Catalysis and Reaction Engineering Commons^™

Voltage-Related Power Quality Issues And Impacts On Distribution Networks With Sensitive Loads - A Review, Godwin Elinazi Mnkeni, Jackson Justo, Aviti Thadei Mushi, Bakari M. M. Mwinyiwiwa

Tanzania Journal of Engineering and Technology (TJET)

Voltage disturbances are the most important power quality (PQ) complications that customers and power utilities face in this smart era. The growing adoption of sophisticated electronic equipment and integration of renewable energy sources (RES) into power grids has increased the susceptibility of power distribution networks (PDNs) to voltage sags, swells, interruptions, flicker, and voltage imbalance. These disturbances, mainly caused by upstream faults, switching operations, and RES integration, compromise voltage PQ and system reliability. Consequently, they accelerate equipment degradation, increase electronic waste (e-waste), raise reactive power demand and maintenance costs, increase power losses, and impose substantial economic losses on customers and …

Recent Advances In Bioethanol Production From Water Hyacinth: A Critical Review, Umuamina A. Matola, Mahir Mohammed Said, Olga-Ioanna Kalantzi, Abraham K. Temu

Tanzania Journal of Engineering and Technology (TJET)

Water hyacinth (WH) is a highly invasive tropical aquatic weed with high holocellulose and low lignin content, making it a promising lignocellulosic feedstock for second-generation bioethanol production. Producing bioethanol from WH offers a sustainable approach to simultaneously managing invasive biomass and producing renewable energy. This review critically evaluates recent advancements in bioethanol production from WH by examining pretreatment, hydrolysis, and fermentation technologies reported between 2014 and 2024. A PRISMA-guided literature search was conducted using the Scopus and Web of Science databases, and fifty-nine original research articles were selected for analysis. The reviewed studies were comparatively assessed based on pretreatment strategies, …

Effect Of Household Oil Contamination And Agricultural Soil Contamination On Phyllosilicate Nanocatalyst Performance During Pyrolysis Of Polyolefins, Joey Velasquez

Master's Theses

The effect of household oil and agricultural soil contamination on catalyst performance during polyolefin pyrolysis was simulated on mixed virgin plastic pellets by evaluating contamination influence on mixed plastic degradation temperatures. Three phyllosilicate nanocatalysts including Fulcat435, Fulcat22F and Y-Zeolite were evaluated in this work based on a literature review of catalyzed plastic pyrolysis and these catalysts’ ability to lower plastic decomposition temperature by 50 °C – 100 °C. These findings were confirmed in this research through thermogravimetric analysis of a polyolefin mixture and further developed in furnace experiments containing household oil and agricultural contamination. Household oil contamination deactivated each of …

Efficient Phosphate Removal From Water Using Ductile Cast Iron Waste: A Response Surface Methodology Approach, Mai Hassan Dr., Nada Alkhashab Eng., Ahmed Osman Dr., Dalia A. Ali Eng

Chemical Engineering

Water scarcity is a critical issue worldwide. This study explores a novel method for addressing this issue by using ductile cast iron (DCI) solid waste as an adsorbent for phosphate ions, supporting the circular economy in water remediation. The solid waste was characterized using XRD, XRF, FTIR, and particle size distribution. Wastewater samples of different phosphate ion concentrations are prepared, and the solid waste is used as an adsorbent to adsorb phosphate ions using different adsorbent doses and process time. The removal percentage is attained through spectrophotometer analysis and experimental results are optimized to get the optimum conditions using Design …

Sustainable Materials For Environment − Multifunctional Material Made From Dead Leaves And Nanostructured Materials For Antibiotic Degradation, Siyuan Fang

Dissertations, Master's Theses and Master's Reports

As environmental pollution from industrial processes and human activities continues to rise, finding efficient approaches to recycle waste materials and degrade persistent contaminants becomes increasingly critical. Dead leaves, an abundant but underutilized biomass, present an opportunity for creating value-added materials if their biocomponents can be preserved and transformed. Simultaneously, antibiotics such as tetracycline are widely found in water bodies but pose serious ecological and health risks, necessitating effective degradation methods. This dissertation addresses these challenges by leveraging natural and nanostructured materials to develop multifunctional products and advanced photocatalytic processes.

