Engineering Commons^™

Topography Of The 410 And 660 Km Discontinuities Beneath The Tibetan Plateau And Adjacent Areas, Zexin Miao

Doctoral Dissertations

"The Tibetan Plateau represents the ongoing geotectonic aftermath of a continental collision initiated approximately 65 million years ago. Despite numerous seismological studies, controversies remain regarding the structure, evolution, and dynamics of the crust and mantle beneath Tibetan Plateau. In this study, we used teleseismic broadband data to investigate the topography of the mantle transition zone (MTZ) discontinuities. A total of ~655,000 receiver functions from 735 stations was utilized to image the 410 and 660 km discontinuities bordering the MTZ. Combining the observed and velocity corrected results, several areas in the central Tibet exhibit a typical d410 and an anomalously deep …

Uv-Enhanced Catalytic Oxidative Cleavage Of Oleic Acid., Trinnasit Wittayakullertsin

Chulalongkorn University Theses and Dissertations (Chula ETD)

Oleic acid, a key component of plant oils such as palm oil, is a versatile feedstock for producing high-value bio-based chemicals. Utilizing its potential aligns with Thailand's objective of promoting sustainability as a premier palm oil producer. The conventional oxidative cleavage of oleic acid typically requires extreme conditions, including high temperatures, and ozone, which are expensive and harmful to the environment. This research provides an innovative method for utilizing ultraviolet (UV) radiation to increase oxidative cleavage at low temperatures (below 80°C). It employs hydrogen peroxide (H2O2) as an oxidizing agent and tungsten trioxide (WO3) as a catalyst to generate hydroxyl …

Process Optimization Of Bioactive Compound Extraction From Aloe Vera Leaf Skin Using Natural Deep Eutectic Solvents: An Integrated Computational-Experimental Approach, Sopita Chanmee

Chulalongkorn University Theses and Dissertations (Chula ETD)

This study aimed to evaluate the efficiency of environmentally friendly natural eutectic solvents (NADESs) for the extraction of bioactive compounds from Aloe vera leaf skin (AVLS) in comparison with conventional solvents, namely water and 80% ethanol. The experiment used NADES based on choline chloride with four hydrogen bonding agents (HBDs), namely xylose, glycerol, propylene glycol and lactic acid. The results showed that ChCl:Xy gave the highest phenolic compounds content, while ChCl:La gave the highest anthraquinone content and antioxidant activity as tested by DPPH and FRAP. COSMO-RS and sigma profile analyses revealed the molecular interactions affecting the extraction efficiency, which showed …

Process Simulation And Techno-Economic Evaluation Of Free Lutein Production From Marigold Flowers, Yada Meayrin

Chulalongkorn University Theses and Dissertations (Chula ETD)

Lutein is a carotenoid widely recognized for its health benefits, including improved vision, cognitive function, and prevention of age-related diseases. This study presents a comprehensive techno-economic and environmental assessment of three crude free lutein production processes using marigold flowers (Tagetes erecta L.) at a processing capacity of 74 tons/year, modeled in Asplen Plus V.11. The evaluated processes include sequential extraction and de-esterification (SQP) using hexane (HEX) or liquefied dimethyl ether (LiqDME), and a one-step simultaneous extraction and de-esterification (SMP) using LiqDME. Among these, the SMP-DME process demonstrated the best performance, with a net present value (NPV) of 146.98 million US$, …

Assessing The Impact Of Geochemical Mechanism And Interpolation Factor Selection On The Precision Of Low-Salinity Waterflooding Modelling: A Comparative Study, Malek Jalilian, Sedigheh Mahdavi, Peyman Pourafshary, Zheinjiang You, Amir H. Mohammadi

