Tag: <span>Variable level system</span>

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It’s no secret that roughly half of your energy goes to heating and cooling your home or commercial space. If you wish to lower your utility bills, it’s important for you to make smart decisions when it comes to your HVAC system.

If your HVAC repair costs keep rising and your system isn’t performing efficiently anymore, it may be time for an upgrade. An HVAC upgrade will not only lead to a significant difference in your electricity bills, but also bring about a positive change in your comfort level.

In this article, we’ll take a look at five amazing benefits of upgrading your HVAC system.

Comfort Control

Once you upgrade your HVAC system, you’ll be able to control the indoor temperature and ensure that it meets the comfort needs of your family. You’ll be able to program your system so the temperature in every room is adjusted automatically and everyone can feel comfortable.

Reduced Carbon Footprint

As environmental concerns continue to increase in severity, going green is imperative for most home and business owners. Upgrading to a new and improved HVAC system will not only be great for your wallet in the long term but also for the environment.

There are some higher efficiency systems available in the market that utilize one-third less fuel as opposed to older models. This means there’ll be less waste and better preservation of the natural resources.

Increased Resale Value

Are you planning to sell your property? It’s important for you to consider that when buyers evaluate any property, they typically examine the HVAC system and its quality before they can decide whether they should make the final investment or not.

They also consider the operating cost of the system before making the purchase. So, if you want to increase your property’s resale value, it’s advisable that you upgrade to a better and more efficient HVAC system.

Healthier Air

Upgrading HVAC systems will make the air inside your home or commercial space a lot cleaner because newer HVAC systems come with variable speed motors than will allow you to ensure there’s constant air flow and sufficient ventilation.

This is great for people with asthma or allergies because breathing in low-quality air can cause further health complications for them. The new filtration system will make sure that pollutants don’t enter your home, allowing you to keep the health of all the inhabitants as a topmost priority.

Lower Repair Costs

Installing a new system also means that all the parts and the unit as a whole will be under warranty for at least a few years. Even though the upfront cost may be higher, you won’t have to spend as much on maintenance and repair costs for a long time, especially if you take proper care of your HVAC system.

Improving the efficiency of HVAC systems is a priority for most home and business owners and understandably so. If your system is quite old and isn’t working efficiently anymore, it may be time for you take the leap and replace it with a better and improved unit.

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Source by Mike Petty

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1 Introduction:

Starting from short haul operation strategy, Air Asia airline in south-east Asia provides cost effective flying solutions for travelers. To formulate this cost effecting strategy, Air Asia first determine different cost such as capital, fixed, variable, maintenance, labor, fuel, facility, inventory, environment and technology cost to establish new point to point airline service. To investigate different kinds of cost Air Asia first identify potential market in south-east Asia by strong commitment at all level of services; for instance in safety, security, customer service and benefits. Air Asia also established their strategy by building strategic alliances with other airlines. This low cost strategy from Air Asia airline also proven to be formidable puzzle of interest as different proportion of constant changing variables affect on policy making, segmenting market, inventory control, yield system and so on. Basically, implementing such strategy was indeed complex in nature for example, providing direct services between two destinations route increase LOS (level of service) but on the contrary if the airline does not fill up with sufficient passenger then the airline surely will incur huge losses..

2 Different Cost Analysis of Air Asia:

2.1 Capital cost:

For Air Asia, capital cost is associated with initial setup of project, generally which occur at the beginning of project likewise, investment or buying airplane, cargo, aircraft, lands, buildings, construction, alternative route, high speed train (HST) facilities for different route and so on. Recently, Air Asia is going to expand its market in air cargo which again asking for lots of capital investment. Though, airline capital investments is highly intensive and most of the potential project failed due to limited funds. For example, MAXjet airways, EOS and SilverJet all failed at the initial stage of capital investment only because lack of funding and competitive business models (Wensveen, Leick, 2009). Thus, Air Asia is required to understand this issue for successful business require sufficient amount of capital investment at initial phase.

2.2 Fixed cost:

Here, the price of Air Asia has to be determined on capacity, seats and utilities to minimize total cost. In addition, fixed cost also consist of ticketing operation, ground facilities, airport counter facilities, forward booking and dispatching aircraft from the fleet which can be spread over more passenger as traffic density rises.

2.3 Variable cost:

These costs are determined based on operating, maintenance, labor, fuel, facility, inventory, environmental and technology cost.

3 Operating cost:

The effects of operating cost are un-quantified as the scope of system is varied on point to point service. Here the basic operating costs are administration, ticketing, sales & promotion, passenger service, en-route airport maintenance and landing cost. These operating costs have determined on the level of various operations on airline including air service such as cargo operation, employees.

3.1 Flight operating cost: Is typically associated with aircraft, fleet, flying operation as well as cost related to repairing of equipment and depreciation & amortization.

3.2 Ground operating costs: this cost incurred from handling airport station, landing fees, charges, processing cargo, passenger baggage, travel agency cost, retail ticket office, distribution, commission, reservation, ticket and sales and so on.

3.3 System operating cost: this cost include passenger service cost (i.e. foods, entertainment, flight attendant and in flight service and transport related cost (i.e. regional airline partners providing regional air service, extra baggage expense and miscellaneous overheads.

4 Maintenance Cost:

The next stage is maintenance cost which is related to engine maintenance and components maintenance cost. In 2009, the proportion of engine maintenance cost was 43 percent where component maintenance cost was 20 percent and line maintenance was 17 percent. The maintenance cost also increases due to direct operating cost as for daily air flight operation. Thus, maintenance cost is crucial for our Air Asia because this overhead cost doesn’t depend although it varies to the number of times due to requirement of service, demand or other factors. For example, any break down on engine or component hamper airline services for on time flight or even any disruptions increase additional charges as well as minimizing level of services which eventually drive away passenger.

5 Labor cost:

For Air Asia, labor cost is major factor as it is related with salary, benefits, pay rate for cabin crew, pilot, stuffs and other employees. However, labor cost also includes with aircraft services, cleaning, and passenger handling and catering. For example, providing service for customers likes catering, cleaning or even emergency service during flight require services from stuffs. For these additional services, employers expect to receive additional incentives.

6 Fuel cost:

Constant fluctuations on fuel price are also causes great impact on airline service in terms of competition on point to point service. This has been evident that approximately overall 20 percent operating costs are incurred from fuel, and due to price sensitivity, flexibility and quick responsiveness fuel price causes negative effect on ticket price.

