检索结果-南通市图书馆

Stabilization of sand dunes with oil residue: Application to civil engineering construction and environmental implications

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Journal of Central South University 2015年第8期22卷 3059-3068页

作者： Esmail Aflaki alborz Hajiannia Civil and Environmental Engineering Department Amirkabir University of Technology

The present work ascertains the feasibility of oil residue treatment for stabilizing wind-blown sand dunes. Various combinations of natural collapsible saline from the Jandaq desert of Iran and oil residue from distillation towers of Iranian refineries were tested in laboratory experiments. Stabilized sands were evaluated in terms of geotechnical properties, permeability, and oil retention characteristics(i.e. bonding mechanisms, leaching and migrating behaviour of oil residue from the stabilized sands). Since the presence of oil residue in soils can pose an environmental threat, the optimum retention capacity of the stabilized sands is of critical concern. Relative to sand that was not augmented with oil residue, specimens made of 7% oil residues had the highest compressive strength, significantly higher cohesion and load bearing capacity, and considerably lower permeability. The effect of distilled water, saline water and municipal sewage on prepared specimens were also evaluated.

关键词：残油处理稳定性土木工程施工环境影响沙丘应用承载能力实验室实验

Effects of TIG Surface Melting and Chromium Surface Alloying on Microstructure, Hardness and Wear Resistance of ADI

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research(International) 2008年第4期15卷 86-94页

作者： A amirsadeghi M Heydarzadeh Sohi S F Kashani Bozorg School of Metallurgy and Materials Engineering University of Tehran Tehran Iran

Microhardness and wear resistance of different rnicrostructures formed by TIG （tungsten inert gas） surface melting and chromium surface alloying （using ferrochromium） of ADI （austempered ductile iron） were studied. Surface melting resulted in the formation of a ledeburitic structure in the melted zone, and this structure has a hardness up to 896 HV as compared to 360 HV in that of ADI. Moreover, chromium surface alloying resulted in the formation of different structures including：（1） a hypereutectic structure consisting of primary （Fe,Cr）7C3 carbides and a eutectic matrix of transformed austenite （into martensite and retained austenite）, as also （Fe,Cr）7C3 carbides, with a hardness of 1078 HV; （2） a hypoeutectic structure consisting of the same eutectic along with transformed primary austenite, with a hardness of 755 HV; and （3） a ledeburitic structure with an acicular morphology and a hardness of 896 HV. The results also indicated that surface melting reduced the wear rate of the ADI by approximately 37%. Also, chromium surface alloying yielded a superior wear behavior and reduced the wear rate of the treated specimens by about 38% and 70%, depending on the structures formed.

关键词： ductile iron surface alloying surface melting chromium wear resistance

Semi-analytical approach for free vibration analysis of cracked beams resting on two-parameter elastic foundation with elastically restrained ends

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Frontiers of Mechanical Engineering 2014年第2期9卷 191-202页

作者： alborz MIRZABEIGY Firooz BAKHTIARI-NEJAD Department of Mechanical Engineering Amirkabir University of Technology Hafez Ave Tehran 15914 Iran

In present study, free vibration of cracked beams resting on two-parameter elastic foundation with elastically restrained ends is considered. Euler-Bemoulli beam hypothesis has been applied and translational and rotational elastic springs in each end considered as support. The crack is modeled as a mass-less rotational spring which divides beam into two segments. After governing the equations of motion, the differential transform method （DTM） has been served to determine dimensionless frequencies and normalized mode shapes. DTM is a semi-analytical approach based on Taylor expansion series that converts differential equations to recursive algebraic equations. The DTM results for the natural frequencies in special cases are in very good agreement with results reported by well-known references. Also, the DTM procedure yields rapid convergence beside high accuracy without any frequency missing. Comprehensive studies to analyze the effects of crack location, crack severity, parameters of elastic foundation and boundary conditions on dimensionless frequencies as well as effects of elastic boundary conditions on cracked beams mode shapes are carried out and some problems handled for first time in this paper. Since this paper deals with general problem, the derived formulation has capability for analyzing free vibration of cracked beam with every boundary condition.

