Environmental Development Program Research Articles

Critical Individual and Organizational Drivers of Circular Economy Implementation in SMEs in Bangladesh

This study aims to examine the influence of individual and organizational factors on the implementation of circular economy (CE) practices in SMEs in Bangladesh. A non-probability sampling technique is utilized to select a sample of 280 respondents from the textile and leather industries. Data are collected through a survey assessing individual factors such as environmental consciousness and innovation propensity, as well as organizational factors including leadership commitment and training and development programs. A frequency table is used to give the respondents’ details, and skewness and kurtosis are conducted to find the data normality. Reliability and validity analyses are conducted to ensure the robustness of the measurement instruments. A correlation matrix is generated to examine the relationships between variables, followed by a multiple regression analysis to test the hypothesized relationships. The preliminary findings indicate a significant correlation between individual and organizational factors and the implementation of CE practices. The multiple regression analysis reveals that both sets of factors contribute significantly to explaining the variance in CE implementation. The results indicate that environmental consciousness, innovation propensity, leadership commitment, and training and development programs emerge as significant predictors of CE implementation within these industries. This study offers valuable insights and sheds light on the role of individual and organizational factors in shaping sustainable practices. The findings contribute to the explanatory literature on CE implementation, providing empirical evidence to inform policymaking and business strategies aimed at promoting sustainability in the SME sector and beyond.

Novel Nanocatalysts for Simultaneous Ammonia Oxidation and Nitrate Reduction

Throughout recent years, nitrate reduction to ammonia has gained popularity in the scientific world to produce a carbon-free fuel [1]. However, research has primarily focused on low-concentration nitrate reduction, specifically for wastewater remediation. High-concentration effluents, such as ANSOL (Ammonium Nitrate), have emerged as a significant waste byproduct and a threat [2], with explosive characteristics and increasing production rates over the years [3]. This research seeks solutions to incorporate onsite waste treatment for generating electrical power, emphasizing the integration of waste streams as a distinctive opportunity. The integration aims to facilitate both power generation and the provision of clean water, with a focus on developing prototype systems designed to convert challenging Department of Defense (DoD) waste streams containing ANSOL into usable fuels for onsite energy generation.In this presentation, results from two distinct systems employing nanoparticle catalysts for the reduction of nitrates to ammonia, while simultaneously oxidizing ammonia to nitrogen and hydrogen, are discussed. This is particularly relevant in the presence of a high concentration of ammonium nitrate in waste (>0.5 M) with industrially relevant electrochemical performance (>300 mA/cm2 with Faradaic Efficiencies higher than 50%). The initial approach involves the integration of CuNi/C and Pt3Ir/C catalysts for reduction and oxidation, respectively [4]. The subsequent approach underscores pulsed electrodeposition of CuNi [5] for nanoparticle synthesis in the reduction process, coupled with the use of Pt3Ir/C catalyst for oxidation. The effect of different applied potentials was studied for the conversion of NO3 - to NH3 and subsequent H2 production. Electrode stability and process integration were investigated.[1] Kani, N. C., Nguyen, N. H. L., Markel, K., Bhawnani, R. R., Shindel, B., Sharma, K., Kim, S., Dravid, V. P., Berry, V., Gauthier, J. A., Singh, M. R., “Electrochemical Reduction of Nitrates on CoO Nanoclusters-Functionalized Graphene with Highest Mass Activity and Nearly 100% Selectivity to Ammonia,” Adv. Energy Mater. 2023, 13, 2204236.[2] United States Occupational Safety and Health Administration, Bureau of Alcohol, Tobacco, Firearms and Explosives, Environmental Protection Agency, "Chemical Advisory: Safe Storage, Handling, and Management of Solid Ammonium Nitrate Prills," EPA 550-F-15-001, June 2015.[3] Strategic Environmental Research and Development Program (SERDP) and Environmental Security Technology Certification Program (ESTCP), "Conversion of Ammonium Nitrate Solutions to Useful Products," SERDP and ESTCP Website, April 5, 2021. [Online].[4] Hariri, M.B., and Botte, G.G., "Simultaneous Removal of Ammonia and Nitrate from Wastewater Using a Pulse Electrolysis Technique," Journal of The Electrochemical Society 170.5. 2023.[5] I. Baskaran, T.S.N. Sankara Narayanan, and A. Stephen, "Pulsed electrodeposition of nanocrystalline Cu–Ni alloy films and evaluation of their characteristic properties," Materials Letters, vol. 60, no. 16, pp. 1990-1995, July 2006.

