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Performance Analysis of 112Gb/s×4-Channel WDM PDM-DQPSK Optical Label Switching System With Spectral Amplitude Code Labels

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Photonic Sensors 2017年第1期7卷 88-96页

作者： isaac Adjaye ABOAGYE Fushen CHen Yongsheng CAO Key Laboratory of Optical Fiber Sensing and Communications Ministry of Education School of Communication andInformation Engineering University of Electronic Science and Technology of China Chengdu 611731 China

We present the performance analysis of ll2Gb/s-4 wavelength division multiplexing （WDM） 100GHz channel spacing polarization division multiplexed-differential quadrature phase shift keying （PDM-DQPSK） optical label switching system with frequency swept coherent detected spectral amplitude code labels. Direct detection is chosen to demodulate the payload by applying a polarization tracker, while 4-bits of 156Mb/s spectral amplitude code label is coherently detected with a scheme of frequently-swept coherent detection. We optimize the payload laser linewidth as well as the frequency spacing between the payload and label. The label and payload signal performances are assessed by the eye-diagram opening factor （EOF） and bit-error rate （BER） at 10 9 as a function of the received optical power （ROP） and the optical signal to noise ratio （OSNR）. The payload could well be demodulated after 900 km at a bit error rate of 10-3 using forward error correction （FEC）.

关键词： Optical label switching (OLS) polarization division multiplexed (PDM) spectral amplitude code(SAC) wavelength division multiplexing (WDM)

In-situ formation characteristic, tribological characterization and anti-corrosion properties of quaternary composites films

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Transactions of Nonferrous Metals Society of China 2014年第10期24卷 3170-3180页

作者： Ojo Sunday isaac FAYOMI Abimbola Patricia Idowu POPOOLA Department of Chemical Metallurgical and Materials EngineeringTshwane University of TechnologyP.M.B. X680 Pretoria South Africa

Improvements of wear and corrosion properties are essential characteristic in engineering application. A study was made on the structure, electro-oxidation and properties of fabricated Zn-Al-SnO 2-Ti O2（Zn-Al-Sn-Ti） thin films using electrodeposition technique from chloride bath. The microstructural studies were performed by scanning electron microscopy with attached energy dispersive spectrometer（SEM-EDS）, optical microscopy（OPM） and X-ray diffractogram（XRD）. The electrochemical oxidation and erosion behavior in 3.65% Na Cl medium were studied by potentiodynamic polarization technique and characterized by atomic force microscopy（AFM）. The hardness and wear behavior of the electrodeposited film were performed by high diamond dura scan microhardness tester and CERT UMT-2 reciprocating sliding machine. It was found that a successful co-deposition of composite and particle were attained. Homogeneous imbedded grain structure distribution and fine refinement of crystal with improved micromechanical behavior was achieved. The corrosion resistance, hardness and wear stability resistance of the fabricated quaternary films improved significantly in all varied process parameter.

关键词： co-deposition microstructural evolution anti-corrosion property composite materials

Anthropogenic land use substantially increases riverine CO_(2) emissions

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Journal of environmental Sciences 2022年第8期34卷 158-170页

作者： Shijie Gu Siyue Li isaac R.Santos School of River and Ocean engineering Chongqing Jiaotong UniversityChongqing 400074China Key Laboratory of Reservoir Aquatic environment Chongqing Institute of Green and Intelligent TechnologyChinese Academy of SciencesChongqing 400714China Chongqing School University of Chinese Academy of SciencesChongqing 400714China Research Center for environmental Ecology and engineering Institute of Changjiang Water Environment and Ecological SecuritySchool of Environmental Ecology and Biological EngineeringKey Laboratory for Green Chemical Process of Ministry of EducationKey Laboratory of Novel Reactor and Green Chemical Technology of Hubei ProvinceEngineering Research Center of Phosphorus Resources Development and Utilization of Ministry of EducationWuhan Institute of TechnologyWuhan 430205China Department of Marine Sciences University of GothenburgGothenburg 41296Sweden National Marine Science Centre Southern Cross UniversityCoffs HarbourNSW 2450Australia

Carbon dioxide(CO_(2)) emissions from inland waters to the atmosphere are a pivotal component of the global carbon budget. Anthropogenic land use can influence riverine CO_(2) emissions, but empirical data exploring cause-effect relationships remain limited. Here, we investigated CO_(2) partial pressures(pCO_(2)) and degassing in a monsoonal river(Yue River)within the Han River draining to the Yangtze in China. Almost 90% of river samples were supersaturated in CO_(2) with a mean ± standard deviation of 1474 ± 1614 μatm, leading to emissions of 557-971 mmol/m^(2)/day from river water to the atmosphere. Annual CO_(2) emissions were 1.6-2.8 times greater than the longitudinal exports of riverine dissolved inorganic and organic carbon. pCO_(2) was positively correlated to anthropogenic land use(urban and farmland), and negatively correlated to forest cover. p CO_(2) also had significant and positive relationships with total dissolved nitrogen and total dissolved phosphorus. Stepwise multiple regression models were developed to predict p CO_(2) . Farmland and urban land released nutrients and organic matter to the river system, driving riverine p CO_(2) enrichment due to enhanced respiration in these heterotrophic rivers. Overall, we show the crucial role of land use driving riverine pCO_(2) , which should be considered in future large-scale estimates of CO_(2) emissions from streams. Land use change can thus modify the carbon balance of urban-river systems by enhancing river emissions, and reforestation helps carbon neutral in rivers.