7 Facility cost:

Here all kinds of aircraft, electricity, water, availability of spare equipments, machine, tools, ground maintenance filtering, pipeline and route maintenance costs are related to facility cost.

8 Environmental cost:

Airline industry is usually always remaining under pressure to decrease negative impact on global warming and noise pollution. Growing awareness on environmental issues is becoming a huge challenge now days to introduce new technology, aircraft and new air flight. For example, Singapore airlines attempted to keep its fleet as modern as possible. The new A380 is a cleaner and greener aircraft compared to the Boeing 747 on a per-seat basis but introducing such new service was really costly.

The only solution is to become greener and eco-friendly is adapting technology which doesn’t pollute air and doesn’t increase global warming. For example, eco-friendly gas could be an alternative solution to mitigate this issue as well as reducing costs. In Air Asia, it’s very important to forecast future environmental threats to sustain in market. This cost is hard to eliminate but since Air Asia is based on south-east Asia; rules and regulation are considerably favorable to sustain in market. On the other hand, it’s necessary to forecast estimating cost of environmental tax.

9 Technological costs:

Poor technology like traditional system i.e. manual ticketing, checking system, decrease significant amount of level of service. Though the cost are differentiate but to reduce substantial amount of cost for example, online booking, online assistance, and online information could be minimized by 24/7 online help line. For safety and security, RFID technology or 2D reader, barcode, e-service can be used.

10 Conclusions:

To sum up, cost is always a major factor in all aspects like in marketing, operational, safety, technological, maintenance, environmental for Air Asia. Though cost is flexible in nature and complex but for Air Asia could easily switch their cost due differentiate their market and taking advantage on existing alliance. Here, Air Asia airline need to identify proportion of cost to invest at the right sector over the long period of time. As, the company is already offering 20 percent low flight than competitors; thus, it’s necessary to control cost with proper budgeting, planning and scheduling. In this case, Air Asia can also learn from Jet Asia and Singapore airlines, how these successful companies operate their cost-effective business to sustain in the market.

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Source by Mohammad Yousuf Chowdhury

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Car audio crossovers are a class of electronic filters designed for use in audio applications such as hi-fi. A dynamic loudspeaker driver that is commonly used is incapable of covering the entire audio spectrum all by itself.

Crossovers split the audio signal into separate frequency bands which can be handled by individual loudspeaker drivers optimized for those frequency bands. Let’s take a closer look at Kenwood’s KE-600 Crossover, KPX-F801 Crossover and Kenwood KPX-L101 Crossover.

Kenwood KE-600 Crossover

Kenwood KE-600, one of the most advanced signal processors, is a 6-Way electronic crossover with built-in parametric equalizer and a DC to DC power supply for high voltage outputs and low noise.

It has input selection, phase switching, variable level controls and the following outputs: subwoofer, low-pass, low-cut, high-cut and high-pass. It is a great component for multi-amp installations and is available for around $370.

Features

● DC to DC converter.

● High-frequency output.

● Input selector.

● Different phase switches.

● Subwoofer output from 30Hz to 800Hz (low-pass).

● 6-way multi-amp configuration.

● Variable level controls.

Kenwood KPX-F801 Crossover

Kenwood KPX-F801 Crossover is a 3-way passive crossover network. It is available for around $75.

Features

● Guard circuit that protects against excessive tweeter inputs.

● Special capacitors and inductors for audio purpose.

● Phase inverter switch for midrange and tweeter.

Kenwood KPX-L101 Crossover

Kenwood KPX-L101 Crossover is a low-pass passive crossover network. It is available for $50.

Features

● Special capacitor and inductor for audio purpose.

● 80Hz crossover.

Remember, an audio crossover splits the incoming audio signal into separate bands that do not overlap at all, and which, when added together, gives the signal unchanged in both frequency and phase response.

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Source by Chimezirim Chinecherem Odimba

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A 170 year old electrical technology, called variable switched reluctance (VSR) motors was resurrected in the 1980s with the advent of electronic controllers. The Texas based Le Tiurneau.inc has developed a wheeled front end loader for mining work which use large horsepower VSR motors for its wheel drives. Basically, a VSR motor comprises a rotor and a stator with a coil winding in the stator. The rotor, which consists of a laminated permeable material with teeth, is a passive device with no coil winding or permanent magnets.

The stator typically consists of slots containing a series of coil winding, the energization of which is electronically switched to generate a moving field. When one stator coil is set on, a magnetic flux path is generated around the coil and the rotor. The rotor experiences a torque and is moved in the line with the energized coils, minimizing the flux path. with the approximate switching and energization of the stator coils, the rotor can be encouraged to rotate at any desired torque and speed.

VSR Motors offers the following advantages: Since there are no brushes ringing, there is no requirement of commutator maintenance. the motor is more robust since there are no coils or moving parts. A VSR motor can maintain higher torque and efficiency over broader speed ranges than is possible with other advanced variable speed systems. In addition, as the commutation can be accurately controlled with respect to the rotor angle, the motor will operate at its predicted high efficiency. With VSR technology it is possible to design a low cost motor with over 90% system efficiency and variable speed.

VSR motors can be programmed to precisely match the loads the serve, and their simple rugged construction has no expensive magnets or squirrel cages like the induction motor. VSR motors are smaller than DC motors. VSR motor is inherently resistant to overload and immune to single point failure. They have a high level of fault tolerance and are immune to switching faults. According t a spokesman of Le Tourneau, While the initial cost of SR motor and control is a little more expensive than standard DC system, in the failure, there may be little or no difference in the manufacturing costs due to decreasing prices of electronic components. VSR motors are not without their drawbacks, however. The most significant downside is the acoustic noise and the large vibration caused by the motor’s high pulsating magnetic flux. Another limitation is torque ripple. But while these drawbacks have an effect in small horsepower VSR motors, they are of no significance in large horsepower traction motors.

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Source by Praise Paul

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ABSTRACT

Biometric identification refers to identifying an individual based on his/her distinguishing physiological and/or behavioural characteristics. As these characteristics are distinctive to each and every person, biometric identification is more reliable and capable than the traditional token based and knowledge based technologies differentiating between an authorized and a fraudulent person. This paper discusses the mainstream biometric technologies and the advantages and disadvantages of biometric technologies, their security issues and finally their applications in day today life.