ANALYSIS OF COMMUNITY DEVELOPMENT ZAKAT PROGRAM AT INSTITUTIONS NATIONAL ZAKAT AMIL AGENCY JAKARTA

The purpose of this research is to find out how the programs conducted by BAZNAS in the Zakat Community Development Division are used to develop the community. This research focuses on the impact the beneficiary community receives through Zakat Community Development (ZCD). Zakat is an act of worship that all Muslims must do. This research was conducted at the Office of the National Amil Zakat Agency (BAZNAS), which is the only official body established by the government based on Presidential Decree No. 8 of 2001, has the task and function of collecting and distributing Zakat, Infaq, and Sadaqah (ZIS) at the national level. This research is qualitative. The primary data source is the Head of BAZNAS. Data collection techniques include interviews, observation, and documentation. Data analysis techniques with data collection, presentation, reduction, and conclusions. Based on the analysis results through interviews and observations made during the research, it can be concluded that the management of the environmental development program has been running by the program's objectives, namely reducing the poverty rate by an average of 3% each year.

Regulation of Corporate Social Responsibility through Environmental Development Program: A Review from a CSR Perspective

The Company, as a business entity, must take on social and environmental responsibility, which is known as corporate social responsibility (CSR). Community empowerment programs are part of implementing CSR forms used in the Company's efforts to support sustainable development based on the 3P principles, namely Profit, People, and Planet. This research aims to analyze the implementation of the Community Development Program as a strategy in CSR management and the implementation of CSR arrangements in managing corporate responsibility in environmental aspects. The method in this research is normative juridical research. The approaches used are the Legislation Approach, Case Approach, and Concept Approach. Implementing the environmental development program is a strategic step that can have a long-term positive impact on the Company. A critical aspect of the Program is that it focuses on sustainable development. Companies involved in this activity are concerned with current environmental elements and aim to leave positive things for future generations. By adopting environmentally friendly practices and sustainability projects, companies can create positive impacts that are sustainable in the long run. Implementing CSR regulations in managing environmental responsibility is an essential step companies take to balance business sustainability and social and environmental impacts. CSR regulation in managing ecological responsibility is about more than just complying with rules or meeting market expectations. But also as an effort to create long-term value, build strong relationships with stakeholders, and become an agent of positive change in society.

The sustainability of developmental programs by the U.S. and China in Sub-Saharan Africa: a comparison of effectiveness

This descriptive comparative qualitative case study examines the sustainability of development programs in Sub-Saharan Africa. We evaluated economic, social, environmental, and institutional development programs from the People’s Republic of China (PRC) and the U.S. to Sub-Saharan Africa for sustainable development to fill the research gap on these technique’s success and effects on Sub-Saharan Africa. Using purposive sampling, we chose eight Sub-Saharan African countries representing distinct geographies and economies. The College of William & Mary’s AID Data-GeoCoded Chinese Official Finance Dataset, China Africa Research Initiative, and USAID’s Foreign Aid Explorer provided data. Results revealed a complex view of Sub-Saharan Africa’s development policy success. Proposition 1, which claims China’s economic tactics exceed those of the U.S., is supported by significant infrastructure investments but presents sustainability problems. Proposition 2, praising the social development initiatives of the U.S., is supported by gains in healthcare and education in other countries. However, context-specific issues persist. Proposition 3 shows that U.S. conservation collaborations have improved environmental preservation. Proposition 4 claims that both countries’ institutional development plans fail. The results highlight local government buy-in issues and the need for adaptation. Some of the ideas find support in recent research; however, country and context differences require unique tactics. Development efforts in Sub-Saharan Africa should focus on long-term sustainability, local objectives, and environmental implications. Effective institutional growth requires adaptation and a strong awareness of local governing dynamics, and policymakers, development practitioners, and scholars may gain insight into sustainability and development projects in Sub-Saharan Africa from this research. A holistic approach that balances economic, social, environmental, and institutional factors is needed to attain sustainable development goals.

