Artykuły w czasopismach: „Lead pencils”

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RITTER, STEVE. "PENCILS & PENCIL LEAD". Chemical & Engineering News 79, nr 42 (15.10.2001): 35. http://dx.doi.org/10.1021/cen-v079n042.p035.

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Abraham, E., A. Younus, A. El Fatimy, J. C. Delagnes, E. Nguéma i P. Mounaix. "Broadband terahertz imaging of documents written with lead pencils". Optics Communications 282, nr 15 (sierpień 2009): 3104–7. http://dx.doi.org/10.1016/j.optcom.2009.04.039.

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Shekhawat, Vibhooti. "Graphite-paper circuit elements: Resistor, capacitor, and π value estimation". Physics Teacher 61, nr 2 (luty 2023): 154–55. http://dx.doi.org/10.1119/5.0077435.

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Graphite, an allotrope of carbon, is also a moderately good conductor of electricity. The shading pencil lead consists of graphite mixed with clay and, therefore, can conduct electricity, allowing one to construct and demonstrate different properties and the underlying concepts of circuit elements. The grade displayed on the pencil relates to the graphite-to-clay ratio, with higher B grades indicating a higher graphite-to-clay ratio. In this paper, the main objective is to show the dependence of resistance and capacitors on different physical parameters and to calculate the value of π electrically. The materials used in this activity are readily available, affordable, and suitable for demonstration purposes. The materials used to perform these activities are shading pencils of different grades, A-4 size papers, crocodile clips, and an LCR meter.

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Liao, Chun-An, Yee-Kwan Kwan, Tien-Chan Chang i Yiin-Kuen Fuh. "Ball-Milled Recycled Lead-Graphite Pencils as Highly Stretchable and Low-Cost Thermal-Interface Materials". Polymers 10, nr 7 (20.07.2018): 799. http://dx.doi.org/10.3390/polym10070799.

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A simple and sustainable production of nanoplatelet graphite at low cost is presented using carbon-based materials, including the recycled lead-graphite pencils. In this work, exfoliated graphite nanoplatelets (EGNs), ball-milled exfoliated graphite nanoplatelets (BMEGNs) and recycled lead-graphite pencils (recycled 2B), as well as thermally cured polydimethylsiloxane (PDMS), are used to fabricate highly stretchable thermal-interface materials (TIMs) with good thermally conductive and mechanically robust properties. Several characterization techniques including scanning electron microscopy (SEM) and thermogravimetric analysis (TGA) showed that recycled nanoplatelet graphite with lateral size of tens of micrometers can be reliably produced. Experimentally, the thermal conductivity was measured for EGNs, BMEGNs and recycled 2B fillers with/without the effect of ball milling. The in-plane thermal conductivities of 12.97 W/mK (EGN), 13.53 W/mK (recycled 2B) and 14.56 W/mK (BMEGN) and through-plane thermal conductivities of 0.76 W/mK (EGN), 0.84 W/mK (recycled 2B) and 0.95 W/mK (BMEGN) were experimentally measured. Anisotropies were calculated as 15.31, 15.98 and 16.95 for EGN, recycled 2B and BMEGN, respectively. In addition, the mechanical robustness of the developed TIMs is such that they are capable of repeatedly bending at 180 degrees with outstanding flexibility, including the low-cost renewable material of recycled lead-graphite pencils. For heat dissipating application in high-power electronics, the TIMs of recycled 2B are capable of effectively reducing temperatures to approximately 6.2 °C as favorably compared with thermal grease alone.

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Bhowmik, R. N. "Ferromagnetism in lead graphite-pencils and magnetic composite with CoFe2O4 particles". Composites Part B: Engineering 43, nr 2 (marzec 2012): 503–9. http://dx.doi.org/10.1016/j.compositesb.2011.07.013.

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Turlyun, L. N. "COMPUTER GRAPHICS AS A FORM OF COMPUTER VISUAL ART". Arts education and science 2, nr 31 (2022): 122–27. http://dx.doi.org/10.36871/hon.202202016.

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The article is devoted to computer graphics as the main type of computer visual art. It gives a historical review of the origin of computer graphics. The first artists in computer graphics are: Ben Laposki, Herbert Franke, Michael Noll, Friederich Nake, Charles Xuri, Harold Cohen. The concepts of pencil, charcoal, computer graphics, computer art, engraving, etching, linocut are covered. A comparative analysis of traditional graphic art and computer graphics is conducted. The article provides a brief historical overview of graphite, Italian and lead pencils and focuses on the imitation of traditional graphic tools in graphic editors. It is emphasized that hatchings modelling plays a special role in imitation of pencil drawing technique by means of computer graphics, as well as in traditional drawing. The shading modelling methods developed by software artists Cortez, Yamamoto, Herzmann, Litvinovich, Shiraishi, and Yamaguchi are described. The popularity of engravings in illustrating books and periodicals is noted. A classification of printed graphics by type and production technique is carried out. The article provides an overview of the main imitation filters for all types of engraving. In particular, such filters as "Engraver", "Cutline" Linocut are considered.

