In practice, this can be difficult when ambient temperatures are high and distances from points of collection to national laboratories are large and the infrastructure is poor.
The nebula also contains a lot of gas, which makes it difficult for the ambient heat from the cosmic microwave background to seep in, helping the gas remain at a low temperature.
Moreover, the Lost City chimney is situated in a deep-sea environment (e.g., Kellley et al. 2005, 2007) which makes a comparison to the shallow marine Icelandic system difficult in general: ambient pressure, temperatures, illumination, and many other physico-chemical and biological parameters vary significantly.
Our results indicate that it will be difficult to reduce ambient PM2.5 to meet air quality standards unless household emissions are addressed, along with other sources (Balakrishnan et al. 2011).
Although several natural and engineered skin substitutes are commercially available, many contain tissue cells or cell remnants, which make quality control difficult, shelf-life under ambient conditions short, or user interface less than friendly.
Steve Huey of Allmusic called the album "a universally acknowledged masterpiece" and "the perfect introduction to his achievements even for those who find ambient music difficult to enjoy".
This study found mixed results and it is difficult to conclude whether ambient air pollution in Brisbane has an adverse association with the birth defects examined.
The formation of CdO@CdS heterostructures through the annealing of the flower-like CdS crystallites in ambient air was difficult to identify using the XRD pattern and SEM image because of the trace content of the CdO phase in the heterostructures.
Conventional beam characterization systems that use photographs of the reflected beam on a tower-mounted target are typically not large enough to capture the beam at long distances, and the magnitude of the irradiance for long-distance heliostats is quite low (only a fraction of a sun), which can make the beam image difficult to discern from the ambient lighting on the target.
Ambient corrections are difficult to achieve with this system and are not usually done.