تأثير التدريب والتطوير الاخضر في الاداء المستدام

تهدف الدراسة الحالية إلى اختبار تأثير التدريب والتطوير الأخضر على الأداء المستدام واستكشاف آثاره داخل وخارج وزارة البيئة العراقية. تدور المشكلة الأساسية للبحث حول مدى تنفيذ التدريب والتطوير الأخضر والأداء المستدام في الوزارة (ما هي طبيعة العلاقة بين التدريب والتطوير الأخضر والأداء المستدام في الوزارة؟). لتوضيح العلاقة بين المتغيرات البحثية، صُيِّغت فرضيتان رئيسيتان بالإضافة إلى فرضيات فرعية. تهدف الدراسة أيضًا إلى تقييم مستوى اهتمام الوزارة بالمتغيرات البحثية وتقديم توصيات رئيسية لتعزيز الأداء المستدام من خلال اعتماد التدريب والتطوير الأخضر. تم استخدام المنهج الوصفي-التحليلي في هذه الدراسة، حيث تم جمع البيانات من عينة عشوائية تتألف من 250 فردًا، وتم جمع 150 استبيانًا. استخدم الباحث مجموعة من الأساليب الإحصائية باستخدام برامج مثل Excel وSPSS V28 وAmos V25.تشير أهم نتائج الدراسة إلى أن الأداء البيئي المستدام يمكن تعزيزه من خلال التركيز على التدريب وتطوير الممارسات البيئية الخضراء بشكل عام. كما لوحظ تأثير ملحوظ لكلا المتغيرين (التدريب والتطوير الأخضر والأداء المستدام)، مع إيلاء الأولوية والتفضيل للأداء المستدام في التنفيذ العملي على التدريب وتطوير البيئة. بناءً على النتائج، يُوصَى بتحسين الأداء المستدام من خلال تنفيذ برامج التدريب والتطوير البيئي داخل وزارة البيئة، مع التركيز أيضًا على المتغيرات البحثية المرتبطة بالأداء المستدام.

The Use of Management Control System in Corporate Social Responsibility (CSR) Strategy Implementation and CSR Activities on Sustainability Reporting

Objective: This study aims to investigate the impact of the relationship between CSR activities and the strategies employed to ensure their proper management in line with company objectives. Global surveys consistently rank the mining, gas and other sectors at the bottom of all sectors in terms of social and environmental performance. Therefore, companies in these sectors have no choice but to change their approach through a comprehensive understanding of their business impacts.
 
 Methodology: The method used in this study is purposive sampling, where the sample criteria include companies featured in sustainability reports, as well as companies that have incurred environmental costs in the form of environmental development program costs.
 
 Result and Conclusion: The study found that the strength of a company's management control system (MCS) plays a significant role in moderating the relationship between CSR activities and sustainable reporting. When the t-value is greater than 2.055 and the significance level (sig) is less than 0.05, the MCS variable acts as a moderator, indicating that a strong control system reinforces the relationship between CSR activities and sustainable reporting. Conversely, when the MCS is weak, the relationship between CSR strategy and sustainability reporting is also weakened.

