Engineering Commons^™

Dual-Modality Smartphone-Based Fiber-Optic Microendoscope System For Early Detection Of Cervical Neoplasia, Xiangqian Hong

Dissertations (1934 -)

Cervical cancer remains the leading cause of death for women in low middle-income countries (LMICs), where the incidence and mortality of cervical cancer are disproportionately high. Due to the poor medical conditions and lack of resources, the benefits of early screening methods such Pap smear and HPV test have yet to be realized in these areas. The more viable screening option - visual inspection with acetic acid (VIA) is relatively easier to implement and lower in cost. However, the effectiveness of VIA on the early detection of cervical cancer is still in question because of its low specificity, which may …

Construction Labor Productivity Benchmarking: A Comparison Between On-Site Construction And Prefabrication, Emad Nadi

Dissertations (1934 -)

Construction labor productivity has been declining over the past sixty years, which has caused a decline in overall construction productivity. The traditional ways of managing construction projects and their delivery have evolved into an inherently inefficient and adversarial process. There was always a need to improve the way construction elements are constructed and delivered to the job site such as adopting lean construction. One way to achieve this goal is to prefabricate the construction elements off site and then deliver them to the site for installation. Prefabrication is a process of assembling building components in a remote location using a …

Supplemental Vibrotactile Feedback Of Real-Time Limb Position Enhances Precision Of Goal-Directed Reaching, Nicoletta Risi, Valay Shah, Leigh A. Mrotek, Maura Casadio, Robert A. Scheidt

Biomedical Engineering Faculty Research and Publications

We examined vibrotactile stimulation as a form of supplemental limb state feedback to enhance planning and ongoing control of goal-directed movements. Subjects wore a two-dimensional vibrotactile display on their nondominant arm while performing horizontal planar reaching with the dominant arm. The vibrotactile display provided feedback of hand position such that small hand displacements were more easily discriminable using vibrotactile feedback than with intrinsic proprioceptive feedback. When subjects relied solely on proprioception to capture visuospatial targets, performance was degraded by proprioceptive drift and an expansion of task space. By contrast, reach accuracy was enhanced immediately when subjects were provided vibrotactile feedback …

Simulating The Impact Of Traffic Calming Strategies, Deo Chimba, Christian Mbuya

Transportation Research Center Reports

This study assessed the impact of traffic calming measures to the speed, travel times and capacity of residential roadways. The study focused on two types of speed tables, speed humps and a raised crosswalk. A moving test vehicle equipped with GPS receivers that allowed calculation of speeds and determination of speed profiles at 1s intervals were used. Multi-regime model was used to provide the best fit using steady state equations; hence the corresponding speed-flow relationships were established for different calming scenarios. It was found that capacities of residential roadway segments due to presence of calming features ranged from 640 to …

17-11 Evaluation Of Transit Priority Treatments In Tennessee, Deo Chimba, Sotonye Ikiriko

Transportation Research Center Reports

Many big cities are progressively implementing transit friendly corridors especially in urban areas where traffic may be increasing at an alarming rate. Over the years, Transit Signal Priority (TSP) has proven to be very effective in creating transit friendly corridors with its ability to improve transit vehicle travel time, serviceability and reliability. TSP as part of Transit Oriented Development (TOD) is associated with great benefits to community liveability including less environmental impacts, reduced traffic congestions, fewer vehicular accidents and shorter travel times among others.This research have therefore analysed the impact of TSP on bus travel times, late bus recovery at …

En-Fuels From Solid Waste Biomass By Thermo-Catalytic Reforming, Andreas Hornung, Andreas Apfelbacher, Robert Daschner, Nils Jäger, Jan Grundwald

Pyroliq 2019: Pyrolysis and Liquefaction of Biomass and Wastes

Intermediate pyrolysis describes a process of converting feedstock by heating it up in the absence of oxygen under moderate, “intermediate” conditions. Typical conditions are a residence time for solids between 5 to 30 minutes, low heating rates and temperatures between 350 °C - 450 °C. Due to these conditions intermediate pyrolysis has remarkable advantages regarding the feedstock, compared to other processes based on flash pyrolysis. Large particles, like pellets or chips can be used. Dry matter content can be below 50% from a technical point of view. For economic reasons the dry matter should be more than 70 % to …