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Ahmadnasab, Morad, i Panayiotis J. Psarrakos. "Eigenvalue characterization of some structured matrix pencils under linear perturbation". Electronic Journal of Linear Algebra 40 (20.02.2024): 274–98. http://dx.doi.org/10.13001/ela.2024.7371.

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We study the effect of linear perturbations on three families of matrix pencils. The matrix pairs of the first two families are Hermitian/skew-Hermitian with special $3\times 3$ block cases appeared in continuous-time control, and the matrix pairs of the third family are special $3\times 3$ non-Hermitian block matrices appeared in discrete-time control. For the first family of matrix pencils and more general cases of the second family of matrix pencils, based on the properties of the involved matrices, we obtain some upper or lower bounds on the set of eigenvalues of linearly perturbed matrix pencils which are on the imaginary axis. Studying a special $3\times 3$ block matrix pencil, which is associated with continuous-time control, leads us to some linear perturbation that do not preserve (properly) the structure of the matrices. This, in turn, leads to a numerical technique for finding the nearest Hermitian/skew-Hermitian matrix pencil which can satisfy conditions such that, for some nonzero real perturbation parameter, some or all of its eigenvalues lie on the imaginary axis. We also study the linearly perturbed matrix pencils, associated with discrete-time control, using an one-to-one equivalence between the matrix pencil of continuous-time problem and the matrix pencil of discrete-time problem.

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Юрков, В., i V. Yurkov. "Approximation of Linear Sets in the Plane". Geometry & Graphics 7, nr 3 (2.12.2019): 60–69. http://dx.doi.org/10.12737/article_5dce6cf7ae1d70.85408915.

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A few general lines in the ordinary Euclidean plane are said to be line generators of a plane linear set. To be able to say that every line of the set belongs to one-parametrical line set we have to find their envelope. We thus create a pencil of lines. In this article it will be shown that there are a finite number of pencils in one linear set. To find a pencil of lines the linear parametrical approximation is applied. Almost all of problems concerning the parametrical approximation of figure sets are well known and deeply developed for any point sets. The problem of approximation for non-point sets is an actual one. The aim of this paper is to give a path to parametrical approximation of linear sets defined in plane. The sets are discrete and consist of finite number of lines without any order. Each line of the set is given as y = ax + b. Parametrical approximation means a transformation the discrete set of lines into completely continuous family of lines. There are some problems. 1. The problem of order. It is necessary to represent the chaotic set of lines as well-ordered one. The problem is solved by means of directed circuits. Any of chaotic sets has a finite number of directed circuits. To create an order means to find all directed circuits in the given set. 2. The problem of choice. In order to find the best approximation, for example, the simplest one it is necessary to choose the simplest circuit. Some criteria of the choice are discussed in the paper. 3. Interpolation the set of line factors. A direct approach would simply construct an interpolation for all line factors. But this can lead to undesirable oscillations of the line family. To eliminate the oscillations the special factor interpolation are suggested. There are linear sets having one or several multiple points, one or several multiple lines and various combinations of multiple points and lines. Some theorems applied to these cases are formulated in the paper.

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Hwang, Yuri, i Namje Park. "Development of a Digilog Learning Model for Training on the Principles of Artificial Intelligence Learning in Elementary Education". Journal of Computational and Theoretical Nanoscience 18, nr 5 (1.05.2021): 1465–68. http://dx.doi.org/10.1166/jctn.2021.9625.

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The importance of nurturing human resources who will lead the 4th Industrial Revolution is increasing, and artificial intelligence is a core factor of innovative technologies. Therefore, developing various and interesting teaching methods for principles of artificial intelligence is necessary. This article suggests teaching principles of artificial intelligence by convergence of digital and analogue, called digilog. Students get to know how machines can learn and operate, which is digital, with paper worksheets and several physical teaching aids, which are analogue. In digilog way, students figure out the principles of image recognition. There are two methods, MAX and filtration box. The principles of artificial intelligence are too abstract to understand for elementary learners who are yet at concrete operational period, according to Piaget. Therefore, the convergence of digital and analogue is effective for teaching and learning about artificial intelligence in elementary education. Elementary learners examine colorful virtual images in their worksheet and use their hands and pencils to trace artificial intelligence’s work. They end up with figuring out how artificial intelligence compresses inserted images into smaller reference images step by step. With the offered method and developing more diverse digilog elements, elementary learners’ knowledge and experiences necessary for the future society will be increased.

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Hwang, Yuri, i Namje Park. "Development of a Digilog Learning Model for Training on the Principles of Artificial Intelligence Learning in Elementary Education". Journal of Computational and Theoretical Nanoscience 18, nr 5 (1.05.2021): 1465–68. http://dx.doi.org/10.1166/jctn.2021.9625.