关键词： free vibration cracked beam elastic foundation restrained ends differential transform method

Numerical study of the effects of split injection strategy and swirl ratio for biodiesel PCCI combustion and emissions

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Propulsion and Power Research 2020年第4期9卷 355-371页

作者： alborz Zehni Navid Balazadeh Mojtaba Hajibabaei Kamran Poorghasemi Engine Research Center Mega Motor CorpTehranIran Department of Mechanical Engineering Sharif University of TechnologyTehranIran Department of Mechanical Engineering Iran University of Science and TechnologyTehranIran Department of Mechanical Engineering Shabestar BranchIslamic Azad UniversityShabestarIran

New methods have been studied in the past few decades to decrease exhaust emissions and fuel consumption of diesel *** new combustion methods as low-temperature combustion(LTC)strategies and also utilizing new fuels as bio-diesel are beneficial ways to overcome diesel engine *** numerical study focused on the effect of split injection strategies as well as swirl ratio(SR)on the biodiesel premixed charge compression ignition(PCCI)combustion process and the related *** this regard,KIVA-3V code as a CFD tool has been utilized to analyze the combustion and emission characteristics of the diesel *** and split injection strategies have been executed on biodiesel PCCI combustion and have been compared in order to probe and examine the injection *** results show that in both strategies,advancing the injection timing can lower the combustion emission and improve the engine performance by optimizing the start of injection(SOI)as sweet spot *** a high swirl ratio with the split injection strategy has a negative effect on overall combustion,emission,and performance in comparison with the single injection *** multi-injection scheme,SOI=−35 ATDC,SR=1.1,and for single injection scheme,SOI=−40 ATDC,SR=1.1 are considered as optimum cases regarding minimum total exhaust emissions and highest performance.

关键词： Premixed charge compression ignition(PCCI) Split injection Swirl ratio Biodiesel Combustion Emission

Pixel super-resolution using wavelength scanning

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Light(Science & Applications) 2015年第1期4卷 22-32页

作者： Wei Luo Yibo Zhang alborz Feizi Zoltan Gorocs Aydogan Ozcan Electrical Engineering Department University of CaliforniaLos AngelesCA 90095USA Bioengineering Department University of CaliforniaLos AngelesCA 90095USA California NanoSystems Institute(CNSI) University of CaliforniaLos AngelesCA 90095USA Department of Surgery David Geffen School of MedicineUniversity of CaliforniaLos AngelesCA 90095USA

Undersampling and pixelation affect a number of imaging systems, limiting the resolution of the acquired images, whichbecomes particularly significant for wide-field microscopy applications. Various super-resolution techniques have been implemented to mitigate this resolution loss by utilizing sub-pixel displacements in the imaging system, achieved, for example, byshifting the illumination source, the sensor array and/or the sample, followed by digital synthesis of a smaller effective pixel bymerging these sub-pixel-shifted low-resolution images. Herein, we introduce a new pixel super-resolution method that is basedon wavelength scanning and demonstrate that as an alternative to physical shifting/displacements, wavelength diversity can beused to boost the resolution of a wide-field imaging system and significantly increase its space-bandwidth product. We confirmedthe effectiveness of this new technique by improving the resolution of lens-free as well as lens-based microscopy systems anddeveloped an iterative algorithm to generate high-resolution reconstructions of a specimen using undersampled diffraction patterns recorded at a few wavelengths covering a narrow spectrum (10–30 nm). When combined with a synthetic-aperture-baseddiffraction imaging technique, this wavelength-scanning super-resolution approach can achieve a half-pitch resolution of250 nm, corresponding to a numerical aperture of ~ 1.0, across a large field of view (420 mm^(2)). We also demonstrated theeffectiveness of this approach by imaging various biological samples, including blood and Papanicolaou smears. Compared withdisplacement-based super-resolution techniques, wavelength scanning brings uniform resolution improvement in all directionsacross a sensor array and requires significantly fewer measurements. This technique would broadly benefit wide-field imagingapplications that demand larger space-bandwidth products.

