Nonmetallic Contaminants Research Articles

Detection of Low-Density Foreign Objects in Infant Snacks Using a Continuous-Wave Sub-Terahertz Imaging System for Industrial Applications.

Low-density foreign objects (LDFOs) in foods pose significant safety risks to consumers. Existing detection methods, such as metal and X-ray detectors, have limitations in identifying low-density and nonmetallic contaminants. To address these challenges, our research group constructed and optimized a continuous-wave sub-terahertz (THz) imaging system for the real-time, on-site detection of LDFOs in infant snacks. The system was optimized by adjusting the attenuation value from 0 to 9 dB and image processing parameters [White (W), Black (B), and Gamma (G)] from 0 to 100. Its detectability was evaluated across eight LDFOs underneath snacks with scanning at 30 cm/s. The optimal settings for puffed snacks and freeze-dried chips were found to be 3 dB attenuation with W, B, and G values of 100, 50, and 80, respectively, while others required 0 dB attenuation with W, B, and G set to 100, 0, and 100, respectively. Additionally, the moisture content of infant snacks was measured using a modified AOAC-based drying method at 105 °C, ensuring the removal of all free moisture. Using these optimized settings, the system successfully detected a housefly and a cockroach underneath puffed snacks and freeze-dried chips. It also detected LDFOs as small as 3 mm in size in a single layer of snacks, including polyurethane, polyvinyl chloride, ethylene-propylene-diene-monomer, and silicone, while in two layers of infant snacks, they were detected up to 7.5 mm. The constructed system can rapidly and effectively detect LDFOs in foods, offering a promising approach to enhance safety in the food industry.

The Design and Study of a Four-Coil Oil Multi-Pollutant Detection Sensor

The operating environment of large mechanical equipment on ships is extremely harsh. Under such harsh conditions, it is necessary to effectively monitor and assess the health status of machinery and equipment and to take appropriate maintenance measures to ensure the normal operation of the ship and the safety of the lives and property of the crew. However, currently used methods are less effective in detecting non-ferromagnetic abrasive particles and non-metallic contaminants and may not be able to respond to certain emergencies promptly. Therefore, in this paper, a quad-solenoid coil multi-contaminant oil detection sensor is proposed to detect metallic abrasive particles and non-metallic contaminants using the voltage–capacitance dual mode. We provide an analytical expression for the magnetic field strength of the present sensor and develop a corresponding mathematical model. In order to verify its accuracy, we compared the model results with finite element analysis and verified them experimentally. Analysis of the experimental results shows that by switching the detection mode of the sensor, ferromagnetic metal particles, non-ferromagnetic metal particles, and non-metallic contaminants in the oil can be identified according to the different experimental signal curves. The sensor recognizes ferromagnetic particles over 70 μm in diameter, non-ferromagnetic particles over 220 μm in diameter, water droplets over 100–110 μm in diameter, and air bubbles over 180–190 μm in diameter. By comparing the sensor with existing sensors, the sensor can provide accurate information about various pollutants, help maintenance personnel to develop a reasonable maintenance program, and reduce the maintenance cost of ship machinery.

Multi-Channel Dual-Mode Oil Multi-Pollutant Detection Sensor

In order to realize the lubricant fluid condition monitoring of ships and offshore engineering equipment, a multi-channel, dual-mode oil multi-pollution detection sensor is proposed and fabricated. The sensor has three detection channels connected via tee tubes, as well as two different detection modes, inductive and capacitive, respectively. In comparison to the traditional sensor, this sensor not only has the ability to distinguish and identify a diverse range of pollutants, but it also experiences an 11-fold increase in its volume of flow, resulting in a significant enhancement in detection efficiency. The mechanism of the inductive and capacitive modes for the differentiated detection of multiple pollutants is elucidated through theoretical analysis. The performance of the sensor is investigated using the constructed experiment platform. The experimental results show that the sensor can realize the simultaneous detection of metallic and non-metallic contaminants in lubricating oil fluids. It can detect the smallest iron particle size of 54 μm, the smallest copper particle size of 90 μm, the smallest water droplet size of 116 μm, and the smallest air bubble size of 130 μm. A novel approach for achieving ship and marine engineering equipment health monitoring and fault diagnosis is presented in this study.