Experimental Study On The Effect Of Moisture On Bolt Embedment And Connection Loaded Parallel To Grain For Timber Structures, Henry Meleki Kiwelu

Tanzania Journal of Engineering and Technology (TJET)

Connections are critical parts of timber structures, transmitting static and dynamic forces between structural elements. The ultimate behaviour of a building depends strongly on the structural configuration and the capacity of its connections. The complete collapse of a building or other less extensive accidents that may occur usually start as a local failure inside or in the vicinity of a joint. The main aim of this study has been to investigate if the short-term capacity of steel-wood dowel joints loaded parallel to the grain is affected by variations in moisture content associated with post fabrication drying or wetting of the …

Nonlinear Direct Torque Control Of Interior Permanent Magnet Synchronous Motor Drive, Jackson Justo

Tanzania Journal of Engineering and Technology (TJET)

This paper presents a nonlinear direct torque control (NDTC) strategy of interior permanent magnet synchronous motors (IPMSMs) for electric vehicle (EV) propulsion. The proposed NDTC scheme applies a nonlinear model of IPMSM to dynamically determine the optimal switching states that optimize the EV drivers’ decision to reduce the workload. Moreover, the proposed NDTC method has a simple control structure and can explicitly handle system constraints and nonlinearities. The performance evaluation is conducted via a prototype IPMSM test-bed with a TMS320F28335 DSP. Comparative experimental results provide the evidence of improvements of the proposed NDTC strategy over the conventional DTC strategy by …

Material Flow Analysis As A Decision Supporting Tool For Faecal Sludge Resource Recovery: Mathematical Formulation And Quantification, Isabela Thomas Mkude

Tanzania Journal of Engineering and Technology (TJET)

In this work, a conceptual framework for faecal sludge (FS) management and resource recovery in Dar es Salaam city was developed. Material Flow Analysis (MFA) approach was used to assess and quantify the current materials and nutrients to support on decisions for nutrient recovery and minimize environmental pollution in three unplanned settlements of Manzese, Keko and Kipawa in Dar es Salaam city. Nitrogen and Phosphorus were chosen as indicators for the evaluation of the process. The results showed that about 75% of the Dar es Salaam city population relies on pit latrines and 15% connected to septic tanks, translating to …

Potential Use Of High Rate Algae Ponds For Resource Recovery In The Water-Food-Energy Nexus For Tanzania: A Review, Mary Kayombo

Tanzania Journal of Engineering and Technology (TJET)

The use of High Rate Algal Ponds (HRAPs) for the treatment of wastewater and resource recovery has raised interest in recent years. Treatment of wastewater through this technology has proved to have high efficiency in reducing the level of pollution, nutrients, dissolved solids as well as pathogens. HRAPs are more efficient than conventional Wastewater Stabilization Ponds (WSPs) due to their design approach that provides room for high rate bio-chemical processes, which increase the mechanisms of nutrients and pathogens removal as well as the rate of micro-algae production for purposes of resource recovery. This paper reviews the upgrading potential of existing …

Development Of Improved Characteristic Equations For Lake Rukwa In Tanzania, Patrick Valimba Dr

Tanzania Journal of Engineering and Technology (TJET)

Often Lake Rukwa characteristics have been misreported in literature giving different volumes and surface areas at similar water surface elevations. This study aimed at establishing reliable lake characteristics elevation-area-storage equations for Lake Rukwa by utilising all available data and information to define the bathymetry and derive characteristic equations. A procedure was developed that combines historical lake extents, spot heights from topographical maps and surveyed lake bathymetry to define refined bathymetry to levels it has never reached. It combined spot heights around the lake and selected 13,934 surveyed points (from 107,938 available) within the lake confined by the 820 m land …

Research Methodology Adopted In Developing Tansse-L System, Ellen Kalinga

Tanzania Journal of Engineering and Technology (TJET)

Research methodology is among the very important part in a research work. It is the heart which describe the activities necessary for the completion of the research work. Research methodology provides a plan of investigation considered to obtain answers to research problems and it depends on the context of application. This paper presents the research methodology adopted when developing Tanzania Secondary Schools e-Learning (TanSSe-L) system, a learning management system (LMS) which was successfully developed through customization of Moodle open source LMS. TanSSe-L system is a context centered platform for secondary schools in Tanzania. TanSSe-L system was developed using a number …