INTRODUCTION:

“Biometrics” are automated methods of recognizing an individual based on their physical or behavioral characteristics. Some common commercial examples are fingerprint, face, iris, hand geometry, voice and dynamic signature. These, as well as many others, are in various stages of development and/or deployment. The type of biometric that is “best ” will vary significantly from one application to another. These methods of identification are preferred over traditional methods involving passwords and PIN numbers for various reasons: (i) the person to be identified is required to be physically present at the point-of-identification; (ii) identification based on biometric techniques obviates the need to remember a password or carry a token. Biometric recognition can be used in identification mode, where the biometric system identifies a person from the entire enrolled population by searching a database for a match.

A BIOMETRIC SYSTEM:

All biometric systems consist of three basic elements:

• Enrollment, or the process of collecting biometric samples from an individual, known as the enrollee, and the subsequent generation of his template.
• Templates, or the data representing the enrollee’s biometric.
• Matching, or the process of comparing a live biometric sample against one or many templates in the system’s database.

Enrollment

Enrollment is the crucial first stage for biometric authentication because enrollment generates a template that will be used for all subsequent matching. Typically, the device takes three samples of the same biometric and averages them to produce an enrollment template. Enrollment is complicated by the dependence of the performance of many biometric systems on the users’ familiarity with the biometric device because enrollment is usually the first time the user is exposed to the device. Environmental conditions also affect enrollment. Enrollment should take place under conditions similar to those expected during the routine matching process. For example, if voice verification is used in an environment where there is background noise, the system’s ability to match voices to enrolled templates depends on capturing these templates in the same environment. In addition to user and environmental issues, biometrics themselves change over time. Many biometric systems account for these changes by continuously averaging. Templates are averaged and updated each time the user attempts authentication.

Templates

As the data representing the enrollee’s biometric, the biometric device creates templates. The device uses a proprietary algorithm to extract “features” appropriate to that biometric from the enrollee’s samples. Templates are only a record of distinguishing features, sometimes called minutiae points, of a person’s biometric characteristic or trait. For example, templates are not an image or record of the actual fingerprint or voice. In basic terms, templates are numerical representations of key points taken from a person’s body. The template is usually small in terms of computer memory use, and this allows for quick processing, which is a hallmark of biometric authentication. The template must be stored somewhere so that subsequent templates, created when a user tries to access the system using a sensor, can be compared. Some biometric experts claim it is impossible to reverse-engineer, or recreate, a person’s print or image from the biometric template.

Matching

Matching is the comparison of two templates, the template produced at the time of enrollment (or at previous sessions, if there is continuous updating) with the one produced “on the spot” as a user tries to gain access by providing a biometric via a sensor. There are three ways a match can fail:

• Failure to enroll.
• False match.
• False nonmatch.

Failure to enroll (or acquire) is the failure of the technology to extract distinguishing features appropriate to that technology. For example, a small percentage of the population fails to enroll in fingerprint-based biometric authentication systems. Two reasons account for this failure: the individual’s fingerprints are not distinctive enough to be picked up by the system, or the distinguishing characteristics of the individual’s fingerprints have been altered because of the individual’s age or occupation, e.g., an elderly bricklayer.

In addition, the possibility of a false match (FM) or a false nonmatch (FNM) exists. These two terms are frequently misnomered “false acceptance” and “false rejection,” respectively, but these terms are application-dependent in meaning. FM and FNM are application-neutral terms to describe the matching process between a live sample and a biometric template. A false match occurs when a sample is incorrectly matched to a template in the database (i.e., an imposter is accepted). A false non-match occurs when a sample is incorrectly not matched to a truly matching template in the database (i.e., a legitimate match is denied). Rates for FM and FNM are calculated and used to make tradeoffs between security and convenience. For example, a heavy security emphasis errs on the side of denying legitimate matches and does not tolerate acceptance of imposters. A heavy emphasis on user convenience results in little tolerance for denying legitimate matches but will tolerate some acceptance of imposters.

BIOMETRIC TECHNOLOGIES:

The function of a biometric technologies authentication system is to facilitate controlled access to applications, networks, personal computers (PCs), and physical facilities. A biometric authentication system is essentially a method of establishing a person’s identity by comparing the binary code of a uniquely specific biological or physical characteristic to the binary code of an electronically stored characteristic called a biometric. The defining factor for implementing a biometric authentication system is that it cannot fall prey to hackers; it can’t be shared, lost, or guessed. Simply put, a biometric authentication system is an efficient way to replace the traditional password based authentication system. While there are many possible biometrics, at least eight mainstream biometric authentication technologies have been deployed or pilot-tested in applications in the public and private sectors and are grouped into two as given,

• Contact Biometric Technologies
• fingerprint,
• hand/finger geometry,
• dynamic signature verification, and
• keystroke dynamics
• Contactless Biometric Technologies
• facial recognition,
• voice recognition
• iris scan,
• retinal scan,

CONTACT BIOMETRIC TECHNOLOGIES:

For the purpose of this study, a biometric technology that requires an individual to make direct contact with an electronic device (scanner) will be referred to as a contact biometric. Given that the very nature of a contact biometric is that a person desiring access is required to make direct contact with an electronic device in order to attain logical or physical access. Because of the inherent need of a person to make direct contact, many people have come to consider a contact biometric to be a technology that encroaches on personal space and to be intrusive to personal privacy.

Fingerprint

The fingerprint biometric is an automated digital version of the old ink-and-paper method used for more than a century for identification, primarily by law enforcement agencies. The biometric device involves users placing their finger on a platen for the print to be read. The minutiae are then extracted by the vendor’s algorithm, which also makes a fingerprint pattern analysis. Fingerprint template sizes are typically 50 to 1,000 bytes. Fingerprint biometrics currently have three main application arenas: large-scale Automated Finger Imaging Systems (AFIS) generally used for law enforcement purposes, fraud prevention in entitlement pro-grams, and physical and computer access.

Hand/Finger Geometry

Hand or finger geometry is an automated measurement of many dimensions of the hand and fingers. Neither of these methods takes actual prints of the palm or fingers. Only the spatial geometry is examined as the user puts his hand on the sensor’s surface and uses guiding poles between the fingers to properly place the hand and initiate the reading. Hand geometry templates are typically 9 bytes, and finger geometry templates are 20 to 25 bytes. Finger geometry usually measures two or three fingers. Hand geometry is a well-developed technology that has been thoroughly field-tested and is easily accepted by users.