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The importance of nurturing human resources who will lead the 4th Industrial Revolution is increasing, and artificial intelligence is a core factor of innovative technologies. Therefore, developing various and interesting teaching methods for principles of artificial intelligence is necessary. This article suggests teaching principles of artificial intelligence by convergence of digital and analogue, called digilog. Students get to know how machines can learn and operate, which is digital, with paper worksheets and several physical teaching aids, which are analogue. In digilog way, students figure out the principles of image recognition. There are two methods, MAX and filtration box. The principles of artificial intelligence are too abstract to understand for elementary learners who are yet at concrete operational period, according to Piaget. Therefore, the convergence of digital and analogue is effective for teaching and learning about artificial intelligence in elementary education. Elementary learners examine colorful virtual images in their worksheet and use their hands and pencils to trace artificial intelligence’s work. They end up with figuring out how artificial intelligence compresses inserted images into smaller reference images step by step. With the offered method and developing more diverse digilog elements, elementary learners’ knowledge and experiences necessary for the future society will be increased.

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Matson, John. "Lunar Pencil Lead". Scientific American 303, nr 3 (wrzesień 2010): 17. http://dx.doi.org/10.1038/scientificamerican0910-17.

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KHAIRNAR, R. S., i D. S. JOAG. "PENCIL LEAD FIELD EMITTER". Le Journal de Physique Colloques 50, nr C8 (listopad 1989): C8–85—C8–90. http://dx.doi.org/10.1051/jphyscol:1989815.

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Enrichi, Francesco, Dorthe Dahl-Jensen, Jørgen Peder Steffensen i Carlo Barbante. "Theoretical and Experimental Analysis for Cleaning Ice Cores from EstisolTM 140 Drill Liquid". Applied Sciences 11, nr 9 (23.04.2021): 3830. http://dx.doi.org/10.3390/app11093830.

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To reconstruct climate history of the past 1.5 Million years, the project: Beyond EPICA Oldest Ice (BEOI) will drill about 2700 m of ice core in East Antarctica (2021–2025). As drilling fluid, an aliphatic ester fluid, EstisolTM 140, will be used. Newly drilled ice cores will be retrieved from the drill soaked in fluid, and this fluid should be removed from the cores. Most of it will be vacuum-cleaned off in a Fluid Extraction Device and wiped off with paper towels. Based on our experiences in Greenland deep ice coring, most of the residual fluid can be removed by storing the cores openly on shelves in a ventilated room. After a week of “drying”, the cores have a dry feel, handling them do not give “wet” gloves and they can easily be marked with lead pencils. This paper presents a theoretical investigation and some simple testing on the “drying” process. The rates of sublimation of ice and evaporation of fluid have been calculated at different temperatures. The calculations show that sublimation of the ice core should not occur, and that evaporation of fluid should be almost negligible. Our test results support these calculations, but also revealed significant fluid run-off and dripping, resulting in the removal of most of the fluid in a couple of days, independent of temperature and ventilation conditions. Finally, we discuss crucial factors that ensure optimal long-term ice core preservation in storage, such as temperature stability, defrosting cycles of freezers and open core storage versus storage of cores in insulated crates.

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Jain, Mansi, Sanjay Kumar, Nitin Saroch i TejinderP Singh. "Intraoral pencil core granuloma with retained pencil lead". Journal of Family Medicine and Primary Care 11, nr 8 (2022): 4830. http://dx.doi.org/10.4103/jfmpc.jfmpc_104_22.

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Gordon, B. Heath, i Andrew J. Velkey. "Pencil Lead Diameter Affects Response Sheet Completion Time". Perceptual and Motor Skills 90, nr 1 (luty 2000): 326–28. http://dx.doi.org/10.2466/pms.2000.90.1.326.

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The effect of pencil lead diameter on the completion time of a multiple-choice response sheet was examined. Participants used three pencil lead diameters (.5 mm, .9 mm, and a standard No. 2 pencil) to fill in “bubbles” on response sheets in one experiment; a .7-mm pencil was substituted for the No. 2 pencil in Exp. 2. Participants using a .5-mm pencil completed response sheets more slowly than when using a 7-mm, .9-mm, or a No. 2 pencil.

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Silberschlag, Eisig, Berl Botwinik i Philip J. Klukoff. "Lead Pencil: Stories and Sketches". World Literature Today 59, nr 1 (1985): 112. http://dx.doi.org/10.2307/40140700.

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Kuryshchuk, Serhii, Taras Kovalyuk, Ivan Koziarskyi i Mykhailo Solovan. "Structural, Electrical and Optical Properties of Graphite Films are Drawn with Pencils of Different Hardness". 3, nr 3 (2.09.2022): 91–96. http://dx.doi.org/10.26565/2312-4334-2022-3-12.

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The paper presents the results of studying the structural, optical and electrical properties of thin films of graphite depending on the hardness of the rods (2H, H, HB, B and 2B) obtained by the "Pencil-on-semiconductor" method. Such studies are of great importance for the further development of highly efficient devices based on heterojunctions for electronics and optoelectronics. Typical images of the surface formed by reflected electrons (BSE) were obtained using a scanning electron microscope and shown at three magnifications (100x, 500x and 1000x). Since the cores of the studied pencils consist of mixtures of clay and graphite, a more detailed analysis of the elements that make up the cores was conducted. EDS analysis showed that the main components of the studied rods are purified graphite powder, as well as O, Al and Si, which are part of kaolin whose formula is H4Al2Si2O9, or Al2O3 • 2SiO2 • 2H2O - the main component of ordinary clay. The elemental composition of the microvolume of the studied samples was also determined. Regardless of the error that occurs when determining the composition of C and O (~ 12%), it can be argued that there is still a regularity between the graphite content and the hardness of the pencil. That is, the higher the graphite content, the softer the rod. The thickness of the graphite films was measured using the MII-4 interferometer according to the standard method. The average thickness of all investigated films was ~ 150 nm since the thickness of the films obtained by this method is mainly determined by the roughness of the surface of the salt substrate. Drawn graphite films have a higher resistivity than bulk samples (pencil rods) from which they were made. The resistance of the films increases with an increase in the hardness of pencils, due to an increase in the number of clay impurities in graphite, which is a dielectric. It was found that an increase in stick hardness leads to an increase in transmission.