A Simple And Effective Way To Overcome Carbon Monoxide Poisoning Of Platinum Surfaces In Direct Formic Acid Fuel Cells, Yaser M. Asal Mr., Islam M. Al-Akraa Dr, Sohair A. Darwish Ms

Chemical Engineering

A glassy carbon (GC) electrode modified with multi-walled carbon nanotubes (MWCNTs) and platinum nanoparticles (PtNPs), Pt/MWCNTs-GC, has been introduced for formic acid electro-oxidation (FAO). A similar loading of PtNPs has been conserved for a proper comparison between the Pt/MWCNTs-GC and the unmodified Pt/GC electrodes. The modification with MWCNTs could enhance the loading of PtNPs onto the GC electrode in a way that minimizes its agglomeration and increases its dispersion in the CNTs network. This not only increases the surface area exposed to the reaction but also interrupts the contiguity of the Pt active sites minimizing the adsorption of the poisoning …

A Promising Modification Of Pt Surfaces With Cnts For Decreasing Poisoning Impact In Direct Methanol Fuel Cells, Yaser M. Asal Mr., Islam M. Al-Akraa Dr, Aya A. Khalifa Ms.

Chemical Engineering

Direct methanol fuel cells (DMFCs) are clean energy sources that have many applications due to the high energy density of methanol as a fuel. However, this type of fuel cells (FCs) has limitations that are preventing it from being commercialized. One such limitation is the adsorption of intermediates such as CO into the surface of the Platinum (Pt) catalyst during methanol oxidation (MO) which deactivates its active sites, where the reaction is taking place, and leads to poisoning of the electrode over the long term. In this study, multi-walled carbon nanotubes (MWCNTs) have been introduced to the Pt-modified glassy carbon …

The Comparative Analysis Of The Performances Of Four And Six Pole Pairs Permanent Magnet Synchronous Generator, Ra Msuya

Tanzania Journal of Engineering and Technology (TJET)

Wind power applications using multi-poles permanent magnet generators have become very attractive especially in small ratings. Low-speed multi-pole PM generators are maintenance-free and may be used in different climate conditions. Most of the low speed wind turbine generators presented is permanent magnet machines, which have advantages of high efficiency and reliability since there is no need of external excitation and conductor losses are removed from the rotor. From the study two types of PM AC generator are designed with 6 pole pairs and the other one with 4 pole pairs. These generators were designed and analysed using Maxwell software. The …

Linking Quality Management Practices With Performance Of Manufacturing Industries In Tanzania, Mussa Iddi Mgwatu Dr.

Tanzania Journal of Engineering and Technology (TJET)

Local products of manufacturing industries in Tanzania are subjected to intense competition in the markets. Product quality is one of key factors that play a considerable role for manufacturing industries to win the competitive advantage. This paper attempts to analyse the extents of quality management practices (QMP) and manufacturing performance (MP) as well as to examine the linkage between practices and performance. Data was collected from seventy-eight (78) manufacturing industries in Dar es Salaam region using questionnaires comprising of both single-item and multi-item questions. Descriptive statistics was used to quantify the extent of quality management practices and manufacturing performance (MP) …

Influence Of Tempering And Cryogenic Treatment On Retained Austenite And Residual Stresses In Carbonitrided 18crnimo7-6 Low Alloy Steel, Richard Katemi

Tanzania Journal of Engineering and Technology (TJET)

This work investigated the influence of tempering conditions coupled with cryogenic treatment on thermal stabilization of retained austenite and residual stress distributions in carbonitrided 18CrNiMo76 low alloy steel samples. The carbonitriding conditions were set to enable attaining surface carbon and nitrogen content of 0.87 and 0.34 mass.-percent respectively. After carbonitriding, some of the samples were subjected to varying tempering conditions followed by cryogenic treatment at-120 °C using nitrogen gas. Analysis of both retained austenite and residual stresses was conducted using X-ray diffraction. In the as-quenched state, carbonitrided samples contained 52 mass.-percent. Samples that were directly subjected to the cryogenic treatment …

Assessment Of Surface Water Resources In Great Ruaha River Sub-Basin Tanzania: Application Of Weap Model For Water Allocation And Utilization Impacts Analysis, Deogratias Mulungu

Tanzania Journal of Engineering and Technology (TJET)

