Attention all wannabe mad scientists! A brief history of the Van de Graaff generator and tips on how to build your own.

October 30, 2009
Van de Graaff electrostatic generator October 2009 marks the 80th anniversary of the Van de Graaff electrostatic generator. While this machine is widely recognized for its loud sparks and hair-lifting demonstrations, more importantly it represents a significant benchmark in the production of static electricity at high voltages.

Dr. Robert J. Van de Graaff developed the electrostatic generator in 1929 while he was a research fellow at Princeton University. He moved to the Massachusetts Institute of Technology where, between the years of 1931 and 1933, he crafted a larger generator that produced significantly higher voltages. While at MIT, he developed the world’s largest Van de Graaff generator which is currently displayed at the Boston Museum of Science.

The Van de Graaff generator is sometimes mistaken for the Tesla coil because of similarities in appearance. However, Nikola Tesla’s invention—which predates the Van de Graaff generator by nearly 40 years—has a completely different function. The Van de Graaff generator creates static electricity, while the Tesla coil creates high-voltage current electricity that is transferrable through the air into other objects (e.g. a light bulb). Nevertheless, Tesla recognized the generator’s potential in the 1934 article titled “Possibilities of Electrostatic Generators,” when he referred to the Van de Graaff generator as a “remarkable device,” agreeing with the assertion “with which wonders will be achieved.” †

Tesla’s statement would prove to be correct. Because of its use of a power supply to a produce continuous static electricity, the Van de Graaff generator quickly eclipsed previous electrostatic models.

Basic principles of the Van de Graaff generator

They come in many sizes, but each Van de Graaff generator is comprised of three central components: the terminal, a belt and pulley system, and a motor. The terminal is the insulated hollow metal sphere elevated at the highest point of the machine where the current is expelled.

basic priciples of the Van de Graaf generator

The belt and pulley system features an insulating belt which transfers charges to the terminal. The belt creates static through friction with a metal electrode, also known as a needle or comb. There are two pulleys—each with a corresponding electrode—in place: one at the bottom of the machine, connected to the motor, and another positioned within the base of the terminal. One side of the belt carries a positive charge, while the opposite carries a negative charge. Both pulleys are contained in a hollow cylinder that is connected to the sphere.

Lastly, at the base, a switch-operated motor powers the generator.

The mother of all science fair projects

Constructing your own Van de Graaff can be a fairly straightforward process. Moreover, it is a safe, cheap, and fun way to demonstrate the properties of static electricity. To commemorate the Van de Graaff generator’s 80th birthday—and to help you stay on the cutting edge of the 20th century—here are few pointers to consider when building your generator:

  1. The most crucial part of the generator is the terminal. As such, to achieve the greatest charge, you should only use a round hollow sphere made of stainless-steel or aluminum. To test the effectiveness of the generator, you can place a negatively charged metal object close to sphere to make a spark. Even more illustrative, place your hands on the sphere and in an instant the hairs on your head will stand up.
  2. The belt is also very important. To create the most static, use a belt made of vinyl or silk. Be sure that the belt is bound tightly to the pulleys so it is unable to move laterally. (Also, bear in mind, the belt and terminal are the most difficult pieces to replace.)
  3. To ensure your machine stays intact, use a strong adhesive to firmly attach the metal sphere to cylinder—PVC piping is highly recommended—surrounding the belt.
  4. The electrodes are also pivotal in the performance of your generator. For both pulleys, position the ends of electrodes close to the belt without touching it.
  5. Lastly, make sure your surrounding conditions are not damp or humid. The generator may not work in such conditions.
If you would like assistance in building your own Van de Graaff generator, talk to a Cole-Parmer Application Specialist. These experts enjoy walking through all types of projects—be it challenging, mundane, or fun! Cole-Parmer also offers Custom Ordering Solutions to meet any desired product modifications.

6 Comments | Cool Tools, eNews | Tagged: , , , , , , , | Permalink
Posted by Cole-Parmer

How Safe are Your Safety Gloves?

October 28, 2009
Safety Glove Chemical Compatibility Database

Safety Glove Chemical Compatibility Database

To help you choose the proper safety gloves, Cole-Parmer offers a detailed Safety Glove Chemical Compatibility Database* containing information about how glove materials interact with various chemicals. This convenient resource eliminates the time you spend sorting through multiple Web sites and paper charts to determine compatibility. Simply select your chemical from more than 190 options. A chart will appear listing specific gloves (culled from a variety of glove manufacturers) and how they are rated for that material.

The database rates the glove material and chemical compatibility by degradation and permeability. Degradation refers to a reduction in one or more physical properties of a glove material. For example, when coming into contact with a particular chemical, certain gloves may become stiff or brittle and their performance is impaired.