Research outputs 2022 to 2026

The efficacy of low salinity waterflooding (LSWF) as an enhanced oil recovery (EOR) method in carbonate formations has been well established; however, its geochemical modelling in such reservoirs remains insufficiently explored. This study aims to bridge this gap by conducting a comparative analysis of three well-recognised geochemical mechanisms including fines migration, rock dissolution/precipitation, and multi-ion exchange (MIE). Our research encompasses two parts: experimental and modelling. First, we conducted four coreflooding experiments to study the effect of LSWF on oil recovery in core scale as well as on rock wettability by measuring the contact angle of the crude oil-brine-rock system. In …

Synthesis Of Glucomannan-Xylan Composite Biofilms: Characterization And Applications For Food Packaging, Kholoud Al-Ajlouni

Dissertations

Scientists are most concerned about the need for green alternatives for efficient food packaging polymers to replace petroleum-based packaging products. The waste of corn cobs and the roots of the konjac plant contain hemicellulose, xylan and glucomannan respectively, and can be used to produce biofilms for food packaging.

The aim of these studies is to formulate biofilms from glucomannan-xylan blends that compete with petroleum-based plastic wrap. The biofilms must be strong, smooth, transparent, have a water vapor barrier, have the required mechanical properties and be cheap. Biofilms from glucomannan were stiff, lacked mechanical properties, and absorbed moisture. Therefore, it reacts …

Employment Of Intelligent Predictive Maintenance On Thermal Power Plant Component Parts Taking Condenser Vacuum As A Case Study, Titus Ajewole

Tanzania Journal of Engineering and Technology (TJET)

This work proposes deployment of machine learning in the maintenance of individual constituent parts of steam power plant assemblages. With the condenser vacuum of a steam turbine (in a six-turbine plant assemblage) taken as a case study, information on the past operating parameters of the selected plant component was used to forecast its future working condition. Based on Exponential Gaussian Process of Regression, a model was developed, trained using the diachronic operational data, and employed in determining the future. A quantitative evaluation was employed to provide the distribution of the test values of the data about the lines of regression, …

Selection Of Natural Surfactants For Possible Use In Improving Oil Recovery Of Carbonate Oil Reservoirs, Hiba Hachem Limam

Theses

Middle East petroleum industry is currently searching for the most suitable enhanced oil technique to improve the oil recovery from local oil reservoirs. The biggest challenge for the application of enhanced oil recovery (EOR) in the Middle East is the harsh environment (high salinity and temperature). Surfactant (synthetic or natural) is one of the EOR major players considered for application in the Middle East. However, synthetic surfactants have several drawbacks, such as economically unattractive and environmental impacts. This study investigated the possible use of natural surfactant extracted from the leaves of three types of plants, namely Aloe Vera, Tetraena qatarensis, …

Planning For The Lake Izabal Basin Research Endeavor (Libre) Continental Scientific Drilling Project In Eastern Guatemala, Jonathan Obrist-Farner, Andreas Eckert, Peter M.J. Douglas, Liseth Perez, Alex Correa-Metrio, Bronwen L. Konecky, Thorsten Bauersachs, Susan Zimmerman, Stephanie Scheidt, Mark Brenner, Steffen Kutterolf, Jeremy Maurer, Omar Flores, Caroline M. Burberry

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

As Earth's atmospheric temperatures and human populations increase, more people are becoming vulnerable to natural and human-induced disasters. This is particularly true in Central America, where the growing human population is experiencing climate extremes (droughts and floods), and the region is susceptible to geological hazards, such as earthquakes and volcanic eruptions, and environmental deterioration in many forms (soil erosion, lake eutrophication, heavy metal contamination, etc.). Instrumental and historical data from the region are insufficient to understand and document past hazards, a necessary first step for mitigating future risks. Long, continuous, well-resolved geological records can, however, provide a window into past …

The Role Of Enhancing Interaction With The Natural Environment In Achieving Social Interaction For Children In Orphanage Institutions, Shamael M. W. Al Dabbagh, Zainab Khalid Rashad Al Khafaji