关键词： River carbon Inland waters Greenhouse gases Climate change Water quality Headwater streams

Fracture strength evaluation of titanium alloys using modified average stress criterion

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Transactions of Nonferrous Metals Society of China 2013年第4期23卷 1072-1079页

作者： H.BRIGHTON isaac JOHN T.CHRISTOPHER Sardar Raja College of engineering AlangulamTirunelveli-627808India Government College of engineering PerumalpuramTirunelveli-627007India

Structural integrity procedures were used to demonstrate the fitness for the purpose of engineering components transmitting loads. The prediction of the fracture strength of titanium alloys containing sharp notches through the damage model depends on the un-notched strength and the critical length of the damage zone ahead of the notch. In general, the critical length of the damage zone depends on the material, specimen, and size of the sharp notch. Modifications were made in one of the stress fracture criteria known as the average stress criterion for accurate prediction of notched tensile strength of titanium alloy specimen containing sharp notches. To examine the adequacy of these modifications, fracture data of center-cracked titanium alloys with various thicknesses are considered. The notched （fracture） strength estimates are found to be close to the test results. The modified average stress criterion is very simple to predict the notched tensile strength.

关键词： titanium alloys center crack tensile specimen stress criterion failure assessment diagram fracture strength

Laboratory investigation into the use of soundless chemical demolitions agents for the breakage of hard rock

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International Journal of Coal Science & Technology 2022年第5期9卷 71-80页

作者： Kelly‑Meriam Habib isaac Vennes Hani Mitri Department of Mining and Material engineering McGill UniversityMontrealCanada

The method of drilling and blasting with explosives is widely used in rock fragmentation applications in the mining industry for mine development and ore ***,the use of explosives is associated with rigorous safety and environmental constraints as blasting creates toxic fumes,ground vibrations,and *** study is focused on the use of Soundless Chemical Demolition Agents(SCDA)as a more environmentally friendly method for rock breakage and a potential replacement of *** this paper,the results of a series of experimental tests are reported to identify the efect of SCDA on hard rock breakage under no load and under uniaxial loading *** granite prismatic specimens of 152.4 mm(6″)×152.4–203.2 mm(6–8″)×406.4 mm(16″)are used to test the infuence of borehole size on the time to fracturing with SCDA borehole size of 25.4 mm(1″),31.75 mm(1.25″)and 38.1 mm(1.5″).It is shown that the fracturing time decreases with increasing borehole *** is also shown that specimens subjected to uniaxial compression of 5 MPa fracture as early as 7 h after SCDA mixing.A borehole spacing to borehole diameter ratio of 12.8 to 14.6 is suggested for practical applications.

关键词： Explosive-free Hard rock fragmentation Soundless chemical demolition agents Uniaxial loading

Anti-Corrosion and Tribo-Mechanical Properties of Co-deposited Zn–SnO_2 Composite Coating

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Acta Metallurgica Sinica(english Letters) 2015年第4期28卷 521-530页

作者： Ojo Sunday isaac Fayomi Abimbola Patricia Idowu Popoola Department of Chemical Metallurgical and Materials EngineeringTshwane University of Technology Department of Mechanical engineering Covenant University

Zn-SnO2 composite coatings were prepared by direct potential using electrolytic co-deposition technique from sulfate solution. The effect of Zn2＋ and SnO2 concentrations in deposited bath on the mechanical properties and mor- phological characteristics of the composite coatings were examined. The characterizations of the sample were analyzed using scanning electron microscopy couple with energy dispersive spectroscopy （SEM/EDS）, X-ray diffraction （XRD） and atomic force microscopy （AFM）. The electrochemical degradation behavior of the samples in 3.65 wt.% NaCl solution was studied using potentiodynamic polarization technique and characterized by high-resolution optical microscope. From all the fabricated composite coatings, obvious diffraction peaks were observed with Zn-7Sn-S-0.3V film with Zn2Sn7, Sn, Zn2Sn5 and Zn phases, confirming the presence and formation of Zn-SnO2 coating. The XRD pattern shows that the presences of SnO2 particle remarkably play a major role in the precipitation and orientation of the alloy matrix. From the SEM/EDS and AFM results, the deposits show that composite particle and proper bath composition have strong influence on the microstructure. An enhanced corrosion resistance was attained as a result of the induced particles.