On the other hand, permeation enables a chemical to pass through a protective film without going through pinholes, pores, or other visible openings. The chemical’s molecules enter the film and pass between the molecules of the glove. This process is not always visible to the eye and can also reduce safety.

Keep in mind that permeation and degradation are not always correlated. In addition to these quality-specific ratings, the database offers an overall rating for chemical compatibility (from excellent to not recommended).

Test-drive the Safety Glove Chemical Compatibility Database today.

*Note: The information in the Safety Glove Chemical Compatibility Database was supplied to Cole-Parmer by other reputable sources and is to be used ONLY as a guide in selecting gloves for chemical compatibility testing. Variability in material thickness, chemical concentration, temperature, and length of exposure to chemicals will affect specific performance. Always test the products with the specific chemicals and under the specific conditions of your application.

Leave a Comment » | Cool Tools, Public Service Announcement | Tagged: , , , , , , , , | Permalink
Posted by Cole-Parmer

Attention all Meat Packers (and other packers), Modified Atmosphere Packaging extends shelf life without requiring chemical preservatives or stabilizers

October 26, 2009
Meat, Veggies and Cheese

Meat, Veggies and Cheese - Modified Atmosphere Packed

Modified Atmosphere Packaging – A fresh and wholesome presentation
Protective Atmosphere enables fresh and minimally processed packaged food products to maintain visual, textural and nutritional appeal. The controlled MAP environment enables food packaging to provide an extended shelf life without requiring the addition of chemical preservatives or stabilisers.

Processors and marketers of food products rely on Modified Atmosphere Packaging to assure fresh and flavourful products that continually meet the consumer’s expectation for brand quality, consistency, freshness and in-stock availability.

More information is also avalible on www.modifiedatmospherepackaging.com

What is Modified Atmosphere Packaging?
Modified Atmosphere Packaging is an optimal blend of pure oxygen, carbon dioxide and nitrogen within a high barrier or permeable package. A finely adjusted and carefully controlled gas blend is developed to meet the specific respiration needs for each packaged food product.

Plastic films, foils and other packaging materials that demonstrate specified gas permeability properties and/or water vapour permeability properties are selected for use. These high barrier substrates become MAP Packages after they are formed into trays, lid stock or bags and filled with a select blend of oxygen, carbon dioxide and nitrogen environmental gasses.

Packaging films are selected to match the characteristics and needs of the food product. Film permeability, water vapour transmission rates and sealing characteristics need to be measured and tested at film selection and again at package converting and product fill stages, since the ability of a film to handle MAP performance characteristics may vary within each stage.

How does Modified Atmosphere Packaging work?
The Modified Atmosphere Package environment is formed from a finely balanced mix of normal atmospheric gases. The finely balanced MAP gas mix slows down the product aging process to reduce colour loss, odour and off-taste resulting from product deterioration, spoilage and rancidity caused by mold and other anaerobic organisms.

A carefully controlled Modified Atmosphere Package achieves and maintains an optimal respiration rate to preserve the fresh colour, taste and nutrient content of red meat, seafood, minimally processed fruits and vegetables, pasta, prepared foods, cheese, baked goods, cured meats and dried foods throughout an extended shelf life.

Modified Atmosphere Packaging offers supply chain efficiencies
Longer shelf life MAP packages allow food processors, food manufacturers, food distributors and food retailers to better control product quality, availability and costs.

Longer freshness cycles permit grocers to eliminate frequent product rotation, removal and restocking; thereby reducing labour and waste disposal costs.

Distributors can extend distribution territories or offer a greater variety of product lines to the retailer, since less frequent product replacement requirements permits growth in other areas.

Food manufacturers are able to take advantage of extended replacement cycles to reduce production replacement demands. Manufacturing capacity can be more profitably utilised by developing and offering new products.

Testing assures Modified Atmosphere Packaging integrity
Performance characteristics of Modified Atmosphere Packages are easily tested to assure that packages meet quality standards. Convenient, reliable and easy-to-use gas analysers, gas mixers, gas control solutions, permeability testers and package leak detectors are available. MAP package testers evaluate, measure, adjust, control and test the modified atmosphere package environment.

Random package testing
Spot testing instruments can check, measure and analyse the amount of “head-space” air between the product and the package substrate within a random sampling of packages. Random MAP testing is typically done at pre-set intervals throughout the packaging operation to assure consistency. Spot testers, which rely on built-in air collection pumps to prevent atmospheric air from entering the package, offer immediate readings.

Hand-held headspace gas analysers offer a fast check on oxygen or oxygen and carbon dioxide gas combinations within representative package samples.

