How to Choose Between Single- Or Dual-energy X-ray Systems


How to Choose Between Single- Or Dual-energy X-ray Systems 1

Food manufacturers across the globe have been relying on x-ray technology since the early 1990s to protect consumers, reduce the risk of product recalls and safeguard their brands.

Two types of x-ray technology are used for food inspection today-single energy and dual energy. Some food processors believe that, irrespective of the application, dual energy is always best. However, this is not always the case. It is a myth that, regardless of the application, dual energy automatically provides better sensitivity.

The right choice of technology depends on five factors:

1. The likely contaminants a manufacturer will encounter;


How to Choose Between Single- Or Dual-energy X-ray Systems 2

In simple terms, an x-ray system uses an x-ray generator to project a beam of low energy x-rays onto a sensor or detector. X-ray inspection involves passing a product or pack through the x-ray beam before it reaches the detector. The amount of x-ray energy absorbed during the beam's passage through a product is affected by the product's thickness, density and atomic number.

When the product passes through the x-ray beam, only the residual energy reaches the detector and measurement of the difference in absorption between the product and a foreign body is the basis of foreign body detection in x-ray inspection.

An x-ray system is essentially a scanning device. When a product passes through the system at a constant speed, the x-ray detector captures a "greyscale" image of the product (see image below). This is generated by measuring the amount of x-ray energy reaching the detector. Each image is made up of pixels and the x-ray energy absorbed by each pixel creates a value on a greyscale (from black 0 to white 65,535). As the product or pack passes over the detector, each line of grey level data is added to previous lines, much like slices of bread can be added to form a loaf, resulting in a complete product image. Software within the x-ray system analyzes the image and compares it to a pre-determined acceptance standard.

On the basis of this comparison, the system either accepts or rejects the image (and the product/pack it represents). In the case of rejection, software sends a signal to an automatic reject system, which then removes the product from the production line.

Like conventional single-energy x-ray inspection technology described above, dual-energy technology involves using a generator to project an x-ray beam onto a detector and passing a product through the beam. However, dual energy diverges from single-energy x-ray inspection as it uses two energy spectrums to discriminate between high and low channel x-rays, as well as a dual-layer detector. While the top detector is sensitive to lower energy (longer wavelength x-rays), the bottom detector is sensitive to higher energy (shorter wavelength x-rays). The two detectors are separated by a small copper plate that filters out the low-energy x-ray and only allows the high-energy x-ray to pass through to the high energy detector.

When an x-ray beam is projected through a product, some of the energies will be absorbed, while others will pass through. What gets absorbed and what passes through depends on the product's composition.

Materials are made up of elements and each element has its own atomic number. For a given x-ray energy, as the atomic number increases, the element absorbs more x-ray energy and passes less. So carbon, with an atomic number of 6, absorbs much less x-ray energy than lead, with an atomic number of 82. Lead absorbs almost all x-ray energies, which is why it is commonly used as shielding in places like medical x-ray labs.

As elements have different atomic numbers, it is possible to measure differences in absorbance based on the elements in a material. The amount of x-ray absorbance a given element has depends on the x-ray energy, and as dual-energy x-ray systems have a detector array that gives values at two different energies-high and low-it is convenient to express these as a ratio.

Two separate images are generated by the two spectra of energy and a relative ratio of energy absorbed can be calculated to determine a material's composition. So, in effect, dual-energy x-ray systems measure the ratio of two different sets of x-ray energies that pass through a product and this measurement enables organic and inorganic materials to be differentiated. Foreign body detection using dual-energy x-ray technology is therefore based on chemical composition (atomic number) rather than just density variation like single-energy x-ray technology.

Which technology is best for your application?

Single-energy x-ray inspection technology used to inspect food products for contamination is effective at detecting foreign bodies that exhibit an x-ray absorption spike relative to the surrounding product's absorption. Such systems give food manufacturers exceptional levels of detection for stainless steel, ferrous and non-ferrous metals. They are also extremely good at detecting glass, calcified bone, mineral stone and high-density plastics and rubber, regardless of their shape, size or location within a product.

However, single-energy x-ray inspection technology is incapable of detecting thin glass, stones, rocks and low-density plastics and rubber in most food-based products.

Dual-energy technology is better at detecting objects that show a small x-ray absorption variation. This means that dense foreign bodies in dense products are more easily detected using dual-energy technology compared with single energy. For example, dual energy makes it possible to detect flat glass and stone in mixed nuts, both of which can be challenging to detect using single-energy detectors.

Dual-energy technology essentially removes most of the effect of product thickness variations and leaves an image that shows density difference based on chemical composition (atomic number). Food products are typically organic in composition and, if solid or liquid, contain water. Chemically, food products consist primarily of hydrogen, carbon and oxygen. Any foreign body containing an element of a higher atomic number than carbon or oxygen becomes more easily detectable using dual-energy technology.