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Papava, V., V. Kvakhajelidze, T. Didbaridze, L. Shanidze, G. Sinauridze, T. Mamasakhlisi, O. Khardzeishvili, Sh Sakhvadze i M. Tsirekidze. "Coexistence of Bladder Cancer and Foreign Body in the Bladder: A Rare Case Report". International Journal of Progressive Sciences and Technologies 38, nr 1 (22.04.2023): 220. http://dx.doi.org/10.52155/ijpsat.v38.1.5233.

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Foreign bodies in the bladder are a rare but significant medical condition that can lead to complications and severe health consequences. While it can be challenging to access the bladder, foreign bodies can occasionally find their way inside. These objects may be intentionally introduced, as in cases of self-insertion or insertion by others, or may enter the bladder accidentally, as in cases of migration from adjacent organs or tissues.Various objects have been found in the bladder, including but not limited to electric cables, pencils, catheters, aluminum braids, and removable parts of medical cystoscopy equipment. In addition, unusual objects such as candles, pens, thermometers, and other household items have been reported. Patients who insert foreign bodies into the bladder may have underlying psychological disorders or curiosity, while accidental insertion may occur due to medical procedures, trauma, or other causes. (A W Badenoch)Complications associated with foreign bodies in the bladder can be acute or chronic and may include pain, infection, inflammation, hematuria, urinary retention,bloody urine or urinary tract obstruction. Patients may present with various symptoms, including dysuria, frequency, urgency, or incontinence. Diagnosing foreign bodies in the bladder is typically done through imaging studies, such as X-rays or ultrasound, and confirmed by cystoscopy.In some cases, foreign bodies in the bladder may be discovered incidentally during medical interventions for other conditions. For example, the discovery of a post-osteosynthesis bolt in the urinary bladder, as in the case presented in this report, is a rare finding that may be associated with asymptomatic conditions and tissue formation of the bladder. The prompt and appropriate management of foreign bodies in the bladder is critical to prevent serious complications and improve patient outcomes. (FOREIGN BODIES IN THE URINARY BLADDER – CASE SERIES, 2017) Categories: Urology, Traumatology,

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Honda, Yoshihito, i Kunio Asayama. "Intraocular Graphite Pencil Lead without Reaction". American Journal of Ophthalmology 99, nr 4 (kwiecień 1985): 494–95. http://dx.doi.org/10.1016/0002-9394(85)90031-5.

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Gurnani, Bharat, Kunal Mandlik, Kirandeep Kaur i Shivanand Narayana. "Penetrating ocular trauma from a pencil lead". Trauma 22, nr 4 (2.12.2019): 326–27. http://dx.doi.org/10.1177/1460408619892139.

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Bashirzadeh, Yashar, Venkat Maruthamuthu i Shizhi Qian. "Electrokinetic Phenomena in Pencil Lead-Based Microfluidics". Micromachines 7, nr 12 (15.12.2016): 235. http://dx.doi.org/10.3390/mi7120235.

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Arıcı, Ceyhun, Osman Şevki Arslan, Burcu Görgülü, Rengin Yıldırım i Umut Onur. "Eye Injuries from Pencil Lead: Three Cases". Türk Oftalmoloji Dergisi 47, nr 1 (17.01.2017): 52–55. http://dx.doi.org/10.4274/tjo.32448.

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Salami, Marcos Alfredo, Joao Bernardes da Rocha Filho i Nara Regina de Souza Basso. "Pencil lead shows nonlinearity in heat experiment". Physics Education 43, nr 2 (21.02.2008): 126–28. http://dx.doi.org/10.1088/0031-9120/43/2/f04.

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Marshall, Rick. "Pencil leads: 20 project ideas". Physics Education 38, nr 2 (1.03.2003): 94–96. http://dx.doi.org/10.1088/0031-9120/38/2/401.

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Chamel, Olivier. "Design/build: A Relevant Pedagogy for Architecture Education". VITRUVIO - International Journal of Architectural Technology and Sustainability 1, nr 2 (20.12.2016): 53. http://dx.doi.org/10.4995/vitruvio-ijats.2016.6773.

