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Articles 61 - 90 of 137

Full-Text Articles in Engineering

Planning For Intermittent Water Supply In Small Gravity-Fed Distribution Systems: Case Study In Rural Panama, Frank B. Dubasik Jan 2017

Planning For Intermittent Water Supply In Small Gravity-Fed Distribution Systems: Case Study In Rural Panama, Frank B. Dubasik

Dissertations, Master's Theses and Master's Reports

Intermittent water supply (IWS) is defined as a piped water distribution system that operates in an intermittent fashion, i.e. less than 24 hours per day. Piped water distribution systems are designed to operate with continuous water supply (CWS), meaning the system is operated continuously and maintains positive pressures in the distribution network. Operating a system in an intermittent fashion can cause inequality of access in a water distribution system. It may also result in lower water quality and wear and tear on the system.

In the community of Espavé, Panamá a new water system was installed and brought online in …


Social, Economic, And Technical Feasibility Of Ablution Gray Water Reuse In Tong, Ghana, Adrienne Masterton Jan 2017

Social, Economic, And Technical Feasibility Of Ablution Gray Water Reuse In Tong, Ghana, Adrienne Masterton

Dissertations, Master's Theses and Master's Reports

Water insecurity is a constant stressor for millions of people around the globe. The potential of gray water as an alternative water source has gained increasing attention in the literature. In water-scarce Muslim communities, the practice of ablution – the rinsing of the face, hands, and feet before prayer – offers a unique opportunity for gray water reuse.

This report investigates the feasibility of treating and reusing ablution gray water (AGW) with respect to religious acceptability, economic measures, and physical parameters in Tong, a rural community of Muslim subsistence farmers in northern Ghana. Investigatory tools included: household water use surveys, …


Mse Annual Report 2017, Department Of Materials Science And Engineering, Michigan Technological University Jan 2017

Mse Annual Report 2017, Department Of Materials Science And Engineering, Michigan Technological University

Department of Materials Science and Engineering Annual Reports

Table of Contents

  • Faculty and Staff News
  • Faculty Research
  • Student News
  • Senior Design Teams
  • Graduate Student News
  • Outreach
  • Alumni News
  • By the Numbers
  • Scholarships


Characterization Of Ecological Water Stress In The U.S. Great Lakes Region Using A Geospatial Modeling Approach, Sara Alian Jan 2017

Characterization Of Ecological Water Stress In The U.S. Great Lakes Region Using A Geospatial Modeling Approach, Sara Alian

Dissertations, Master's Theses and Master's Reports

Anthropocentric water resources management affects aquatic habitats by changing streamflow regime. Understanding the impacts of water withdrawal from different sources and consumption by various economic sectors at different spatial and temporal scales is key to characterizing ecologically harmful streamflow disturbances. To this end, we developed a generic, integrative framework to characterize catchment scale water stress at annual and monthly time scales. The framework accounts for spatially cumulative consumptive and non-consumptive use impacts and associated changes in flow due to depletion and return flow along the stream network. Application of the framework to the U.S. Great Lakes Region indicates that a …


A Global Catalogue Of Large So < Inf> 2 Sources And Emissions Derived From The Ozone Monitoring Instrument, Vitali E. Fioletov, Chris A. Mclinden, Nickolay Krotkov, Can Li, Joanna Joiner, Nicolas Theys, S. Carn, Mike D. Moran Sep 2016

A Global Catalogue Of Large So < Inf> 2 Sources And Emissions Derived From The Ozone Monitoring Instrument, Vitali E. Fioletov, Chris A. Mclinden, Nickolay Krotkov, Can Li, Joanna Joiner, Nicolas Theys, S. Carn, Mike D. Moran

Michigan Tech Publications, Part 1

Sulfur dioxide (SO2) measurements from the Ozone Monitoring Instrument (OMI) satellite sensor processed with the new principal component analysis (PCA) algorithm were used to detect large point emission sources or clusters of sources. The total of 491 continuously emitting point sources releasing from about 30 kt yr-1 to more than 4000 kt yr-1 of SO2 per year have been identified and grouped by country and by primary source origin: volcanoes (76 sources); power plants (297); smelters (53); and sources related to the oil and gas industry (65). The sources were identified using different methods, including through OMI measurements themselves applied …