Dynamic Signature Verification

Dynamic signature verification is an automated method of examining an individual’s signature. This technology examines such dynamics as speed, direction, and pressure of writing; the time that the stylus is in and out of contact with the “paper”; the total time taken to make the signature; and where the stylus is raised from and lowered onto the “paper.” Dynamic signature verification templates are typically 50 to 300 bytes.

Keystroke Dynamics

Keystroke dynamics is an automated method of examining an individual’s keystrokes on a keyboard. This technology examines such dynamics as speed and pressure, the total time of typing a particular password, and the time a user takes between hitting certain keys. This technology’s algorithms are still being developed to improve robustness and distinctiveness. One potentially useful application that may emerge is computer access, where this biometric could be used to verify the computer user’s identity continuously.

CONTACTLESS BIOMETRIC TECHNOLOGIES:

A contactless biometric can either come in the form of a passive (biometric device continuously monitors for the correct activation frequency) or active (user initiates activation at will) biometric. In either event, authentication of the user biometric should not take place until the user voluntarily agrees to present the biometric for sampling. A contactless biometric can be used to verify a persons identity and offers at least two dimension that contact biometric technologies cannot match. A contactless biometric is one that does not require undesirable contact in order to extract the required data sample of the biological characteristic and in that respect a contactless biometric is most adaptable to people of variable ability levels.

Facial Recognition

Facial recognition records the spatial geometry of distinguishing features of the face. Different vendors use different methods of facial recognition, however, all focus on measures of key features. Facial recognition templates are typically 83 to 1,000 bytes. Facial recognition technologies can encounter performance problems stemming from such factors as no cooperative behavior of the user, lighting, and other environmental variables. Facial recognition has been used in projects to identify card counters in casinos, shoplifters in stores, criminals in targeted urban areas, and terrorists overseas.

Voice Recognition

Voice or speaker recognition uses vocal characteristics to identify individuals using a pass-phrase. Voice recognition can be affected by such environmental factors as background noise. Additionally it is unclear whether the technologies actually recognize the voice or just the pronunciation of the pass-phrase (password) used. This technology has been the focus of considerable efforts on the part of the telecommunications industry and NSA, which continue to work on

improving reliability. A telephone or microphone can serve as a sensor, which makes it a relatively cheap and easily deployable technology.

Iris Scan

Iris scanning measures the iris pattern in the colored part of the eye, although the iris color has nothing to do with the biometric. Iris patterns are formed randomly. As a result, the iris patterns in your left and right eyes are different, and so are the iris patterns of identical-cal twins. Iris scan templates are typically around 256 bytes. Iris scanning can be used quickly for both identification and verification

Applications because of its large number of degrees of freedom. Current pilot programs and applications include ATMs (“Eye-TMs”), grocery stores (for checking out), and the few International Airports (physical access).

Retinal Scan

Retinal scans measure the blood vessel patterns in the back of the eye. Retinal scan templates are typically 40 to 96 bytes. Because users perceive the technology to be somewhat intrusive, retinal scanning has not gained popularity with end-users. The device involves a light source shined into the eye of a user who must be standing very still within inches of the device. Because the retina can change with certain medical conditions, such as pregnancy, high blood pressure, and AIDS, this biometric might have the potential to reveal more information than just an individual’s identity.

Emerging biometric technologies:

Many inventors, companies, and universities continue to search the frontier for the next biometric that shows potential of becoming the best. Emerging biometric is a biometric that is in the infancy stages of proven technological maturation. Once proven, an emerging biometric will evolve in to that of an established biometric. Such types of emerging technologies are the following:

• Brainwave Biometric
• DNA Identification
• Vascular Pattern Recognition
• Body Odor Recognition
• Fingernail Bed Recognition
• Gait Recognition
• Handgrip Recognition
• Ear Pattern Recognition
• Body Salinity Identification
• Infrared Fingertip Imaging & Pattern Recognition

SECURITY ISSUES:

The most common standardized encryption method used to secure a company’s infrastructure is the Public Key Infrastructure (PKI) approach. This approach consists of two keys with a binary string ranging in size from 1024-bits to 2048-bits, the first key is a public key (widely known) and the second key is a private key (only known by the owner). However, the PKI must also be stored and inherently it too can fall prey to the same authentication limitation of a password, PIN, or token. It too can be guessed, lost, stolen, shared, hacked, or circumvented; this is even further justification for a biometric authentication system. Because of the structure of the technology industry, making biometric security a feature of embedded systems, such as cellular phones, may be simpler than adding similar features to PCs. Unlike the personal computer, the cell phone is a fixed-purpose device. To successfully incorporate Biometrics, cell-phone developers need not gather support from nearly as many groups as PC-application developers must.

Security has always been a major concern for company executives and information technology professionals of all entities. A biometric authentication system that is correctly implemented can provide unparalleled security, enhanced convenience, heightened accountability, superior fraud detection, and is extremely effective in discouraging fraud. Controlling access to logical and physical assets of a company is not the only concern that must be addressed. Companies, executives, and security managers must also take into account security of the biometric data (template). There are many urban biometric legends about cutting off someone finger or removing a body part for the purpose of gain access. This is not true for once the blood supply of a body part is taken away, the unique details of that body part starts to deteriorate within minutes. Hence the unique details of the severed body part(s) is no longer in any condition to function as an acceptable input for scanners.

The best overall way to secure an enterprise infrastructure, whether it be small or large is to use a smart card. A smart card is a portable device with an embedded central processing unit (CPU). The smart card can either be fashioned to resemble a credit card, identification card, radio frequency identification (RFID), or a Personal Computer Memory Card International Association (PCMCIA) card. The smart card can be used to store data of all types, but it is commonly used to store encrypted data, human resources data, medical data, financial data, and biometric data (template). The smart card can be access via a card reader, PCMCIA slot, or proximity reader. In most biometric-security applications, the system itself determines the identity of the person who presents himself to the system. Usually, the identity is supplied to the system, often by presenting a machine-readable ID card, and then the system asked to confirm. This problem is “one-to- one matching.” Today’s PCs can conduct a one-to-one match in, at most, a few seconds. One-to-one matching differs significantly from one-to-many matching. In a system that stores a million sets of prints, a one-to-many match requires comparing the presented fingerprint with 10 million prints (1 million sets times 10 prints/set). A smart card is a must when implementing a biometric authentication system; only by the using a smart card can an organization satisfy all security and legal requirements. Smart cards possess the basic elements of a computer (interface, processor, and storage), and are therefore very capable of performing authentication functions right on the card.

