Archive for June, 2014

Clean Room Pass Box

June 11th, 2014

Pass Boxes: Ultraviolet-Bathed Portals used for passing potentially contaminated items out of the laboratory.

Pass box is a kind of laboratory equipment which is used for transferring the materials from and into the Clean Room or the uncontrolled environment to the controlled environment. Controlling the ingress of particulate contamination into Clean Rooms and other controlled environments is paramount in order to maintain the integrity of products and processes.

Personnel traffic is the most important factor which should be controlled. Pass Box allows materials to be transferred into the controlled environment without actual personnel movement. Pass Box may also be used to protect the external environment from egress (the act of coming and going our) of contamination, for example, in biological safety laboratory applications.

Pass Box is equipped with the UV lamp which is used for sterilization/bacteria control. Pass box is provided with two interlocked doors, when one door is open the other door cannot be open, in this way it prevents the direct contact between the connected areas.  A Reliable Interlock System prevents the two opposite doors of the Pass Box from being opened at the same time, to maintain thestability of the Clean Room atmosphere.

Salient Features of Pass Box

  • Compact
  • Cost-effective
  • Corrosion resistance
  • Good quality raw material

Major application areas

  • Factories
  • Laboratories
  • Drug & Pharma industries
  • Research and development laboratory

Pass Box allows laboratory personnel to stay within the Clean Room instead of moving to different parts of the lab to fetch tools or materials, therefore eliminating a potential cause of contamination. When a door of a Pass Box is opened, a Laminar Air Flow begins inside to safeguard the cleanliness of the materials and of the Pass Box interior. Some types of Pass Box include built-in high velocity showers of HEPA-filtered air that spray materials entering or exiting the Clean Room. Optional Pass Box fixtures include Fluorescent Light Tubes.

PAR and Photosynthesis

June 11th, 2014

PAR stands for Photosynthetically Active Radiation; it represents the fraction of sunlight with a spectral range from 400 nm to 700 nm, usually expressed in µmol (photons) m-2 s-1 though it is also expressed in micro Einsteins OR it is the amount of light which is available for Photosynthesis. “Photosynthetically active” means the portion of the spectrum that plants need for Photosynthesis.

A measure of PAR is a measure of the amount of those wavelengths available to plants. In the process of Photosynthesis, plants use energy from sunlight to convert carbon dioxide and water into molecules of sugar (the simplest units of food). They need a certain threshold level of PAR to do this, which differs for different species of plants.

Photosynthetically Active Radiation (PAR) is measured by a Silicon Photovoltaic Detector.



This spectral region corresponds more or less with the range of light visible to the human eye. Photons at shorter wavelengths tend to be so energetic that they can be damaging to cells and tissues, but are mostly filtered out by protective compounds in leaves when plants are grown in the presence of UV light. Photons at longer wavelengths do not carry enough energy to allow Photosynthesis to take place.

PAR is needed for Photosynthesis and Plant Growth.PAR measurements are also used to calculate the Euphotic depth in the ocean. In oceans and lakes, the limits of PAR mark the lower boundary of the Euphotic Zone. Below that depth, plants can’t photosynthesize more food than they use up in respiration. How far PAR reaches depends on the clarity of the   water.

Increase in PAR enhances the Light Reactions of Photosynthesis before reaching a saturation point. Beyond that saturation point, any further increase in PAR will not result in more light-fixation. The photosynthetic response to different levels of PAR varies with plant species and leaf position. Shade plants and shaded leaves harvest PAR more efficiently at low light levels but less efficiently at high light levels compared with sun plants and sunlit leaves. Light levels measured by PAR are very useful in agronomic and agricultural research.

Muffle Furnaces

June 9th, 2014

It refers to a box that is loaded from the front and is capable of maintaining high temperatures (95degreeC-1600degreeC) within. Both ovens and kilns (thermally insulated chamber) qualify as Muffle Furnaces by this definition. In historical usage it is a furnace in which the subject material is isolated from the fuel and all of the products of combustion including gases and flying ash. After the development of high-temperature electric heating elements and widespread electrification in developed countries, new Muffle Furnaces quickly moved to electric designs.

These Muffle Furnaces use open coil heating elements on both sides of the heating chamber to allow fast heating with minimal temperature gradient. This energy efficiency is enhanced through the use of high thermal-efficient ceramic insulation surrounding the chamber. The free-floating, ceramic fiber door includes a chamber plug that prevents heat loss around the door by totally sealing when the spring-loaded door is closed. These ovens have a door safety switch which cuts power to the elements if the door is opened during use.

Operating principle

The furnace chamber is heated by Electric Resistance Elements and is insulated with Ceramic Fiber Insulation. The controller is located under the Furnace Chamber and is well insulated from the heat generated in the Furnace Chamber. A door safety switch removes power to the heating elements whenever the Furnace door is opened. The temperature is controlled by one of three types of controllers.

A Muffle Furnace most frequently uses the heating method known as Conduction, which involves heating a surface and allowing the heat to radiate into nearby areas such as holding cavity. However, some Muffle Furnaces use Convection heating instead, which involves the circulation of hot air and sometimes Black Body Radiation method too.


Muffle Furnaces are used in a variety of applications

i) Craft Applications

  • Hardening enamel coating onto clay
  • Firing ceramics
  • Melting and fusing glass
  • Soldering items together
  • Brazing

ii) In sciences; A common procedure in chemistry is to burn a sample of particular material to determine Chemical Composition, including water content and the proportion of combustible and non-combustible materials. The presence of ash after a complete burning indicates certain chemical property and can be used to determine the level of volatile versus non-volatile products in the sample.

iii) Used in Nutritional Analysis, making it possible to determine the relative proportions of proteins, fat, carbohydrate, and water in food under study.