Chapter 3 of this dissertation addresses the challenge of converting waste …

Modeling Of Amine-Based Co2 Capture Process, Zafar Safarovich Turakulov

Chemical Technology, Control and Management

A significant factor influencing climate change is the release of carbon dioxide (CO₂) into the atmosphere as a consequence of human activities such as the combustion of fossil fuels. Climate change can be slowed down by taking action to mitigate industrial-scale CO₂ emissions. Currently, the most advanced technology for capturing CO₂ from industrial flue gases is the post-combustion CO₂ capture based on amine absorption. However, due to the high energy penalties of existing CO₂ capture technologies and insufficient carbon markets, it is necessary to develop methods that compete with these technologies or minimize their …

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 …

Élimination Des Vapeurs Toxiques Par Oxydation : Développement De Procédures D'Évaluation Des Systèmes De Purification De L'Air Des Conduits De Ventilation, Chang-Seo Lee, Fariborz Haghighat, Alireza Haghighat Mamaghani, Zahra Shayegan, Ali Bahloul, Mélanie Huard, Lexuan Zhong, Mitra Bahr

Rapports de recherche scientifique

L'exposition à des composés organiques volatils (COV) dans les lieux de travail peut avoir des effets aigus, notamment sous forme d'irritation de la peau, des yeux, de la bouche et du nez. Certains produits peuvent également provoquer des effets chroniques, comme l'asthme et le cancer. La prévention de tels effets nocifs sur la santé des travailleurs par l'adoption et la mise en œuvre de mesures visant à en éliminer ou à tout le moins réduire le risque s'avère importante. Parmi les approches développées à ce jour pour réduire l'exposition aux polluants de l'air intérieur – dont les COV –, la …

Removal Of Toxic Vapors By Oxidation: Development Of Laboratory Test Procedures For In-Duct Air Cleaning Systems, Chang-Seo Lee, Fariborz Haghighat, Alireza Haghighat Mamaghani, Zahra Shayegan, Ali Bahloul, Mélanie Huard, Lexuan Zhong, Mitra Bahr

Rapports de recherche scientifique

L'exposition à des composés organiques volatils (COV) dans les lieux de travail peut avoir des effets aigus, notamment sous forme d'irritation de la peau, des yeux, de la bouche et du nez. Certains produits peuvent également provoquer des effets chroniques, comme l'asthme et le cancer. La prévention de tels effets nocifs sur la santé des travailleurs par l'adoption et la mise en œuvre de mesures visant à en éliminer ou à tout le moins réduire le risque s'avère importante. Parmi les approches développées à ce jour pour réduire l'exposition aux polluants de l'air intérieur – dont les COV –, la …

Wind Tunnel Modeling Of Jack Rabbit Ii Mock Urban Environment Gas Concentration Measurements, Sami S. Fares

Graduate Theses and Dissertations

The 2015 Jack Rabbit (JR) II field trials were conducted to improve understanding of the denser-than-air dispersion of chlorine in an urban environment. The field study involved five large-scale, outdoor release trials of chlorine in a mock urban environment (MUE) at Dugway Proving Ground (DPG). Various instrumentation was deployed, including JazTM Ultraviolet-Visible (UV-Vis) point sensors capable of measuring gas-phase chlorine concentration throughout the mock urban array.

The Chemical Hazards Research Center (CHRC) was tasked by the Chemical Security Analysis Center (CSAC) with the Mock Urban Wind Tunnel (MUWT) program to study the 2015 JR II Trials at wind tunnel scale. …

Isotherm And Kinetics Study For The Adsorption Of Nitrate From An Aqueous Solution Using A Modified Rice Straw, Dalia A. Ali Eng, Mohamed A. Sadek Prof., Nagwa Mahmoud Al-Mansi Prof, Ahmad Wafiq Aboelnasr Dr.