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The predominance of drawing as a mean to create and represent architecture, whether in an educational setting or in professional practice, has had a profound influence on the design process. Drawings are so much a part of that process that they can often be mistaken for architecture itself. But drawings are not architecture, rather they are tools to create and control.Historically, drawings greatly contributed to the establishment of the profession of architect inaugurated by the Italian Renaissance. They became the means by which architects gained control over design and by extension over the construction process. Control of the design process eventually moved from the hands of the master builders to architects’ pencils.The long-held monopoly of drawings in architecture has perpetuated a structural disconnect between design process and the “making of things”. The heavy reliance on drawings has lead to tendencies for abstraction, repetition, self reference and a diminished sense of genuine innovation.Design/build as an alternative delivery method focuses on a more intuitive approach based on the creative powers of manual labor and the interaction of the designer with the material world. This methodology has the advantage to re-engage a generation of student increasingly invested in a world of virtual stimuli with the physical materiality of things and promote the creative value of Homo Faber. By “making things” students are designing. A hands-on approach would also meet the needs of a student body who responds well to active learning pedagogy.This paper will present a series of recent furniture design/build exercises where students designed and furniture and small building prototypes with limited reliance on drawings. We will discuss how subjects such as structures, material sourcing and construction detailing can be transposed from various courses and applied to design/build projects. We believe that a pedagogy based on physical experimentations could infuse energy throughout curricula no matter the course subject.

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Feizi, Rozhan, Nematollah Jaafarzadeh, Hamideh Akbari i Sahand Jorfi. "Evaluation of lead and cadmium concentrations in lipstick and eye pencil cosmetics". Environmental Health Engineering and Management 6, nr 4 (6.12.2019): 277–82. http://dx.doi.org/10.15171/ehem.2019.31.

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Background: The aim of this study was to determine the concentrations of lead (Pb) and cadmium (Cd) in lipstick and eye pencil cosmetics of different grades in the markets of Iran. Methods: This descriptive study was conducted in Ahvaz city in 2018. Sixty different samples of lipstick and eye pencil of three common brands were selected and analyzed using the Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-OES) and the results were compared with standard values recommended by the Food and Drug Administration (FDA). The analysis of lipsticks was based on producer country and colors and producer country only for eye pencil. Results: The mean concentrations of Pb and Cd were 41.86 and 53.42 µg/g, respectively. Concentrations of lead were higher than those of Cd in lipsticks, while for eye pencil, Cd showed higher concentrations. The overall results indicated that in all brands and colors of lipsticks, only 33% of the samples had Pb content less than the FDA limit, and among lipstick samples, 44% had Cd concentration less than the FDA limit of 3 μg/g, however, in 100% of the eye pencil samples, the concentration of Cd was higher than the recommended value of 3 μg/g. Conclusion: Given the health risks of exposure to heavy metals and in order to increase community awareness about the harmful effects of cosmetics, it is necessary to monitor the concentration of these toxic elements in these products and encourage the manufactures to meet the FDA standards.

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Chiaverina, Chris. "Exploring electric circuits and resistance using pencil lead". Physics Teacher 52, nr 9 (grudzień 2014): 570–71. http://dx.doi.org/10.1119/1.4902212.

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Djamilah Arifiyana i MA Hanny Ferry Fernanda. "ANALISIS KUALITATIF DAN KUANTITATIF CEMARAN LOGAM BERAT TIMBAL (Pb) DAN KADMIUM (Cd) PADA PRODUK KOSMETIK PENSIL ALIS MENGGUNAKANSPEKTROFOTOMETER SERAPAN ATOM (SSA)". Journal of Research and Technology 4, nr 1 (30.06.2018): 55–62. http://dx.doi.org/10.55732/jrt.v4i1.331.

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The aim of this study was to identify and determine the heavy metal content of lead (Pb) and cadmium (Cd) towards eyebrow pencil registered and not registered by the Food and Drug Supervisory Agency (BPOM). This research was conducted in several markets in Surabaya. Twelve eyebrow pencil items were investigated for lead (Pb)and cadmium (Cd). Simple reagents, included HCl, NaOH, KI, Na2S2O3 and NH4OH were used to identify the presence of these heavy metal first. The study results showed that samples of eyebrow pencil registered and unregistered by BPOM RI after being tested turned out to contain lead and cadmium in a range of 1.092-5,834 mg/kg and 0,054-0.243 mg/kg, respectively. The content is still within what is required based on the regulations of BPOM RI, < 20 mg/kg for lead content and < 5 mg/kg for cadmium content. In short, all the sample of eyebrow pencil contained lead (Pb) and cadmium(Cd)within what is required based on the regulations of BPOM RI.

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Brown, Alan R. "Geometry's Giant Leap". Mathematics Teacher 92, nr 9 (grudzień 1999): 816–19. http://dx.doi.org/10.5951/mt.92.9.0816.

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After many years during which graphing calculators were used for algebra and other advanced mathematics subjects, dynamic software for geometry is finally available. Such software programs as The Geometer's Sketchpad and Geometric Supposer have existed for several years; however, they require expensive hardware and dedicated space and have limited transportability. Technology for most geometry classes has traditionally consisted of a compass, a straightedge, pencils, and, more recently, a scientific calculator. However, the TI-92 graphing calculator is the first of a new breed of handheld calculators with dynamic software.