Detection of Nonmetallic Contaminants in Lubricating Oil Using a Microwave Rectangular Cavity Resonator Sensor

Detection of Nonmetallic Contaminants in Lubricating Oil Using a Microwave Rectangular Cavity Resonator Sensor

Prioritizing metal detector for finished pharmaceutical formulation: Manufacturing safe, quality product

Background: The pharmaceutical metal detector is a device to detect metal as well as non-metal contaminants of large size in the pharmaceutical dosage form. The detection of unwanted metal (contaminant) is important to produce a high quality of the dosage form. Main body: Pharmaceutical dosage forms are highly sensitive to the environment to which they are surrounded. It is challenging to keep a product in its original form throughout its shelf life. These metals find entry in the pharmaceutical formulation during various phases of manufacturing while passing through pipelines, sieves, conveyors, wires, buds, error in mixing processes, through raw materials. The Food and Drug Administration Hazard Evaluation board has given that the length of 0.3 inches to 1 inch of metal is considered unacceptable. The article highlights source of the metal contamination in pharmaceutical formulation types of detectors used, FDA standard for the metal detector, the need for a metal detector with its ideal properties, effect, hazards of ingesting metal fragments through medicines, working principle, uses, separation of metal contamination, test for the metal detector go about when metal is detected. Monitoring of system in a metal detector at the Critical control points some case studies involve reputed pharmaceutical manufacturers, which were forced to recall the batches for metal fragments detected in finished product. Conclusion: The pharmaceutical companies are bounded to produce quality safe products. One adulteration may cause recalls of products, cost loss of millions of dollar or total disruption of business as well. The selection of suitable metal detector is much needed. As the metal detector inclusively controls the contamination maintains a tough control on the quality of products.

Sustainable Strategies for Solving Perennial Water Crisis in Enugu Using Infiltration/Sump Technology

Purpose: Perennial water crises is a monster that threatens the very essence of human existence globally. Efforts have been made to stamp out water crises by the provision of pipe borne water, artisanal well, etc but to no avail. Notwithstanding these efforts, a visit to the streets of Enugu showed the excruciating hardship faced by the people as a result of scarcity of portable water. This study aimed at determining the current condition of portable water supply, challenges to sustainable water supply as well as suitability and sustainability of harvesting portable water through infiltration/sump technology adaptation in solving Enugu metropolis water crises.
 Methodology: The survey and experimental research methods were used. A total number of 48 water samples were aseptically collected from 3 points on a weekly basis. The points are A: from the flowing Asata River, B: from the infiltration sump and, C: from the locally fabricated water treatment plant. These samples were subjected to physical, chemical and biological analysis to determine the level of impurities, chemical and biological pollutants contained therein. Atomic Absorption Spectrophotometer (AAS) was used to determine the concentration of heavy metals in the water samples. Direct culture plate count was used to determine bacterial load while sample concentration method was used for the microscopic examination.
 Findings: The results were presented in tables and analyzed with simple percentages. It was discovered that water supply to Enugu residents has been abysmally low compared to the Enugu State Water Corporation (ENSWC) installed capacity. Out of the six (6) years under study, the highest annual water production of 6,082,962 m3 representing 12.62% of the installed capacity, supplied to the inhabitants of Enugu metropolis was achieved in the year 2018. The study discovered that the raw Asata River is contaminated with (a) heavy metals, (b) E. coli and Coliforms (c) debris, non-metallic contaminants etc. However, with the application of sump/infiltration technology and minimal treatment the river is a veritable and sustainable alternative to the epileptic pipe borne water supply from ENSWC to the inhabitants.
 Recommendation: Adaptation and application of sump/infiltration smart indigenous water harvesting technology in solving the perennial water crisis in Enugu metropolis is recommended.