Chemical Engineering

In this research, modified rice straw (MRS) is proposed. The proposed production process of the modified rice straw (MRS) adsorbent is carried out by precipitation of iron nano particles on the surface of acid activated rice straw. The nitrate adsorption is carried out through batch experiments. The optimum nitrate removal 94.8 % was achieved at pH = 7, adsorbent dose 3 = g/L, 150 rpm, initial nitrate concentration = 23 mg/L and contact time 180 = min. The new adsorbent synthesis, kinetics and isotherm models were studied. The nitrate adsorption was well described by pseudo second order kinetic model (R2 …

Optimization Of Nitrate Removal From Aqueous Solution By Acid-Activated Rice Straw Supported Nano Zero-Valent Iron Using Response Surface Methodology, Dalia A. Ali Eng, Nagwa Mahmoud Al-Mansi Prof, Mohamed Amin Sadek Prof., Ahmad Wafiq Abolnasr Dr.

Chemical Engineering

Rice straw is one of the most common agricultural wastes due to its large production amounts. Energy valorization of rice straw is a technology used for nitrate removal as the produced ashes used to generate the adsorbent by means of an alkali dissolution followed by acid precipitation. The novelty of the proposed process is that the production of the nano zero-valent iron supported acid-activated rice straw (AARS-nZVI) adsorbent is carried out without the energy valorization process but, through an acid activation for rice straw followed by precipitation of nZVI particles on its surface. The new adsorbent synthesis, characterization and application …

Analysis And Optimization Of Colorimetric Nanosensors For Rapid Detection Of Microbes In Water, Ruby A. Lang

Master's Theses

Access to safe water is a basic human right recognized by the United Nations General Assembly in 2010 (WHO, 2020). However, a least 2.2 billion people globally still are without safely managed water services meaning they use a drinking water source that can be contaminated with faeces (WHO, 2020). With such a pressing global health issue, it is clear that improvement to water systems is important and required in the Agenda 2030 Sustainable Development Goals (SDGs). However, to improve water systems and prove they are safe water sources, water quality testing must occur. A solution to this issue is the …

Aqueous And Oil Products From Hydrothermal Liquefaction Of Manure Digestate, Kenzie Burns

Honors Theses

Hydrothermal liquefaction is a promising thermochemical waste-to-energy (WtE) technology for conversion of wet biomasses, such as manure and digested manure, into value-added products, namely energy-rich biofuel and a nutrient-rich aqueous product. WtE technologies can address environmental issues relating to overproduction of organic wastes and increasing dependence on fossil fuels, which leads to climate change. HTL has not been implemented on a commercial scale, in part due to the uncertainty regarding specific reaction pathways for different feedstocks and ideal conditions for production of the most valuable products.

This research investigates the compositions of the aqueous and oil products from HTL of …

The Potentials Of Faecal Sludge Treatment Using Local Conditioners In Tanzania: A Review, Doglas Benjamin1

Tanzania Journal of Engineering and Technology (TJET)

Worldwide, every day human beings generate millions of tons of Faecal Sludge (FS), which is rich in water, nutrients, energy, and organic compounds. Yet FS is not being managed in a way that permits us to derive value from its reuse, while at the same time, millions of farmers struggle with depleted soils and lack of water. In most of the developing countries, energy for cooking is mainly derived from cutting of trees, either as wood or charcoal. Resource recovery and reuse from FS can create livelihoods, enhance food security, support green economies, reduce waste and contribute to cost recovery …

Tunable Nanocomposite Membranes For Water Remediation And Separations, Sebastián Hernández Sierra

Theses and Dissertations--Chemical and Materials Engineering

Nano-structured material fabrication using functionalized membranes with polyelectrolytes is a promising research field for water pollution, catalytic and mining applications. These responsive polymers react to external stimuli like temperature, pH, radiation, ionic strength or chemical composition. Such nanomaterials provide novel hybrid properties and can also be self-supported in addition to the membranes.