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Moriwaki, Hiroshi, Tomoya Kamine, Yukari Kawabe i Yusuke Okada. "Structural Color on Pencil Lead Formed by Plasma Etching". Advanced Optical Materials 10, nr 7 (13.02.2022): 2102127. http://dx.doi.org/10.1002/adom.202102127.

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Tong, Zhan, Lu Guanghan i Yao Xin. "SOLID-PHASE MICROEXTRACTION DETERMINATION OF ALCOHOL USING PENCIL LEAD*". Analytical Letters 34, nr 4 (4.02.2001): 627–34. http://dx.doi.org/10.1081/al-100002600.

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Koudelkova, Vera. "How to simply demonstrate diamagnetic levitation with pencil lead". Physics Education 51, nr 1 (11.12.2015): 014001. http://dx.doi.org/10.1088/0031-9120/51/1/014001.

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Hsieh, Bo-Chuan, Tzong-Jih Cheng, Syuan-He Shih i Richie L. C. Chen. "Pencil lead microelectrode and the application on cell dielectrophoresis". Electrochimica Acta 56, nr 27 (listopad 2011): 9916–20. http://dx.doi.org/10.1016/j.electacta.2011.08.058.

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Nawi, Siti Nurasiah Mat, Mayeen Uddin Khandaker, D. A. Bradley, S. F. Abdul Sani, K. S. Almugren i Abdelmoneim Sulieman. "Polymer pencil lead graphite for in vivo radiation dosimetry". Diamond and Related Materials 106 (czerwiec 2020): 107860. http://dx.doi.org/10.1016/j.diamond.2020.107860.

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Majidi, Mir Reza, Afsaneh Saadatirad i Esmaeel Alipour. "Voltammetric Determination of Hemoglobin Using a Pencil Lead Electrode". Electroanalysis 23, nr 8 (5.07.2011): 1984–90. http://dx.doi.org/10.1002/elan.201100009.

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Shibuya, Rintaro, Yuichiro Endo, Akihiro Fujisawa, Miki Tanioka i Yoshiki Miyachi. "Granuloma Caused by Carbon Deposition in the Dermis". Case Reports in Dermatological Medicine 2014 (2014): 1–2. http://dx.doi.org/10.1155/2014/686489.

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Pencil core granuloma is characterized by a delayed foreign-body reaction against retained fragments of pencil lead. Previous case reports presented pencil core granuloma resembling malignant melanoma, haemangioma, or soft tissue sarcoma. We present a case of pencil core granuloma arising from the palm 25 years after the initial injury. The patient presented a bluish nodule that had been present over 25 years before. The nodule initially measured 5 mm in diameter. However, five years before presentation, it suddenly enlarged to the size of 30 mm during six months. Computed tomography (CT) of the lesion revealed a linear radiopaque structure of 8 mm long with a mass on its distal end. Surgical resection revealed a bluish muddy mass and pencil lead. Histological examination revealed degenerative tissue with calcification surrounded by massive amounts of black granular material in the middle and lower dermis.

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Singh, Saravjeet, Minakshi Sharma i Geeta Singh. "Graphene Oxide Nanoparticles Decorated Pencil Lead as Urea Sensing Electrode". Asian Journal of Chemistry 33, nr 11 (2021): 2857–63. http://dx.doi.org/10.14233/ajchem.2021.23501.

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In present study, a low-cost and steady electrochemical biosensor has been developed based on graphene oxide nanoparticles (GONPs), electrodeposited on the pencil lead electrode (PLE). The physical and morphological studies revealed the nano-scale range of GONPs that has an average grain size/layer thickness of 2.27 nm and agglomeration size of 90-120 nm. Urease enzyme was immobilized on PLE/GONPs electrode after surface treatment with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC)/N-hydroxysuccinimide (NHS) to impart stable peptide bond. Scanning electron microscopy (SEM) studies demonstrate the difference between unmodified and modified PLE electrodes and depict the spherical, circular and flaky-like morphology. The electrochemical analysis of urea considerably improved on the PLE/GONPs/Ur compared to the untailored PLE electrode. The reported urea biosensor operated in a linear dynamic range between 0.30-50 mM that attained a recognition limit of 0.06 mM and exhibited an advanced exposure sensitivity of 0.814 μA mM-1 cm-2.

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Witkowska Nery, Emilia, Magdalena Kundys-Siedlecka, Yoshitaka Furuya i Martin Jönsson-Niedziółka. "Pencil Lead as a Material for Microfluidic 3D-Electrode Assemblies". Sensors 18, nr 11 (19.11.2018): 4037. http://dx.doi.org/10.3390/s18114037.

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We present an electrochemical, microfluidic system with a working electrode based on an ordered 3D array of pencil leads. The electrode array was integrated into a plexiglass/PDMS channel. We tested the setup using a simple redox probe and compared the results with computer simulations. As a proof of concept application of the device we showed that the setup can be used for determination of dopamine concentration in physiological pH and ultrasensitive, although only qualitative, detection of p-nitrophenol with a limit of detection below 1 nmol L−1. The observed limit of detection for p-nitrophenol is not only much lower than achieved with similar methods but also sufficient for evaluation of exposure to pesticides such as methyl parathion through urinalysis. This low cost setup can be fabricated without the need for clean room facilities and in the future, due to the ordered structure of the electrode could be used to better understand the process of electroanalysis and electrode functionalization. To the best of our knowledge it is the first application of pencil leads as 3D electrochemical sensor in a microfluidic channel.