Single-energy technology typically finds foreign bodies that are visible in an x-ray image, but many foreign bodies that are not readily visible in an x-ray image may be detected using dual-energy technology. For example, dual energy brings a distinct advantage when detecting inorganic foreign bodies such as flat glass (as opposed to cylindrical glass), bone, stones, rocks and low-density rubber and some plastics. Plastics and rubber that have inorganic filler or have a component of chlorine, bromine or fluorine also fall into this category.

Dual-energy x-ray technology shares some similarities with single-energy x-ray technology, but also diverges. Dual energy's ability to discriminate materials by their chemical composition enables the detection of historically undetectable inorganic foreign bodies, and also enables food manufacturers to inspect products with complex density levels and in innovative pack styles.

However, as we have mentioned, dual-energy x-ray systems are not suitable for all food applications. There are some instances where dual energy will be best and many others where single energy will provide a better solution. The right choice of x-ray energy depends on five factors outlined earlier in this article: the likely contaminants, product, packaging, production speed and customer specification.

One thing is for sure: There is not usually an overlap regarding the selection of single-energy or dual-energy x-ray technology. Each application should be independently evaluated and food manufacturers should seek the advice of a reputable x-ray system supplier before making a decision.

As marketing manager at Eagle Product Inspection, author Christy Draus manages all areas of the marketing program and initiatives to drive strategy and business development across North America, Latin America, Europe, the Middle East, South Africa and Asia Pacific. With more than 13 years of experience, she successfully manages implementation of projects that support strategic marketing initiatives. Her diversified skill set in business-to-business environments includes product launches, brand management, lead generation and sales support. Draus holds a Bachelor of Science in Marketing from the University of South Florida.

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x ray related knowledge:
  • X-rays of Classical

    X-rays have been detected from V473 Lyrae during a survey looking for x-rays from young main sequence companions to Cepheid variables. However, the x-rays in this case appear to originate from the Cepheid itself, not from the companion. There may be a closer unseen companion or the x-rays may have another cause.

    .

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x ray related q&a:
  • Soft X-rays and Hard X-rays

    At 80 keV you are definitely in the hard X-ray region. These are the most energetic characteristic K-shell lines of the heaviest elements. One way of demarcation is by the experimental techniques.

    Monochromators and spectrographs of hard x-rays are based on crystal diffraction, for soft x-rays grating diffraction is often more suitable. That is at about a few keV.There is also a difference in experimental techniques for how to use the x-rays, whether one needs vacuum or not. Below about 5 keV absorption by window materials and by air becomes a problem.

  • X Ray

    Since their discovery in 1895, X rays have proved a vital tool of science, making it possible to examine previously hidden worlds ranging from the tiniest of atoms to the most distant galaxies in space. Like light and radio waves, X rays are a type of electromagnetic radiation—oscillating electric and magnetic fields traveling at the speed of light. Their usefulness lies in their ability to penetrate matter.

    X rays owe their penetrating power to their relatively short wavelengths and high energy. The wavelengths of X rays range from about 0.05 angstrom to hundreds of angstrom units. (An angstrom is equal to 0.000000004 inch, or 0.00000001 centimeter.) The shorter the wavelength and the higher the energy of an X ray, the deeper it penetrates matter.

    Visible light, by contrast, has much longer wavelengths and lower energy. When light rays encounter the surface atoms of an opaque substance, they are reflected or absorbed (see Light). One of the earliest applications of X rays was in medicine, where they were used for both diagnosis and therapy.

    Today X rays are still most widely used in this field. They penetrate soft tissues but are stopped by bones, which absorb them. Thus if a photographic plate that is sensitive to X rays is placed behind a part of the body and an X-ray source is placed in front, X-ray exposure will result in a picture of the internal bones and organs.

    When the plate, or radiograph, is developed, a negative image is produced: bones and dense tissues show up as light or white regions, while tissues that are easily penetrated by X rays appear dark. Although bones are the most opaque structures in the body, there are many dense tissues, such as cancer tumors, that can also show up unusually light in radiographs. Doctors use these images to diagnose diseases, detect foreign objects in the body, examine dental cavities, and study damaged or broken bones.

    In order for X rays to be used for the study of other, less dense tissues of the body, such as the gastrointestinal tract, the tissues must first be made opaque to X rays. Generally, doctors ask patients to drink a liquid mixture containing an opaque material, such as barium, so that the internal contours of the alimentary tract become visible with X rays. In a similar process—fluoroscopy—doctors use X rays to watch certain internal organs in action.

    The patient is positioned between an X-ray source and a screen coated with fluorescent material that glows when X rays strike it. In the fluoroscope, a visible image appears when the X rays strike the fluorescent material. The image is brightened by an electronic device called an image intensifier.

    The image is then displayed on a television monitor that the doctor can observe. Conventional X-ray techniques such as these have one major flaw. Structures may be obscured by overlying organs, or soft tissues may be insufficiently delineated for clear viewing.

    This issue is of particular importance in localizing brain tumors and other damaged sites in the brain. For such applications, a new form of X-ray process was developed, called computed tomography, or CT. It was formerly known as computerized axial tomography, or CAT.