Developing The Greatest Blue Economy: Water Productivity, Fresh Water Depletion, And Virtual Water Trade In The Great Lakes Basin, A. L. Mayer, Stanley Mubako, Benjamin L. Ruddell May 2016

Developing The Greatest Blue Economy: Water Productivity, Fresh Water Depletion, And Virtual Water Trade In The Great Lakes Basin, A. L. Mayer, Stanley Mubako, Benjamin L. Ruddell

Michigan Tech Publications, Part 1

The Great Lakes basin hosts the world's most abundant surface fresh water reserve. Historically an industrial and natural resource powerhouse, the region has suffered economic stagnation in recent decades. Meanwhile, growing water resource scarcity around the world is creating pressure on water-intensive human activities. This situation creates the potential for the Great Lakes region to sustainably utilize its relative water wealth for economic benefit. We combine economic production and trade datasets with water consumption data and models of surface water depletion in the region. We find that, on average, the current economy does not create significant impacts on surface waters, …


High-Efficiency Solar-Powered 3-D Printers For Sustainable Development, Jephias Gwamuri, Dhiogo Franco, Khalid Khan, Lucia Gauchia, Joshua M. Pearce Jan 2016

High-Efficiency Solar-Powered 3-D Printers For Sustainable Development, Jephias Gwamuri, Dhiogo Franco, Khalid Khan, Lucia Gauchia, Joshua M. Pearce

Michigan Tech Publications, Part 1

The release of the open source 3-D printer known as the RepRap (a self-Replicating Rapid prototyper) resulted in the potential for distributed manufacturing of products for significantly lower costs than conventional manufacturing. This development, coupled with open source-appropriate technology (OSAT), has enabled the opportunity for 3-D printers to be used for sustainable development. In this context, OSAT provides the opportunity to modify and improve the physical designs of their printers and desired digitally-shared objects. However, these 3-D printers require electricity while more than a billion people still lack electricity. To enable the utilization of RepRaps in off-grid communities, solar photovoltaic …


Comparison Of Ignition Delays And Liquid Penetrations Of Jp-8, Synthetic Jp-8, And A Jp-8 Surrogate Under Diesel Engine Conditions, Kyle Yeakle Jan 2016

Comparison Of Ignition Delays And Liquid Penetrations Of Jp-8, Synthetic Jp-8, And A Jp-8 Surrogate Under Diesel Engine Conditions, Kyle Yeakle

Dissertations, Master's Theses and Master's Reports

The U.S. Army and many NATO affiliates have adopted a ‘one fuel forward fuel policy’ (OFF). The goal of the OFF policy is reducing the logistics and cost involved with providing fuel for military vehicles. With this policy, the logical choice fuel is military grade jet petroleum, JP-8, because of the fuel constraints of turbo-jet engines. This requirement has made it necessary to run military compression ignited engines on JP-8. To reduce the Army’s reliance on petroleum based fuels an alternative fuel, synthetic JP-8, derived from coal and made in the Fischer-Tropsch production method is allowed to be blended up …


Evaluating Groundwater Recharge In The Saloum Region Of Senegal, Alexander Wohlgemuth Jan 2016

Evaluating Groundwater Recharge In The Saloum Region Of Senegal, Alexander Wohlgemuth

Dissertations, Master's Theses and Master's Reports

Approximately 1.2 billion people in the world live in an area facing physical, or absolute, water scarcity (defined as access to less than 1,000 cubic meters of water). This number is projected to increase to 1.8 billion by the year 2025. Thirty-eight percent of the world’s population lives in arid, semi-arid or dry subhumid regions, which translates to a high dependence on the 30% of the world’s freshwater present in the ground. Further, the rate of water use is increasing rapidly – between two and two and a half times that of population growth, over the last century.

In regions …


The Effect Of Community Connectivity On Water And Sanitation Systems In Rural Panama, M.C. Moritz Jan 2016

The Effect Of Community Connectivity On Water And Sanitation Systems In Rural Panama, M.C. Moritz

Dissertations, Master's Theses and Master's Reports

The world has yet to realize universal access to water and sanitation. Various academic and professional fields provide frameworks for understanding water and sanitation access, but none directly consider the impact of community connectivity. Community connectivity refers to the infrastructures linking rural communities with urban centers. These infrastructures fall under the broad categories of transportation, energy, and telecommunication. This paper examines 23 rural Panamanian communities and compares connectivity measures with the functionality of the communities’ rural water and sanitation systems (RWSS). Community connectivity was evaluated with the Community Connectivity Analysis Tool (CCAT), while the water and sanitation systems were evaluated …