The function of performing authentication within the confines of the card is known as ‘Matching on the Card (MOC)’. From a security prospective MOC is ideal as the biometric template, biometric sampling and associated algorithms never leave the card and as such cannot be intercepted or spoofed by others (Smart Card Alliance). The problem with smart cards is the public-key infrastructure certificates built into card does not solve the problem of someone stealing the card or creating one. A TTP (Trusted Third Party) can be used to verify the authenticity of a card via an encrypted MAC (Media Access Control).

CULTURAL BARRIERS/PERCEPTIONS:

People as diverse as those of variable abilities are subject to many barriers, theories, concepts, and practices that stem from the relative culture (i.e. stigma, dignity or heritage) and perceptions (i.e. religion or philosophical) of the international community. These factors are so great that they could encompass a study of their own. To that end, it is also theorized that to a certain degree that the application of diversity factors from current theories, concepts, and practices may be capable of providing a sturdy framework to the management of employees with disabilities. Moreover, it has been implied that the term diversity is a synonymous reflection of the initiatives and objectives of affirmative action policies. The concept of diversity in the workplace actually refers to the differences embodied by the workforce members at large. The differences between all employees in the workforce can be equated to those employees of different or diverse ethnic origin, racial descent, gender, sexual orientation, chronological maturity, and ability; in effect minorities.

ADVANTAGES OF BIOMETRIC TECHNOLOGIES:

Biometric technologies can be applied to areas requiring logical access solutions, and it can be used to access applications, personal computers, networks, financial accounts, human resource records, the telephone system, and invoke customized profiles to enhance the mobility of the disabled. In a business-to-business scenario, the biometric authentication system can be linked to the business processes of a company to increase accountability of financial systems, vendors, and supplier transactions; the results can be extremely beneficial.

The global reach of the Internet has made the services and products of a company available 24/7, provided the consumer has a user name and password to login. In many cases the consumer may have forgotten his/her user name, password, or both. The consumer must then take steps to retrieve or reset his/her lost or forgotten login information. By implementing a biometric authentication system consumers can opt to register their biometric trait or smart card with a company’s business-to-consumer e-commerce environment, which will allow a consumer to access their account and pay for goods and services (e-commerce). The benefit is that a consumer will never lose or forget his/her user name or password, and will be able to conduct business at their convenience. A biometric authentications system can be applied to areas requiring physical access solutions, such as entry into a building, a room, a safe or it may be used to start a motorized vehicle. Additionally, a biometric authentication system can easily be linked to a computer-based application used to monitor time and attendance of employees as they enter and leave company facilities. In short, contactless biometrics can and do lend themselves to people of all ability levels.

DISADVANTAGES OF BIOMETRIC TECHNOLOGIES:

Some people, especially those with disabilities may have problems with contact biometrics. Not because they do not want to use it, but because they endure a disability that either prevents them from maneuvering into a position that will allow them to make use the biometric or because the biometric authentication system (solution) is not adaptable to the user. For example, if the user is blind a voice biometric may be more appropriate.

BIOMETRIC APPLICATIONS:

Most biometric applications fall into one of nine general categories:

• Financial services (e.g., ATMs and kiosks).
• Immigration and border control (e.g., points of entry, precleared frequent travelers, passport and visa issuance, asylum cases).
• Social services (e.g., fraud prevention in entitlement programs).
• Health care (e.g., security measure for privacy of medical records).
• Physical access control (e.g., institutional, government, and residential).
• Time and attendance (e.g., replacement of time punch card).
• Computer security (e.g., personal computer access, network access, Internet use, e-commerce, e-mail, encryption).
• Telecommunications (e.g., mobile phones, call center technology, phone cards, televised shopping).
• Law enforcement (e.g., criminal investigation, national ID, driver’s license, correctional institutions/prisons, home confinement, smart gun).

CONCLUSION:

Currently, there exist a gap between the number of feasible biometric projects and knowledgeable experts in the field of biometric technologies. The post September 11 th, 2002 attack (a.k.a. 9-11) on the World Trade Center has given rise to the knowledge gap. Post 9-11 many nations have recognized the need for increased security and identification protocols of both domestic and international fronts. This is however, changing as studies and curriculum associated to biometric technologies are starting to be offered at more colleges and universities. A method of closing the biometric knowledge gap is for knowledge seekers of biometric technologies to participate in biometric discussion groups and biometric standards committees.

The solutions only needs the user to possess a minimum of require user knowledge and effort. A biometric solution with minimum user knowledge and effort would be very welcomed to both the purchase and the end user. But, keep in mind that at the end of the day all that the end users care about is that their computer is functioning correctly and that the interface is friendly, for users of all ability levels. Alternative methods of authenticating a person’s identity are not only a good practice for making biometric systems accessible to people of variable ability level. But it will also serve as a viable alternative method of dealing with authentication and enrollment errors.

Auditing processes and procedures on a regular basis during and after installation is an excellent method of ensuring that the solution is functioning within normal parameters. A well-orchestrated biometric authentication solution should not only prevent and detect an impostor in instantaneous, but it should also keep a secure log of the transaction activities for prosecution of impostors. This is especially important, because a great deal of ID theft and fraud involves employees and a secure log of the transaction activities will provide the means for prosecution or quick resolution of altercations.

REFERENCES:

• Pankanti S, Bolle R & Jain A, Biometrics:The Future of Identification
• Nalwa V, Automatic on-line signature verification
• Biometric Consortium homepage, http://WWW.biometrics.org

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Source by Murali Kiruba

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An optical attenuator is an electronic device commonly used to decrease the level of power of an optical signal in a fiber optic communication system. In fiber optics, attenuation is also called transmission loss. It is the reduction in light signal intensity with respect to the distance traveled by the signal in a transmission medium. Attenuation is an important element to limit the transmission of a digital signal traveling in large distances. An optical attenuator reduces this optical signal as it travels along a free space or an optical fiber.

