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Schroeder A.J.,Trinity Consultants
Proceedings of the Air and Waste Management Association's Annual Conference and Exhibition, AWMA | Year: 2012

A study of 1-hr NO2 concentrations predicted by AERMOD for a hypothetical source at four locations throughout the US with hourly varying background O3 concentrations was carried out. The sensitivity of the model-predicted concentrations to the tier used was presented based on distance from the source and evaluated on a 1-hr NO2 NAAQS design concentration basis. The case studies highlighted important sensitivities to be considered when implementing the three-tiered NO to NO2 conversion methodology to predict 1-hr NO2 concentrations using AERMOD. The Tier 1 assumption of full conversion would always result in the highest predictions of NO2 concentrations. However, there were some situations when the use of the Tier 2 methodology would lead to lower predictions of NO2 concentrations than Tier 3 methodologies. For a particular ambient O3 concentration, the Tier 3 methodologies would also yield a greater difference in NO2 and NOx concentrations for higher emission rate sources than for lower emission rate sources. This is an abstract of a paper presented at the 105th AWMA Annual Conference and Exhibition 2012 (San Antonio, TX 6/19-22/2012).

Darrat I.,Trinity Consultants
EM: Air and Waste Management Association's Magazine for Environmental Managers | Year: 2014

EPA will continue to conduct LDAR audits and seek enhanced LDAR requirements for facilities undergoing enforcement action. Facilities subject to LDAR requirements that have not been affected thus far should consider the lessons learned from the refining and chemical sectors that have already been affected.

Muscenti T.,Trinity Consultants
EM: Air and Waste Management Association's Magazine for Environmental Managers | Year: 2012

With the recent boom in U.S. shale gas production operations, there has been a surge in air permitting activities throughout the country. One of the key elements of developing a permitting and compliance strategy is the development of appropriate emission calculations for the new or modified facility. Accurately quantifying actual emissions is essential for the development of proper policies and regulations for this growing industry. This article addresses emission sources and calculation methodologies for criteria and hazardous air pollutants. © 2012 Air & Waste Management Association.

Juang C.H.,Clemson University | Juang C.H.,National Central University | Wang L.,Clemson University | Hsieh H.-S.,Trinity Consultants | Atamturktur S.,Clemson University
Structural Safety | Year: 2014

In this paper, the authors present a methodology for the robust geotechnical design (RGD) of braced excavations in clayey soils. The maximum wall deflection induced by the excavation was chosen as the response of concern in the design and was computed using a finite element analysis model based upon the beam-on-elastic-foundation theory. The variation of the maximum wall deflection of a given design of a braced excavation due to uncertainty in the soil parameters and the surcharges was used as a measure of the design robustness. The robust design of the braced excavation system (including soil, wall, and support) was then formulated as a multi-objective optimization problem, in which the variation of the maximum wall deflection (a signal of the design robustness) and the cost were optimized with the strict safety constraints. Using a multi-objective genetic algorithm, the optimal designs were then determined, the results of which were presented as a Pareto Front that exhibited a trade-off relationship useful for design decision-making. Furthermore, the "knee point" concept, based upon the "gain-sacrifice" trade-off is used in the selection of the most-preferred design from the Pareto Front. Finally, a design example of a braced excavation system was used to illustrate the significance of this proposed methodology. © 2013 Elsevier Ltd.

Fillo J.F.,Trinity Consultants
Air and Waste Management Association - Climate Change Conference 2013: Impacts, Policy and Regulation | Year: 2014

The complexity of ESG and carbon reporting and disclosure continues to increase, with such disclosures often addressing corporate strategy, risk and opportunity management, and associated programs and initiatives: • Reporting and disclosure of GHG emissions has evolved from voluntary to mandatory in many parts of the world • Disclosure of ESG performance is becoming increasingly embedded in the fabric of statutory securities reporting for publicly traded companies • While sustainability reporting is largely voluntary, it is mandatory in selected countries and for targeted industry sectors • The bar is being raised on 'voluntary' reporting frameworks, driven by stakeholder interests, including those of shareholders, business partners and civil society While there is overlap between these myriad requirements, they all have their own unique attributes that must be addressed. Consistency in reporting between these different venues is critical to corporate sustainability, credibility and reputation.

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