On the reduction and effect of non-metallic impurities in mechanically alloyed nanocrystalline Ni-W alloys

Non-metallic contamination is a practically unavoidable byproduct of commercial synthesis processes; however, non-metallic impurities are often overlooked when considering material design and performance of nanostructured materials. Importantly, there is disputing evidence as to whether non-metallic contamination stabilize or destabilize nanocrystalline materials against grain growth. Furthermore, it is unclear if non-metallic contamination has a significant impact on hardness of nanocrystalline systems. In this work, two nanocrystalline Ni-28at%W alloys with different impurity concentrations were produced via mechanical alloying to directly evaluate the effect of contamination on thermal stability and hardness of nanostructured materials. The alloys were isothermally annealed at several temperatures, and the microstructures were compared by applying atom probe tomography and aberration-corrected scanning transmission electron microscopy. It was determined that impurity concentrations can be substantially reduced by using specific milling media and pre-milling reduction processes. Furthermore, the clean and contaminated alloys exhibited similar thermal stabilities against grain growth, but the clean alloy displayed a 100% improvement in hardness despite a similar grain size and distribution of second phases. Impurity phases including CrOx, Ni6W6C, and trapped Ar pores were also identified and likely contributed to the thermal stability and mechanical properties observed in this study. Overall, this work suggests that impurities my not always be detrimental to thermomechanical behavior of nanocrystalline systems.

Simultaneous Recovery of Display Panel Waste Glass and Wastewater Boron by Chemical Oxo-precipitation with Fluidized-Bed Heterogeneous Crystallization.

Silica-based carrier is a promising material for recovery of metal and nonmetal contaminants in chemical oxo-precipitation-fluidized bed crystallization (COP-FBC) system. Boron species are an essential element for plant growth and can cause health concerns in human beings at high concentrations in water environments. The composition of thin-film transistor liquid crystal display (TFT-LCD) contains a wide variety of metal oxides and can be tailored as promising functional mesoporous carriers for boron crystallization recovery in the presence of barium ions and hydrogen peroxide. In this study, waste-derived mesoporous aluminosilicate (MAS) nanomaterial in the presence of barium ions and hydrogen peroxide was used as a carrier for sustainable recovery of crystallized boron, a priority wastewaters pollutant. The MAS shows the hierarchically homogeneous distribution of nanostructured aluminosilicate particles with an average size of 12.8 ± 3.6 nm on the surface after the activation with Na2CO3 at 1000 °C. Moreover, the negatively charged surface and the mesoporous structure of MAS enhance the adsorption of Ba2+ onto MAS, and the Langmuir adsorption capacity of 105 mg/g is achieved, which is conducive to the enhancement of the recovery of boron species. Moreover, the recovery efficiency and crystallization ratio of boron by MAS can be up to 84.5 and 93.4%, respectively. The cross-sectional scanning electron microscopy images and the high-temperature X-ray diffraction results confirm the boron recovery mechanism that the negatively charged functional group as well as the mesoporosity of MAS triggers the rapid formation of needle-shaped precipitates of barium peroxoborate, and then converted to barium borate after calcination at 1050 °C. Results obtained in this study clearly demonstrate the possibility of fabricating environmentally benign mesoporous aluminosilicate adsorbents from TFT-LCD waste to sustainably recover and crystallize boron species from water and wastewater in COP-FBC.

Thermal resistance of magnetic polymeric composites based on styrene, divinylbenzene, and Ni and Co particles

Polymers based on styrene (STY) and divinylbenzene (DVB) are widely used for water treatment. The chemical modification of these materials, with the introduction of chemical groups, increases their selectivity for certain types of contaminants. The incorporation of magnetic particles makes these systems useful for removing contaminants from aquifers, due to their magnetic attraction of certain residues. In this work, STY–DVB resins (unmodified, sulfonated, and impregnated with nickel and cobalt particles) were analyzed by thermogravimetry. The thermal stabilities of all the samples were compared, showing that sulfonation reduces the thermal stability of the resin, but the incorporation of metal particles restores that stability, with the extent of this recovery depending on the type of metal. This result shows that even when the incorporation of metal particles does not involve removal of contaminants by magnetic attraction, this inclusion is still justified because it increases the material’s thermal stability and also makes it more efficient for removing certain types of non-metallic contaminants, as observed in a previous study. Besides this, the thermogravimetric analysis was highly useful to ascertain the changes caused to the materials, including allowing inferences on the semi-quantitative results of the degree of sulfonation and confirming that metal compounds are not only physical mixtures.

