fiber and a selective layer composing of polyether-block-amide (Pebax) and zeolite Y (ZeY) and surface modification of zeolite Y (mo-ZeY) was coated on support. A [3-(2-Aminoethylamino)propyl]trimethoxysilane (AEAPTMS) was used to grafted on surface of pristine …


Simulation Of Water Effect On Biodiesel Production Using Waste Cooking Oil Via Ester-Transesterification In A Reactive Distillation Column, Ajala Anantapinitwatna Jan 2018

Simulation Of Water Effect On Biodiesel Production Using Waste Cooking Oil Via Ester-Transesterification In A Reactive Distillation Column, Ajala Anantapinitwatna

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research investigated the effect of water content in waste cooking oil (WCO) on the performance of a reactive distillation column for biodiesel production via ester-transesterification. A mixture of triolein and oleic acid was used as a WCO model compound. Amberlyst-15 was used to catalyze esterification while CaO was used for transesterification. From Langmuir-Hinshelwood-Hougen-Watson (LHHW) kinetic model taking into account water absorption for esterification of oleic acid (FFA), biodiesel yield was decreased with increasing of water content in WCO feedstocks. On the other hand, the initial rate of transesterification was increased with increase of amount of water in WCO feedstocks …


Synthesis Of Activated Carbons From Coffee Ground Residues And Their Application As Catalysts For Ethanol Dehydrogenation, Jeerati Ob-Eye Jan 2018

Synthesis Of Activated Carbons From Coffee Ground Residues And Their Application As Catalysts For Ethanol Dehydrogenation, Jeerati Ob-Eye

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this present study, characteristics and catalytic properties of activated carbon derived from coffee ground residue, cobalt metal (Co) supported-activated carbon and various metals (Ce, Co, Cu and Ni) supported-commercial activated carbon were determined and characterized. This study was divided into three parts. Regarding to the first part, the synthesis of activated carbon catalysts derived from coffee ground residues with different methods of physical activation was investigated. The results showed that the catalyst with physically activated by CO2 for 4 hours, exhibited the best catalytic activity of ethanol dehydrogenation to acetaldehyde. In the second part, the best catalyst from the …