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Janowska, I., F. Vigneron, D. Bégin, O. Ersen, P. Bernhardt, T. Romero, M. J. Ledoux i C. Pham-Huu. "Mechanical thinning to make few-layer graphene from pencil lead". Carbon 50, nr 8 (lipiec 2012): 3106–10. http://dx.doi.org/10.1016/j.carbon.2012.02.064.

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Oliveira, Thawan G., Irlan S. Lima, Wilson A. Ameku, Josué M. Gonçalves, Rodrigo S. Souza, Henrique E. Toma i Lúcio Angnes. "Laser-Scribed Pencil Lead Electrodes for Amperometric Quantification of Indapamide". Chemosensors 11, nr 12 (5.12.2023): 574. http://dx.doi.org/10.3390/chemosensors11120574.

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Laser engraving is a convenient, fast, one-step, and environmentally friendly technique used to produce more conductive surfaces by local pyrolysis. The laser’s thermal treatment can also remove non-conductive materials from the electrode surfaces and improve electrochemical performance. The improvement was assessed by electrochemical tools such as cyclic voltammograms and electrochemical impedance spectroscopy using [Fe(CN)6]3−/4− and dopamine as redox probes. The electrochemical results observed showed that a treated surface showed an improvement in electron transfer and less resistance to charge transfer. To optimize the electrode performance, it was necessary to search for the most favorable graphite mines and optimize the parameters of the laser machine (laser power, scan rate, and output distance). The resultant material was adequately characterized by Raman spectroscopy and scanning electron microscopy (SEM), where an irregular surface composed of crystalline graphite particles was noticed. Furthermore, as a proof-of-concept, it was applied to detect indapamide (IND) in synthetic urine by flow injection analysis (FIA), a diuretic drug often used by athletes to alter urine composition to hide forbidden substance consumption in doping tests.

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Gomesh, Nair, Mohammad Shafawi, Muhammad Irwanto, Mohd Irwan Yusoff, Muhammad Fitra i Norman Mariun. "Performance Improvement of Dye Sensitized Solar Cell by Using Recycle Material for Counter Electrode". Applied Mechanics and Materials 446-447 (listopad 2013): 823–26. http://dx.doi.org/10.4028/www.scientific.net/amm.446-447.823.

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This project is to investigate the counter electrode material from two different carbon sources to fabricate dye sensitized solar cell (DSSC). The carbon sources are extracted from battery and pencil lead. The method to prepare the DSSC is through the conventional Dr.Blading method. The same method is also used for the counter electrode which uses carbon from recycle batteries, the carbon from pencil lead are scribbled onto the ITO glass to get a uniform coating. Both thickness of the counter electrode vary accordingly. The solar cells are then placed under outdoor solar irradiation and the output is taken every 10 minutes. Based on observation, the solar cells which have the carbon from batteries shows higher cell efficiency which is 8.2 % with lower FF of 0.78, compared to by using the pencil lead, the cell efficiency is only 7.23% but with a higher FF of 0.93.

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Saucedo Cañas, Manuel Alberto, Monica Galicia i Katya Aimee Carrasco Urrutia. "Low Cost Electrochemical PGE Platform for Sensitive Determination of Pb(II) and Cd(II)". ECS Transactions 110, nr 1 (13.02.2023): 255–72. http://dx.doi.org/10.1149/11001.0255ecst.

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Low-cost electrochemical platform for sensitive Pb(II) and Cd(II) detection in aqueous solution were fabricated using pencil graphite leads. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were applied to electrochemical characterization of the Pencil Graphite Electrode (PGE). Average electroactive surface was determined as 2.58 times its geometrical area. Parameters for the electrochemical detection of lead and cadmium ions were optimized using Anodic Stripping Square Wave Voltammetry (ASSWV) in 0.1 M HCl (Edep= -1 V, tdep= 60 s). Electroanalysis results exhibited linear increment of electrochemical signals with an increase in the concentration of Pb(II) and Cd(II) in two different ranges. Based on the calibration curve, limits of detection (LOD = 3σ m-1) were 0.946 mg L-1 and 1.107 mg L-1 respectively. This electrochemical platform constitutes an effective and low-cost approach (0.20 USD per unit) that may be useful to industry, academia, or regulatory agencies.

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Philip, Swetha Sara, Deepa John i Sheeja Susan John. "Asymptomatic Intracorneal Graphite Deposits following Graphite Pencil Injury". Case Reports in Ophthalmological Medicine 2012 (2012): 1–2. http://dx.doi.org/10.1155/2012/720201.

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Reports of graphite pencil lead injuries to the eye are rare. Although graphite is considered to remain inert in the eye, it has been known to cause severe inflammation and damage to ocular structures. We report a case of a 12-year-old girl with intracorneal graphite foreign bodies following a graphite pencil injury.