MIGRATION AND BURIAL TENDENCIES OF VARIABLE DENSITY MUNITIONS: INITIAL RESULTS FROM A LARGE-SCALE STUDY

Past military activity close to the coast has discarded numerous ordnances in the nearshore environment. These ordinances (some of them unexploded; also called UXOs or munitions) are transported by waves and currents and may become exposed on beaches. The increased intensity of storm events may lead to a subsequent increase in UXO exposure and migration. Prolonged exposure of UXOs to ocean conditions leads to surface growth that alters their bulk density. Hence, it is essential to understand the influence of bulk density on mobility characteristics. This study, funded by the Strategic Environment Research and Development Program (SERDP), aims to quantify the processes that affect the mobility and burial of variable density munitions in the surf and swash zones during scaled extreme forcing.

CSR Strategy of PTPN 7 Bekri Business Unit in Accommodating the Interests of Oil Palm Farmers

This research aims to find out and describe the CSR strategy of PTPN 7 Bekri business unit in accommodating the interests of oil palm farmers. The background in this writing is that many oil palm farmers choose to deposit their palm oil products with the private sector and collectors. The reason oil palm farmers sell their palm oil to the private sector or collectors is that PTPN 7 Bekri business unit buys palm oil at a price that tends to be low compared to other parties. The low purchase value of oil palm from farmers by PTPN 7 Bekri business unit is the cause of purchases dominated by the private sector and collectors. This research uses descriptive research with a qualitative approach; the data source in this study was obtained through interviews with informants, namely the public relations of the PTPN 7 Bekri business unit. In addition, through direct observation and collection of documents related to the research. The results of this study are the CSR strategy used by the PTPN 7 Bekri business unit in accommodating the interests of oil palm farmers; the first is a partnership program by making oil palm farmers company partners, second is through PTPN 7 Care which is implemented through the environmental development program. The company's CSR program is based on the interests of oil palm farmers; it needs to be more evenly distributed, and other interests of oil palm farmers need attention.

Environmental Engagement in Higher Education Institutions

Higher Education Institutions (HEIs) are the potential stewards of the environment. Their influence extends from the workplace to the communities and homes where they play a vital role in environmental engagement. Hence, this paper investigates the 3 drivers of environmental engagement, namely, Knowledge and Awareness (KA), Personal Engagement (PE), and Policies and Practices (PP) in Environmental Engagement (EE) of the 213 faculty of the 9 HEIs in the Philippines. The study used a Quantitative Approach employing the comparative and correlational analyses of the survey results derived from the duly validated instruments. Pearson Product Moment Correlation test shows that the Knowledge and Awareness (KA) driver has no relationship while Personal Engagement (PE), and Policies and Practices (PP) have a significant relationship with Environmental Engagement (EE). The consistency of the faculty's Environmental Engagement at home and at work, as supported by the Behavior Consistency Theory, prevails over Knowledge and Awareness. The faculty's Environmental Engagement is high in the tasks with tangible economic value such as energy and water conservation but low in those with intangible benefits like recycling or waste segregation. While the Policies and Practices driver is significantly related to Environmental Engagement, less than half of the faculty are engaged in training, campaign, and policy participation. Thus, the study recommends incentivizing faculty Environmental Engagement and needs assessment for environmental learning and development programs. The study offers a valuable contribution to the latent literature on Environmental Engagement in Higher Education.

3D finite element modeling techniques and application to underwater target scattering

Underwater acoustic target scattering measurements rely on high fidelity modeling for experimental comparison and understanding. Three-dimensional (3D) finite element models are well suited for this purpose, as they can account for arbitrary or unknown target properties and configurations/orientations within complex and asymmetrical seafloor environments. High acoustic frequencies and large physical distances associated with in situ scattering measurements pose challenges to 3D modeling efforts in terms of model sizes and runtimes. Certain model considerations must be made to keep the 3D model computationally efficient, yet accurate in predictive capability. Numerically determined Green’s functions are demonstrated to permit 3D model reduction, while still preserving far-field scattering prediction capability through the Helmholtz-Kirchhoff integral. By determining Green’s functions within the model, they need not be known or estimated for complex ocean environments a priori. Nontraditional scattering formulations and a survey of boundary truncation methods also are explored and implemented for maximal accuracy within small 3D computational domains. Model results for canonical elastic targets within varying seafloor environments are shown and compared to theory and experimentation. [This work has been supported by the Strategic Environmental Research and Development Program, and by the Office of Naval Research, Ocean Acoustics.]

