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Tiberius Brastaviceanu

Open Source Completely 3-D Printable Centrifuge - Appropedia, the sustainability wiki - 0 views

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    "Centrifuges are commonly required devices in medical diagnostics facilities as well as scientific laboratories. Although there are commercial and open source centrifuges, the costs of the former and the required electricity to operate the latter limit accessibility in resource-constrained settings. There is a need for low-cost, human-powered, verified, and reliable lab-scale centrifuges. This study provides the designs for a low-cost 100% 3-D printed centrifuge, which can be fabricated on any low-cost RepRap-class (self-replicating rapid prototyper) fused filament fabrication (FFF)- or fused particle fabrication (FPF)-based 3-D printer. In addition, validation procedures are provided using a web camera and free and open source software. This paper provides the complete open source plans, including instructions for the fabrication and operation of a hand-powered centrifuge. This study successfully tested and validated the instrument, which can be operated anywhere in the world with no electricity inputs, obtaining a radial velocity of over 1750 rpm and over 50 N of relative centrifugal force. Using commercial filament, the instrument costs about U.S. $25, which is less than half of all commercially available systems. However, the costs can be dropped further using recycled plastics on open source systems for over 99% savings. The results are discussed in the context of resource-constrained medical and scientific facilities."
Tiberius Brastaviceanu

Optical force sensor for high density planar electrical interconnects - 0 views

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    "Optical force sensor for high density planar electrical interconnects"
Tiberius Brastaviceanu

Access control - Wikipedia, the free encyclopedia - 0 views

  • The act of accessing may mean consuming, entering, or using.
  • Permission to access a resource is called authorization.
  • Locks and login credentials are two analogous mechanisms of access control.
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  • Geographical access control may be enforced by personnel (e.g., border guard, bouncer, ticket checker)
  • n alternative of access control in the strict sense (physically controlling access itself) is a system of checking authorized presence, see e.g. Ticket controller (transportation). A variant is exit control, e.g. of a shop (checkout) or a country
  • access control refers to the practice of restricting entrance to a property, a building, or a room to authorized persons
  • can be achieved by a human (a guard, bouncer, or receptionist), through mechanical means such as locks and keys, or through technological means such as access control systems like the mantrap.
  • Physical access control is a matter of who, where, and when
  • Historically, this was partially accomplished through keys and locks. When a door is locked, only someone with a key can enter through the door, depending on how the lock is configured. Mechanical locks and keys do not allow restriction of the key holder to specific times or dates. Mechanical locks and keys do not provide records of the key used on any specific door, and the keys can be easily copied or transferred to an unauthorized person. When a mechanical key is lost or the key holder is no longer authorized to use the protected area, the locks must be re-keyed.[citation needed] Electronic access control uses computers to solve the limitations of mechanical locks and keys. A wide range of credentials can be used to replace mechanical keys. The electronic access control system grants access based on the credential presented. When access is granted, the door is unlocked for a predetermined time and the transaction is recorded. When access is refused, the door remains locked and the attempted access is recorded. The system will also monitor the door and alarm if the door is forced open or held open too long after being unlocked
  • Credential
  • Access control system operation
  • The above description illustrates a single factor transaction. Credentials can be passed around, thus subverting the access control list. For example, Alice has access rights to the server room, but Bob does not. Alice either gives Bob her credential, or Bob takes it; he now has access to the server room. To prevent this, two-factor authentication can be used. In a two factor transaction, the presented credential and a second factor are needed for access to be granted; another factor can be a PIN, a second credential, operator intervention, or a biometric input
  • There are three types (factors) of authenticating information:[2] something the user knows, e.g. a password, pass-phrase or PIN something the user has, such as smart card or a key fob something the user is, such as fingerprint, verified by biometric measurement
  • Passwords are a common means of verifying a user's identity before access is given to information systems. In addition, a fourth factor of authentication is now recognized: someone you know, whereby another person who knows you can provide a human element of authentication in situations where systems have been set up to allow for such scenarios
  • When a credential is presented to a reader, the reader sends the credential’s information, usually a number, to a control panel, a highly reliable processor. The control panel compares the credential's number to an access control list, grants or denies the presented request, and sends a transaction log to a database. When access is denied based on the access control list, the door remains locked.
  • A credential is a physical/tangible object, a piece of knowledge, or a facet of a person's physical being, that enables an individual access to a given physical facility or computer-based information system. Typically, credentials can be something a person knows (such as a number or PIN), something they have (such as an access badge), something they are (such as a biometric feature) or some combination of these items. This is known as multi-factor authentication. The typical credential is an access card or key-fob, and newer software can also turn users' smartphones into access devices.
  • An access control point, which can be a door, turnstile, parking gate, elevator, or other physical barrier, where granting access can be electronically controlled. Typically, the access point is a door. An electronic access control door can contain several elements. At its most basic, there is a stand-alone electric lock. The lock is unlocked by an operator with a switch. To automate this, operator intervention is replaced by a reader. The reader could be a keypad where a code is entered, it could be a card reader, or it could be a biometric reader. Readers do not usually make an access decision, but send a card number to an access control panel that verifies the number against an access list
  • monitor the door position
  • Generally only entry is controlled, and exit is uncontrolled. In cases where exit is also controlled, a second reader is used on the opposite side of the door. In cases where exit is not controlled, free exit, a device called a request-to-exit (REX) is used. Request-to-exit devices can be a push-button or a motion detector. When the button is pushed, or the motion detector detects motion at the door, the door alarm is temporarily ignored while the door is opened. Exiting a door without having to electrically unlock the door is called mechanical free egress. This is an important safety feature. In cases where the lock must be electrically unlocked on exit, the request-to-exit device also unlocks the doo
  • Access control topology
  • Access control decisions are made by comparing the credential to an access control list. This look-up can be done by a host or server, by an access control panel, or by a reader. The development of access control systems has seen a steady push of the look-up out from a central host to the edge of the system, or the reader. The predominant topology circa 2009 is hub and spoke with a control panel as the hub, and the readers as the spokes. The look-up and control functions are by the control panel. The spokes communicate through a serial connection; usually RS-485. Some manufactures are pushing the decision making to the edge by placing a controller at the door. The controllers are IP enabled, and connect to a host and database using standard networks
  • Access control readers may be classified by the functions they are able to perform
  • and forward it to a control panel.
  • Basic (non-intelligent) readers: simply read
  • Semi-intelligent readers: have all inputs and outputs necessary to control door hardware (lock, door contact, exit button), but do not make any access decisions. When a user presents a card or enters a PIN, the reader sends information to the main controller, and waits for its response. If the connection to the main controller is interrupted, such readers stop working, or function in a degraded mode. Usually semi-intelligent readers are connected to a control panel via an RS-485 bus.
  • Intelligent readers: have all inputs and outputs necessary to control door hardware; they also have memory and processing power necessary to make access decisions independently. Like semi-intelligent readers, they are connected to a control panel via an RS-485 bus. The control panel sends configuration updates, and retrieves events from the readers.
  • Systems with IP readers usually do not have traditional control panels, and readers communicate directly to a PC that acts as a host
  • a built in webservice to make it user friendly
  • Some readers may have additional features such as an LCD and function buttons for data collection purposes (i.e. clock-in/clock-out events for attendance reports), camera/speaker/microphone for intercom, and smart card read/write support
Philippe Comtois