The Great Ruaha River (GRR) sub-basin is one of the most important waterways in Tanzania as it supports important economic activities. The sub-basin is progressively faced with an inevitable situation of increasing water demand among competing users while the quantity and quality of water is diminishing. The focus of this study was to assess allocation of existing (2012) and future (up to 2025) quantities of surface water in the GRR sub-basin with consideration of priorities given in the Tanzania Water Resources Management Act, 2009 in the order: domestic, environment, agriculture, livestock and non-domestic. Simulation of water allocation scenarios of irrigation …

A Research On Biologically Active Compounds From Black Sea Grass Crab Palaemon Adspersus, L.V. Bal-Prylypko, S.O. Lebskiy, T.K. Lebskaya, A.A. Menchinskaya

Chemical Technology, Control and Management

An investigation has been conducted to study the possibility of isolation in a single technological cycle and purification of a complex of collagenolytic enzymes, and the lipids from hepatopancreas of the Black Sea grass crabs. It was found that the activity of collagenolytic enzymes corresponds to this indicator of enzymes isolated from other crustaceans. Hepatopancreas lipids are characterized by high biological efficiency due to the high content of polyunsaturated fatty acids. Their total content is as 3 times as the recommended amount for a healthy diet. A high content of eicosapentaenoic and docosahexaenoic fatty acids has been established.

An Improvement Of Information Reliability For Electronic Documents Based On Knowledge Bases With Implication Matrix Adjustment, I.I. Jumanov, Kh.B. Karshiev

Chemical Technology, Control and Management

The new methods, algorithms and software tools have been developed to increase the reliability of information based on the extraction and use of quantitative, qualitative, specific characteristics, useful properties (interrelations between elements of document concept relationships). New approaches and principles to improve the traditional techniques and developed new methods of processing documents using a database (DB) and setup knowledge base (KB) to optimize the accuracy of the information have been proposed. The algorithms of increase of reliability of elements of the concept of the input document based on the proximity measures and comparison with the elements of the test set …

To Developing A Device Based On A Luminescent Sensitive Element For Determining Antioxidant Activity By Oxygen Concentration, V.Kh. Shamsutdinova, J. Abdukamilov

Chemical Technology, Control and Management

The article analyzes the main photophysical processes involving excited phosphor and oxygen molecules and reveals the relationship between the oxygen concentration and the integrated luminescence intensities in the absence and presence of oxygen. It is shown that the implementation of the method based on the measurement of the energy characteristics of luminescence can be brought to instrumentation by using a relatively simple measuring technique. In addition, a description is given of available devices for measuring the concentration of oxygen in liquid and gaseous media based on optical methods, and also their disadvantages are identified. A device is proposed for the …

Meshless Modeling Of Flow Dispersion And Progressive Piping In Poroelastic Levees, Anthony Khoury, Eduardo Divo, Alain J. Kassab, Sai Kakuturu, Lakshmi Reddi

Publications

Performance data on earth dams and levees continue to indicate that piping is one of the major causes of failure. Current criteria for prevention of piping in earth dams and levees have remained largely empirical. This paper aims at developing a mechanistic understanding of the conditions necessary to prevent piping and to enhance the likelihood of self-healing of cracks in levees subjected to hydrodynamic loading from astronomical and meteorological (including hurricane storm surge-induced) forces. Systematic experimental investigations are performed to evaluate erosion in finite-length cracks as a result of transient hydrodynamic loading. Here, a novel application of the localized collocation …

Nonlinear Observer For Visual-Inertial Navigation Using Intermittent Landmark Measurements, Miaomiao Wang

Western Research Forum

The development of reliable orientation, position and linear velocity estimation algorithms for the 3D visual-inertial navigation system (VINS) is instrumental in many applications, such as autonomous underwater vehicles (AUVs), and unmanned aerial vehicles (UAVs). It is extremely important when the global position system (GPS) is not available in GPS-denied environments. Recently, observers design for VINS using landmark position measurements from Kinect sensors or stereo cameras has been increasingly investigated in the literature.