    In this process the patient is placed inside an X-ray machine, and a narrow beam of X rays sweeps across an area of the body, moving through a slight angle after each X-ray pulse. The resulting series of X-ray images, each taken from a different angle, is recorded electronically and analyzed by a computer. From them, the computer produces a three-dimensional X-ray image.

    While CT scanners are expensive machines, generally costing a million dollars or more, they have become invaluable aids in the diagnosis of brain diseases and head injuries. They are capable of displaying subtle differences among materials in the body. X rays are used extensively in dentistry as well as in medicine.

    To obtain an X-ray image of the mouth, a piece of photographic film, covered by paper, is held against the inner surface of the teeth. The dentist then switches on the X rays, which travel from a source outside the cheek, through the tissues and dental structures, to the film. Such X rays are used both to detect disease and cavities and to examine the alignment of teeth and their roots.

    Considerable care must be taken with X rays, since this radiation is sufficiently energetic to ionize some atoms within the cell—that is, to separate electrons from nuclei—and cause damage. All areas of the patient's body outside the area intended for the radiograph must be shielded by a material (generally a metal) that absorbs X rays, and X-ray doses should be kept to a minimum. Doctors, dentists, nurses, and technicians must be similarly protected by opaque shields to prevent excessive X-ray damage.

    On the other hand, the damaging effects of X rays, like those of other forms of energetic radiation, may be put to medical use. All forms of radiation affect rapidly dividing cells more than slowly developing cells because the genetic material that governs cell division is sensitive to radiation. Therefore, doctors sometimes use concentrated bursts of X rays to kill cancer cells, which divide rapidly, while minimizing damage to the surrounding healthy cells that divide more slowly.

    Gamma rays, radioactive isotopes, and energetic electrons and nuclei are also used in cancer treatment. (See also Cancer.) Because of their short wavelengths and great penetrating power, X rays can be used to study not only the structure of living organisms, but that of inanimate matter as well. Their chief application as a scientific tool is in crystallography—the study of the structure of crystalline solids.

    When X-ray waves pass through the regular lattice of a crystal, they interfere with each other and produce a characteristic pattern of spots on a photographic plate. With the aid of a computer, scientists can analyze this pattern and determine how the atoms of the crystal are arranged. X-ray crystallography has been used to study the structure of DNA, the molecule vital to conveying genetic information in all living organisms (see Genetics).

    X rays can also be used to identify unknown materials. When an object is bombarded with X rays, its atoms absorb the energy and reemit it with a set of characteristic frequencies. These reemitted X rays are called fluorescence X rays, and by analyzing them scientists can determine the particular elements that make up the material.

    Since the 1970s X rays have been used as a powerful probe to study distant astronomical objects. X rays, which can penetrate all mirrors, are difficult to focus in a conventional telescope, but special X-ray telescopes are designed so that incoming X rays strike deeply concave mirrors at small, glancing angles so that they can be brought to a focus on detectors (see Telescope). Extremely hot bodies of gas in space radiate their energy primarily in the form of X rays, as do certain very dense objects such as neutron stars, the collapsed cores of ancient stars.

    Although these X rays from space are absorbed by the Earth's atmosphere, X-ray telescopes on board satellites orbiting far above the atmosphere have brought back a wealth of new information. Industrial and Other Uses Just as doctors can use X rays to find hidden diseases inside the human body, so manufacturers can use the same radiation to find concealed flaws inside a product. Since X rays can penetrate even the thickest material, small cracks in rockets or other large machines can be detected.

    X-ray inspection is routinely used to examine metal parts for internal stress defects, which show up as shadows on X-ray photographs. During the 1980s the use of X rays was introduced in the production of exceedingly small electronic microcircuits. Previously, integrated circuits had been manufactured by coating a silicon wafer with a photosensitive material, then exposing it to a light masked by a special pattern of lines corresponding to the circuit design.

    The portions of the photosensitive material that were struck by the light could then be removed to create the permanent pattern of lines that made up the finished circuit (see Electronics, "Integrated Circuits"; Microprocessor). As finer and finer lines were required for ever smaller circuits, the wavelength of the light became too long, and X rays with much shorter wavelengths were substituted. In addition to their uses in medicine, science, and industry, X rays have also been widely employed for security purposes.

    Millions of travelers have had their hand baggage X-rayed at airport inspection stations, and similar machines are frequently used for customs inspections as well. With the aid of X-ray inspection, art historians and museum curators have discovered hundreds of art forgeries. X-ray photographs of metal sculptures purported to be from ancient Greece or Egypt, for example, may show internal support structures of a type used only in modern times.

    Similarly, X rays can reveal older paintings that have been covered up by layers of paint. The principal method by which scientists generate X rays is to allow accelerated electrons to collide with a target of heavy metal foil. The electrons are accelerated in a vacuum under the influence of an electric field.

    When they collide with the target they produce X rays by two processes. First, the accelerated electrons collide with the target electrons and excite them to higher energy levels. When, after a time, the target electrons drop back from these excited levels to their initial energy levels, they emit X rays.