Al-Esraa University College Journal for Engineering Sciences

The child deprived of family care is considered the child most in need of attention and care. When the orphan child enters a new environment for him, it is obvious that he feels alienated, isolated, and loses the sense of interaction and communication with society. The research sees the possibility of mitigating this feeling by enhancing interaction with the natural environment within the internal spaces of the orphanage building and at the neighborhood level. In order to solve the research problem, the research adopted a hypothesis stating that "interaction with the natural environment enhances the achievement of social interaction for …

Evolution Of Glassy Carbon Derived From Pyrolysis Of Furan Resin, Josh Kemppainen, Ivan Gallegos, Aaron Krieg, Jacob R. Gissinger, Kristopher E. Wise, Margaret Kowalik, Julia A. King, S. Gowtham, Adri Van Duin, Gregory Odegard

Michigan Tech Publications

Glassy carbon (GC) material derived from pyrolyzed furan resin was modeled by using reactive molecular dynamics (MD) simulations. The MD polymerization simulation protocols to cure the furan resin precursor material are validated via comparison of the predicted density and Young's modulus with experimental values. The MD pyrolysis simulations protocols to pyrolyze the furan resin precursor is validated by comparison of calculated density, Young's modulus, carbon content, sp carbon content, the in-plane crystallite size, out-of-plane crystallite stacking height, and interplanar crystallite spacing with experimental results from the literature for furan resin derived GC. The modeling methodology established in this work can …

Designing A Cylindrical Capacitive Based Sensor For Monitoring The Table Salt’S Moisture Content During Iodization, Mwajuma Lungo

Tanzania Journal of Engineering and Technology (TJET)

Coaxial cylinder capacitive moisture sensor for determination of moisture content of table salts has been fabricated. The CMS method for determination of moisture content of table salts overcomes the effect of evaporation of iodine in table salt which results from heating in the oven drying method. The CMS overcomes the polarization effect result from the resistive methods of moisture content determination and it is non expensive to construct and it has high accuracy since measurements involves programming system in interpretation of the results. In this research, moisture content sensor based on capacitive principal created using two coaxial cylinders with height …

Development Of The Computer Model Of The Waste Water Treatment Process Using Ion-Exchange Resins In The Matlab Program, Jaloliddin Abdurazzakovich Eshbobaev, Bakhodir Tajiddinovich Khamidov, Adham Tilovovich Norkobilov, Orifjon Sharipovich Kodirov

Chemical Technology, Control and Management

In this work, a mathematical model of industrial wastewater treatment technology was formed. First, wastewater treatment technologies were analyzed and the technology of ion-exchange resin treatment was selected. A water purification device using ion-exchange resins was made, and tested on the Kungrad soda plant and the results were obtained. According to these results, it was determined that the cleaning coefficient of the device is up to 98-99%. In this article, a mathematical model of a wastewater treatment device using ion-exchange resins was developed using the stoichiometric matrix method. After the mathematical model of the process was found, a graph of …

Removing Ilmenite-Based Filter Cakes Using Hydrochloric Acid And Chelating Agent – Experimental Study, Jianping Su, Omar Mahmoud, Hisham A. Nasr-El-Din

Future Engineering Journal

Ilmenite is often used as a weighting agent in drilling fluids to increase the fluid density, but the formation of a filter cake on the borehole wall can impact cementing operations and reduce well productivity. To remove the filter cake, various techniques can be employed such as chemical treatments, mechanical methods, or a combination of both. The goal of this study is to evaluate the effectiveness of chemical removal of ilmenite-based filter cake using 7.5 wt.% hydrochloric acid (HCl) and hydroxyethyl ethylenediamine triacetic acid (HEDTA) – chelating agent. The filter cakes were generated using API filter press under harsh conditions …

Product Costing And Pricing In Small And Medium Enterprises In Tanzania, Cosmas F Kindole

Tanzania Journal of Engineering and Technology (TJET)

metalwork small and medium enterprises located in Dar es Salaam with the aim of establishing methods used by SMEs in Tanzania in setting selling prices of their products. The study was necessitated by the apparent discrepancy of prices for similar products from SMEs. The approach used to gather information was mainly through direct interview and the use of questionnaires. Direct observation and literature review were also used to establish the whole costing and pricing practices in metal manufacturing SMEs. The findings of the study established that product selling practices of the surveyed SMEs were based on instinct and appearance of …