Experimental And Theoretical Investigation Of Sustainable Fast Pyrolysis Biofuels From Woody Biomass, Bethany Jean Klemetsrud Jan 2016

Experimental And Theoretical Investigation Of Sustainable Fast Pyrolysis Biofuels From Woody Biomass, Bethany Jean Klemetsrud

Dissertations, Master's Theses and Master's Reports

Biofuels are an important advancement in alternative energy that can provide substantial environmental benefits compared to their conventional fossil fuel counterparts Said benefits are usually measured using life cycle assessments. However, it is not well understood yet how different methodological choices such as system boundaries, biomass feedstocks, conversion pathways, geographical data, etc. affect the conclusions drawn from biofuels LCA. This research shows large variability in life cycle assessment results and limits comparison across different biofuel pathways due to methodological choices set forth by policy and certification schemes. Advanced biofuels have not reached large scale production due to a limited understanding …


Comparative Analysis Of Locally Available Materials For Treadle Pump Seals In Senegal, West Africa, Brennan Tymrak Jan 2016

Comparative Analysis Of Locally Available Materials For Treadle Pump Seals In Senegal, West Africa, Brennan Tymrak

Dissertations, Master's Theses and Master's Reports

For rural farmers in Senegal, West Africa, pulling water for irrigation can be a laborious but necessary task during the dry season to earn income from vegetable gardening. Traditional water pulling methods are inexpensive but require great physical effort, while modern machines decrease the labor burden but at a high financial cost. This study looked at an intermediate water pulling technology, the treadle pump, and how it could be improved to become more desirable for use in agricultural irrigation. A treadle pump was built and tested during field work in a rural Senegalese village. Observations from field testing prompted a …


Capturing Optically Important Constituents And Properties In A Marine Biogeochemical And Ecosystem Model, S. Dutkiewicz, A. E. Hickman, O. Jahn, W. W. Gregg, C. B. Mouw, M. J. Follows, C. Mouw Jul 2015

Capturing Optically Important Constituents And Properties In A Marine Biogeochemical And Ecosystem Model, S. Dutkiewicz, A. E. Hickman, O. Jahn, W. W. Gregg, C. B. Mouw, M. J. Follows, C. Mouw

Michigan Tech Publications, Part 1

We present a numerical model of the ocean that couples a three-stream radiative transfer component with a marine biogeochemical-ecosystem component in a dynamic three-dimensional physical framework. The radiative transfer component resolves the penetration of spectral irradiance as it is absorbed and scattered within the water column. We explicitly include the effect of several optically important water constituents (different phytoplankton functional types; detrital particles; and coloured dissolved organic matter, CDOM). The model is evaluated against in situ-observed and satellite-derived products. In particular we compare to concurrently measured biogeochemical, ecosystem, and optical data along a meridional transect of the Atlantic Ocean. The …


The Application Of Biomedical Engineering Techniques To The Diagnosis And Management Of Tropical Diseases: A Review, Fatimah Ibrahim, Tzer Hwai Gilbert Thio, Tarig Faisal, Michael Neuman Mar 2015

The Application Of Biomedical Engineering Techniques To The Diagnosis And Management Of Tropical Diseases: A Review, Fatimah Ibrahim, Tzer Hwai Gilbert Thio, Tarig Faisal, Michael Neuman

Michigan Tech Publications, Part 1

This paper reviews a number of biomedical engineering approaches to help aid in the detection and treatment of tropical diseases such as dengue, malaria, cholera, schistosomiasis, lymphatic filariasis, ebola, leprosy, leishmaniasis, and American trypanosomiasis (Chagas). Many different forms of non-invasive approaches such as ultrasound, echocardiography and electrocardiography, bioelectrical impedance, optical detection, simplified and rapid serological tests such as lab-on-chip and micro-/nano-fluidic platforms and medical support systems such as artificial intelligence clinical support systems are discussed. The paper also reviewed the novel clinical diagnosis and management systems using artificial intelligence and bioelectrical impedance techniques for dengue clinical applications.


