Portable Worn Research Articles

A high sensitivity wear debris sensor using ferrite cores for online oil condition monitoring

Detecting wear debris and measuring the increasing number of wear debris in lubrication oil can indicate abnormal machine wear well ahead of machine failure, and thus are indispensable for online machine health monitoring. A portable wear debris sensor with ferrite cores for online monitoring is presented. The sensor detects wear debris by measuring the inductance change of two planar coils wound around a pair of ferrite cores that make the magnetic flux denser and more uniform in the sensing channel, thereby improving the sensitivity of the sensor. Static testing results showed this wear debris sensor is capable of detecting 11 µm and 50 µm ferrous debris in 1 mm and 7 mm diameter fluidic pipes, respectively; such a high sensitivity has not been achieved before. Furthermore, a synchronized sampling method was also applied to reduce the data size and realize real-time data processing. Dynamic testing results demonstrated that the sensor is capable of detecting wear debris in real time with a high throughput of 750 ml min−1; the measured debris concentration is in good agreement with the actual concentration.

Image based portable wear debris analysis tool

Purpose – The purpose of this paper is to show the development of an image processing-based portable equipment for an automatic wear debris analysis. It can analyze both the qualitative and quantitative features of machine wear debris: size, quantity, size distribution, shape, surface texture and material composition via color. Design/methodology/approach – It comprises hardware and software components which can take debris in near real-time from a machine oil sump and process it for features diagnosis. This processing provides the information of the basic features on the user screen which can further be used for machine component health diagnosis. Findings – The developed system has the capacity to replace the existing off-line methods due to its cost effectiveness and simplicity in operation. The system is able to analyze debris basic quantitative and qualitative features greater than 50 micron and less than 300 micron. Originality/value – Wear debris basic features analysis tool is developed and discussed. The portable and near real-time analysis offered by the discussed work can be more technically effective as compared to the existing off-line and online techniques.

From Discard to Divination: Demarcating the Sacred Through the Collection and Curation of Discarded Objects

AbstractThe artifact assemblage recovered in a sealed undisturbed context inside a ceremonial building (Structure 12) in the ancient village of Joya de Cerén (A. D. 600), a Classic Period site located on the Southeast Maya Periphery, has been particularly enigmatic and difficult to interpret. This assemblage consists of small portable worn objects, some of which show physical and chemical damage consistent with having been previously discarded prior to being carefully curated in a ceremonial building, suggesting that they were collected in antiquity. A review of the ethnographic literature reveals that contemporary Maya ritual practitioners routinely collect small portable objects, many of which are Pre-Columbian in origin, as personal sacra. This practice of “ritual collecting” serves multiple purposes including: 1) the acquisition of divining tools, 2) personal verification of divine election, and 3) evidence to one's community of supernatural sanction for a change in social status. Through engaging in this practice, social actors create and manipulate power in local ritual systems that exist outside of the control of contemporary institutionalized religions. It is suggested that collecting may represent an alternative avenue to supernatural power for past, as well as present-day, rural ritual practitioners.

Correlation of portable wear metal analyzer (PWMA-2) and Baird A/E35U-3 oil analysis data

Correlation of the Perkin-Elmer Corporation portable wear metal analyzer, version two (PWMA-2) and the Baird Corporation A/E35U-3 spectrometric oil analysis data is accomplished by curve fitting of data from aircraft, bearing test rigs, and organometallic oil samples analyzed on both instruments. Each of nine wear metal elements (iron, silver, aluminum, chromium, copper, magnesium, nickel, silicon and titanium) was separately fitted to linear, logarithmic, power law and low order polynomial curves. Power law curve fits were best for most of the elements, especially in the important low concentration (0–5 ppm) range, where U.S. Air Force gas turbine aircraft engines typically operate. The power law curve was applied to all the elements to construct correlation algorithms, with a general uncertainty in correlation values of about 0.5–1 ppm or 10%, whichever was the greater. The coefficients of determination for the power law curve fits ranged from 0.935 for aluminum to 0.993 for iron. The fit for silicon was poor for any type of curve (the best coefficient of determination was 0.564 for the power law curve fit) and therefore correlation of silicon values is not recommended.

A Portable Slurry Wear Test for the Field

A new portable slurry wear test apparatus developed by the Bureau of Mines, U.S. Department of the Interior, makes it possible to gather materials wear and corrosion data at a mineral processing site. The portable wear cell is identical in design to a laboratory cell reported previously. It allows simultaneous evaluation of 16 specimens in a continuous flow of fresh slurry. Data obtained from selected metals and polymers showed high-chromium white cast irons to perform particularly well in tests with an aqueous lead-zinc sulfide ore slurry. However, ultra-high-molecular-weight polyethylene that exhibited superior wear resistance in comparable laboratory tests with an aqueous slurry of silica sand did not perform as well in field tests. Such results show how misleading it can be to use laboratory data to predict relative rates of wear in industrial slurries, even under nominally identical flow conditions. Field testing is therefore needed. In situ electrochemical corrosion measurements on a low-alloy steel showed that the field and laboratory slurries were similarly corrosive.

New device for analysis of metal particles in oil

A portable graphite furnace atomic absorption (AA) spectrometer, developed under a contract for this laboratory, has been evaluated using powdered metal particles suspended in oil. The portable wear metal analyzer (PWMA) was designed to support the deployed aircraft requirement for spectrometric oil analysis. The PWMA is a microprocessor-controlled automatic sequential multielement AA spectrometer packaged in two cases having a total weight of 49 kg. The PWMA will analyze for nine elements (nickel, iron, copper, chromium, silver, magnesium, silicon, titanium and aluminum) at a rate of 4 min per sample. The graphite tube and modified sample introduction system increase the detection of particles in oil when compared with the currently used techniques of flame AA or spark atomic emission spectroscopy and represent the major reason for this work — the qualification and calibration of the PWMA with known “wear metal” samples in turbine engine oil. Five (nickel, iron, copper, chromium and silver) of the nine elements analyzed by the PWMA are reported here owing to space limitations. These five elements represent the minimum and maximum concentration ranges of all nine elements. The PWMA shows good-to-excellent response for particles in the size ranges 0–5 and 5–10 μm and fair response to particles of 10–20 and 20–30 μm. All trends in the statistical variations are easily explained by system considerations. Correction factors to the calibration curves are necessary to correlate the analytical capability of the PWMA to the performance of existing spectrometric oil analysis instruments.

軸受材料の耐摩耗性について

The wear tests of some bearing materials are carried out by using a newly designed portable wear tester. And the characteristics of the process of wear about each material are discussed by introducing a value Ws which is defined by the following equation.Ws=h/pLwhere h; depth of wearp; contact pressureL ; sliding length.

ポータブル摩耗試験機の試作研究

A newly designed portable wear testing machine is presented in this paper. The spherical rotating wheel of this machine is impressed on the flat surface of the test piece under the load which is increased in proportion to the increase of the contact area between the rotating wheel and the test piece, and therefore the mean contact pressure is constant notwithstanding the increase of the depth of the impression. The load is applied by means of an electro-magnet, and hence the more deelply the wheel is lowered into the wear track of the test piece, the less the gap of the electromagnet and so the heavier the load. It is investigated theoretically and experimantally that the pressure varies little during test. The wear amount is estimated by measuring diameter of the wear impression microscopically. Microwear volume can be detected by the machine within a short time. The machine is portable (about 6 kg) and can be fixed on a large test piece.