    Second, when the accelerated electrons are slowed by the electrons and nuclei in the target, they themselves emit X rays. A similar process occurs when any electron is accelerated—that is, changes direction or speed. An accelerated electron emits radiation, and the higher the energy of the electron the higher the energy of the radiation (see Radiation).

    By controlling the voltage of the accelerating tube, an X-ray technician or scientist can control the energy of the accelerated electrons and thus the energy and frequency of the emitted X rays. For extremely high-energy X rays, such as those used to penetrate thick metal parts, a linear accelerator (commonly abbreviated linac) may be used. Linacs repeatedly apply small accelerating voltages to electrons as they move down the tube.

    Therefore, electrons that began with around one electron volt of energy arrive at their destination with energies of millions of electron volts. In the mid-1980s a new method of generating X rays was developed—the X-ray laser. These lasers focus the light produced by a conventional laser onto a thin metal wire, heating it intensely to produce a hot plasma, or ionized gas.

    The atoms of this gas are highly excited and emit X-ray photons, or packets of light (see Light). These photons, in turn, strike other excited atoms, stimulating them to emit more X rays. This cascading effect produces an intense beam of X rays.

    Such X-ray lasers, once perfected, could be used in chemical studies to produce X-ray holographs (three-dimensional images) of individual molecules during the course of chemical reactions. The United States Department of Defense is developing another type of X-ray laser as a potential weapon in which the initial source of energy is an exploding hydrogen bomb. This laser would concentrate a fraction of the bomb's energy into a narrow beam capable of striking targets in space at a distance of thousands of miles.

    This weapon system is called the Strategic Defensive Initiative. Popularly named "Star Wars," it was announced by President Ronald Reagan in March 1983. In nature, X rays are produced deep in space when highly energetic electrons are accelerated as they move through magnetic fields.

    The excited atoms of hot plasma in interstellar space are another X-ray source (see Plasma and Plasma Physics). In medical imaging, X rays can be detected with a fluorescent screen/photographic film combination. The fluorescent screen accepts the energy of the X rays and produces a visible image that is permanently recorded by the photographic film.

    There are a number of detection methods. Ionization counters exploit the tendency of X rays to ionize gases or solids. X rays strip electrons from atoms and leave the electrons free to conduct electricity.

    By measuring the conductance of a gas or solid with an ionization counter, scientists can determine the amount of ionization and thus the amount of X rays that created the ions. Someionization detectors use semiconductor materials across which a voltage is applied. These are termed solid-state detectors.

    A second category of detectors is based on the phenomenon of scintillation. When an atom is excited by an X ray, but emits radiation in the visible range, the process is called scintillation. The resulting photons are amplified in a photomultiplier and then counted by electronic circuits.

    In many applications, it is necessary to know not only the intensity of the X rays, but also their energy distribution, or spectrum. For this purpose, X-ray spectrometers are used to differentiate between X rays of varying energy. (See also Spectrum and Spectroscope.) X rays were discovered during the course of research into the effects of high-voltage electricity on gases.

    In these experiments, a gas was thinned to a partial vacuum in a glass tube called a Crookes tube. Researchers found that, when a current was passed through the gas between electrodes, the gas glowed in a pattern of light and dark areas that changed with changes in voltage and in the degree of vacuum. Sir William Crookes of England and Philipp Lenard and Heinrich Geissler of Germany found that the glow is caused by particles or waves streaming from the cathode, or electron-emitting electrode, to the anode, or electron-collecting electrode, of the tube.

    (Hence for many years the stream of particles now known to be electrons was called a cathode ray.) In 1895 Wilhelm Conrad Roentgen of Germany was experimenting with these cathode rays when he noticed that a fluorescent material glowed when a Crookes tube was operated nearby, even though the tube was well masked in cardboard. Materials placed between the Crookes tube and the fluorescent material diminished the glow but did not eliminate it. Roentgen could not determine how the radiation was carried through space or why it had such penetrating power.

    For this reason he called the radiation X rays, taking the name from the mathematician's use of x to denote the unknown quantity in a problem. The formal name given the radiation is Roentgen rays, in honor of the discoverer. (Radiographs are also sometimes called roentgenograms.) (See also Roentgen.) Although scientists have since come to understand the nature of X rays, the original name has persisted in common usage.

    In 1916 American physical chemist William D. Coolidge patented the Coolidge tube, which became the prototype of the modern X-ray tube. Earlier X-ray tubes had obtained electrons by ionizing the few molecules of gas left in the tube.

    The Coolidge tube supplied electrons from a coiled, hot wire of tungsten in the cathode. (Hence the tube is often called a hot-cathode tube.) The tube is capable of producing highly predictable amounts of radiation, and its efficiency was later increased by using a high vacuum.

  • Why X-rays Are Called X-rays???not Y-rays.?

    Wilhelm Röntgen called them "X-rays" and the name has been used ever since. He used "X" to signify that they were unknown, which they were at that time. Wikipedia: On November 8, 1895, Wilhelm Conrad Röntgen, a German physics professor, began observing and further documenting X-rays while experimenting with vacuum tubes.