A Field Investigation Of Composite Mud Brick Compressive Strength, Kevin D. Hale Jan 2015

A Field Investigation Of Composite Mud Brick Compressive Strength, Kevin D. Hale

Dissertations, Master's Theses and Master's Reports - Open

It has been highlighted in numerous publications that in the field of earth construction there is a strong disconnect between experimental work in the laboratory and its application in the field. The current study attempts to help bridge this gap with a field test conducted in Nampula, Mozambique. Mud bricks were made with a simple hand mold and reinforced with bamboo and straw fibers. Fibers were cut into lengths of 3 cm and 6 cm while being mixed in fractions of 0.125%, 0.25% and 0.50% by weight and compressive strength was measured using an application of the 3-point bending test. …


Undergraduate Education 2015, College Of Engineering, Michigan Technological University Jan 2015

Undergraduate Education 2015, College Of Engineering, Michigan Technological University

Michigan Tech Engineering Magazine

Table of Contents

  • Research
  • International
  • Design


Beautiful Forms And Compositions Are Not Made By Chance: Exploring The Efficacy Of Portable X-Ray Fluorescence To Sort And Source English Lead Glazed Ceramics, Steven J. Sarich Jan 2015

Beautiful Forms And Compositions Are Not Made By Chance: Exploring The Efficacy Of Portable X-Ray Fluorescence To Sort And Source English Lead Glazed Ceramics, Steven J. Sarich

Dissertations, Master's Theses and Master's Reports - Open

Advances in portable X-ray fluorescence (pXRF) technology have made it a viable option for the non-destructive exploration of the underlying chemical composition of ceramic artifacts for the purposes of classification. However, because the literature regarding the use of this instrument on historic artifacts is limited, it is necessary to begin with a broad scale exploratory assessment that might act as a jumping off point for future studies on this topic. Toward that end, this research uses a collection of British and Continental European ceramics ranging from 1650-1920, owned and curated by the Chipstone Foundation in Fox Point, WI, to explore …


Evaluating The Potential For Passive Greywater Irrigation In Northern Ghana, Chelsea L. Fagan Jan 2015

Evaluating The Potential For Passive Greywater Irrigation In Northern Ghana, Chelsea L. Fagan

Dissertations, Master's Theses and Master's Reports - Open

Water scarcity, malaria, and malnutrition are all concerns facing the people of Chirifoyili and the Northern Region of Ghana. Greywater pooling outside of homes increases human exposure to pathogens and provides breeding grounds for disease carrying insects, especially malaria spreading mosquitoes. This project looks at draining this water away from the home and using it to irrigate vegetables, fruit trees and other beneficial plants.

The purpose of this study is to estimate the effects of greywater irrigation on the growth of plants commonly found in village home gardens. The field project consisted of constructing and managing household greywater irrigation systems …


A Technical And Cultural Feasibility Assessment Of Household Microbial Fuel Cells For Use In Hanan'g District, Tanzania, Erinn Kunik Jan 2015

A Technical And Cultural Feasibility Assessment Of Household Microbial Fuel Cells For Use In Hanan'g District, Tanzania, Erinn Kunik

Dissertations, Master's Theses and Master's Reports

Microbial fuel cells (MFCs) are an emerging electricity generation technology that has the potential for use in developing countries. This study assessed the feasibility of using MFCs in Tanzania through technical analysis of a MFC prototype alongside with interviews with Tanzanians for a cultural feasibility assessment of MFCs. For the technical analysis, this study evaluated the inputs needed for a household MFC to operate and produce electricity with cattle manure as a fuel and evaluated the electrochemical and chemical performance as well as the fecal coliform reduction of the manure during MFC operation. For this study, a MFC was built …


A Market-Based Approach To 3d Printing For Economic Development In Ghana, Wade Aitken-Palmer Jan 2015

A Market-Based Approach To 3d Printing For Economic Development In Ghana, Wade Aitken-Palmer

Dissertations, Master's Theses and Master's Reports - Open

The purpose of this report is to create the foundation for further study of a market-based approach to 3D printing as an instrument for economic development in Ghana. The delivery of improved products and services to the most underserved markets is needed to spur economic activity and improve standards of living. The relationship between economic development and the advancement of technology is considered within the context of Ghana. An opportunity for market entry exists within both the bottom of the economic pyramid and the mid-segment market. 3D printing (additive manufacturing) has proven to be a disruptive technology that has demonstrated …


