Nuts & Volts - September 2004

TechKnowledgey 2004

cations.” The iron nearly eliminates costly hysteresis effects that otherwise appear during the on-and-off cycling of the applied magnetic field that drives the refrigeration device.

In operation, when exposed to a magnetic field, the gadolinium alloy and other materials heat up as their spinning electrons align with the field, thereby magnetizing the materials and raising their temperatures. When the external field is removed, the materials demagnetize (the electrons revert to a disordered magnetic spin state), and their temperature drops. The two stage process forms the magnetic refrigeration cycle.

Magnetic refrigeration is already a potential contender for specialized applications, such as cooling sensors in spacecraft and the liquification of gases. With additional development, it could be extended to household refrigerators and freezers, dehumidifiers, and air conditioners — which now account for about 25% of residential power use.

Intel EM64T processors.

Also introduced were the xw6200 and xw8200 models. All support Windows^®XP Professional and Red Hat Enterprise Linux WS 3.0 operating systems. The xw4200, xw6200, and xw8200 are priced at $849.00, $1,399.00, and $1,799.00, respectively.

624 MHz Pocket PC

Dell has introduced three new Axim handheld computers that include Intel’s PXA270 processors, Windows Mobile^®2003 Second Edition software for Pocket PC, and Bluetooth^®wireless technology. Two of the three configurations feature a combination of Bluetooth and WiFi^®802.11b wireless. Bluetooth allows personal area networking with computer systems and Bluetooth-enabled devices such as mobile phones, GPS receivers, keyboards, and other handheld computers. Integrated WiFi enables users to

Dell’s Axim handhelds employ Intel’s PXA270 processor and are available

with wireless technology.

Computers and
Networking
HP Introduces New
Workstations

Continuing with now-typical evolutionary — rather than revolutionary — developments in the microcomputer industry, Hewlett-Packard ( www.hp.com) has introduced three new machines. The HP Workstation xw4200 is the entry level machine aimed at engineers, artists, designers, scientists, and other users who have intense application demands, require large, complex models or data sets, and have multitasking requirements or extensive graphic needs.

The xw4200 features Intel’s 925X Express chipset and Pentium 4 processors with Hyper-Threading technology and speeds up to 3. 6 GHz with an 800 MHz front-side bus. The new chipset drives the PCI-Express graphics and input/output interface, DDR-2 memory architecture, integrated Serial ATA RAID controller, and — when available — support for future