    Röntgen, on December 28, 1895, wrote a preliminary report "On a new kind of ray: A preliminary communication". He submitted it to the Würzburg's Physical-Medical Society journal. This was the first formal and public recognition of the categorization of X-rays.

    Röntgen referred to the radiation as "X", to indicate that it was an unknown type of radiation. The name stuck, although (over Röntgen's great objections), many of his colleagues suggested calling them Röntgen rays. They are still referred to as such in many languages.

    Röntgen received the first Nobel Prize in Physics for his discovery.

  • Are X-ray Sensors Damaged by the X-rays They Detect?

    Yes, eventually x-ray sensors are damaged by the very x-rays they detect. Absolute NO technology lasts forever nor is any infinitely immune to external energy inputs (heat, radiation, electrical inputs, mechanical stress/strain, etc.) in terms of reliability. But this reality is generally "baked into" the overall product lifetime planning of the sensors.

    The type of damage is called "total dose" damage which primarily affects semiconductor/dielectric boundaries and dielectric bulk properties. The amount of total dose depends on the X-ray wavelength - harder X-rays cause more damage typically because the photon energy deposited is higher.X-ray sensor arrays are made up of photodiodes which themselves are relatively immune to radiation damage but the manufacturing of the array requires oxide interfaces and sometimes MOSFET transistors which are the weak link. As total dose is accumulated, oxide interfaces are damaged, creating and accumulating interface states and traps that can invert adjacent semiconductor to form parasitic circuit paths along the very insulating boundaries that normally assure very small photocurrents can be detected.

    These parasitic currents interfere with those signal photocurrents effectively increasing the noise floor of the array thus increasing the smallest signal that can be resolved/detected.However, there is no expectation of, say, 100 year useful lifetimes. So as long as this cumulative effect has an end-point far enough into the future, it wo not be a problem. The lifetime should be "sufficiently high" compared to the economic useful lifetime so that obsolescence occurs for reasons other than actual technology failure.

    Also specifications are typically defined with a margin assuming aging damage will occur. Are x-ray sensors damaged by the x-rays they detect?are x-ray sensors damaged by the x-rays they detect?

  • Science X-rays?

    X-rays are stopped by bones. The rest hair,muscle and skin absorb X-rays.