The aim of this work is to design a nonlinear observer for VINS under the assumption that landmark position measurements are intermittent. In practice, the landmark measurements are …

A Ph-Sensitive Delivery System For The Prevention Of Dental Caries Using Salivary Protein, Yi Zhu, Yizhi Xiao, Elizabeth Gillies, Walter L. Siqueira

Western Research Forum

Dental caries remains one of the most common chronic diseases worldwide. In previous studies, salivary proteins (e.g. histatin 3, statherin) have demonstrated biological functions including the inhibition of crystal growth, antibacterial activities, which are directly related to tooth homeostasis and prevention of dental caries. However, proteins are susceptible to the high proteolytic activities in the oral environment. Therefore, pH-sensitive chitosan nanoparticles (CNs) have been proposed as potential carriers to protect proteins against enzymatic degradation at physiological salivary pH, in addition to swell selectively at lower pH conditions to facilitate the release of the encapsulated proteins, as major oral complications occur …

Comparative Study Of The Structure Of Castings Fromwear Resistant Chuguns, Ganiyev Y.U., Jumaev Akhmat, Komilov J.M., Khudoyberdiyev R.Kh.

Gorniy vestnik Uzbekistana

In this article, white wear-resistant cast irons of the grades 280H29NL and 300H32N2M2TL are investigated, the chemical compositions and their structures are compared. It has a composition close to eutectic, but is prone to brittle chipping. At high magnifications in the metal base, the places of chipping are found, and where the chipping has not yet passed, gray sulphides are clearly visible. The carbide sizes of the cast irons under investigation vary widely from 8.6 μm to 31 μm.

Improvement Of Scheme Of Drug Training At Hydrometallurgical Plant №2, K. Sanakulov, Ergashev Ulugbek Abdurasulovich, Tkachenko Evgeniy, Vasilyonok O.P.

Gorniy vestnik Uzbekistana

The article discusses the issues of improvement of grinding schemes, aimed at improving the productivity of ore preparatory redistribution on the example of the current production of GMZ-2. Based on the analysis of the results of testing mill blocks, the reserves for increasing their productivity were revealed. The results of industrial tests and the introduction of an improved scheme on an industrial scale.

Analysis Of Factors Determining Efficiencyhead Leaving Stain Rays, A.E. Vorobev, Чекушена Т.В., Tcharo X

Gorniy vestnik Uzbekistana

The efficiency of irrigation of stacks is an important component, ensuring the intensification of the heap leaching process in the extraction of metals from poor ores. The study of the irrigation process in heap leaching should be aimed at improving the economic and technological efficiency of the applied irrigation methods. In this regard, the study of the factors affecting the evaporation of leaching solutions in HL will make it possible to make new and improved decisions regarding the devices and methods for the supply of solutions. The influence of coarseness and agglomeration on irrigation efficiency was also considered.

History And Prospects Of Gamma-Activation Analysis Of Muruntau Mine, Melnikov L.N., Mingboyev X.S., Yermakov K.S.

Gorniy vestnik Uzbekistana

he article describes the history of the development of a new type of analysis of geological samples for gamma-activated gold method. The Central Mining Administration of the Navoi Mining and Metallurgical Combine announces the creation of a gamma-activated analytical laboratory at the Muruntau deposit. The prospect of gamma-activated analysis of gold, silver and rare metals in Uzbekistan and around the world.

Conceptual Bases For Solving The Problems Of Processing Technological Raw Materials, K.S. Sanakulov

Gorniy vestnik Uzbekistana

Currently in the world, in the mining and metallurgical industry there is a forced need to reduce the share of processing ores and increase the share of previously accumulated industrial wastes. A phased concept of the use of man-made waste is proposed. At the first stage, the existing industrial wastes are considered as resources and are subject to complete processing with the minimum amount of new waste. At the second stage, the task is to develop non-waste technologies. The example of Uzbekistan (Navoi and Almalyk MMC) shows one of the possible options for the integrated use of industrial waste for …

New Method For Cleaning And Filtration Of Liquid Sulfur, Ashurov O.T., Tureyev F.E., Karimov A.K.

Gorniy vestnik Uzbekistana

The article presents the results of sulfur purification research with an inorganic adsorbent released as waste during the production of vanadium pentoxide from spent vanadium catalyst. High purification of liquid sulfur from organic impurities, ash and acids is achieved by treating the molten sulfur with an inorganic adsorbent, followed by separating the purified sulfur by filtration. The silicate base of the spent vanadium catalyst is used as the inorganic sorbent after vanadium pentoxide is removed from it. The consumption of the silicate base of the spent vanadium catalyst after removal of vanadium pentoxide from it is regulated in the range …