Prediction Of Terephthalic Acid Yield In Aqueous Hydrolysis Of Polyethylene Terephthalate, Hossein Abedsoltan, Zeinab Zoghi, Amir H. Mohammadi

Chemical and Biochemical Engineering Faculty Research & Creative Works

Aqueous hydrolysis is used to chemically recycle polyethylene terephthalate (PET) due to production of high-quality terephthalic acid (TPA), the PET monomer. PET hydrolysis depends on various factors including PET size, catalyst concentration, and reaction temperature. So, modeling PET hydrolysis by considering the effective factors can provide useful information for material researchers to specify how to design and run these reactions. It will save time, energy, and materials by optimizing the hydrolysis conditions. Machine learning algorithms enable to design models to predict the output results. For the first time, 381 experimental data were gathered to model aqueous hydrolysis of PET. Effective …

Integrated Experimental And Dft Study Of Palladium And Nickel Metals Supported On Reducible Metallic Oxides For Selective Hydrogenation Of Alkynes And Dienes Bonds, Toyin Daniel Shittu

Dissertations

This dissertation investigates the capacity of ceria (CeO₂) to serve as a stand-alone reactive catalyst, and to act as catalyst support for different catalyst configurations. Experimental and density functional theory (DFT) approach were used to critically predict and to design ceria-containing catalysts. Ceria owes the catalytic propensity to the ability to undergo switch in the oxidation state from the +4 to +3 states. Motivated by experimental studies involving CeO₂ catalysts, defects CeO₂ surface with an oxygen vacancy (CeO2(111)_Vo) was used to explore the decomposition chemistry of methanethiol based on DFT. The potential formation pathways revealed that …

Towards Lean Manufacturing In Developing Countries: Research Gaps And Directions In Tanzania, Francis D. Sinkamba

Tanzania Journal of Engineering and Technology (TJET)

In the current knowledge-driven economy, many industries across the globe are forced to adopt manufacturing technologies such as lean manufacturing to remain competitive in the globalized world. Despite the increase in lean manufacturing implementations, the adoption rate in Tanzania is very low and estimated to be 8 percent. Likewise, the sustainability of lean manufacturing tools and practices is still questionable, which shows the need to develop lean maturity models. To date, several lean maturity models have been developed but there is ARTICLE INFO Submitted: July 5, 2022 Revised: Sept. 28, 2022 Presented: Oct. 20, 2022 a lack of maturity models …

Current And Future Trends Of Construction Project Performance Models: A Review, Method Mtana

Tanzania Journal of Engineering and Technology (TJET)

The construction industry (CI) has experienced outstanding growth and contributed to economic growth for many countries, with enormous foreign investments that require quality projects. High pressure to reduce the construction cost and time commonly put the industry at risk of lower quality and safety of the construction facilities. Like many other developing countries, Tanzania needs more stringent quality control measures in the construction sector to contribute positively to sustainable growth. This study thus reviews current and future trends in construction industry performance in Tanzania. The literature review on construction projects (CPs) performance is based on information on time overruns from …

Towards The Development Of A Framework For Assessing Organizational Governance Maturity For Technical Audit Of Public Works, George Haule

Tanzania Journal of Engineering and Technology (TJET)

The quality of the audit work and its products is often associated with the organizational maturity of the audit function. The absence of a well-defined organizational maturity for an audit function leads to poor quality of audit work or products and ineffective audit function. The lack of a framework for measuring governance maturity was identified as a major deterrent factor to the attainment of quality audit work. Measuring the governance maturity of the technical audit of public works is challenging due to the absence of a maturity framework that fits its needs. The noted shortcomings include: (a) existing maturity frameworks …