关键词： Metal matrix composite Co-deposition Mechanical property Corrosion resistance

Large-scale destress blasting for seismicity control in hard rock mines:A case study

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International Journal of Mining Science and Technology 2020年第2期30卷 141-149页

作者： isaac Vennes Hani Mitri Damodara Reddy Chinnasane Mike Yao Department of Mining and Materials engineering McGill UniversityMontrealQuebec H3A 0E8Canada Copper Cliff Mine Vale Canada LtdSudbury P0M 1N0Canada

Destress blasting is a rockburst control technique where highly stressed rock is blasted to reduce the local stress and stiffness of the rock,thereby reducing its burst *** technique is commonly practiced in deep hard rock mines in burst prone developments,as well as in sill or crown pillars which become burst-prone as the orebody is ***-scale destressing is a variant of destress blasting where panels are created parallel to the orebody strike with a longhole,fanning blast pattern from cross cut drifts situated in the host *** aim of panel destressing is to reduce the stress concentration in the ore blocks or pillars to be *** paper focuses on the large-scale destress blasting program conducted at Vale's Copper Cliff Mine(CCM)in Ontario,*** merits of panel destressing are examined through field measurements of mining induced stress changes in the *** destressing mechanism is simulated with a rock fragmentation factor(a)and stress reduction/dissipation factor(b).A 3D model is built and validated with measured induced stress *** is shown that the best correlation between the numerical model and field measurements is obtained when the combination of a and b indicates that the blast causes high fragmentation(a=0.05)and high stress release(b=0.95)in the destress *** is demonstrated that the burst proneness of the ore blocks in the panel stress shadow is reduced in terms of the brittle shear ratio(BSR)and the burst potential index(BPI).

关键词： Destress blasting Preconditioning Rockbursts Strainbursts Numerical modeling

Assessment of Ti-6Al-4V particles as a reinforcement for AZ31 magnesium alloy-based composites to boost ductility incorporated through friction stir processing

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Journal of Magnesium and Alloys 2022年第4期10卷 979-992页

作者： isaac Dinaharan Shuai Zhang Gaoqiang Chen Qingyu Shi IDM-Joint Lab Department of Mechanical EngineeringTsinghua UniversityBeijing 100084China The State Key Laboratory of Tribology Department of Mechanical EngineeringTsinghua UniversityBeijing 100084China

Poor ductility is the primary concern of magnesium matrix composites(MMCs)inflicted by non-deformable ceramic particle *** particles which melt at elevated temperature can be used as reinforcement to improve the deformation ***-6Al-4V particles reinforced AZ31 MMCs were produced through friction stir processing(FSP)which was carried out in a traditional vertical milling *** microstructural features as well as the response to external tensile load were explored.A homogenous distribution of Ti-6Al-4V was achieved at every part of the stir *** was no chemical decomposition of ***,Ti-6Al-4V did not react with Al and Zn present in AZ31 alloy to form new compounds.A continuous strong interface was obtained around Ti-6Al-4V particle with the ***-6Al-4V particles underwent breakage during processing due to severe plastic *** was a remarkable refinement of grains in the composite caused by dynamic recrystallization in addition to the pinning of smaller size broken *** dislocations were observed in the matrix because of plastic deformation and the associated strain ***-6Al-4V particles improved the tensile behavior and assisted to obtain appreciable deformation before *** mode of failure was avoided.

关键词： Magnesium matrix composite Friction stir processing Ti-6Al-4V Microstructure Tensile strength

Exponential Continuous Non-Parametric Neural Identifier With Predefined Convergence Velocity

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IEEE/CAA Journal of Automatica Sinica 2022年第6期9卷 1049-1060页

作者： Mariana Ballesteros Rita Q.Fuentes-Aguilar isaac Chairez Instituto Politécnico Nacional Centro de Innovación y Desarrollo Tecnológico en Cómputo Unidad Profesional Interdisciplinaria de Biotecnología 07340Mexico CityMexico Tecnológico de Monterrey School of Engineering and SciencesZapopanJalisco 45138Mexico Department of Bioprocesses UPIBIInstituto Politécnico Nacional07340Mexico City

This paper addresses the design of an exponential function-based learning law for artificial neural networks(ANNs)with continuous *** ANN structure is used to obtain a non-parametric model of systems with uncertainties,which are described by a set of nonlinear ordinary differential *** novel adaptive algorithms with predefined exponential convergence rate adjust the weights of the *** first algorithm includes an adaptive gain depending on the identification error which accelerated the convergence of the weights and promotes a faster convergence between the states of the uncertain system and the trajectories of the neural *** second approach uses a time-dependent sigmoidal gain that forces the convergence of the identification error to an invariant set characterized by an *** generalized volume of this ellipsoid depends on the upper bounds of uncertainties,perturbations and modeling *** application of the invariant ellipsoid method yields to obtain an algorithm to reduce the volume of the convergence region for the identification *** adaptive algorithms are derived from the application of a non-standard exponential dependent function and an associated controlled Lyapunov *** examples demonstrate the improvements enforced by the algorithms introduced in this study by comparing the convergence settings concerning classical schemes with non-exponential continuous learning *** proposed identifiers overcome the results of the classical identifier achieving a faster convergence to an invariant set of smaller dimensions.

关键词： Exponential Lyapunov functions learning laws non-parametric identifier predefined convergence rate