Optical fiber attenuators may employ several principles when used in fiber optic communications. One common principle is the gap loss principle. Attenuators using this principle are sensitive to the modal distribution ahead of the attenuator. Thus, they should be utilized at or near the transmitting end. If not, the attenuators could establish less loss than intended. This problem is avoided by attenuators that use absorptive or reflective principles.

There are three basic types of optical attenuator: the fixed attenuator, step-wise attenuator and the continuously variable attenuator. Fixed attenuators reduce light signals by specific amount with negligible or no reflection. Because signal reflection is not an issue, fixed attenuators are known for more accurate data transmission. Important elements associated with fixed attenuators include the flatness over a specified frequency, range, voltage standing wave ratio (VSWR), amount of attenuation, average and peak power-handling capability, performance over a specific temperature, size and height. Fixed attenuators are also often used to enhance interstage matching in an electronic circuit. Thorlab’s fixed attenuators are available from 5 dB to 25 dB. Mini-Circuits’ fixed attenuators are packaged in rugged plug-in and connector models. They are available in both 50- and 76-ohm models ranging from 1to 40 dB spanning DC to 1500 MHz.

In variable optical attenuators (VOA), resistors are replaced with solid state devices such as the metal semiconductor field effect transistor (MESFETs) and PIN diodes. VOA attenuates light signal or beam in a controlled manner, thus producing an output optical beam with different attenuated intensity. The attenuator adjusts the power ratio between the light beam coming from the device and the light beam entering the device over a changeable rate. VOA is usually used in fiber optic communication systems to regulate optical power levels in order to prevent damages in optical receivers which may be due to irregular or fluctuating power levels. The price of commercial VOA varies depending on the manufacturing technology used. Some of manufacturers of VOA are Timbercon and Arcoptix.

Timbercon claims that its optical attenuator units produce precision levels of attenuation, with the added flexibility of adjustment. Timbercon’s variable attenuators are available in single mode and multi-mode versions. They have low insertion loss and back reflection. The attenuators are also compact in size and available in multiple packaging options. Arcoptix’s electrical adjustable variable attenuators are a liquid crystal device which allows the precise control of the attenuation of beams traveling in free space. These attenuators can be adjusted in milliseconds with a simple square wave bias between 0 and 10 volts.

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Source by Gavin Cruise

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Abstract:

Knowledge and control of chemical engineering systems requires obtaining values for process variables and functions that range in difficulty of computation and measurement. The present report aimed to demonstrate the connections between entropy and diffusion and to highlight the avenues to convert data from one into the other. The correlation between the two concepts was explored at the microscopic and single-particle level. The scope of exploration was restricted to the particle level in order to identify commonalities that underlie higher-level phenomena. A probabilistic model for molecular diffusion was developed and presented to illustrate the close coupling between entropic information and diffusion. The relationship between diffusivity and configurational/excess entropy was expounded by analyzing the Adam-Gibbs and Rosenfeld relations. A modified analog of the Adam-Gibbs relation was then found to accurately predict experimental data on diffusion and translational entropy of single water molecules. The quantitative relations declared in this report enable the chemical engineer to obtain information on the abstract entropy potential by mapping from more concrete dynamical properties such as the diffusion coefficient. This correspondence fosters greater insight into the workings of chemical engineering systems granting the engineer increased opportunity for control in the process.

Introduction:

Systems, whether observed or simulated, consist of the complex interplay between several degrees of freedom, both of time and space. The analysis of chemical engineering systems, in particular, frequently requires knowledge of both thermodynamic potentials and dynamic state variables. The set of thermodynamic potentials that appear in the analysis of these systems include enthalpy, entropy and free energy as members. Each of these potentials is a function of system variables such as pressure, temperature and composition. This dependence on the system’s parameters allows the thermodynamic potentials, along with their first and second derivatives, to constrain the stability and equilibrium of chemical systems. The constraining ability of these potentials derives from the first and second law of thermodynamics, entropy maximization principles and arguments from mathematical analysis.

Occupation of states of equilibrium and stability is only one aspect of a system; it is also critical to understand how systems evolve towards or away from these states. Dynamic processes, such as transport phenomena, mediate this time evolution. Transport phenomena encompass the movement of conserved quantities: heat, mass and momentum. The movement of mass, heat and momentum represent the pathways systems trace out in state space. Therefore, the full description, understanding and control over chemical engineering systems necessitate knowledge of the active dynamic and thermodynamic processes, and their correlations, of the system.

This report will concentrate on the relationship between entropy and diffusion. Diffusion signifies a process that systems undergo in response to some non-uniformity or asymmetry in the system. Entropy generation can be understood as a consequence of diffusional phenomena. It is the apparent interconnection between the two concepts that this report intends to highlight and characterize. This report aims to define relations between entropy and diffusion so that it is possible to translate qualitative and quantitative information between the two.

Theory and Procedure:

Entropy (S) is recognized as a measure of the size of configuration space where configuration space is the space of all possible microscopic configurations a system can occupy with a certain probability. This is stated with Gibbs entropy formula,

S=-k_b ∑ p_i lnâ ¡(p_i ), k_b ≡ Boltzmann constant, p_i ≡ probability of microstate.

If the probability of each microstate is equal then,

S=k_b lnΩ, where Ω ≡ number of microscopic configurations consistent with equilibrium state. These expressions for thermodynamic entropy closely resemble the expression for information theoretic entropy and indicate that entropy can be viewed as a measure of the degree of uncertainty about a system caused by information not being communicated by macrostate variables, like pressure and temperature, alone. Microscopic configurations are determined by the vibrational, rotational and translational degrees of freedom of the molecular constituents of a system. As such, any process that increases the number of microscopic configurations available to a system will also increase the extent of the system’s configuration space, consequently, elevating its entropy.

Diffusion is defined as a process whereby a species moves from a region of high chemical potential to a region of low chemical potential; without loss of generality, the driving force for particle movement is frequently a concentration difference. This is captured with Fick’s First Law of Diffusion, J = -D∇c with ∇ =(d/dx,d/dy,d/dz), where J ≡ diffusive flux, c ≡ concentration, D ≡ diffusion coefficient. Fick’s Second Law asserts the time dependence of a concentration profile,

∂c/∂t=∇∙D∇c. From the above equations, diffusion can be conceptualized as a response function, whose value is determined by a forcing function (gradient in concentration), which seeks to reduce the forcing function to zero. The translational motion of the particles will continue until a state of uniform particle distribution is achieved. Equivalently, diffusion is the process by which a system transitions from a non-equilibrium configuration towards one that more closely resembles an equilibrium state, that being, a state where the chemical potentials of all species are equivalent.