Environmental Development Program of CSR: Analysis of Waste Bank in Karya Mulia Village, Palembang, Indonesia

This study aims to analyze the environmental development program of the Corporate Social Responsibility (CSR) waste bank of PT. Pertamina Limau Field. This study used a qualitative method with in-depth interview data collection. This research model is interactive by reducing data, presenting and drawing conclusions. The results of this study indicate that the implementation of PT. Pertamina Limau Field makes a positive contribution to the surrounding community. The application of community development provides education and awareness to the community in appreciating environmentally friendly values and reducing the waste of resources. The synergy with the Prabu Mulih waste bank makes waste management more efficient and optimal. The waste bank program also has an impact on the social and economic aspects of the community. The sustainability of the waste bank program applies the green economy concept which refers to the Sustainable Development Goals (SDGs) number 11 concerning sustainable cities and communities, number 12 concerning responsible consumption and production. The positive impact of PT. Pertamina Limau Field has resulted in the participation of more than 100 customers who have deposited non-organic waste.

Per- and polyfluoroalkyl substances (PFAS)-free aqueous film forming foam formulations: Chemical composition and biodegradation in an aerobic environment

Per- and poly-fluoroalkyl substances (PFAS) have been historically used in fire-suppression activities, including aqueous film-forming foam (AFFF), given their unique structures and characteristics. However, the same properties that make them durable, resistant, and valuable also make them persistent, bioaccumulative, and toxic. This has led to recent investigations on alternative PFAS-free AFFF formulations for suppression of hydrocarbon-based fires. Such foams should contain certain classes of chemicals to remain effective, while being more environmentally friendly; part of the latter involves thoroughly characterizing the constituents and performing necessary biodegradability and toxicity studies. As part of the Department of Defense’s Strategic Environmental Research and Development Program (SERDP), we performed comprehensive constituents’ characterization and assessed the biodegradability of seven PFAS-free AFFF and a reference PFAS-based AFFF. We discovered that most of PFAS-free formulations share similar constituents with similar biodegradability through a 28-day reaction period. In PFAS-based AFFF, 4:2 and 6:2 fluorotelomer sulfonates (6:2 FTS) were identified with 6:2 FTS concentration at ∼ 9000 ng/mL. In biodegradation studies, the concentrations of 4:2 FTS and 6:2 FTS decreased while generating some perfluoroalkyl acids (PFCAs). These results increase the current knowledge on the biodegradability of AFFF alternatives but also highlight the need for future efforts on development of novel PFAS-free AFFF formulations that are more biodegradable than PFAS-based AFFF.

Assessing Electrolyte Transport through an Aircraft Coating System Using EIS

Electrochemical impedance spectroscopy (EIS) is frequently employed to nondestructively evaluate coating systems. However, there are several challenges associated with this approach. One of these challenges is associated with isolating the physical processes that are contributing to the measured impedance. We attempted to address this concern by measuring several of the coating system components before starting the exposures and attempted in-situ measurements of some properties during the course of the exposures.In this work, we analyze impedance data obtained from a two-layer coating system that was applied to AA 2024 substrates that were subjected to either immersion and simulated outdoor exposure conditions. The impedance data from the full coating system is compared with data obtained from coating systems in which gold electrodes were inserted between the layers of the coating system that could be used to monitor changes in each coating layer. Several equivalent circuit models were evaluated before settling on a modified coatings equivalent model. Using this approach, we were able to estimate several coating system parameters, including electrolyte penetration depth as a function of temperature, and solution concentration from the values obtained from the equivalent circuit model. Acknowledgments The Department of Defense Strategic Environmental Research and Development Program (SERDP) sponsored this project under work unit 5399. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of the Office of Naval Research, the U.S. Navy, the Department of Defense, or the U.S. government.