Review of Standards for Surface and Dermal Sampling

Abstract This article summarizes the body of available standards for sampling of chemical and biological agents on workplace surfaces, including skin. These standards consist of voluntary consensus standards such as those promulgated by ASTM International, the International Organization for Standardization (ISO), and the European Committee for Standardization (CEN), as well as methods produced by U.S. Federal agencies such as the National Institute for Occupational Safety and Health (NIOSH) and the Occupational Safety and Health Administration (OSHA). Gaps in availabilities of standards are discussed along with activities underway to address needs in the field of occupational and environmental hygiene. In many cases, the available standards have been developed largely in response to regulatory requirements. For example, ASTM International standards, which describe requirements for wiping surfaces and methodologies for determining metals and metalloids such as lead and beryllium, were produced primarily in response to regulatory requirements for sampling settled dust for these elements in the United States. Methods for collection of asbestos samples, vacuum sampling, dry wipe sampling, and bulk sampling have also been promulgated. Standardized methods for non-metal contaminants and biological agents are more limited in availability. In particular, there is a lack of standardized methodologies for dermal sampling and limited standard guidance on selection of appropriate surface sampling methods and data evaluation. Activities are currently ongoing within ASTM International and ISO to address some of the gaps, but additional activity is needed to address remaining requirements for consensus standards.

Extractable, elevated ion charge states in the transition regime from vacuum sparks to high current vacuum arcs

Metal ions were extracted from pulsed discharge plasma operating in the transition region between vacuum spark and vacuum arc. At a peak current of about 4kA, and with a pulse duration of 8μs, we observed mean ion charges states of about 6 for several cathode materials. In the case of platinum, the highest average charge state was 6.74 with charge states present as high as 10, and with gold we found traces of charge state 11. At higher currents, nonmetallic contaminants started to dominate the ion beam, preventing further enhancement of the metal charge states.

RELEASE OF THE LIPID PEROXIDATION MARKER 8-EPI-PROSTAGLANDIN F2α FROM ISOLATED GILL PAVEMENT CELLS

The aim of the present study was to evaluate oxidative injury in gill pavement cells (GPCs) from fathead minnow (Pimephales promelas) using F2-isoprostane (F2-iP) release as an index of lipid peroxidation. Cells were isolated from pooled gill tissue by collagenase treatment, mechanical sieving, and Percoll density gradient centrifugation. Baseline levels of 8-epi-prostaglandin F2 alpha (8-epi-PGF2 alpha) were measured by incubating GPCs in physiological buffer (10(6) cells/ml) and enzyme immunoassay. After 60 min, the amount of immunoreactive 8-epi-PGF2 alpha (ir8-epi-PGF2 alpha) in control medium ranged from 1,374 to 5,515 pg/ml. Lead nitrate, 0.6 to 120 microM, did not influence ir8-epi-PGF2 alpha release, whereas FeCl3 stimulated release at 500 microM but not at 5 microM. Incubation medium was extracted for acidic lipids and analyzed by liquid chromatography/mass spectrometry/electrospray ionization. A compound in the medium exhibited a retention time on reverse-phase high-performance liquid chromatography nearly identical to that of synthetic 8-epi-PGF2 alpha The mass spectrum taken from the total ion chromatogram from 14.8 to 15.1 min contained a prominent ion at m/z 353, as expected for the molecular ion of 8-epi-PGF2 alpha. Similar results were obtained with tissue subjected to base hydrolysis. Mass spectra of extracted ion chromatograms obtained with gill extracts and authentic standard showed a close correspondence of fragment ions, providing definitive evidence for production and storage of F2-iPs by fish gills. In summary, F2-iP release occurs during lipid peroxidation injury to fish gill epithelium, and its measurement may facilitate aquatic toxicology studies of metallic and nonmetallic contaminants.

