There are two main reasons why the chemical process industry should be motivated
to reduce energy consumption and CO 2 emissions: rising concerns in companies,
the public and scientifi c community about climate change or global
warming, and the increasing fraction of energy in manufacturing costs.
‘ Climate change ’  in this context, means a change of climate, which is attributed
directly or indirectly to human activity that alters the composition of the
global atmosphere and which is in addition to natural climate variability observed
over comparable time periods....
The first edition of
(1989) was written to bridge the gap between
toxicology and chemistry. It defined toxicological chemistry as the science that deals with the
chemical nature and reactions of toxic substances, their origins and uses, and the chemical aspects
of their exposure, transformation, and elimination by biological systems. It emphasized the chemical
formulas, structures, and reactions of toxic substances. The second edition of
(1992) was significantly enlarged and increased in scope compared to the first edition.
Essential oil of Cinnamomum longepetiolatum Costerm. apud Phamh. Obtained by hydro distillation. The essential oil yield was 0.91% in fresh leaves. The chemical composition of this oil was study by GC and GC/MS. Twelve compounds were identified representing 98.8% of this oil with camphor as major constituent (87.5%). Eleven other compounds were found with lower content. The results of this study shows that Cinnamomum longepetiolatum Costerm. apud Phamh. was a new natural source of camphor in Vietnam. ...
Analytical chemistry is the study of the separation, identification, and quantification of the chemical components of natural and artificial materials. Qualitative analysis gives an indication of the identity of the chemical species in the sample and quantitative analysis determines the amount of one or more of these components. The separation of components is often performed prior to analysis
The compounds of La1-xCaxMnO3- δ with x=0.46 and 0.50 occupy special positions in the phase diagram of La1-xCaxMnO3-δ system due to their interesting properties and charge-ordering phase transition. The samples were prepared by a solid-state reaction method. The XPD patterns show that the samples are of a single-phase orthorhombic-perovskite structure. The chemical compositions of the samples are investigated by EDS. The concentrations of oxygen and Mn3+; Mn4+ ions have been determined by dichromate method.
Although the chemical nature of the catalytic mechanism of the serine pro-tease a-chymotrypsin (a-CT) is largely understood, the influence of the
enzyme’s structural dynamics on its catalysis remains uncertain. Here we
investigate whether a-CT’s structural dynamics directly influence the kinet-ics of enzyme catalysis.
RecD is essential for growth at low temperature in the Antarctic psychro-trophic bacterium Pseudomonas syringaeLz4W. To examine the essential
nature of its activity, we analyzed wild-type and mutant RecD proteins
with substitutions of important residues in each of the seven conserved
Human activities have a large and important impact on the environment.
Naturally occurring elements or compounds are often concentrated and
redistributed in the environment through industrial processes, power production,
and consumer activity. For example, lead, which is found in
naturally occurring mineral deposits, has become a major pollutant through
its use in batteries, paints, and gasoline additives.
As early as the middle of the 19th century, scientists were beginning to isolate and characterize
organic compounds from nature. Modern studies of the nature of natural products, those compounds
not involved in primary metabolic processes, began in the 1930s and 1940s. In the decades that
followed, scientists began to focus on why organisms produce these compounds.
Economic and environmental consequences of natural and man-made disasters have grown exponentially during the past few decades. Whether from hurricanes, chemical spills, terrorist incidents, or other catastrophes, the negative impacts can often be felt on a global scale. Natural Hazards Analysis: Reducing the Impacts of Disasters evaluates critical preparedness issues that emergency managers must face before, during, and after disasters of any kind.
Food safety is of great importance to consumers. To
ensure the safety of the food supply and to facilitate
international trade, government agencies and international
bodies establish standards, guidelines, and regulations that
food producers and trade partners need to meet, respect,
and follow. A primary goal of national and international
regulatory frameworks for the use of veterinary drugs,
including antimicrobials, in food-producing animals is to
ensure that authorized products are used in a manner
that will not lead to non-compliance residues.
Forty-five years ago, agricultural and pharmaceutical chemistry appeared to be following
divergent paths. On the agricultural scene industrial companies were concentrating on the
synthesis of various classes of compounds and when a successful chemical candidate was
discovered, there was a good deal of joy among the synthetic chemists. We were told that
as a result of chemistry life would be better and, indeed, it was. Armed with synthetic agrochemicals,
the American farmer became the envy of the world....
Natural gas is a vital component of the world's supply of energy and an important
source of many bulk chemicals and speciality chemicals. It is one of the cleanest, safest,
and most useful of all energy sources, and helps to meet the world’s rising demand for
cleaner energy into the future. However, exploring, producing and bringing gas to the
user or converting gas into desired chemicals is a systematical engineering project, and
every step requires thorough understanding of gas and the surrounding environment.
Due to the success of the first edition of
The Engineering Handbook
published in 1995 I am pleased to
provide the second edition ten years later fully updated and expanded.
The purpose of
The Engineering Handbook, Second Edition
is to provide in a single volume a ready
reference for the practicing engineer in industry, government, and academia. The book in its comprehensive
format is divided into 30 sections which encompass the field of engineering and includes 19
brand new chapters and 131 fully updated contributions.
Wet processing of textiles uses large quantities of water, and electrical and thermal energy.
Most of these processes involve the use of chemicals as assisting, accelerating or retarding
their rates and are carried out at elevated temperatures to transfer mass from processing
liquid medium across the surface of textile material in a reasonable time. So, we can use
some natural materials and some physical tools to reduce the chemicals, water, energy and
The Tertiary Publications Committee of the Chemical Society decided that after
the appearance of Volume 5 the Specialist Periodical Report ‘Aliphatic Chem-
istry’ should be replaced by two new titles: ‘General and Synthetic Methods’ and
‘Aliphatic and Related Natural Product Chemistry’. This latter will be produced
biennially and this represents the first volume in this series.
The heroine of this book is nature’s simplest atom, the hydrogen atom. With one exception—the helium atom—hydrogen is the mother of all atoms and molecules. The hydrogen atom consists of a single electron and a single proton; the proton is the nucleus of the hydrogen atom and serves as the electron’s anchor. The universe is teeming with hydrogen: every cubic centimeter of dark interstellar space, essentially void of any other known matter,1 contains a few atoms of hydrogen
Sewage sludge as an uncalled for product of wastewater treatment poses the challenge to
society of disposing of it, but at the same time gives us the opportunity of beneficial use by
closing the cycle of nutrients: sludge derived from agricultural activity must return to soil if
a sustainable and ecologically sound management of these materials is desirable (SEQUI et
al. 2000). At present the major ways of disposing of sewage sludges are deposition, landfill
and incineration, only part of the sludges are used in agriculture. ...