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Select from a variety of advanced and smart medical diagnostic digital x ray machine at Alibaba.com for precision diagnosis and health detection. These technologically advanced digital x ray machine are equipped with the latest features and are ideal for all kinds of radiology tests and diagnosis at hospitals and clinics. These smart digital x ray machine are portable and digital devices that are automated and aids in attaining sharp images through the available perfect image chains. These digital x ray machine are equipped with features such as advanced CCD cameras with noise reduction algorithms for providing optimum images in all kinds of scenarios and applications. These digital x ray machine are also equipped with enhanced movement controlling systems and high-frequency diagnosis. These class II digital x ray machine are available in distinct voltage capacities and the CCU units are advanced in realizing the multi-grade denoise ranging from various storage, LIH to image reverse. Find the smartest and advanced systems-driven digital x ray machine for detecting and diagnosing health aspects with high precision and efficiency at Alibaba.com. These digital x ray machine come with superior durability battery that can take as much as 500 pictures post charging and can be charged at least 1000 times in its lifetime. Some of the applications for these digital x ray machine are breast-health detection, oral X-Ray tests, Chest X-Ray, CT Scan, and many more. These products are sustainable and eco-friendly. Alibaba.com offers varied digital x ray machine ranges that go in sync with your budgets and requirements at the same time. These products are available as OEM orders and you can also opt for customized packaging. These products are ISO, CE, SHS, RoHS certified.1. Cheap options for high precision distance measurement?I think you should get to the bottom of what is causing your errors. Either you are missing steps or your mechanical setup is too flexible or has backlash in the nuts/bearings. Your homing switches may also have poor repeatability if you are not using an edge finder to locate the tool precisely. Or perhaps it's a combination. Things like backlash and flexibility are very difficult to compensate for with software. For example, depending on the direction of cut you may start off with the tool in the right position but as soon as it bites in kerchunk and you've dug into the work as the cutter pulls itself in. Or you may be doing climb milling and the cutter runs well outside of the desired path if the gantry and slides are too flexible. Anyway, glass scales are a sort of mid-priced way to measure a few microns down to 1um resolution. Accuracy over the full scale might be 10-15um over 1m for a cheap one. They typically have a quadrature 5V digital output (incremental), some may have quadrature sinusoidal signals. But each axis will probably cost about as much as you've put into this so far, and there is no guarantee you will be able to do much better in part accuracy. Photo from this pageIf you win the lottery you can consider Renishaw and Heidenhain encoders, which can reach resolutions orders of magnitude less than a wavelength of light and do it with absolute measurement2. How to Choose Press Brake Controller, NC or CNC?With the continuous improvement of industrial automation, more and more manufacturers choose to buy sheet metal equipment (such as CNC bending machine and CNC shearing machine) with an automatic intelligent CNC system. Different CNC systems are suitable for the production of different standard products, and the price difference is also very large. Therefore, for manufacturers, the correct choice of CNC system can effectively help the mass production of products. This article will mainly take the press brake (hydraulic bending machine) as an example to briefly introduce the dedicated CNC system for the press brake machine, and help the manufacturer who needs to purchase the CNC press brake to have a preliminary understanding of the CNC system. The numerical control system can be divided into: In the CNC system of the bending machine, the digital control generally means that when the system is produced, the manufacturer has programmed the program, and the purchaser cannot modify the programmed program. Computer numerical control means that the purchaser can edit the program according to the actual operational requirements before bending, and can make any modifications to the program. In short, the NC digital control system is the first generation of the CNC system, and the CNC computer numerical control system is an upgraded version of the CNC system. As an upgraded version of the system, it has more advantages. The computer numerical control system is based on the computer operating system, which is easy to operate and does not require skilled workers to operate. In addition, the operating system is easy to learn, and after simple training, workers can get on the job quickly. The digital control system is highly demanding for the operator, requiring the worker to understand every function of the machine and to operate the machine in an accurate manner. In the CNC system of the numerical control bending machine, multiple programming can be performed, and the system has a storage function. The larger the system storage capacity, the more programs the machine can store. Take the ESA S500 series controller used on CNC bending machine as an example. 20GB of hard disk space can store at least 2 million programs, and 256M U disk can store at least 50,000 programs. Each program can contain hundreds of bending steps. If the manufacturer needs to fold a variety of different specifications or workpieces with complex manufacturing processes, it is better to choose a computer numerical control system to complete the batch production in the shortest time. Digital control systems do not have storage capabilities. The workpieces bent by the bending machine with the computer numerical control system have better quality and higher precision, which cannot be achieved by the bending machine using the digital control system. The convenient operating system of computerized numerical control system's allows workers to operate for shorter periods of time and can work 24 hours a day. In contrast, CNC bending machines with CNC controller have more advantages. However, computer numerical control systems are more expensive, so the price of CNC bending machines is generally more expensive than NC bending machines. The value of the CNC numerical control system is much higher than that of the NC digital control system if it is considered in terms of production efficiency. Moreover, with the increasingly fierce competition in the global market, shaped workpieces emerge one after another, requiring machines to produce workpieces that meet the diverse needs of customers with high efficiency, high precision, and high standards. The advantages of the computer numerical controlled press brake are also increasingly prominent, and it is increasingly able to cater to the ever-changing market demand, which is the trend of the future.3. Very high precision zero crossing detectionYou will likely want to measure the total of many zero crossings (and divide by 'many' before taking the reciprocal).. or average many measurements.. otherwise noise in the signal will unduly affect your measurement, and you do not need the answer that quickly. You can measure easily to a couple hundred nanoseconds with a typical 8-bit micro (so 200ns in a 5kHz note would give you 3 digits) but that does not translate necessarily into results anywhere near that stable or accurate.
