Environmental Sem
Environmental Sem - Related Videos
10:48
Aseptic Technique in Environmental Science
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2023
Source: Laboratories of Dr. Ian Pepper and Dr. Charles Gerba - The University of Arizona Demonstrating Author: Luisa Ikner Aseptic technique is a fundamental skill widely practiced in the field of environmental microbiology that requires a balance of mindfulness and practice in the laboratory. Proper use of this technique reduces the likelihood of bacterial or fungal contamination of reagents, culture media, and environmental samples. Aseptic technique is also vital to ensure data integrity and...
09:46
Production and Measurement of Organic Particulate Matter in the Harvard Environmental Chamber
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Cited by 5 •
2018
This paper describes operation procedures for the Harvard Environmental Chamber (HEC) and related instrumentation for measuring gaseous and particle species. The environmental chamber is used to produce and study secondary organic species produced from the organic precursors, especially related to atmospheric organic particulate matter.
01:13
Psychology as a Science
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2024
Psychology, as a scientific discipline, aims to understand the mind and behavior through rigorous and systematic methods. The foundation of psychological research is evidence-based, relying heavily on the scientific method to derive and validate knowledge. This structured approach ensures that findings are reliable, valid, and applicable to broader contexts. The scientific method in psychology involves six critical steps: making observations, formulating hypotheses, conducting tests, analyzing...
09:17
Detection of Bacteriophages in Environmental Samples
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2023
Source: Laboratories of Dr. Ian Pepper and Dr. Charles Gerba - The University of Arizona Demonstrating Author: Alex Wassimi Viruses are a unique group of biological entities that infect both eukaryotic and prokaryotic organisms. They are obligate parasites that have no metabolic capacity, and in order to replicate, rely on host metabolism to produce viral parts that self-assemble inside host cells. Viruses are ultramicroscopic—too small to be viewed with the light microscope, visible only with...
09:08
Developing a Salivary Antibody Multiplex Immunoassay to Measure Human Exposure to Environmental Pathogens
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Cited by 11 •
2016
In the current climate of scarce resources, new technologies are emerging that allow researchers to conduct studies cheaper, faster and with more precision. Here we describe the development of a bead-based salivary antibody multiplex immunoassay to measure human exposure to multiple environmental pathogens simultaneously.
FAQs
Differential pumping maintains two apparently conflicting conditions: gas remains around the specimen, while the electron path stays at high vacuum. This pressure separation allows imaging in a controlled gaseous environment rather than requiring the entire microscope path to contain the specimen atmosphere. For engineering studies, that arrangement makes it possible to observe surfaces while environmental exposure is maintained.
In ESEM, gas molecules near the specimen help neutralize surface charge, a key issue when imaging electrically nonconductive materials. The gas also contributes to detectable signals, so the instrument can obtain useful surface information without relying on the same conditions as conventional SEM. This charge-control mechanism expands the range of engineering materials that can be examined.
The specimen can remain in gas while electrons still travel through a high-vacuum path. This separation supports signal generation and image formation without eliminating the controlled atmosphere around the material. Consequently, observations can focus on surface structure and environmental changes under conditions that more closely represent the material’s state during exposure.
Researchers would choose ESEM when the specimen is wet, uncoated, or electrically nonconductive, or when the study focuses on environmental exposure. In engineering, that selection supports investigations of hydration, corrosion, fracture, coatings, polymers, and soils. The method is therefore useful when surface behavior under controlled conditions matters to material characterization rather than simply observing an idealized sample.
A basic engineering examination requires controlling the gaseous environment around the specimen while differential pumping preserves the high-vacuum electron path. The selected material is then examined for surface structure or changes during exposure. This approach is suited to comparisons involving hydration, corrosion, coatings, polymers, soils, and fracture-related features.
ESEM can reveal surface structure and changes that develop during environmental exposure, rather than providing only a static description of a prepared specimen. That information supports material characterization across systems such as coatings, polymers, soils, and corroding or hydrating materials. Engineers can use these observations to strengthen material characterization and design decisions.