Water Use And System Reliability Under Dieselgenerator And Solar Photovoltaic Powered Pumping Systems: A Case Study Of Solla Togo, Alicia R. Sherrin Jan 2015

Water Use And System Reliability Under Dieselgenerator And Solar Photovoltaic Powered Pumping Systems: A Case Study Of Solla Togo, Alicia R. Sherrin

Dissertations, Master's Theses and Master's Reports - Open

Access to improved potable water sources is recognized as one of the key factors in improving health and alleviating global poverty. In recently years, substantial investments have been made internationally in potable water infrastructure projects, allowing 2.3 billion people to gain access to potable water from 1990-2012. One such project was planned and installed in Solla, Togo, a rural village in the northern part of the country, from 2010-2012. Ethnographic studies revealed that, while the community has access to potable water, an estimated 45% of the village’s 1500 residents still rely on unprotected sources for drinking and cooking. Additionally, inequality …


The Use Of Jatropha Curcas To Achieve A Self Sufficient Water Distribution System: A Case Study In Rural Senegal, Alexandra Archer Jan 2015

The Use Of Jatropha Curcas To Achieve A Self Sufficient Water Distribution System: A Case Study In Rural Senegal, Alexandra Archer

Dissertations, Master's Theses and Master's Reports - Open

The use of Jatropha curcas as a source of oil for fueling water pumps holds promise for rural communities struggling to achieve water security in arid climates. The potential for use in developing communities as an affordable, sustainable fuel source has been highly recommended for many reasons: it is easily propagated, drought resistant, grows rapidly, and has high-oil-content seeds, as well as medicinal and economic potential. This study uses a rural community in Senegal, West Africa, and calculates at what level of Jatropha curcas production the village is able to be self-sufficient in fueling their water system to meet drinking, …


A Sub-Basin Water Resource Quantification And Aquifer Productivity Assessment For The Northwest Borehole Scheme Near Opuwo, Namibia, Lucas C. Moilanen Jan 2015

A Sub-Basin Water Resource Quantification And Aquifer Productivity Assessment For The Northwest Borehole Scheme Near Opuwo, Namibia, Lucas C. Moilanen

Dissertations, Master's Theses and Master's Reports - Open

Namibia is the most arid country in southern Africa, and is classified as experiencing medium-water stress from 2010-2014 by the Water Resources Institute (WRI) (World Bank, 2015) (Gassert, 2013). Increased water-resources management responsibility at the municipal level, population growth and urbanization trends necessitate community-scale quantification of water resources.

An annual water balance for the contributing sub-basin to Opuwo, Namibia was performed. The Behnke and Maxey method was used to estimate PET, and the methodology outlined by Allen, et al was used to determine soil moisture response to individual rainfall events for one hypothetical year. Water balance results indicate that of …


Seasonal Variability And Long-Term Evolution Of Tropospheric Composition In The Tropics And Southern Hemisphere, K. M. Wai, S. Wu, A. Kumar, H. Liao May 2014

Seasonal Variability And Long-Term Evolution Of Tropospheric Composition In The Tropics And Southern Hemisphere, K. M. Wai, S. Wu, A. Kumar, H. Liao

Michigan Tech Publications, Part 1

Impacts on tropospheric composition in the tropics and the Southern Hemisphere from biomass burning and other emission sources are studied using a global chemical transport model, surface measurements and satellite retrievals. Seasonal variations in observed CO at remote island sites are examined. Easter Island (eastern Pacific Ocean) is impacted indirectly by the hemispheric zonal transport of CO due to the burning in southern Africa/South America, via the westerlies. An increasing trend in CO by 0.33 ppb yr-1 in the past decade at Ascension Island is attributed to the combined effects of South American/southern Africa burnings and the increases in CH4 …


Tank Sizing And Optimizing Loop Placement In A Branched Water Distribution System, Colin G. Mccorkle Jan 2014

Tank Sizing And Optimizing Loop Placement In A Branched Water Distribution System, Colin G. Mccorkle

Dissertations, Master's Theses and Master's Reports - Open

More than eighteen percent of the world’s population lives without reliable access to clean water, forced to walk long distances to get small amounts of contaminated surface water. Carrying heavy loads of water long distances and ingesting contaminated water can lead to long-term health problems and even death. These problems affect the most vulnerable populations, women, children, and the elderly, more than anyone else. Water access is one of the most pressing issues in development today.

