Engineering Commons^™

A New Interpretation Of The √7×√7 R19.1° Structure For P Adsorbed On A Ni(111) Surface, Elizabeth Barrow, Grant S. Seuser, Hiroko Ariga-Miwa, Donna A. Chen, Jochen A. Lauterbach, Kiyotaka Asakura

Faculty Publications

We have studied P adsorption on Ni(111), a system which shows complex adsorbate structures. We determined the phase diagram of the surface P adsorbed on Ni(111). At low coverage, amorphous P was observed. At temperatures between 373 and 673 K and coverages above 0.1 monolayer, we found a √7×√7 R19.1° structure, but above 673 K, other complex structures were created. These structures seemed to correlate with each other and we reinterpret a √7×√7 R19.1° structure of P adsorbed on Ni(111) based on the similarities of these surface structures. The new rectangular structure for the √7×√7 19.1° is discussed in relation …

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 …

Prediction Of Haul Units’ Requirements For The Open Pit Mines Operating Towards Closure, Bartłomiej Skawina

Tanzania Journal of Engineering and Technology (TJET)

The determination of haul units is one of the important steps in the equipment selection process. The process should aim at minimizing the operational costs and create an optimal match for the haulage system. When open pit mines operating towards closure, reducing the operational costs results in significant gaining, and the savings can be used to implement some of the closure plans. In this paper, the prediction of haul units for an open pit mine which operates towards the final pit limit was analysed using discrete event simulation and multiple linear regressions. The result shows that the changes in production …

Practical Approach For Removal Of Natural Organic Matter And Defluoridation Of Maji Ya Chai River Water: Use Of Acid Pre-Treated Bone Char And Coagulants, Godfrey Mbabaye

Tanzania Journal of Engineering and Technology (TJET)

The removal of natural organic matter (NOM) and fluoride from Maji ya Chai River water (MCRW) using bone char (BC) and coagulants was investigated. Fine BC particles ranging from 0.045 to 0.2 mm were used in a 1 litre half-filled container, stirred at 300 rpm for 60 min followed by addition of a commercial coagulant and allowed to settle for 24 hours to remove NOM. MCRW practicable and affordable defluoridation method for removal of NOM through defluoridation with BC pre-treated with 0.3 N HCl followed by coagulation with Poly-aluminium chloride (PACl) is proposed. Reduction of fluoride from 21 mg/L to …

Reviewing The Potential And Constraints Of Modified Technology Options For Faecal Sludge Management In Dar Es Salaam, Tanzania, Amour Seleman

Tanzania Journal of Engineering and Technology (TJET)

Cities in the developing world face the challenge of safe management of faecal sludge because of rapid population growth that overwhelms the sanitation infrastructure and services. In developing countries, only 50% of faecal sludge (FS) generated is safely managed the remaining portion is haphazardly disposed of in the environment risking public health and environment. In response to the urgent need for safely managed sanitation services, technological options for containment, desludging and transportation of FS are being modified. This paper reviewed current desludging practices and the potential of modified technological options for addressing FSM at containment, desludging, and transportation in Dar …

Study And Modelling Of Lithium Ion Cell With Accurate Soc Measurement Algorithm Using Kalman Filter For Electric Vehicles, Kasthuriramanan Mahendravadi Sivaguru

Theses

Lithium Ion cells are preferred over lead acid cells for electric vehicles due to their energy density, higher discharge current and size. The cost of lithium ion cells is scaling down compared to ten years earlier, but as their performance characteristics increase, the need for safety and accurate modelling also increases.

The absence of a generic cell model is associated to the different makes of cells and different chemistries of Lithium ion cells behave differently under the testing conditions required for every unique application. The focus of this thesis will be on how to provide intelligence to the battery management …

Establishment Of Wildflower Islands To Enhance Roadside Health And Aesthetics, Walter Schacht, Judy Wu-Smart

Nebraska Department of Transportation: Research Reports

Wildflowers are crucial in the ecological function of the low-input roadside plant communities in terms of water andnutrient cycling, nutrient inputs such as nitrogen, total plant canopy cover, stand longevity, and provision of habitat for numerous small animals. Further, wildflowers provide critical foraging and nesting resources for birds, insects, and other wildlife. Unfortunately, habitat loss from agricultural and urban development has led to rapid population declines in wild bees and other pollinators across the US, thereby jeopardizing not only food production but also the sustainability of our natural landscapes (Kearns & Inouye, 1997). One way to mitigate wild bee decline …

Blind Algorithm Development For Peak To Average Power Ratio Reduction In Ofdm Systems Under Frequency Selective Channels, Kwame S. Ibwe

