Impact prediction methods

A number of EIA theorists believe in incorporating formal RA methods into EIA as a way to cope with uncertainties, especially in impact prediction where a formal framework for ecological risk assessment (EcoRA) is already developed. It includes three generic phases problem formulation, analysis, and risk characterization followed by risk management. The analysis phase includes an exposure assessment and an ecological effects assessment (see, e.g., US EPA (1998)). 

It is important to note that the LCA is a tool and cannot provide an all-encompassing assessment. One of the reasons is that industrial processes are interconnected globally, so that complete consideration of all these interdependencies is practically impossible. Also, the results of an LCA are approximations and simplifications of cumulative burdens to the environment and of resources used. Therefore, the LCA process does not directly measure actual environmental impact, predict effects, or represent causal linkages with specific effects. As a result, to meet the needs of the study users, it may be necessary to supplement the LCA with other tools or methods to provide a basis for decision making. These tools include risk assessment, site-specific environmental assessment, etc. As a part of the scoping process, it is useful to identify where and how these other tools will be used to augment the findings of the LCA [5]. 

Prediction of the restitution coefficient has been a challenging research topic for decades. Unfortunately, no reliable and accurate prediction method has been found so far. However, some useful simplified models with certain limits have been developed. One of them is the elastic-plastic impact model in which the compression process is assumed to be plastic with part of the kinetic energy stored for later elastic rebounding, with the rebound process considered to be completely elastic [Johnson, 1985]. In this model, it is postulated that (1) during the plastic compression process, a — r3/2a (2) during the compression process, the averaged contact pressure pm is constant and is equal to 3 Y and (3) the elastic rebound process starts when maximum deformation is reached. Therefore, the compressional force is... 

Due to limitations of space, this section emphasizes only two major aspects of hydrate thermodynamics - namely the phase diagram and the hydrate prediction method. For examples of several counter-intuitive spectroscopic measurements results that impact the thermodynamic perspective, the reader is referred to a recent review, presented with an overview of the 2002 Fourth International Hydrate Conference. 

In addition, the availability of experimental or predicted secondary structure information on the query sequence as well as other experimental constraints such as knowledge on disulfide bridges, on distances or distance intervals between residues and functional groups within proteins and on accessibility of side chains could have large impact on the prediction methods and results as well as on the confidence in the predicted model structure. 

Prediction of bioavailable heavy metal concentration appears to be more complex, and appropriate normalizing factors still have to be evaluated. Until predictive methods for determining bioavailability of contaminants in sediments can be validated, empirical measurements of body burden and effects as determined by the toxicity test and field monitoring provide the most direct approach for evaluating the impact of contaminated sediment in the aquatic environment (Fava et al., 1987). 

Acoustical properties of soybeans can be used to help distinguish between healthy and diseased soybeans. Misra et al. (1990) measured acoustic properties of soybeans by transmitting sound waves through soybeans using acoustic transmission and by an impact force method. In the impact force method, a seed is dropped on an acoustic transducer creating an impulse wave. The acoustic transmission method was slow but was able to predict the mass of individual soybeans. The impact force method showed that diseased soybeans had a narrower bandwidth than healthy soybeans. Soybeans with wrinkled surfaces and diseased and damaged soybeans were detected from healthy soybeans based on wide variations at low frequencies. 

Interactiveness - Environmental, sociological, and economic processes often contain feedback mechanisms - A change in the magnitude of an environmental effect or impact indicator may then produce unexpected amplihcations or dampening in other parts of the system - Prediction methods should include a capability to identify interactions and to estimate their magnitudes... 

Xiong Y, Poon C, Straznicky PV, Vietinghoff H. A prediction method for the compressive strength of impact damaged composite laminates. Compos Struct 1995 ... 

Additionally, some of the impact identification methods previously discussed may also be of value in impact prediction (i.e. checklists, assessment matrix and networks). 

Generally, the sophistication of prediction methods used should be in proportion to the scope of the ElA and relevant to the importance of the particular impact. 

Types of methods in EIA Impact identification Impact prediction Impact significance evaluation... 

AATCC Test Method 35 provides a method of testing the penetration of water by impact. This method can be used to predict the rain penetration resistance of fabrics. A test specimen of 20 x 20cm backed by 15.2 x 15.2 cm blotter paper is mounted in a vertical rigid support frame, as shown in Hg. 2.11. The specimen is exposed to horizontal... 

From among the prediction methods of impact sensitivity, three methods can be mentioned here. Vaullerin and Espagnacq discuss a criterion that aids in such screening for all families of EMs [94]. This criterion is based on the... 

ABSTRACT. Analytical evaluation of the performance of multibody mechanical systems becomes rapidly unmanageable as the complexity of the systems increase. For problems that involve intermittent motion due to an impact, prediction of the responses is even more difficult. In an impact, nonlinear contact forces of unknown nature are created, which act and disappear over a short period of time. In this paper, different contact force models are formulated, with which a continuous analysis method is developed for a simple two-particle impact. The procedure is then generalized to impact in multibody systems using the concept of effective mass. A piecewise analysis method is discussed, which is based on a canonical form of the system impulse/momentum equations. The suitability of these methods are discussed by application of these procedures to some examples. An optimization methodology is then discussed for the selection of proper parameters in a given contact force model. The use of this technique in the selection of the most suitable materials, which are impact-resistant, is also discussed. 

A collision between the two bodies is known as an impact during which forces are created that act and disappear over a short period of time. The duration of the contact period governs the choice of the method used to analyze the impact. The methods for predicting the impact responses can primarily be classified into two groups. In one, the impact is treated as a discontinuous event. Momentum-balance/impulse equations are usually formulated by integrating the acceleration-based form or the canonical form of the governing equations of motion. The solution to these equations gives the jump in the... 

EIA Preparation is the scientific and objective analysis of the scale, significance and importance of impacts identified. Various methods have been developed, in relation to baseline studies impact identification prediction evaluation and mitigation, to execute this task. 

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