Macroscale response

By far, the most thoroughly studied material regarding the relationship of micromechanical behavior to macroscale response is LiF [23]-[35]. These data, taken as a whole, remain an important resource from which we are able to develop further understanding of dynamic micromechanical response to shock compression. 

Mechanical Properties and Failure of Biopolymers Atomistic Reactions to Macroscale Response... 

In summary, it is clear that the micromechanical shock response of single crystal LiF is extremely complex. These results certainly temper the initial enthusiasm associated with Taylor s [9] study of Armco iron as a eomplete explanation for the relationship between the microscale and the macroscale in shock-loaded solids. 

The shear rate between liquid layers moving at the average velocity is an important factor in macroscale processes involving large blobs. The velocity fluctuations are responsible for microscale processes of homogenization at the molecular level. The data for turbine agitators show that the mean velocity fluctuation, defined as... 

In practice, granular beds comprising a very large number of catalyst pellets are used. It is well known that the efficiency of a catalytic reactor depends crucially on the liquid phase distribution within the catalyst bed [14]. It is likely that the development of hot spots in a catalyst bed is also related to the character of liquid phase distribution. Therefore, it is very important to map the spatial distribution of the liquid phase in a catalytic reactor for various operation regimes. This eventually should lead to the formulation of the mechanisms responsible for the development of critical phenomena on both a micro- and macroscale. 

Specificity of molecular bioactivity and differentially induced defenses are only two examples of factors that can confound the interpretation of patterns at the macroscale. As our knowledge of marine systems continues to expand, the relative abundance of secondary metabolites in different geographic locations may be better understood. However, the literature supports the idea that local pressures and habitat, genetic composition, mode of response and metabolism of the algae play a significant role in shaping distribution patterns of secondary metabolites (e.g. Wright... 

Further study is needed of the phenomenon of kinetic limitations to the neutralization of acidic aerosols. Simultaneous occurrences of acidic aerosols at gaseous [NH3] well above the equilibrium values have been reported (56, 67), and it is still unclear whether kinetic limits to microscale neutralization or boundary layer mixing (macroscale) kinetics (or both) are responsible for these limitations. An understanding of the extent of human exposure to acidic aerosols, as well as of the availability of acidic aerosols for wet scavenging... 

Other advantages of microfabricated devices include faster response times, and the fabrication of multiple test sites for simultaneous replicate assays in one microfabricated device. This analytical redundancy provides a safeguard that is not easily attained in a conventional macroscale analyzer, where duplicate assays represent the usual extent of repetitive assay of a sample. Encapsulation technology used in the microelectronics industry may also be applicable to microscale devices and could be extended to operations over a wide range of environmental conditions of humidity, and temperature. 

The challenge now is to design individual POM cluster molecules that can interact both with each other and with the macroscale (as shown in Figure 2.12), in a desired fashion in response to inputs and environmental effects, so that a functioning molecular system is really constructed. 

Figure 22 shows the flow pattern when there is sufficient power and low enough viscosity for turbulence to form. Now a velocity probe must be used that can pick up the high frequency response of these turbulent flow patterns, and a chart as shown in Fig. 23 is typical. The shear rate between the small scale velocity fluctuations is called microscale shear rate, while the shear rates between the average velocity at this point are called the macroscale rates. These macroscale shear rates still have the same general form and are determined the same way as shown in Fig. 21. 

Fig. 18.58a evolve in response to the square patterned region of Fig. 18.57a, while Fig. 18.586 shows the same region for the uniform coverage case. The square macroscale pattern clearly affects temperature uniformity (+88°C) relative to the uniform distribution case (+33°C). This example demonstrates that broad ranges of relevant length scales can be spanned with an approximate analysis and that micro-macroscale coupling can result in significant modification to system thermal response. 

CD-containing polymeric systems have been considered as optimal to achieve stimuli-induced macroscale effects and dual or even multiple responsivity. Both covalent polymers and supramolecular polymers have been intensively investigated. The latter are based on components bridged by dynamic connections that can be assembled or disassembled... 

The elastoplastic multiscale analysis requires several computational modules, including (1) a microscale computation module, which consists of a set of numerical solutions for the local constitutive equation of each subphase, (2) a micromechanical computation module, which provides numerical tools to link the mechanical properties of each of the local subphases to the macroscopic responses, and (3) a macroscale computation module, in which the continuum mechanics governing equations are enforced to simulate the overall mechanical response of the material and to identify the local loading conditions over the R VE. Each of these computational modules is discussed in the following. A flowchart of the multiscale analysis is shown in Figure 5.24. 

Cell responses to physical or chemical cues are measured in microfluidic devices primarily via optical or electrochemical means. Huorescence is the most widely used optical detection technique, because absorbance detection (commonly used for macroscale assays) is of limited value in microchannels because of the short path lengths. Fluorescence detection, characterized by its unparalleled sensitivity, is easy to implement in microfluidic systems. Chemiluminescence and bioluminescence also offer low detection limits and have less background noise than fluorescence [8]. Electrochemical detectors are even more easily integrated with microfluidic devices and often are much less expensive than optical systems. However, fabrication of electrodes in microchannel devices is a technical challenge, and the electrical fields used in detection can interfere with on-chip processes such as electrophoresis. Electrochemical techniques include potentiometry, amperometry, and... 

True cell mechanical stimuli can hardly be implemented in macroscale assays. Therefore, most of the work prior to the advent of microfluidics was focused on cellular response to chemicals or soluble signals. In contrast, as illustrated by the studies above, microfluidic devices are capable of mimicking in vivo physical conditions including topography and shear stress, which enables new research focused... 

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