Gas analysers automatically measure and record in a seamless process that provide uniform, traceable data reports. Measurements are displayed on a screen, stored in the computer and may be simultaneously sent to a printer, when a paper record is desired.

On-line quality control
Regular, systematic in-line testing of every package provides total output assurance to measure package integrity and management of the MAP gas blend. When installed onto a flow-wrapping machine, a single test unit interfaces with each package to measure its on-line gas composition and evaluate the targeted oxygen level.

Automatic flow control enables a packaging machine operator to adjust filling speeds without impacting the oxygen level. When combined with an automated gas flushing system, the operator is able to gain greater control over both gas mix and package filling speeds.

A fully automated in-line, all-in-one package testing and gas mix blending controller is available to measure, evaluate and adjust the MAP gas mix for each package. Greater control over each package assures that each package has an optimum gas mix. In addition to providing package-to-package uniformity, the seamless package measurement and precision gas adjustment process assures a more efficient gas usage with a corresponding cost savings.

MAP testing options for thermoformed packages
On-line gas monitoring equipment tests two critical areas for assuring quality in MAP packages. In the first analysis, measurement is made to check the actual oxygen or oxygen and carbon dioxide gas blend put into thermoformed packages and tray sealers. Secondly, the reading reveals air leaks within each package. These leaks are typically caused by faulty maintenance or misalignment of dies or sealing heads on thermoforming and tray sealing machinery.

MAP package measurement tests are performed on-line during both the vacuum and injection process without causing disruption or delay.

Protection against leaks
Finished modified atmosphere package leak testing and package stress testing equipment is used to verify package integrity and seal strength. Unlike messy, manual old-fashioned water testing, new non-destructive testing technology uses carbon dioxide CO2 as a trace gas in a fast, easy, user-independent test.

As part of an overall quality check, leak testing can be conducted in a closed, airtight chamber at each stage within the package forming process and during final package output.

Annual calibration offers one-time setup for maximum reliability
Advances in gas analyser technology requires less frequent instrument calibration. Once a year calibration is now available to offer greater reliability and faster set-up. Checking of recorded calibration data should be made using certified gases.

MAP package quality assurance
Although Modified Atmosphere Packaging is a well-established process, it is a good practice to maintain tight quality control through package testing. Incorrect oxygen levels, empty gas tanks and bad sealing bars can cause imprecise gas blends and poor package seals that can result in product spoilage. Routine package testing with gas analysers assures package quality, uniformity and brand consistency.

Complete Selection of CheckMate II O2 and O2/CO2 Analyzers
Complete Selection of CheckPoint O2 and CO2/O2 Analyzers

Leave a Comment » | eNews | Tagged: , , , , , , , , , , , , , , , | Permalink
Posted by Cole-Parmer

Pump up the volume for this H1N1 Rap Video by John D. Clarke, MD

October 16, 2009
Check out the H1N1 Rap, written, composed, produced and performed by John D. Clarke, MD, FAAFP.  This music video is a fun, highly educational and entertaining way to learn about prevention of the H1N1 virus.

youtube video: http://www.youtube.com/watch?v=_gwUdmPl0bU

pandemic preparedness:  http://bit.ly/2SeJmk

from flu.gov: http://www.flu.gov/psa/contest/2009/index.html

Leave a Comment » | Videos | Tagged: , , , , , , | Permalink
Posted by Cole-Parmer

Pimp your CSI DNA Lab, yo. Check out this pimpin microcentrifuge.

October 16, 2009
 

Thermo Scientific Heraeus Pico 21, 24-place microcentrifuge

Thermo Scientific Heraeus Pico 21, 24-place microcentrifuge

 

Abstract
Searching for environmental microorganisms (i.e., organism mining) is a very common process today and there are many commercially available kits for the detection of DNA in soil and water. The readily available kits minimize process preparation time and the need for on-hand reagents and consumables. The end user only needs to provide pipettes and a microcentrifuge. The Thermo Scientific Sorvall 24-place microcentrifuge was selected for this application to demonstrate how easy it is to use a soil DNA isolation kit in this Thermo Scientific Sorvall microcentrifuge.

The effective performance of the Sorvall 24-place microcentrifuge is representative of our entire new line of microcentrifuges, which includes the Heraeus Pico 21, Heraeus Fresco 21, Sorvall Legend Micro 17, Sorvall Legend Micro 21, IEC Micro 17 and IEC Micro 21.

Harvested soil samples were isolated following the FastDNA SPIN Kit instructions step by step. Gel results show clear extracted DNA which will then be subjected to further downstream analysis for identification. Harvested DNA are typically further analyzed to match for known organisms or new organisms.