Boajibu, a small village in Sierra Leone, where the author served in Peace Corps for two years, lacks access to clean water. Construction of …


Participant Impacts From A Participatory Water Modeling Workshop In The Sonora River Basin, Mexico, David J. Kossak Jan 2014

Participant Impacts From A Participatory Water Modeling Workshop In The Sonora River Basin, Mexico, David J. Kossak

Dissertations, Master's Theses and Master's Reports - Open

Much of the research in the field of participatory modeling (PM) has focused on the developed world. Few cases are focused on developing regions, and even fewer on Latin American developing countries. The work that has been done in Latin America has often involved water management, often specifically involving water users, and has not focused on the decision making stage of the policy cycle. Little work has been done to measure the effect PM may have on the perceptions and beliefs of decision makers. In fact, throughout the field of PM, very few attempts have been made to quantitatively measure …


Water Access And Maintenance In Karonga, Malawi, Donald A. Norris Jan 2014

Water Access And Maintenance In Karonga, Malawi, Donald A. Norris

Dissertations, Master's Theses and Master's Reports - Open

This report is a case study of how Mwangalala community accesses water and how that access is maintained. Mwangalala community is located in the northern tip of Karonga district in Malawi, Africa. The case study evaluates how close the community is to meeting target 10 of the Millennium Development Goals, sustainable access to safe drinking water, and evaluates the current water system through Human Centered Design’s criteria of desirability, feasibility, and viability. It also makes recommendations to improve water security in Mwangalala community.

Data was collected through two years of immersive observation, interviews with 30 families, and observing two wells …


State-And-Transition Modeling And Adaptive Management: Tools For Future Co-Development Of Madagascar’S Natural Resources And People, Patrick Thomas Spencer Jan 2014

State-And-Transition Modeling And Adaptive Management: Tools For Future Co-Development Of Madagascar’S Natural Resources And People, Patrick Thomas Spencer

Dissertations, Master's Theses and Master's Reports - Open

Madagascar’s terrestrial and aquatic ecosystems have long supported a unique set of ecological communities, many of whom are endemic to the tropical island. Those same ecosystems have been a source of valuable natural resources to some of the poorest people in the world. Nevertheless, with pride, ingenuity and resourcefulness, the Malagasy people of the southwest coast, being of Vezo identity, subsist with low development fishing techniques aimed at an increasingly threatened host of aquatic seascapes. Mangroves, sea grass bed, and coral reefs of the region are under increased pressure from the general populace for both food provisions and support of …


Beneficial Reuse Of Locally-Available Waste Materials As Lightweight Aggregate In Lightweight Concrete, Brienna E. Rust Jan 2014

Beneficial Reuse Of Locally-Available Waste Materials As Lightweight Aggregate In Lightweight Concrete, Brienna E. Rust

Dissertations, Master's Theses and Master's Reports - Open

This study investigated the physical characteristics of lightweight concrete produced using waste materials as coarse aggregate. The study was inspired by the author’s Peace Corps service in Kilwa, Tanzania. Coconut shell, sisal fiber, and PET plastic were chosen as the test waste products due to their abundance in the area. Two mixes were produced for each waste product and the mix proportions designed for resulting compressive strengths of 3000 and 5000 psi. The proportions were selected based on guidelines for lightweight concrete from the American Concrete Institute. In preparation for mixing, coconut shells were crushed into aggregate no larger than …


Impact Of Aging Mechanism On Model Simulated Carbonaceous Aerosols, Y. Huang, S. Wu, M. K. Dubey, N. H.F. French Aug 2013

Impact Of Aging Mechanism On Model Simulated Carbonaceous Aerosols, Y. Huang, S. Wu, M. K. Dubey, N. H.F. French

Michigan Tech Publications, Part 1

Carbonaceous aerosols including organic carbon and black carbon have significant implications for both climate and air quality. In the current global climate or chemical transport models, a fixed hydrophobic-to-hydrophilic conversion lifetime for carbonaceous aerosol (τ) is generally assumed, which is usually around one day. We have implemented a new detailed aging scheme for carbonaceous aerosols in a chemical transport model (GEOS-Chem) to account for both the chemical oxidation and the physical condensation-coagulation effects, where τ is affected by local atmospheric environment including atmospheric concentrations of water vapor, ozone, hydroxyl radical and sulfuric acid. The updated τ exhibits large spatial and …