关键词： holographic imaging on-chip microscopy pixel super-resolution wavelength scanning wide-field imaging

Performance Comparison of Photovoltaic Modules under Low Sunlight

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Electrical Engineering 2017年第3期5卷 128-136页

作者： A. Cigdem Besed Ertan Arikan alborz Ebrahimi R&D Center GTC Foreign Trade Limited Adiyaman 02040 Turkey

Lipid Production by <i>Rhodotorula glutinis</i>from Pulp and Paper Wastewater for Biodiesel Production

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Sustainable Bioenergy Systems 2015年第3期5卷 114-125页

作者： Marta amirsadeghi Sara Shields-Menard W. Todd French Rafael Hernandez Dave C. Swalm School of Chemical Engineering Mississippi State University Starkville Mississippi USA Department of Biological Science Mississippi State University Starkville Mississippi USA College of Engineering University of Louisiana at Lafayette Lafayette Louisiana USA

This study investigated the potential of oleaginous yeast Rhodotorula glutinis utilizing pulp and paper wastewater effluents as cultivation media for the sustainable production of microbial lipids as biodiesel feedstock. R. glutinis is oleaginous yeast, which has the ability to produce significant quantities of intercellular lipids in the form of triacylglycerols. Yeast lipids are a promising potential feedstock for biodiesel production due to similar fatty acid composition to plant oils. The effect of various carbon sources on biomass production, lipid accumulation, substrate utilization, and fatty acid composition using R. glutinis in the pulp and paper wastewater media was studied. The pulp and paper wastewater was supplemented with glucose, xylose, and glycerol as carbon sources under nitrogen-limited conditions. The maximum lipid productions of 1.3 - 2.9 g•L–1, which corresponded to the intracellular lipid contents of 8% - 15% cell dry weight (CDW), were obtained under various carbon substrates. A kinetic study of the batch fermentation was performed in a 3 L aerobic batch fermenter to describe the cell growth, lipid accumulation, and substrate utilization process, and the kinetic parameter was estimated. The fatty acid profile of oleaginous yeast was rich in palmitic, oleic, and linoleic acids and comparable to vegetable oils. Thus, the results of this study indicated that pulp and paper wastewater could be used to produce lipids as biodiesel feedstock.

关键词： Biofuels Lipid Production Biodiesel Feedstock Rhodotorula glutinis Pulp and Paper Wastewater

Air quality monitoring using mobile microscopy and machine learning

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Light(Science & Applications) 2017年第1期6卷 555-566页

作者： Yi-Chen Wu Ashutosh Shiledar Yi-Cheng Li Jeffrey Wong Steve Feng Xuan Chen Christine Chen Kevin Jin Saba Janamian Zhe Yang Zachary Scott Ballard Zoltán Göröcs alborz Feizi Aydogan Ozcan Electrical Engineering Department University of CaliforniaLos AngelesCA 90095USA Bioengineering Department University of CaliforniaLos AngelesCA 90095USA California NanoSystems Institute(CNSI) University of CaliforniaLos AngelesCA 90095USA Computer Science Department University of CaliforniaLos AngelesCA 90095USA David Geffen School of Medicine University of CaliforniaLos AngelesCA 90095USA

Rapid,accurate and high-throughput sizing and quantification of particulate matter(PM)in air is crucial for monitoring and improving air *** fact,particles in air with a diameter of≤2.5μm have been classified as carcinogenic by the World Health *** we present a field-portable cost-effective platform for high-throughput quantification of particulate matter using computational lens-free microscopy and *** platform,termed c-Air,is also integrated with a smartphone application for device control and display of *** mobile device rapidly screens 6.5 L of air in 30 s and generates microscopic images of the aerosols in *** provides statistics of the particle size and density distribution with a sizing accuracy of~93%.We tested this mobile platform by measuring the air quality at different indoor and outdoor environments and measurement times,and compared our results to those of an Environmental Protection Agency–approved device based on beta-attenuation monitoring,which showed strong correlation to c-Air ***,we used c-Air to map the air quality around Los Angeles International Airport(LAX)over 24 h to confirm that the impact of LAX on increased PM concentration was present even at 47 km away from the airport,especially along the direction of landing *** its machinelearning-based computational microscopy interface,c-Air can be adaptively tailored to detect specific particles in air,for example,various types of pollen and mold and provide a cost-effective mobile solution for highly accurate and distributed sensing of air quality.

关键词： air-quality monitoring holography machine learning particulate matter