Seismic Azimuthal Anisotropy Beneath A Fast Moving Ancient Continent: Constraints From Shear Wave Splitting Analysis In Australia, Kailun Ba, Stephen S. Gao, Jianguo Song, Kelly H. Liu

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Seismic Azimuthal Anisotropy Beneath Australia is Investigated using Splitting of the Teleseismic PKS, SKKS, and SKS Phases to Delineate Asthenospheric Flow and Lithospheric Deformation Beneath One of the Oldest and Fast-Moving Continents on Earth. in Total 511 Pairs of High-Quality Splitting Parameters Were Observed at 116 Seismic Stations. Unlike Other Stable Continental Areas in Africa, East Asia, and North America, Where Spatially Consistent Splitting Parameters Dominate, the Fast Orientations and Splitting Times Observed in Australia Show a Complex Pattern, with a Slightly Smaller Than Normal Average Splitting Time of 0.85 ± 0.33 S. on the North Australian Craton, the Fast …

Batch And Fixed-Bed Adsorption Of Ciprofloxacin Using Magnetic Biochar From Macadamia Nutshell, Sakonsupa Damdib

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this research, the utilization of macadamia nutshell as a potential adsorbent for ciprofloxacin (CIP) removal was investigated. The distinctive features of macadamia nutshell, characterized by its lignocellulosic composition and hardness, make it suitable as a precursor for synthesizing magnetic biochar, aimed at CIP adsorption in both batch and fixed-bed column processes. The influence of temperature activation and carbonization temperature on the properties of the resulting biochar was examined. Macadamia nutshell impregnated with a 0.10 M iron nitrate solution and carbonized under a nitrogen atmosphere at 800°C (MB-BI-800) exhibited the highest micropore and mesopore volumes, with values of 0.14 and …

Oil Recovery Performance And Asphaltene Deposition Evaluation Of Miscible And Immiscible Carbon Dioxide Or Nitrogen Huff-N-Puff Processes In Shale Reservoirs, Mukhtar Elturki, Abdulmohsin Imqam, Shari Dunn-Norman, Hasan Shaglouf, Ahmed Kablan

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

The utilization of gas enhanced oil recovery to extract oil from unconventional reservoirs has become a widely discussed topic, as it has proven to be effective in significantly boosting oil recovery rates. Among various enhanced oil recovery methods, Gas Enhanced Oil Recovery (GEOR) is a frequently implemented approach. However, a significant challenge encountered during the process of injecting Carbon Dioxide (CO₂) or Nitrogen (N₂) to displace oil is the occurrence of asphaltene precipitation and deposition, which can impede production. This work is an experimental study to examine the effects of cyclic (huff-n-puff) CO₂ or N …

Descriptive Systematics Of Upper Palaeocene–Lower Eocene Pollen And Spores From The Northern Niger Delta, South-Eastern Nigeria, Luke Mander, Carlos Jaramillo, Francisca Oboh-Ikuenobe

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Fossil pollen and spores are a vital source of information on the geological history of tropical vegetation including reconstructions of vegetation diversity and composition. However, such work relies on a sound taxonomic framework, and this is challenging to achieve because of the large number of pollen and spore morphotypes that are encountered in palynological preparations from tropical sediments. In tropical West Africa, for example, extensive taxonomic work on Cretaceous–Paleogene pollen and spores was undertaken in the later part of the twentieth century, but more recent palynological work has focused on stratigraphy and basin evolution, and there is a need for …

Review Of The Fluid Dynamics And Heat Transport Phenomena In Packed Pebble Bed Nuclear Reactors, Rahman S. Almusafir, Ahmed A. Jasim, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

Knowledge and proper safety analyses of the gas coolant and heat transport mechanism in the dynamic core of packed pebble bed nuclear reactors pose challenges to the reliable design and efficient operation of these reactors. Therefore, this paper carefully reviews most of the gas coolant mixing and heat transport studies performed for the fluid flow and heat transfer processes in packed pebble bed reactors (PBRs). It begins with a brief introduction and description of nuclear PBRs. The second section summarizes the physical characteristics of packed bed reactors in terms of the bed structure (porosity) and its radial and axial distributions. …