Polyelectrolytes (as hydrogels) have pH responsiveness. The hydrogel moieties gain or lose protons based on the pH, displaying swelling properties. These responsive materials can be exploited to synthesize metal nanoparticles in situ using their functional groups, or to immobilize other polyelectrolytes and biomolecules. Due to their properties, these …

Optimising The Performance Of Cement-Based Batteries, Aimee Byrne, Shane Barry, Niall Holmes Dr., Brian Norton

Articles

The development of a battery using different cement-based electrolytes to provide a low but potentially sustainable source of electricity is described. The current, voltage, and lifespan of batteries produced using different electrolyte additives, copper plate cathodes, and (usually) aluminium plate anodes were compared to identify the optimum design, components, and proportions to increase power output and longevity. Parameters examined include water/cement ratio, anode to cathode surface area ratio, electrode material, electrode spacing, and the effect of sand, aggregate, salts, carbon black, silica fume, and sodium silicate on the electrolyte. The results indicate that the greatest and longest lasting power can …

Study Of Poisoning Mechanism Of Hg And As On V2o5–Wo3/Tio2 Scr De-Nox Catalysts, Qingcai Liu, Ming Kong, Lu Yao, Shan Ren, Jian Yang

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.

State-Of-The-Art Review Of Cathodic Protection For Reinforced Concrete Structures, Aimee Byrne, Niall Holmes, Brian Norton

Articles

Cathodic protection (CP) limits the corrosion of a metal surface by making it the cathode of an electrochemical cell. This can be achieved either by using a more active sacrificial anode to create a driving current, or by using inert anodes and impressing a current onto the cathode surface using an external direct current (DC) source. Impressed current cathodic protection (ICCP) is preferred where widespread protection is required, particularly in reinforced concrete structures. ICCP needs a constant DC power supply that is usually provided through a grid connection or independent generators. This paper presents the currently available CP systems for …

Cement Based Batteries And Their Potential For Use In Low Power Operations, Aimee Byrne, Niall Holmes, Brian Norton

Articles

This paper presents the development of an innovative cement-electrolyte battery for low power operations such as cathodic protection of reinforced concrete. A battery design was refined by altering different constituents and examining the open circuit voltage, resistor loaded current and lifespan. The final design consisted of a copper plate cathode, aluminium plate anode, and a cement electrolyte which included additives of carbon black, plasticiser, Alum salt and Epsom salt. A relationship between age, temperature and hydration of the cell and the current it produced was determined. It was found that sealing the battery using varnish increased the moisture retention and …

An Overview Of The Development Of Cement-Based Batteries For The Cathodic Protection Of Embedded Steel In Concrete, Aimee Byrne, Niall Holmes, Brian Norton

Conference papers

This paper presents an overview of the cement-based batteries developed in DIT for use in the cathodic protection of embedded steel in reinforced concrete undergoing chloride-induced corrosion. Cathodic protection delivers an external current (approximately 20mA per m2 of embedded steel) which effectively polarises the internal current generated during corrosion. The batteries developed in DIT comprise of a cement-based electrolyte containing different additives including sand, aggregate, salts, carbon black and plasticiser with protruding anode and cathode metal plates. These batteries produced an initial electrical output of 1.5V and 23mA through a 10 resistor as measured using data acquisition units and a …

Photocatalytic Mineralization Of Phenol On Fluidized Titanium Oxide-Coated Silica Gel, Guillermo J. Rincon