Tanzania Journal of Engineering and Technology (TJET)

One major drawback of orthogonal frequency division multiplexing (OFDM) system is peak to average power ratio (PAPR). This effect causes high power amplifier (HPA) to introduce intermodulation and out of band radiation as the signal goes through, thus degrades the performance of OFDM systems. This paper proposes blind algorithms which takes advantage of signal transformation technique and signal distortion technique. Simulation results show that at complementary cumulative distribution function (CCDF) level of 10-3, the proposed algorithm achieved 3.2 dB PAPR improvement compared to discrete Fourier transform with interleaved frequency division multiple access (DFT-IFDMA) based algorithm. The bit error rate (BER) …

Polyaniline Coated Hollow Sulfur Prepared Using Sublimate 2,4,6-Tri(Propan-2-Yl)-1,3,5-Trioxane As Template For Sulfur Electrode, Zhang-Feng Li, Xiao-Rui Wang, Wen-Sheng Tian, Jin-Ze Yang, Ping Zhang, Li-Ping Ma, Yang Chen, Xiao-Li Cui, Zhi-Yu Jiang

Journal of Electrochemistry

An advance method for preparing polyaniline-coated hollow sulfur material using sublimate material ADD(2,4,6-tri(propan-2-yl)-1,3,5-trioxane) as a template was developed for lithium-sulfur battery. At first, the smashed ADD particles were coated by a sulfur layer through the reaction of Na₂S₂O₃ with diluted HCl. Then polyaniline layer was coated again on the surface of sulfur layer through the reaction of aniline with (NH₄)₂S₂O₈. After being dried at 60 ^oC for 12 h, the ADD in such a composite evaporated totally, and resulted in the formation of polyaniline-coated hollow sulfur …

Zif-67-Derived Ag/Co-Embedded N-Enriched Mesoporous Carbon For Oxygen Reduction Reaction, Zheng-Ling Di, Jing Zhu, Lei Dai, Wei Meng, Yue-Hua Li, Zhang-Xing He, Ling Wang

Journal of Electrochemistry

Nitrogen-doped porous carbon materials are considered as one of the most promising catalysts for oxygen reduction reaction (ORR). Herein, in order to further improve the activity of the nitrogen-doped porous carbon, Ag/Co bimetal is embedded into nitrogendoped porous carbon to form Ag/Co-embedded nitrogen-doped porous carbon material (AgCo@NC). The AgCo@NC was derived by the wet impregnation of Ag+ into ZIF-67 precursor, followed by chemical reduction and a subsequent pyrolysis process under Ar atmosphere at different temperatures (500 ℃, 600 ℃, 700 ℃). The morphologic characterization shows that the Ag/Co nanoparticles were successfully embedded in the mesoporous carbon framework with abundant nitrogen …

Morphology Controlled Preparations And Electrochemical Properties Of Znco2O4 Electrode Materials For Supercapacitors, Yue-Shen Zhou, Meng Li, Shuang Wu, Zhao-Lei Li, Yan-Min Gao

Journal of Electrochemistry

In this work, hydrothermal reaction and high temperature were used to grow ZnCo₂O₄ active materials on Ni foam. The crystal stuctures and surface morphlogies of four samples were investigated by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The electrochemical performances were characterized by cyclic voltammetry (CV), galvanostatic charge/discharge (GCD) testing and electrochemical impedance spectroscopy (EIS) on an electrochemical station. It can be seen that active materials tended to form denser stuctures with an increasing amount of NH₄F in the solution system and four different morphologies of ZnCo_{2 …}

Study On Electro-Sorption Of Heavy Metals And Sulfamethoxazole On Activated Carbon Fibers, Wen-Jun Zhao, Bing-Xin Jia, Ya-Nan Zhang, Jiu-Nian Guan, Jiao Qu, Ying Lu

Journal of Electrochemistry

To study the optimal removal condition, adsorption mechanism and comparative analysis of the three typical cationic pollutants, i.e., Zn(II), anionic pollutant Cr(VI) and molecular pollutant sulfamethoxazole (SMX), using self-made upflowed electro-sorption device for adsorptions of above three pollutants by modified activated carbon fiber were researched. The activated carbon fiber (ACF) was modified by hydrochloric acid. The ACF morphology and structure before and after modification were characterized by SEM, BET and FTIR. The characterization results show that the modified ACF had fewer surface impurities than the modified surface and the gully is more obvious, the specific surface area was increased by …