Effects of chronic electrical stimulation on... [Differentiation. 1994] - PubMed - NCBI - 0 views

  • Our results suggest that enhanced contractile activity promotes the expression of the slow phenotype predetermined in satellite cells of slow-twitch, type I fibers.
  • stimulation enhanced the mRNA and protein expression of a developmental isoform of slow myosin (MHCI).
Tiberius Brastaviceanu

g.Sensors - measure physiological and physical signals, connect directly to the amplifi... - 0 views

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    "Limb Movements This piezo-electric sensor is placed on the ankle to detect movements of the feet during sleep. For investigation of restless leg syndrome (RLS) and periodic limb movements (PLM)."
Philip Solars

Go Solar Today! - 1 views

started by Philip Solars on 29 Nov 12 no follow-up yet
Tiberius Brastaviceanu

Piezo electronic micromanipulator PM10 by Märzhäuser. intracellular, injectio... - 0 views

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    piezo xyz micromanipulator, alternative, similar to ours
Francois Bergeron

MyoStretcher - 0 views

  • IonOptix is proud to announce the release of the MyoStretcher, our new cardiomyocyte force measurement system.  Facilitated by the arrival of IonOptix MyoTak, our bio-compatible cell adhesive, we've developed the MyoStretcher with a focus on simplicity, ease-of-use and reliability.  The MyoStretcher includes all of the necessary components to stretch as well as record force in isolated myocytes.  In addition to the sensitive force transducer, motorized micro-manipulators and all component fittings, we also offer an optional piezo-electric translator for programmable stretching and a kit to facilitate attachment of glass rods to the MyoStretcher arms.
Philip Solars

The Must Have Solar Equipment - 0 views

Due to the increasing cost of electricity bills, I have finally decided to switch to solar energy. Aside from being free, it also helps save mother earth. I must admit that at first I was confused ...

started by Philip Solars on 28 Sep 12 no follow-up yet
Philip Solars

The Must Have Solar Equipment - 2 views

Due to the increasing cost of electricity bills, I have finally decided to switch to solar energy. Aside from being free, it also helps save mother earth. I must admit that at first I was confused ...

started by Philip Solars on 29 Nov 12 no follow-up yet
Tiberius Brastaviceanu

A Robust Uniaxial Force Sensor for Minimally Invasive Surgery - 0 views

  • miniature uniaxial force sensor for use within a beating heart during mitral valve annuloplasty
  • provides a hollow core to pass instrumentation
  • Fiber optic transduction eliminates electrical circuitry within the heart, and acetal components minimize ultrasound-imaging artifacts
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  • 0–4-N force range
  • errors of 0.13 N (<3.2%)
  • MINIMALLY invasive surgery (MIS)
  • surgeons lose the critical sense of touch during MIS because instruments are passed through ports that mask the surgeon's feel of the internal operating environment.
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