For simple applications, switching devices such as contactors or solid-state relays can be used to control electrical power. The electrical power in a process can be regulated by varying the ON and OFF times of these devices. But in many processes this provision of energy in large blocks will cause significant variations in the process output. As an example, it would not be possible to control lighting levels simply by using such two-state on/off switching elements. Neither could good temperature controllers be implemented in this way...
Television is a means of changing patterns of light into electrical signals for storage or transmission and then recreating those patterns on a screen. In order to do this well, the television camera must be presented with properly illuminated scenes. The three important considerations are overall level, contrast range, and color temperature. Level Lighting levels for television are generally set by adjusting the incident light, or the light striking the subject.
Optimal production results depend crucially on the level of employee commitment. Correct lighting helps boost motivation, prevents fatigue, maintains health and guards against accidents at work. According to DIN EN 12464-1 “Lighting of indoor work places”, the objectives of lighting are to ensure visual comfort and visual performance.
Street lighting and other forms of exterior lighting normally found in cities ensure that the basic requirements of residents and visitors are met: an adequate level of lighting facilitates orientation and provides security after dark.
Semiconductor nanostructures are currently one of the largest and most exciting
areas in solid state physics. Low-dimensional electron systems (realized in
semiconductor quantum structures) are particularly appealing because they
allow one to study many-particle effects in reduced dimensions. Inelastic light
scattering gives direct access to the elementary excitations of those systems.
Brillouin scattering was discovered in 1922 by Louis Brillouin . It is one of
a number of characteristic scattering phenomena that occur when light interacts
with solid, liquid or gaseous media and corresponds to the scattering of
light from thermally-induced acoustical waves (propagating pressure/density
waves) present in media at all temperatures. At normal light levels the
amount of scattering is small. The characteristics of the scattering can offer
interesting information about the properties of the medium (temperature,
pressure) and form the basis for remote fibre sensor devices.
This book is designed to serve as a first course in an electrical engineering or
an electrical engineering and computer science curriculum, providing students
at the sophomore level a transition from the world of physics to the world of
electronics and computation. The book attempts to satisfy two goals: Combine
circuits and electronics into a single, unified treatment, and establish a strong
connection with the contemporary worlds of both digital and analog systems
I started my first photobiological research project almost exactly 50 years ago,
in the spring of 1957. My scientific interest ever since has been focused on
photobiology in its many aspects. Because I have been employed as a botanist,
my own research has dealt with the photobiology of plants, but throughout this
time I have been interested in other aspects, such as vision, the photobiology of
skin, and bioluminescence. A first edition of the present book was published in
2002, but this second edition is much expanded and completely updated.
A primary purpose in creating this 3rd Edition is the addition of a stair design
component. Over many years as a design studio teacher and critic, I have
been regularly reminded of the significant difficulty that many students have
in learning to design and draw stairs correctly. From a design perspective,
stairs are among the more complex elements within buildings, particularly
when there are multiple levels to be accommodated and/or complex building
configurations to be considered.
More precisely, he
insists on the fundamental role of the sudden appearance of the rain that literally
‘irradiates’ the frame with an inexplicable but vibrating light. The rain becomes a ‘golden
rain’, similar to the golden background of the icons, and transcends the cinematic image
until a real transfiguration arises. Tarkovsky’s cinematic gesture in this shot is then similar
to the one of religious painters. But Tarkovsky creates a specific cinematic icon since the
icon appears within a temporality.
On a regional average, in countries that witnessed uprisings or popular movements - there are slight gender differences
between men’s and women’s uses of social media during the “Arab spring” according to the survey respondents.
While the top two uses of social media were for the purpose of raising awareness and spreading information about the
events related to uprisings and revolutions, a slightly larger percentage of men than women used social media for these
This introduction to Evidence-Based Dentistry provides a much-needed orientation in the subject for students and professionals alike. It is a ground-level book for those seeking to understand evidence-based dentistry and its significance for clinical practice. The book is anchored in the dental literature: the majority of the chapters offer guidance on interpreting a full published paper; where both the subject of the paper and the study design is of relevance to the field of dentistry.
Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành y học dành cho các bạn tham khảo đề tài: Shedding light on walking in the dark: the effects of reduced lighting on the gait of older adults with a higher-level gait disorder and controls
Over the last few years, there has been a convergence between the fields
of ultrafast science, nonlinear optics, optical frequency metrology, and
precision laser spectroscopy. These fields have been developing largely
independently since the birth of the laser, reaching remarkable levels of
our portfolio of brands includes rowe, Clayton Marcus and robin Bruce – each with a distinctive styling and set of
features that sets it apart from other custom-order upholstery collections. The unified vision across the portfolio of
brands is a high level of design, customer service, quality and reliability. our intention is to be a great home furnishings
resource offering you a selection of styling, from contemporary to traditional to eclectic chic.
Consequently the chemical contamination builds to
higher levels in these organisms. Indigenous peoples in the Arctic, whose traditional diets are
heavy in fatty foods and who often have no alternatives for nourishment, thus have some of
the highest recorded levels of POPs. Yet they are hundreds or thousands of kilometres from
where these pesticides and industrial chemicals were released, and they certainly received
little benefit from the chemicals' original use.
An important feature in many countries is the role of securitization in the lending and housing
prices boom and burst. At the macroeconomic level, the dynamics of the relationship between
lending, housing prices and securitization have been largely unexplored although a rising
interest has recently emerged with the financial crisis.
We use a series of computational models to estimate health damages attributable to air
pollution from these plants, we compare these damages to estimates of damanges from non-
maquiladora industrial polluters, and we use regression analysis to determine whether the poor
suffer disproportionately from maquiladora air pollution. Two important caveats are in order.
The two maquiladora plants for which we estimate health damages were selected for
idiosyncratic reasons, and therefore may not be particularly representative.
We have used a limited data set—comprised of a sector-level emissions inventory and
original emissions estimates for a small sample of industrial facilities—to shed light on the links
between maquiladoras, air pollution, and human health in Paso del Norte. We found that
particulate emissions from maquiladoras undoubtedly have significant impacts on human
health—collectively, these plants are probably responsible for dozens of cases of premature
mortality and thousands of cases of respiratory disease each year.