Do Objects Scanned Through an X-ray Machine at an Airport Absorb and Emit Radiation If the Same Obje
Do Objects Scanned Through an X-ray Machine at an Airport Absorb and Emit Radiation If the Same Obje
Yes they do depending on what the object is. Some objects cannot be penetrated by radiation. for example your keys. No difference in how many times object is scanned or time frame.1. If the TSA can't spot a loaded gun on an x-ray machine, what makes anyone think the body scans are effective?Two different technologies, so I do not think the x-ray results are indicative of what will happen with the body scanners. 9/11 still wo not happen again, because everyone knows the game, the cockpit doors have been hardened and the pilots know better than to come out of the cockpit.2. Are calcifications and kidney stones the same thing? I was told u201cOh no, stonesu201d after an X-ray found one and then I got a CT and he came back and said u201cOh, no stones, just an 8 mm calcification.u201d Why would he say this if itu2019s not the same?Because they do not know what they are talking about. Remember some people try to fake their knowledge. My mother was very ill from kidney stones when I was young so, I learned everything I could about them which at the time was not much about them in the library back in 1970. But I did learn this a kidney stone can be made by salt, with is very painful even a small one that almost can not be seen by x-ray, because it is a crystal and x-rays go right through salt without seeing it. Then the other is calcification of minerals, the one ingredient most common is calcium oxalate. Which calcium is used by the body in bones, thous is stone bone. A calcification of minerals or anything is to make it stone.Do not worry what they call it it is a kidney stone. Tech's are not suppose to tell you anything a doctor will. If you understand what it is do not worry about what they think it is. I even had a doctor once tell me that I did not have a kidney stone I had nephro calcium and not a kidney stone. I was so mad because he told me in one breath I did not have a kidney stone but nephro calcium. I said " You just said I did not have a kidney stone but nephro calcuim, Nephro is kidney and calcuim is bone, stone. Kidney stone." I told him I needed a real doctor, and if he did not know what he was saying he needed to look it up before telling someone. I was the last person he should have said that too, I studied kidney stones since I was 10 years old.3. what does the x mean in x-ray?Roentgen got confused, i guess4. What job makes more, paralegal or x-ray technician? Which one is more in demand?I personally do not know any employers who will hire one. The ones that I know will only hire registered radiologic technologists5. i think i may have given myself a fracture but i dont want to go to the hospital for an x ray?Hi! You have to go to the Hospital whether you have a broken bone or not, no matter if you are 1 or 90 years old. First things first, if your father do not understand you, Honestly I would not like to have a father like him, neither I would be proud of. If you do not want to go through this anymore, you may think twice before hitting on something. Try a boxing bag or try not to get mad unless you are close to your mattress or your pillow and by the way, why to get mad? you are going to end up breaking all of your bones6. Would an EXTERNAL Hard Drive's (with a plastic housing) data be safe to pass under an airport X-ray?X-ray machines can not affect the data on a hard drive. The metal detectors and motors potentially COULD, but it's ridiculously unlikely, plus you would need to be close (within 1-2cm) to one with it. If you are still worried just ask them about it when you get there.7. In religion and your part of the World, will the Halloweenies have to have mace, x-ray machines for the candy and drug-sniffing dogs ?Halloween is a more important holiday that christmas, easter, thanksgiving, etc... The term "halloweenies" is just as offensive as n***** or any other taboo word that the masses find offensive in my opinion. I do however understand what you are trying to get at, the safety of the children correct? I fortunately live in an area where we do not have things like razor blades in candy, perverts stalking kids, etc. .. About 10 years ago there was an incident, but they caught the guy who happened to be just travelling through, or so he said. The older kids around here look after the younger kids, the parents and neighbors all get along for the most part, (we all have some differences after all), and the worst that has happened here since the incident 10 years ago is the kids going to the park and putting toilet paper in a tree. The police even get to go trick or treating here along with other adults, we all get to have fun.
How Do I Determine (without an X-ray Machine) If I Have Broken Or Dislocated the Small Toe on My Rig
How Do I Determine (without an X-ray Machine) If I Have Broken Or Dislocated the Small Toe on My Rig
Even if it is broken, here is what would happen if you went to the hospital: A doctor would give you a special sandal to wear to keep it in the location in should be in. There's nothing else that can be done except (maybe) taking ibuprofen or another OTC drug for the swelling and pain.1. My boyfriend got exposed to an x-ray he got done 6 years ago and they didn't cover his testicles.?Depends entirely on the dosage and degree of exposure. You could get him tested for a sperm count.2. Does leukemia manifest in the bone marrow or in blood? Are there visible differences without x-ray?Leukemia starts in the bone marrow. Because the marrow makes the blood, it also simultaneously effects the blood. Xrays have nothing to do with leukemia. Its not a solid tumor. There are several different types of leukemia, but in general what happens is that the bone marrow goes crazy making deformed white blood cells that circulate in the peripheral blood. The only official way to diagnose leukemia is a bone marrow biopsy. Blood counts will show signs of leukemia, but it is not a diagnosis, and if the leukemia is the chronic type, it can be a while before the signs are strong enough to actually see a difference in the blood counts.3. my daughter by accident passed through airport x-ray machine.?How can that happen by accident? Not sure what the question is... but she will be fine4. Just for dental professionals please, what kind of digital x-ray are the best option? including software?There is direct or indirect digital xrays. Direct is better because you plug it right to a computer so when you take the radiograph it automatically appears on the computer screen. I hear the sensors are about 8 to 10,000 dollars a piece. Most dental places buy 1 or 2 Size 2s and 1 size 1 because of the price.5. what does the x in x-ray stand for?Nothing really. In most scientific terms, anything that is unknown or cannot be explained at the time gets the label of X. (An example - Pluto was once known as "Planet X" when it was first discovered) Why X? No one is sure when it started being used but it is thought that X stood for all things mysterious and unholy. X is also the one letter in the dictionary that has the fewest words, even less than Y or Z. How many x-words can you think of? Not many right?6. Did an X-ray burst interrupt radio signals shortly after D-Day?I am a little out of my comfort zone here, but I will give it a stab.Cosmic particles