Aluminium Recycling and Environmental Issues of Salt Slag Treatment

Environmental friendly recycling is the trend toward total recycling of aluminium metal. In the secondary aluminium industry, due to the complexity of compositions and contaminants in the various types of aluminium scraps, an understanding of the behavior of different scraps during melting is crucial in the recycling process. Salt slags are the byproducts of the secondary aluminium industry, which should be recycled and processed in a proper way by taking the environmental impact into consideration. This article provides qualitative assessment on 10 different commercial aluminium scraps for their relative recyclability via well-designed and controlled laboratory experiments. It confirms that more nonmetallic contaminants, smaller size, and higher ratio of surface area to body volume generally lead to a lower metal recovery. Recycling the scraps with lower recyclability normally generates more salt slags. High slag viscosity leads to more fine aluminum metal entrapped in the salt slag and thus increases the load of salt slag recycling. It was found that viscosity of the salt flux is increased with the amount of entrapped nonmetallic components, which affect the settling of heavier materials. In addition, the slag samples from the melting tests were leached and analyzed to evaluate the behavior of carbon containing scrap. The elevated carbon content in the scrap resulted in more carbide formation in salt slags and thus more methane generation in salt slag recycling with a higher environmental impact.

A single asperity study of Au/Au electrical contacts

Interfacial force microscopy (IFM) is used to measure the electrical contact properties of electroplated gold thin films of the type used in microelectromechanical system relays. Force and current levels consistent with those present in metal-metal contact switches are examined in an atmospheric-pressure, dry-nitrogen ambient at room temperature, and the nature of a nonmetallic contamination layer which limits contact resistance and lifetime is explicitly examined mechanically, electrically and chemically. The electrical and mechanical properties of the contamination layer on the gold substrate are observed by IFM both before and after being exposed to ozone for an extended period of time. The contamination film is characterized by x-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry, and found to consist mostly of hydrocarbons; the film remains relatively stable in both composition and thickness following ozonation. However, some subtle chemical changes in the contamination layer induced by the ozonation process are found to profoundly affect the electrical properties of the gold-gold contact, reducing the resistance by more than 3 orders of magnitude and considerably reducing variability in the contact resistance between contact events. These results clearly demonstrate the critical role both positive and negative of the latent contamination present on the contact surfaces.

Contaminant source and mobilization in industrial wastes in Dalälven river drainage area, Sweden

From a summary of mineralogical and geochemical studies, this paper presents patterns of contaminant source, mobilization, and retention in three types of industrial wastes deposited in the Dalälven river drainage area in central Sweden. These industrial wastes contain significant amounts of sulfides and have been subjected to atmospheric oxidation for several tens to hundreds of years. They are the major sources of metals and non-metal contaminants discharged into the Dalälven river. The collected data are of considerable value toward the remedial management of this kind of industrial wastes. The mill-tailings initially contain carbonate minerals which neutralize the acidity and maintain the leachate pH at near neutral values at the bottom of the oxidation zone (about 40 cm deep beneath the surface). The acid neutralization results in a great deal of precipitation of ferric iron hydroxides, leading to the formation of Fe-precipitated layers - a potential barrier to metal movement and O2 diffusion downward through the tailings. The mine waste dump is composed of coarse-grained rock fragments and has been covered by crushed limestone since 1985 in an attempt to neutralize the acid leachate. However, limestone cover has much less buffering effect than expected. As a result, the underlying soil and ground water contains high levels of SO4, Fe, and other metals, and have low pH values. The sulfuric acid industry wastes consist of 70-80% iron oxides which are porous in texture. The porous texture provides a large surface area for the adsorption of SO4. During roasting, sphalerite acquired alteration rim which is composed of Zn-oxides. The mineralogical properties of the SAI wastes play an important role in the formation of hydrated sulfates of Fe and Zn. Due to the occurrence of these highly soluble sulfates, in situ flushing is a practical remedial approach for the SAI wastes, and a cleansing project is carrying out in Falun.