Effect Of Brønsted And Lewis Acid On Ni-Based Bifunction Catalyst On Hydroprocessing Of Palm Oil To Biojet Fuel, Settapong Kantangkul

Chulalongkorn University Theses and Dissertations (Chula ETD)

Jet fuels are mainly generated by refining petroleum feedstock, resulting in the emission of greenhouse gases. Therefore, biojet fuel is proposed as an alternative solution for solving this issue. Hydroprocessing of vegetable oils is an efficient pathway for producing biojet fuel. This process includes three reaction which are hydrodeoxygenation, hydrocracking and hydroisomerization over metal-acid catalyst. Biojet fuel series ranging from C8 to C16 must have a freezing point around -47 °C or lower, requiring the use of iso-paraffins which have low freezing points. There are challenges in improving the quantity and quality of biojet fuel production. This study aims to …

Lead Acid Battery Recycling In The Current Tanzania Industrialization Drive: Challenges And Opportunities, Divina D. Kaombe

Tanzania Journal of Engineering and Technology (TJET)

ABSTRACT Advancements in automotive technologies, Information and Communications Technology and renewable energy technologies have increased the use of lead acid batteries as a source of portable and rechargeable energy. This has considerably increased the number of spent batteries with adverse effects on the environment and human health; which calls for recycling of spent batteries. This work was conducted to investigate challenges facing the formal business of recycling spent batteries and potential manufacturers of new lead-acid batteries in Tanzania. The work involved collection of information from key stakeholders such as collectors, dealers, Tanzania Revenue Authority and recyclers. It was found out …

A Chemical Study Of Archaeometallurgical Ceramics From Southwestern Tanzania, Edwinus Lyaya

Tanzania Journal of Engineering and Technology (TJET)

Archaeometallurgical ceramics, including furnaces, tuyères, and potteries, were required for successful pre-industrial iron smelting and refining. However, there are limited chemical studies on archaeometallurgical ceramics in Tanzania. This paper examined the nature of clay source in terms of refractoriness, determined whether there were multiple clay sources, and verified the refractoriness of the archaeometallurgical ceramics. An x-ray fluorescence (XRF) analytical technique and experimental re-firing of the archaeometallurgical ceramics were employed. The chemical data clustered in the mullite region on the Al2O3-SiO2-FeO ternary system indicate that iron smelters and refiners chose refractory clay sources for making archaeometallurgical ceramics. Small range and standard …

Properties Of (Cd, Zn)S Films Deposited By Dc Co-Sputtering, Lwitiko P. Mwakyusa

Tanzania Journal of Engineering and Technology (TJET)

CdS thin film is commonly used as a buffer layer in most thin film solar cells. However, the buffer layer with less absorption in the visible region of the solar spectrum as well as that which provides perfect lattice matching with the absorbers is required. The incorporation of Zn in the CdS films can affect the structural and optical properties of the buffer layer. In this work, films of CdS and (Cd,Zn)S films were deposited by DC sputtering utilizing CdS and Zn targets. The concentration of Zn in the CdS was varied by changing the sputtering power of the Zn …

Performance Evaluation Of Udsm Network To Deliver Multimedia Elearning Contents: Case Of Coict, Mercy Mbise

Tanzania Journal of Engineering and Technology (TJET)

The use of technology in education in Sub-Saharan Africa has been reported to be hindered by many factors including inadequate Information and Communication Technology (ICT) infrastructure, low internet speed, and lack of skills to use educational technologies. This paper aim at evaluating how the available ICT infrastructure at the College of Information and Communication Technologies (CoICT) can support, with acceptable Quality of Service (QoS), the delivery of multimedia applications for eLearning services. The evaluation was performed over a network testbed implemented in a computer laboratory for wired and wireless connections. The testbed consisted of five personal computers (PCs) connected via …