Bipolar-Membrane Electrodialysis Method To Treat Industrial High Saline Perfume Wastewater, Jian Zhang, Dong-Fang Niu, Shuo-Zhen Hu, Xin-Sheng Zhang

Journal of Electrochemistry

Large amount of organic saline wastewater is generated from various chemical industries. The contents of organic saline wastewater are more and more complicated as they are created from different types of industries. Directly discharging the organic saline wastewater without pre-treatment can generate severe environmental problem and waste useful resources. It is necessary to use an economical method to treat the organic saline wastewater and recover the salt into useful materials to achieve resource reuse. Bipolar-membrane electrodialysis (BMED) is one of the methods that can remove salt from the wastewater and convert it into certain acid and base with higher value …

Transient Electrochemical Surface-Enhanced Raman Spectroscopic Study In Electrochemical Reduction Of P-Nitrothiophenol, Yun Ling, Jing Tang, Guo-Kun Liu, Cheng Zong

Journal of Electrochemistry

P-nitrothiophenol (PNTP) is one of the most common probe molecules studied by surface-enhanced Raman spectroscopy (SERS). The research in electrochemical reduction behavior of PNTP will help understanding the mechanism for the nitrobenzene reduction. In this paper, we used transient electrochemical surface-enhanced Raman spectroscopy (TEC-SERS) to study the SERS of PNTP with cyclic voltammetry and chronoamperometry on gold electrodes. The results show that the TEC-SERS provide a time resolution that equals the transient electrochemical methods, and we concluded that the reaction was so quick that we did not observe the spectral information of intermediate species described in the literatures with a …

An Aptasensor Based On Aunps/Pani/Tnts Nanocomposite For Electrochemical Detection Of Tobramycin, Yong-Ling Nong, Ni-Na Qiao, Ying Liang

Journal of Electrochemistry

A novel well-constructed electrochemical aptamer-based sensor for the detection of tobramycin was presented, using differential pulse voltammetry (DPV) as a detection technique and methylene blue(MB) as an electrochemical indicator. A glassy carbon electrode modified with a nanocomposite of Au nanoparticles/polyaniline/titania nanotubes (AuNPs/PANI/TNTs) was constructed as the electrode scaffold. The nanocomposite was characterized by transmission electron microscopy and X-ray photoelectron spectroscopy in detail. The results of cyclic voltammetry and electrochemical impedance measurements demonstrated that the AuNPs/PANI/TNTs nanocomposites can improve greatly the electron transfer on the interface. For the detection of tobramycin, the DPV results showed a linear relationship between the current …

Electrochemical Preparation And Photocatalytic Performance Of Lanio3/Tio2 Nanotube Arrays, Cheng Gong, Ze-Yang Zhang, Si-Wan Xiang, Lan Sun, Chen-Qing Ye, Chang-Jian Lin

Journal of Electrochemistry

The LaNiO₃/TiO₂ nanotube arrays were prepared by pulse electrodeposition combined with high temperature annealing. The LaNiO₃ nanoparticles modified on the TiO₂ nanotube arrays had small particle size (< 10 nm), uniform distribution and controllable loading. Some LaNiO₃ nanoparticles were deposited inside the TiO₂ nanotubes. The UV-visible absorption spectra displayed that the absorption band edge of LaNiO₃/TiO₂ nanotube arrays was obviously red-shifted as compared with that of TiO₂ nanotube arrays, and the visible light absorption was enhanced significantly. The photocatalytic degradation results of rhodamine B (RhB) under visible light showed that the LaNiO₃/TiO₂ nanotube arrays prepared …

Ionic Liquid Assisted Synthesis Of Porous Carbons From Rice Husk For Supercapacitors, Han-Fang Zhang, Feng Wei, Jian Sun, Meng-Ying Jing, Xiao-Jun He

Journal of Electrochemistry

It is still a challenge to prepare carbon materials with high specific surface area at low cost from renewable resources. Herein, the authors report an efficient approach to synthesize porous carbons (PCs) from rice husk with ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF₆)) as a template and an activation agent. The as-made PCs featured the high specific surface area up to 1438 m²·g^-1. As electrodes for supercapacitors, PCs showed a high specific capacitance of 256 F·g^-1 at 0.05 A·g^-1 in 6 mol·L^-1 KOH aqueous electrolyte and a good rate performance of 211 F·g …

Electrochemical Determination Of Trace Copper Ions In Drinking Water Source, Jing-Ji Peng, Hong Zheng, Yi-Song Zou, Guo-Kun Liu, Dong-Xing Yuan