Although elementary, the theoretical information presented above identifies a unifying link between the two concepts, phase space expansion. Entropy is the control variable for this expansion whereas diffusion is the process. This connection will be exhibited by first presenting and relating probability based descriptions of particle diffusion and entropy. By evaluating the relationship between the diffusion coefficient and entropy terms, a further extension of the linkage between the two will be arrived at. Lastly, a focus on single water molecules will further illustrate and support the connectivity between diffusion and entropy.

Results and Discussion:

The molecular motions executed by particles were revealed to be reducible to a probabilistic model incorporating statistical mechanical arguments in Albert Einstein’s 1905 Investigation on the Theory of Brownian Movement (14-18). The assumption that each particle underwent motion, restricted to the single x co-ordinate, independently of neighboring particles was advanced; this was achieved by selecting time intervals of motion (τ) and space (Δx) to not be too small. A particle density function f(x,t) which express the number of particles per unit volume was posited. This probability density function was formed by the spatial increments particles traveled over the time interval. This function was then expanded in a Taylor series yielding,

f(x+∆x,t)=f(x,t)+∆ ∂f(x,t)/∂x+∆^2/2! (∂^2 f(x,t))/(∂x^2 )+∙∙∙ad inf.

f(x,t+τ)dx=dx∫_(∆=m)^(∆=∞)f(x+∆)Ï•(Δ)dΔ

This expansion can be integrated, since only small values of Δ contribute to the function.

f+∂f/∂t∙τ=f∫_(-∞)^∞(Ï•(∆)d∆+∂x/∂f ∫_(-∞)^∞(∆ϕ(∆))d∆+(∂^2 y)/(∂x^2 ) ∫_(-∞)^∞(∆^2/2) Ï•(∆)d∆ ∙∙∙

The first integral on the right-hand side is unity by the measure of a probability space whereas the second and other even terms vanish due to space symmetry Ï•(x)=Ï•(-x). What remains after this simplification is

∂f/∂t = (∂^2 f)/(∂x^2 ) ∫_(-∞)^∞(∆^2/2τ) Ï•(∆)d∆∫_(-∞)^∞(Ï•(∆))d∆

whereby setting the term after the second derivative to D results in ∂f/∂t = D (∂^2 f)/(∂x^2 ) which is Fick’s Second Law. Solving the above integral equation generates the particle density function,

f(x,t) = n/√4πD* e^(-x^2/4Dt)/√t

This is a normal distribution that has the unique property of possessing the maximum entropy of any other continuous distribution for a specified mean and variance, equal to 0 and √2Dt, respectively, for the particle distribution above. Einstein later found that the mean displacement (diffusion) of particles λx which depends on temperature, pressure, Avogadro’s number N and the Boltzmann constant k_b to be,

λ_x = √t∙√((RT∫_(-∞)^∞(Ï•(∆))d∆)/(3πkPN)

It is fascinating that measurable physical properties such as the diffusion coefficient appear in a mathematical model that ensures maximization of entropy.

Equation-based relationships between diffusion and entropy have been investigated for many years. One such relation is,

D(T) = D(T=T_0)e^(C/(TS_c )),

where S_c the configuration entropy of the system defined as,

S_c (T) = S(T)-S_vib(T)

and S_vib is the vibrational entropy of the system and D(T_0) is the diffusion coefficient at some higher temperature T_0. This is known as the Adam-Gibbs relation and explicates the strong dependence diffusion has on entropy. The Rosenfeld relation between the diffusion coefficient and entropy provides another interesting connection,

D = a∙e^(((bS_ex)/k_b ))

S_ex is excess entropy found by subtracting the entropy of an ideal gas at the same conditions from the system’s total entropy, a and b act as fitting parameters and k_b is the Boltzmann’s constant. These above expressions broadcast a pronounced and well-founded connection between diffusion and entropy to the extent that knowing one enables the determination of the other.

Saha and Mukherjee in their article “Connecting diffusion and entropy of bulk water at the single particle level,” implemented molecular dynamic simulations to establish a linkage between thermodynamic and dynamic properties of individual water molecules (825-832). Translational (S_trans) and rotational (S_rot) entropies were calculated at varying temperatures along with calculations of self-diffusion coefficient (D) thereby permitting the construction of a generalization of the Adam-Gibbs relation above to relate configurational entropy with translation relaxation (self-diffusion) time. S_trans was evaluated from the entropy of a solid-state quantum harmonic oscillator as shown below,

S_trans^QH = k_b ∑_(i=1)^3((â„ ω_i)⁄(k_b T))/e^((â„ ω_i)⁄(k_b T)) – lnâ ¡(1-e^((â„ ω_i)⁄(k_b T)))

where T indicates temperature, k_b is the Boltzmann constant and â„ =h/2π, h being the Planck constant. A method known as permutation reduction which considers water molecules to be indistinguishable and to reside in an effective localized configuration space was utilized to obtain a covariance matrix of translational fluctuations of each permuted molecule along the x, y and z co-ordinates. This produced a 3×3 matrix, whereupon diagonalization of the matrix produced 3 eigenvalues and three frequencies (ωi), which were input to the expression above. Diffusion was evaluated with the Vogel-Fulcher-Tammann (VFT) equation,

D^(-1) (T) = D_0^(-1) e^[1/(K_VFT (T/T_VFT -1))]

with KVFT denoting the kinetic fragility marker and TVFT signifying the temperature at which the diffusion coefficient diverges. The idea of thermodynamic fragility, which appears in the above analysis, quantifies the rate at which dynamical properties such as inverse diffusivity grow with temperature. Also, according to IUPAC Compendium of Chemical Terminology, self-diffusion is the diffusion coefficient (D_i*) of species i when the chemical potential gradient is zero (a is the activity coefficient and c is the concentration).

D_i* = D_i (∂lnc_i)/(∂lna_i )

Saha and Mukherjee fitted the variant of the Adam-Gibbs equation D=ae^((bS_trans⁄k_b)) to their data.