Acute Toxicity of Eight Aqueous Film-Forming Foams to 14 Aquatic Species.

Researchers have developed numerous per- and polyfluoroalkyl substances (PFAS)-free aqueous film-forming foam (AFFF) formulations to replace PFAS-containing AFFF used for fire suppression. As part of the Department of Defense's Strategic Environmental Research and Development Program (SERDP), we examined the direct lethal effects of seven PFAS-free AFFF and a PFAS-containing AFFF on 14 aquatic species using a series of lethal concentration (LC50) tests. We assessed the LC10, LC50, and LC90 values using log-logistic and logit analyses. Across all aquatic species tested, we discovered that exposure to at least one PFAS-free AFFF was more or as toxic as exposure to the PFAS-containing AFFF. For most cases, National Foam Avio F3 Green KHC 3% and Buckeye Platinum Plus C6MILSPEC 3% were the most and least toxic formulations, respectively. Moreover, we found consistency among results from multiple experiments using the same minnow species (Pimephales promelas) and among closely related taxa (e.g., daphnids, amphibians). Lastly, the LC50 values for AFFF formulations trended lower for tested marine species as compared to those of freshwater species. These results dramatically increase the current knowledge on the potentially toxic effects of AFFF but also highlight the need for additional research and the development of new PFAS-free AFFF that are more "ecologically friendly" than those containing persistent PFAS.

3D finite element modeling techniques and application to underwater target scattering

Underwater acoustic target scattering measurements rely on high-fidelity modeling for experimental comparison and understanding. Three-dimensional (3D) finite element models are well suited for this purpose, as they can account for arbitrary or unknown target properties and configurations/orientations within complex and asymmetrical seafloor environments. High acoustic frequencies and large physical distances associated with in situ scattering measurements pose challenges to 3D modeling efforts in terms of model sizes and runtimes. Certain model considerations must be made to keep the 3D model computationally efficient, yet accurate in predictive capability. Numerically determined Green’s functions are demonstrated to permit 3D model reduction, while still preserving far-field scattering prediction capability through the Helmholtz–Kirchhoff integral. By determining Green’s functions within the model, they need not be known or estimated for complex ocean environments a priori. Nontraditional scattering formulations and a survey of boundary truncation methods also are explored and implemented for maximal accuracy within small 3D computational domains. Model results for canonical elastic targets within varying seafloor environments are shown and compared to theory and experimentation. [Work supported by the Strategic Environmental Research and Development Program and by the Office of Naval Research, Ocean Acoustics.]

Diseminasi produk paving blok berpori dan disain infrastruktur pejalan kaki anak di SLB Kreasi Mandiri

The dissemination product of technology is a continuing research result previously in related to the design prototype of child pedestrian pathway with building block concept. Material developed is the porous paving block. The aim of this paper is to describe and evaluate the dissemination product of technology of the porous paving block and the child pedestrian pathway design. The school area which is used by students and children need safety, comfortable and creative access as well as understanding the use of product porous paving block. The area of school for special needs Kreasi Mandiri does not have access with pavement yet and the school less understanding of suitable material for access of student’s activity. The community service team have constructed the porous paving block with design for children pedestrian as user. The result shows that area of dissemination has been used for pedestrian access and school activity such as sport. Outdoor activity has been the priority for school during pandemic era. Therefore, the dissemination has supported school activity. In the future the community service can be continued by the school with the program in improving school infrastructure through school environment development program.