Journal of Electrochemistry

Aiming at the on-site and quick safety evaluation of the dissolved trace copper ions (Cu²⁺) in drinking water source, an electrochemical detection platform was developed on the basis of the square wave anodic stripping voltammetry using the gold nanoparticles (Au NPs) modified glassy carbon electrode, where Au NPs were deposited via electrochemical cyclic voltammetry. The proposed method displayed the limit of detection as low as 1.3 μg·L^-1 in the linear range of 2 ~ 50 μg·L^-1. The proposed method was applied to the determination of Cu²⁺ in the midstream of Minjiang River, one of …

The Study Of Dynamic Modes Of Converters With Movable Electromagnetic Screens And Distributed Parameters, S.F. Amirov, О.Т. Boltayev

Chemical Technology, Control and Management

In article for research of dynamic characteristics of the created Converter with mobile electromagnetic screens and with the distributed parameters, the parametric block diagram is made. Based on the parametric block diagram, the analytical equation of the output voltage in the operator form is compiled for the dynamic mode. In order to study the dynamic properties of the transducer with moving electromagnetic screens and distributed parameters, the influence of input values on the reaction of the transducer is considered. On the basis of the revealed expressions the nonlinearities of the transient process are considered.

Optimization Of Image Processing Using Characteristics And Peculiarities Of Pollen Grains, I.I. Jumanov, O.I. Djumanov, R.A. Safarov

Chemical Technology, Control and Management

The problem is formulated and methods for processing images, in particular pollen grains, based on the mechanisms for extracting statistical, dynamic, texture and specific characteristics, as well as geometric features of micro-objects, are developed. Methods are proposed for assessing the accuracy of processing information on the characteristics of points, point and non-linear verification of the contour of the input and reference images, highlighting, segmenting, contrasting, interpolating. The mechanisms of extracting frequency, cytoplasm, reticules, spores, textures, morphology, and geometric features of pollen grain images are studied. A set of programs for processing microobject images in C ++ language in the CUDA …

Sustainable Algorithms For Generalized Estimation Of Dynamic Control Objects, Yulduz Muhtarhodjaeva Abdurakhmanova

Chemical Technology, Control and Management

The problems of separate and generalized assessment of the state and parameters of controlled objects under conditions of varying degrees of a priori uncertainty are considered. Stable algorithms for the generalized estimation of the state and parameters based on the quasilinearization method and the formal model of motion under conditions of statistical uncertainty, as well as the correction of the results of the generalized estimation, are presented. It is shown that the considered regularized generalized coordinate and parametric estimation algorithms make it possible to recover with sufficient accuracy the extended state vector of a dynamical system. The above algorithms make …

Calculation Of Heat Exchange Intensity At Gas-Liquid Flow Washing Tube-Lattice Nozzles, Elbek Tulkinovich Mavlonov, Zakirova Nafisa Sanatovna, Kudratilla Fuadovich Karimov, Khabibulla Sagdullaevich Nurmukhamedov

Chemical Technology, Control and Management

Several experiments were conducted on removing the heat of reaction upon contact of carbon dioxide with purified brine. Pipes with a developed heat exchange surface formed by spiral grooves on the outside and similar protrusions inside the pipes are used for effective conduction. The experiments were carried out on two and four pipes with different pitch and depth of grooves,i.e. h / S = 0.017-0.095. Studies on the intensification of convective heat exchange when washing a bundle of spiral-rolled pipes with a gas-liquid flow have found an increase in heat transfer by 1.8-2.7 times compared to a smooth pipe. Such …

A Study On Electrical Energy Measuring Device In Installation Place, Anatoliy Plakhtiev, Gayratjon Gaziev

Chemical Technology, Control and Management

An analysis of the metrological support of electric energy metering devices has been carried out, which allows us to note a number of shortcomings, which include the insufficiency and imperfection of normative and technical documentation on electric energy metering and control, operation and verification of existing measuring instruments, poor equipment of enterprises and territorial bodies of Uzstandart Agency with high-performance calibration installations, the absence of portable compact installations for checking meters at the place of use, braztsovyh higher accuracy of measuring (standards). Information is provided on the developed device that allows structurally minimizing the error in current conversion and using …

Development Of Structures Of Intellectual Information Protection System, Tulkun Fayzievich Bekmuratov, Fayzullajon Bakhtiyorovich Botirov

Chemical Technology, Control and Management

The structures of intelligent information protection systems are considered. The tree of tasks for protecting information of the information system of enterprise is presented. Information security management systems without automation of management processes and automated information security management systems are considered. The functional capabilities of multi-agent information protection systems are investigated and possible risks are analyzed. The proposed schemes of automated and automated information security management systems are described. The proposed technology for constructing a software package for an enterprise information security management system is considered, based on the concept of multi-agent systems as the basic technology for software implementation …