The Pearson’s correlation coefficient (R), which is the covariance of two variables divided by the product of their standard deviations, attained a value of 0.98. This value indicates a directed and strong statistical association between translational entropy and translational diffusivity. Such a good fit implies that an underlying physical relation between entropy and diffusion does exist and that one can convert knowledge of dynamics, information that demands fewer computational resources, to an understanding of thermodynamics, information that is computationally more costly. As communicated by the authors, this connection was verified for a specific system and generalization of its findings to other systems should occur only upon application of the same methods to other systems. Nonetheless, if additional analysis can provably satisfy empirical and theoretical constraints, the methods detailed above can provide insight to more complicated environments.

Conclusion:

Controllability, a notion open to several definitions, can be thought of as the capacity to move a system between different regions of its configuration space through the application of a certain number of admissible manipulations. The ultimate objective of chemical engineering analysis is the ability to determine the output of some system through the rational and systematic control of input variables. This controllability allows optimization of processes such as separations. However, without the ability to monitor a systems response to perturbations, it becomes challenging to know in what direction or to what degree a change should be conducted. Thus, controllability implies observability of process variables; or state differently, all relevant process variables can be measured to some extent.

This report concentrated specifically on the interconnection between diffusion and entropy. Both of these entities are important in the design, characterization and control of engineering systems. A barrier to achieve full control arises from the difficulty of attaining and measuring abstract quantities such as entropy. A method to overcome this challenge is to identify a one-to-one correspondence between the intractable variable and one that is more compliant and more easily measured. Diffusion and the related diffusion coefficient represent the property that complies with computational and empirical methods and enables completion of the mapping. The equations and relations presented above are structurally diverse and apply to different conditions but show that from knowledge of a system’s dynamics (diffusivity) one obtains knowledge of the system’s thermodynamics.

References:

Engel, Thomas and Philip Reid. Physical Chemistry. San Francisco: Pearson Benjamin Cummings, 2006.

Seader, J.D, Ernest J. Henley and D. Keith Roper. Separation Process Principles: Chemical and Biochemical Operation 3rd Edition. New Jersey: John Wiley & Sons, Inc., 2011

Einstein, Albert. “Investigation on The Theory of Brownian Movement.” ed. R. Furth. Trans. A. D. Cowper. Dover Publications, 1926 and 1956.

Seki, Kazuhiko and Biman Bagchi. “Relationship between Entropy and Diffusion: A statistical mechanical derivation of Rosenfeld expression for a rugged energy landscape.” J. Chem. Phys. 143(19), 2015. doi: 10.1063/1.4935969

Rosenfeld, Yaakov. “Relation between the transport coefficients and the internal entropy of simple systems,” Phys. Rev. A 15, 2545, 1977

Rosenfeld, Yaakov. “A quasi-universal scaling law for atomic transport in simple fluids.” J. Phys.: Condensed Matter 11, 5415, 1999.

Sharma, Ruchi, S. N. Chakraborty and C. Chakravarty. “Entropy, diffusivity, and structural order in liquids with waterlike anomalies.” J. Chem. Phys. 125, 2006. Doi: 10.1063/1.2390710

Saha, Debasis and Arnab Mukherjee. “Connecting diffusion and entropy of bulk water at the single particle level.” J. Chem. Sci. 129(7), 2017. Pg 825-832. Doi: 10.1007/s23039-017-1317-z

Hogg, Robert V. and Elliot A. Tanis. Probability and Statistical Inference 6th Edition. Prentice-Hall Inc., 2001

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Source by Corban Zachary Allenbrand

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For years JET has been known for producing some of the best mini lathes in the woodworking industry. Building upon the success of these models and developing upon the technology of their most loved machines, JET has taken that standard to an entirely new level of high-performance. The new JWL-1220VS variable speed wood lathe, for example, brings a whole new ball game to your benchtop.

To begin, the lathe has a powerful 3/4-HP motor with variable speed settings. Owing to a sophisticated electronic system and finely machined six-step pulleys, the JWL-1220VS offers continuous speed operation between 270 and 4,200 RPM. Accordingly, the lathe has more than enough muscle to run smooth, strong and consistent throughout each application. Having 5 numerical speed settings, the electronic variable speed system also ensures making very specific RPM settings is simple. Because the motor is mounted directly below the lathe bed, that big-muscle-motor doesn’t get in the way, but it’s easy to access for belt tensioning, maintenance or etc. Tool-free levers on the front of the lathe also make belt tensioning a fast and simple process.

The lathe bed is built well and of heavy-duty cast iron to enhance the stability of the machine and to limit vibration during use. It supports stock up to 12-inches in diameter and 20-inches in length giving you the capacity to handle large projects and, despite being a benchtop machine, the JWL-1220VS can be outfitted with a bed extension (giving you nearly 50-inches between centers) and/or with a rock-solid adjustable stand for greater versatility. Heavy-duty metal handles also contribute to the lathe’s portability.

The JWL-1220VS additionally features a self-ejecting tailstock for safe and simple removal of your tooling and, because the tailstock is also hollow, the removable tip on the live-center allows you to bore holes through your stock as well. The lathe’s centers are well laid out to turn your projects on perfect center and with an easy-to-use spindle lock and 24-position indexing capabilities, the lathe helps users creates all types of ornamentation (like fluting or veining applications) with consistency and total precision. The machine also features an integrated worklight to keep your workpieces well-lit and has rubber-tipped adjustable leveling feet to reduce movement during use.

To ensure you can easily outfit the lathe with both common and specialty accessories, the JWL-1220VS is engineered to be compatible with most popular accessories. The spindle and tailstock accept #2 Morse taper and the spindle nose exterior is threaded with the popular 1 x 8 thread pattern. This makes it simple to find what you need and allows you to keep using any accessories you might already have. Of course, the lathe also includes a full range of accessories like a four-wing spur drive, a superior quality ball bearing live-center, a knockout rod (just in case you need it), 10-inch and 6-inch tool rests, a 3-inch diameter face plate and a sweet pair of goggles.

Ultimately, JET’s JWL-1220VS wood lathe is built tough to deliver optimal longevity and built smart to produce total accuracy. If you’re searching for a high-performance lathe that’s both powerful and compact, there is no better choice than JET’s JWL-1220VS variable speed wood lathe. Nurture your skills and enhance the quality of your results with this versatile, totally superior benchtop lathe.

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Source by Malcolm Haslett