and X-Ray bursts are made of difference sorts of things, and both come from outer-space (as opposed to be created in the atmosphere). X-Ray bursts do not get through the atmosphere. So suggesting a X-ray burst (electromagnetic rays from outer space) caused a cosmic shower (particles from outer space) causing radio interference (electromagnetic noise) at the surface of the Earth (beneath the protection of the atmosphere) makes no sense7. I was attacked and wish to file a personal injury lawsuit. What is the proper x-ray/medical procedure?go to the dr/er immediately and get the documentation of the event started. they will order x-rays for you. you have to have the documentation to prove injury8. Is teeth x-ray can affect your pregnancy?I've had 5 babies, but at the beginning of my last pregnancy - before I knew I was pregnant - I found a lump in one of my breasts. I went in for a mammogram and then a couple weeks later found out I was pregnant. I am happy to report the lump was nothing and the baby I was pregnant with is now 15 mos old and perfectly normal. I am sure your fine. As for the wine - I think I probably had some alcohol with all my pregnancies before I knew I was pregnant. They are all fine! Good luck!9. Single crystal x-ray diffraction experiment backwards: from CIF to genuine set of raw data without performing actual experimentStructure determination by X-ray diffraction, regardless if powder diffraction, or single crystal diffraction analysis, is a spatial mapping of electron density. After solving a crystallographic structure (phase problem), the subsequent structure refinement includes steps to complete the crystallographic model, and to minimise the differences in the Fourier maps mapping observed electron density ($F_O$), with electron density predicted by your current model ($F_C$). This minimisation is done until this said difference is below a threshold value, and if the experimenter is satisfied with the result. For the later, this includes the complete and reasonable attribution of atoms (does this electron density belong to an atom of Carbon, or Nitrogen?), checking if bond distances and angles included in the model are consistent with the body of data determined in other experiments. Some of the critera applied are interdependent to others.If the crystallographic model is completed (in layman's terms, if there is a *. cif file), than it is easy to predict a theoretical powder diffraction pattern. Programs like CCDC Mercury just ask about the wavelength to consider and offer graphical and numerical output likeSuch a theoretrical diffractogram is then compared with an experimentally recorded one; for example to check the newly prepared sample's phase identity (polymorphism) and purity.In PXRD, spatial arrangement and conformations of subunits in the crystallographic model are optimised (refined) until yielding a model that chemically and mathematically is reasonable. This is the reason you see in publications a difference trace below the the superposition of experimental and predicted diffraction pattern:(source)For single crystal diffraction, the generation of a 3D diffraction model computationally might be more costly than for PXRD, on the other hand, as said, programs like ShelX routinely compare experimentally recorded $F_O$ with predicted / calculated diffraction intensities $F_C$ derived from the current set of atoms (their coordinates, occupancy, etc.) of the model. It is done internally. ShelX' *.lst listings for example include a section like:Hence I answer your question, if diffraction pattern may be simulated / faked with a "yes it is possible, provided there is a good data set about how the atoms / molecules are spatially arranged". Initiatives like the recurrent CSP blind tests to predict crystal structures and databases like PCOD may provide a foundation for this. Then how to spot an artifical and wrong diffraction model? Checkcif / Platon are tools to check for consistency and integrity of such models against the raw data (hkl-files), structure factors. The recent installation of checksums into *.cif files (currently under watch as Platon errors PLAT012, 013, and 014), may be seen as one element of protection if few entries were changed after completing the work described above. These bells probably remain silent if data were compromised very early on
How to Protect the Radiation From Handheld Dental X Ray Unit?
How to Protect the Radiation From Handheld Dental X Ray Unit?
Not only should you register properly and comply with all applicable regulations, but you should also consult the relevant state, provincial, and local regulations which govern radiation protection and use of x-ray equipment.The operator of the device should carefully follow all enforced regulations in relation to pregnant or expecting to be pregnant women. Operators of the device should also be completely familiar with the industry safety recommendations and permissible doses. To ensure optimal radiation backscatter protection you should:Position the backscatter shield at a correct angle to the operatorKeep backscatter shield close to the patientThe patient tilts their head when required to do soThe operator stays immediately behind the permanently attached backscatter shield, in the Significant Zone of OccupancyOnly begin using the handheld dental x ray unit when you are sure there will be no interruptions, putting other people under risk of being exposed to radiation. The assistant should also wear proper protective gear. In using Position Indicating Devices (PIDs), models allowing the operator to position the unit at the correct angle should be preferred. The depressed trigger can be used to end exposure at any given point. Low-class image detectors should not be used.Check here more china dental instrument. Related articles:What Are The Differences Between Different Dental Delivery Systems?What are the advantages of air abrasion over conventional dental drills? RELATED QUESTION What is the best way to choose custom cosmetic manufacturers? Cosmetic products are specialized as they often require containers that either come with applicators or dispensers or mirrors as value added propositions. Choosing the best custom cosmetic manufacturer The best custom Cosmetic Manufacturers USA will offer you innovate and creative solutions for packaging the cosmetics, at the same time keeping market demand and product usage in view. Cosmetic packaging is largely done in a range of plastics, though occasionally glass may be called for. Among the packages used for cosmetic products are: Cosmetic bottles Tubes for personal care products Tubes for cosmetics Cosmetic tubes Lipstick tubes Because cosmetic products are used on the skin and hair, they need to be packaged such that they are not damaged and remain fresh and in usable condition for their shelf life. Often smaller containers may also require external or secondary packaging to ensure against damage and make for easier packaging when large quantities are in transit. Sometimes two or more products may need to be packaged together (as in hair colors which will container the color, developer, perhaps an applicator, gloves, shampoo or other small sized items all bundled in one box). Most custom cosmetic manufacturers opt for product differentiation through packaging, shapes, containers and graphics that enhance brand value because cosmetic purchase is often impulsive. From above details we understand the value of custom cosmetic packaging for custom cosmetic manufacturers.
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