Prediction of Mobility and Burial of Objects on Sandy Seafloor

A numerical model was developed to predict mobility and burial of seafloor cylindrical objects. The model contains four components: 1) object's physical parameters such as diameter, length, mass, and rolling moment; 2) dynamics of rolling cylinder around its major axis; 3) empirical sediment scour model; and 4) seabed environmental characteristics such as currents, waves (peak period, significant wave height), sediment density, and medium sediment grain size. Under the sponsorship of the Department of Defense Strategic Environmental Research and Development Program, a field experiment was conducted from April 21 to May 23, 2013 off the coast of Panama City, FL, USA to measure both objects' mobility using sector scanning and pencil beam sonars and simultaneous environmental time-series data of the boundary layer hydrodynamics and sediment transport conditions for driving mobility. Comparison between modeled and observed data shows the model capability. Future work needs to consider more realistic object shapes and motions such as pitch and yaw, and wavy seabed.

Determinant Factors of Sustainability Reporting: A Study in Indonesian Green Index of Sri-Kehati

This research aims to examine the determinant factors of sustainability report disclosure. Determinant factors include regulation of partnership and environmental development programs by state-owned firms, regulation of sustainability finance by listed firms on the Indonesian Stock Exchange, industry sensitivity, analyst coverage, and information asymmetry. Regulation of partnership and environmental development programs by state-owned firms is measured by state-owned status. Regulation of sustainability finance by listed firms on the Indonesian Stock is measured by period of before and after regulation issuance. Industry sensitivity is measured by level of environmental risk. Analyst coverage is measured by number of analysts who analyze the firms’ share in the stock market. Information asymmetry is measured by bid-ask spread. Sample consists of listed firms in Indonesian Green Index of Sri- Kehati 2015-2019. State-owned firms, sustainability finance regulation, industry sensitivity, analyst coverage, and information asymmetry have effect on sustainability report disclosure. State-owned status lead firms to disclose sustainability reporting as a picture of effective monitoring by government shareholders and to meet regulation needs. Sustainability finance regulation leads firms to disclose sustainability reporting as regulation needs. Higher industry sensitivity leads firms to disclose sustainability since sensitive industry brings higher risk to the environment. Higher analyst coverage and lower information asymmetry leads firms to implement higher transparency by disclosing sustainability report. Keywords: state-owned firms, sustainability finance regulation, industry sensitivity, analyst coverage, information asymmetry, sustainability report

Convergence of Levenberg-Marquardt Estimates of Nonlinear Parameters in EIS Analysis of Coated Aluminum Panels

Equivalent circuit models are frequently employed to analyze electrochemical impedance spectroscopy (EIS) data. However, aside from some simple cases in which the equivalent circuit element parameters can be estimated directly from a plot of the data, the parameters for each of the equivalent circuit elements must often be estimated through the implementation of a nonlinear least-squares regression method. One frequently-used approach is the powerful Levenberg-Marquardt algorithm. This algorithm functions as a damped least-squares method that performs an interpolation between the steepest-descent and the Gauss-Newton methods for estimating nonlinear parameters. However, there are several challenges to using a Levenberg-Marquardt algorithm to model EIS data. The nonlinear nature of the impedance equations along with the difference in the magnitude of the parameter values can result in the algorithm failing to converge to a local minimum in the parameter space. This convergence challenge can be seen in determining equivalent circuit values for undamaged coating systems that have a high pore resistance, a small capacitance, as well as contributions from the underlying metal substrate. A Levenberg-Marquardt algorithm, along with a heuristic approach to use the raw data to improve the initial parameter estimates, is implemented that provides an improved approach for nonlinear regression fits of equivalent circuit models. A comparison of three equivalent circuit models fits, with residuals, for a two-layer coating system on an aluminum substrate is shown in the attached figure.Figure caption: Plot of EIS data (+ symbols) from a cured coating system prior to any environmental exposures compared with 3 equivalent circuit model fits (solid lines). The model fits were obtained using an NRL-developed Levenberg-Marquardt nonlinear regression fitting routine.The Department of Defense Strategic Environmental Research and Development Program (SERDP) sponsored this project under work unit 5399. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of the Office of Naval Research, the U.S. Navy, the Department of Defense, or the U.S. government. Figure 1