Implications of Surface Contaminants in a BPSG Deposition and Reflow Process

Chemically vapor deposited borophosphosilicate glass (BPSG) has been widely used in microelectronic device fabrication as interlayer dielectric film due to its excellent planarization, gettering and flow properties. A BPSG reflow step, performed either in a diffusion furnace or a RTP reactor, normally follows the deposition step. With device geometry reducing to sub micron levels, there is an increasingly greater emphasis on detection and elimination of surface contaminants and sub micron defects particularly on deposited film. In this paper, we report on the implications of surface contaminants in a BPSG deposition/reflow process. The deposition and reflow processes have been carried out in an atmospheric-pressure CVD system and a vertical diffusion furnace respectively. Ellipsometric measurements, SIMS, TXRF, and vapor phase dissolution (VPD) methods have been used to detect both metallic and non-metallic contaminants as a function of both BPSG deposition and furnace reflow process parameters. It was found that surface contaminants emanating under specific deposition conditions can cause an uncontrolled, enhanced oxidation during the reflow process. Process modifications and in line defect monitoring schemes are discussed.

Model planar alumina catalyst preparation and aging under hydrotreating conditions

Pore blockage and metal deposition on low surface area porous alumina films was monitored at several positions along a hydrotreater which processed heavy Arabian atmospheric residuum. Scanning Electron Microscopy and Energy Dispersive Analytical X-ray techniques were used to study the alumina film's surface morphology and degree of contamination after the aging process. After a period of two months in the hydrotreater, pore blockage at the reactor entrance was observed to occur within pores of ca. 1000A˚diameter. Pores of the same size located further down the bed show no evidence of blockage, however metallic and non-metallic contaminants are still present. The porous alumina films from the second bed of the hydrotreater show no trace of any contaminants. In fact, the porous surface looks remarkably clean as compared with the inlet surface. Porous anodic alumina films are demonstrated to be suitable probes for monitoring catalyst deactivation.

An electrolytic method of manufacture of a coarse tungsten powder

the purity and particle size of the starting metal. Tungsten produced by powder metallurgy plants is characterized by a narrow particle size range (0.5-100 ~m), and is therefore not very suitable for direct use in electron-beam and arc furnaces owing to the difficulties arising in the melting of fine powders. Use of bar and rod materials leads to additional contamination of fused tungsten by impurities (particularly carbon) introduced during the powder pressing stage. Of particular interest from the point of view of rational utilization of tungsten waste is a solid-phase process (involving no melting) in which a coarse metal powder is grown by electrolysis in a fused medium. During electrodeposition tungsten is refined -- purified from a number of metallic contaminants and from the majority of gaseous and nonmetallic contaminants. The cathodic metal can, after being purified from electrolyte salts, be employed directly for melting. In this article are presented some results of laboratory investigations and pilot-plant tests of a technique for the manufacture of a coarse tungsten powder by electrorefining in an oxide-~hloride--fluoride fused bath. Under laboratory conditions use was made of a hermetic multicathode electrolytic cell [i] enabling the process to be performed in batches and electrolyte samples to be collected without stopping and dehermetizing the apparatus. Combined with constancy of the inert atmosphere employed, this ensures that cathodic deposits and bath samples of better quality are obtained. The electrolyte was a fused mixture of 60% NaCI, 15% NaF, and 25% WO3 [2]; the process parameters were D c = 0.4-1.0 A/cm 2, D a ! 0.i A/cm 2, and T = 830-930~ The principal factors affecting the quality and structural characteristics of deposits were found to be cathodic current density, temperature, electrolysis time, and purity and degree of utilization of anode material. Tungsten crystallized on the cathode in the form of individual acicular crystals and agglomerates. The acicular crystals were, depending on their internal structure, of two -- single-crytsal and twinned -- types. Their relative amounts in the cathodic deposit varied and depended mainly on the current density, rate of supply of tungsten ions to the cathode, and passivation of the growing faces. All crystals grew in the direction of the close-packed row of the bcc lattice. The faces were clearly defined, but varied in size and type of growth. The needle length attained 20-40 mmo In most cases along the whole needles there formed, without any apparent regularity, buildups of fine crystals and branches of large crystals.

Use of zirconium in liquid‐sodium systems

AbstractThe attractive nuclear properties of zirconium make it a highly desirable core material for sodium‐cooled reactors. The elevated temperature strength while low is sufficient for certain applications. Development of higher strength alloys is underway. Sodium in itself is completely compatible with zirconium; however, the nonmetallic contaminants, namely oxygen, hydrogen, and nitrogen, can effect serious damage. The primary problem in the use of zirconium in a sodium system, then, lies in controlling these impurities in the sodium.