Algebraic Correction Of Algorithms For Recognition And Identification Of Biological Objects In Data Mining Problems, Mirzoyan Kamilov, Mirzaakbar Hudayberdiev

Chemical Technology, Control and Management

The integration of information technologies with biology is considered, enabling specialists to further study the subject area. The object of the study is the identification of the information structure and parameters of Insects Orthoptera of Uzbekistan. For this purpose, an information and identification software complex were created and the analysis of the variety of orthoptera having a certain internal structure and, accordingly, the formed structure of the relational database of the Insecta Orthoptera species was carried out. At the same time, attention will also be paid to the study of a number of scientific issues, one way or another related …

Modeling Of Multicomponent Rectification Under Uncertainty, Nodirbek Rustambekovich Yusupbekov, Djalol Patxiddinovich Mukhitdinov, Yorkin Bakhodirovich Kadirov

Chemical Technology, Control and Management

This paper presents a complete computer model for an industrial distillation column, which considers the input, output and model (nonlinearity and high-frequency dynamics of the process) uncertainties. The proposed model has a great advantage of covering the entire working range of the distillation column. This model can be used as a main tool for the analysis and synthesis of distillation process control systems.

Algorithms For Regular Synthesis Of Adaptive Systems Management Of Technological Objects Based On The Concepts Of Identification Approach, Husan Zakirovich Igamberdiev, Jasur Usmonovich Sevinov

Chemical Technology, Control and Management

Stable algorithms of adaptive control, estimation of controller parameters, synthesis of adaptive control of dynamic objects by the criterion of minimum dispersion, and synthesis of suboptimal adaptive-local control of dynamic objects based on predictive models are presented. Algorithms for the stable identification of dynamic control objects based on regularization and pseudoinversion methods based on a singular decomposition are presented. Based on the use of approximations in the form of a finite sum of Gaussian distributions, recurrent identification algorithms have been developed using multiple models and adapting their parameters. Stable algorithms are proposed for identifying the parameters of an object and …

Electrochemical Behaviors Of Azopurine On Gold Electrodes, Ming-Xue Li, Hang Shi, Jia Liu, Meng Zhang, Jian-Zhang Zhou, De-Yin Wu, Zhong-Qun Tian

Journal of Electrochemistry

In this paper, we studied the electrochemical behaviors of azopurine on polished gold electrodes with cyclic voltammetry (CV). On the basis of analyzing scan rate and peak current, it was supposed that the redox process belonged to a reversible process controlled by adsorption in 0.2 mol·L^-1 PBS (pH = 4.0 ~ 10.0) solutions. The potentials of redox peaks moved more negatively with increasing pH value. This proved that the H⁺ proton has participcted in the electrochemical reaction. The further data analysis and the calculation of surface adsorption excess demonstrated that the reaction was a two-proton and two-electron process. …

Electrochemical Cycling Stability Of Polyaniline Films In Different Color Ranges, Kun Xu, Kai-Ling Zhou, Hao Wang, Jing-Bing Liu, Hui Yan

Journal of Electrochemistry

The electrochromic behaviors of polyaniline films were investigated by potential step and cyclic voltammetry coupled with UV viscosity photometer. The polyaniline films show colorful changes from pale yellow to green and then to blue. Electrochromic stability, electrochemical behavior, coloring performance, optical properties and surface formations of the produced films were studied in detail. The working electrode was the flexible PANI electrode, and the counter electrode and the reference electrode were a platinum sheet and Ag/AgCl, respectively. The in situ optical transmittance of the PANI film at 650 nm was measured using an ultraviolet-visible-near-infrared spectrophotometer (Shimadzu UV-3101PC) combining with a square …

Electrochemical Properties Of Sulfur In Different Carbon Support Materials, Bo Zhang, Jia Liu, Xiao-Chen Liu, De-Jun Li

Journal of Electrochemistry

In order to investigate the effect of carbon structure on electrochemical performance of sulfur/carbon composite in lithium-sulfur battery, in this paper, sublimation sulfur was incorporated into three types of carbon materials, namely, graphene, carbon black and porous carbon. The three sulfur/carbon composites were characterized by scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET), and X-ray diffraction (XRD) techniques, and their electrochemical performances were also studied. The results showed that the sulfur/porous carbon composite offered an initial discharge capacity of 1623.2 mA·h·g^-1 and remained 845 mA·h·g^-1 after 100 cycles. Compared with graphene and carbon black, the mesopores and micropores in porous …