LSU New Orleans Theses and Dissertations

A bench-scale tubular reactor with recirculation was built in order to study the efficiency of the photocatalytic oxidation of phenol on fluidized titanium oxide-coated silica gel beads. A UV-C lamp placed along the central vertical axes of the reactor was used as source of photons. A bed of silica gel beads was fluidized by means of fluid recirculation and forced to follow upward helical flow around the lamp. Anatase was successfully synthetized on silica gel particles of average diameters 224, 357 and 461 µm, as confirmed by scanning electron micrographs, through a sol-gel technique using a titanium (iv)isopropoxide / hydrochloric …

Socio-Economic Impacts Of Computer Viruses In Tanzania, M Victor

Tanzania Journal of Engineering and Technology (TJET)

This paper reports on a research project conducted with an objective of identifying and assessing various approaches used by different computer users (Management, System Administrators and end users) in Tanzania to combat computer viruses (CVs), and to assess users' awareness level on CVs. Specifically, the study aimed at assessing the awareness level on CVs to the Tanzanian business community; analyze the socio -economic impact caused by CVs in Tanzania and; assess existing methods, capacity and limitations on controlling CVs in Tanzania. Data was collected using both questionnaires and interview from financial institutions such as NBC and BOT, and telecommunications sector …

Ceramic Properties Of Chimala Kaolin Clay, Leonard Akwilapo

Tanzania Journal of Engineering and Technology (TJET)

The physico-chemical properties of kaolinite clays occurring in abundance near Chimala were studied with a view of finding out their suitability in sanitary ware production. The viscosity of the clay was found to be within the range acceptable in industrial application (≤ 500 cp for 70% solids), enhancing its prospects for the manufacture of slip cast shapes with satisfactory properties. The chemical composition of the clay reveals a high content of Fe₂O₃, 1.48%, which is expected to affect the translucency and colour of the finished ware. However, such quantity would not have detrimental effects in the production of sanitary ware. …

Quality Of Common Salt In The Tanzanian Market, Kamwanya E

Tanzania Journal of Engineering and Technology (TJET)

The quality of edible salts in the Tanzanian market has been studied by comparing the levels of iodine, heavy metals, and non-metals. Among the 19 analyzed local salt samples, only two of them—Kipepeo salt (76.67 mg/kg) and Super salt (79.95 mg/kg)—met the recommended level of iodine as per TBS (Tanzania Bureau of Standards) specifications. Other brands have iodine levels below the TBS specification.

Review Of The Product Development Process And Information Flow In The Manufacturing Industry: Problems And A Possible Wav Forward, E Opiyo

Tanzania Journal of Engineering and Technology (TJET)

No abstract provided.

Application Of Vibrational Techniques In Determination Of Dynamic Properties Of Agricultural Products-State Of The Arton Of Vibrational Techniques In Determination Of Dynamic Properties Of Agricultural Products-State Of The Art, Silas Kajuna

Tanzania Journal of Engineering and Technology (TJET)

Vibration is one of the techniques employed in the determination of dynamic properties of fruits and vegetables. It entails generation of a mechanical or acoustic vibrational signal which is propagated through the flesh of the agricultural material. A transducer is either attached or held close to the specimen to monitor the propagation of the signal through the specimen. The manner in which the signal is transmitted through the material is analyzed, and the dynamic properties of the specimen which relate to its firmness or its internal being are derived. The technique has been around for the past 30 years or …

Use Of Dissolved Oxygen Concentration Probes In Biological Wastewater Treatment Plants, S Manyele

Tanzania Journal of Engineering and Technology (TJET)

A study on use Of dissolved oxygen probes (DOP) for measurement Of oxygen concentration in warer and wastewater treatment is presented. The principles Of operation, design considerations and selection criteria for Two types of probes, viz. galvanic and polarographic, are discussed Use of polarographic probes in n rhree-phase fluidized bed bioreactor and in laboratory experiments is presented and discussed. The effect of airflow rate and treatment time on dissolved oxygen concentration was found to be significant. It was found that polarographic probes are important equipment in determining the pollution of the industrial effluents. Finally, the use of the DOC probes …