Materials and Methods
Soil cores were collected from the Cataloochee plot in the Great Smoky Mountains National Park in March 2006. The plot was located and sample areas identified by their GPS coordinates using a hand-held GPS device. A clean metal corer was used to obtain 100 mm long soil cores1 with minimal disturbance to the site.

Soil cores collected at these sites were held at ambient temperature during transport to the Department of Biology at the Asheville, NC campus of the University of North Carolina (UNCA) and held at ambient temperature until use by microbiology lab students. All samples were used within three days of collection.

1. Samples containing 2.5 g of wet soil were diluted into a 22.5 ml sterile 0.8 % sodium chloride solution and incubated with shaking for 15 minutes; larger particles were allowed to settle out for 2 minutes.

2. Saline above the soil layer was serially diluted using sterile water.

3. Then, 0.1 ml dilutions were plated on solid microbiological media.

4. Plates were incubated at ambient temperature for seven days.

5. Isolated colonies were streaked on fresh plates to obtain pure cultures.

6. Colony and cellular morphologies were recorded for pure cultures.

7. DNA was isolated from pure cultures using a FastDNA SPIN Kit for soil (Qbiogene). The procedure was followed per the FastDNA SPIN Kit instructions. All centrifugation steps were performed using a Thermo Scientific 24-place microcentrifuge.

8. rDNAs of the resulting DNA samples were amplified by PCR with universal primers.2

Results
Post PCR, rDNA isolates were successfully visualized using electrophoresis in 1 % agarose gels (Figure 1). DNA isolates were subjected to further downstream analysis for identification.

Lanes 2, 3, 4, 5      

name of image 
Figure 1. Lanes 2, 3, 4, and 5 are PCR products from DNA samples prepared using the FastDNA SPIN Kit for soil (Obiogene) and Thermo Scientific 24-plce microcentrifuge.

Conclusion
Our full line of 24-place microcentrifuges is ideal for today’s busy labs using FastDNA SPIN Kits for isolation of rDNAs. These microcentrifuges have simple-to-use user interfaces with easily understood icons and a brightly lit display. Those features plus the snap-on bio-containment (Click-Seal) lid make this line of microcentrifuges a perfect choice for the multi-user lab.

The Thermo Scientific Heraeus 24-place microcentrifuges are small and quiet, making them easy to place in a busy setting without interfering with valuable bench space or the work process. They are valuable tools for all laboratories.

Shop: http://bit.ly/1M7bap

1 Comment | Latest and Greatest | Tagged: , , , , , , | Permalink
Posted by Cole-Parmer

BioConnection. The sexy side of sterile biopharm processing.

October 7, 2009

At the 2009 Cole-Parmer talent show, a new comedy boy band called BioConnection brought the house down. We hope the scientist in you enjoys the sexy side of sterile biopharm processing.

YouTube video:http://www.youtube.com/watch?v=umNJHSlNIZc

Leave a Comment » | Videos | Tagged: , , , | Permalink
Posted by Cole-Parmer

Protect yourself from the H1N1 flu!

October 7, 2009

Pandemic Preparedness:
Local Preparation for a Global Issue

Over the past several months there has been a flurry of news activity surrounding pandemic flu (specifically swine and bird flu) and preparations at the global, federal, and local level to address this concern. It can be difficult for those in private industry and for those government customers not directly involved in planning to understand their role.

Business continuity planning for this type of event can have far-reaching benefits. The same strategies adopted for pandemic preparedness can be modified for use in similar catastrophes. Health and Human Services (HHS), in partnership with the Centers for Disease Control, has developed guidelines to assist businesses with planning efforts. A host of additional resources are available to become informed on pandemic flu and to develop sound contingency plans. Planning and preparing now will have a positive impact on an organization’s survival during times of crisis.

Full Article, contains links to planning checklists and other excellent resources.
 

Respiratory Protection: Preparing Workplaces for an Influenza Breakout

An influenza outbreak in a workplace can deliver a devasting blow to productivity and morale. Learn ways to best protect your place of business from an outbreak and how to maintain operations should a pandemic occur. Full Story

Leave a Comment » | Public Service Announcement | Tagged: , , , | Permalink
Posted by Cole-Parmer

Cole-Parmer products featured on CSI: Miami.

October 7, 2009

Cole-Parmer’s products hit the big screen on CBS’s CSI: Miami – Episode 24 “Dissolved,” which aired on May 11th. The show featured the Oakton® pH 11 Economy Meter and a probe.  The meter and probe were used to detect the pH level of a pool that was part of a crime scene.

Please go to http://www.cbs.com/primetime/csi_miami and look for “Dissolved” Season 7 Episode 24.

Leave a Comment » | Hollywood | Tagged: , , , , | Permalink
Posted by Cole-Parmer

Follow

Get every new post delivered to your Inbox.

Join 684 other followers