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Aloni, Michel, Pauline Lecerf, Catherine Heijmans, Phu-Quoc Le, Sophie Huybrechts, Christine Devalck, Malou Ngalula Mujinga i Alina Ferster. "Pica In Children with Sickle Cell Disease". Blood 116, nr 21 (19.11.2010): 4807. http://dx.doi.org/10.1182/blood.v116.21.4807.4807.

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Abstract Abstract 4807 Background: Pica defined as a compulsive and persistent intake of inedible substances or atypical food combinations at least one month. Association of pica and sickle cell disease (SCD) are poorly documented. Alerted by parents, we decided to verify systematically a) the occurrence of pica in SCD children b) to determine its duration, c) to identify the substances commonly ingested and d) to determine the characteristics among children and adolescents with SCD who reported practicing pica. Methods: SCD patients were seen in the outpatient clinic at the University Children's Hospital Queen Fabiola at Brussels between May 1, 2010 and July 30, 2010 as part of their regular follow-up. Data on sex, age, weight, height, body mass index, sickle cell phenotype, G6PD deficiency as well as biological data such as hematocrit mean corpuscular volume, fetal hemoglobin, plasma iron, zinc, copper, lead levels were recorded from their medical chart. Parents and patients were interviewed for the presence of eating disorders. Children and care givers completed questionnaires assessing symptoms of pica. Patients with acute illness, pregnancy, developmental delay, cognitive impairment or age younger than 3 years were excluded. Student t-test was used for difference in mean values groups by pica presence or absence. Fisher exact test was used to compare categorical variable. Difference in means values were considered statistically significant at p < 0.05. Results: Fifty-Five patients (24 males and 31 females) with a median age of 8. 9 years (6. 7– 11. 3) were evaluated during the study period. Forty-five patients (81.8%) originate from Central Africa, 10.9% (6/55) from West Africa, 1.8 %(1/55) from respectively East Africa, Italy and 3.6% (2/55) have mixed origin. Fifty –two (94.5%) patients are homozygous for Hb S (Hb SS), 3 are SC and 1 has Sβ° thalassemia. Thirty-one patients (56.4%) reported an history of pica and during the study period 29.1% (16/55) reported practicing pica regularly. The mean age of patient with pica was 7. 4 years significantly lower than non-pica patients (p <0.05). Pica prevalence by substances ingested was 16 for amylophagia, 14 for paper and powder, 13 for geophagia, 7 for pencils and textiles, 5 for foam, 4 for soap, and 3 for hair. In 6 cases, there was a familial history of pica in non SS individuals. Except for the fact that the mean hematocrit was lower in pica patients compared to non-pica ones (p < 0.05), all the other biological variables were similar in both groups (p> 0.05) (Table 1). Iron status was identical. Lead overload was absent in the entire cohort. Hemolytic phenotype assessed by LDH was identical in both group and mild zinc deficiency was present in both groups. We did not observe difference due to hydroxyurée intake (p>0.05) Conclusion: In our study, pica appeared to have a very high prevalence in SCD children and adolescents. However, its etiology is still unknown. Except lower age and significant lower hematocrit value in pica patients when compared to non-pica ones, no differences in iron status, zinc deficiency or hematological parameters was found. The general health status evaluated by BMI was identical in both groups and the trend to more boys in the pica group is not significant. Further studies are necessary to establish the etiology of pica and its possible consequences on SCD. Disclosures: No relevant conflicts of interest to declare.

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Swain, Samabesh. "An asymptomatic case of intracorneal graphite particles following pencil injury since 30 years". Indian Journal of Ophthalmology - Case Reports 4, nr 2 (kwiecień 2024): 591–92. http://dx.doi.org/10.4103/ijo.ijo_2968_23.

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Reports of graphite pencil lead injuries to the eye are rare. Although graphite is considered to remain inert in the eye, it has been known to cause severe inflammation and damage to ocular structures. We report a case of a 35-year-old lady with intracorneal graphite foreign bodies following a graphite pencil injury in childhood.

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Vishnu, Nandimalla, Mansi Gandhi, Sushmee Badhulika i Annamalai Senthil Kumar. "Tea quality testing using 6B pencil lead as an electrochemical sensor". Analytical Methods 10, nr 20 (2018): 2327–36. http://dx.doi.org/10.1039/c8ay00557e.

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Gormley, Rachel H., Stephen J. Kovach i Paul J. Zhang. "Role for trauma in inducing pencil “lead” granuloma in the skin". Journal of the American Academy of Dermatology 62, nr 6 (czerwiec 2010): 1074–75. http://dx.doi.org/10.1016/j.jaad.2009.02.027.

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Sakač, Nikola, Maja Karnaš, Marija Jozanović, Martina Medvidović-Kosanović, Sanja Martinez, Jelena Macan i Milan Sak-Bosnar. "Determination of anionic surfactants in real samples using a low-cost and high sensitive solid contact surfactant sensor with MWCNTs as the ion-to-electron transducer". Analytical Methods 9, nr 15 (2017): 2305–14. http://dx.doi.org/10.1039/c7ay00099e.

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Küçüközer, Asuman. "Teaching the Factors Affecting Resistance Using Pencil Leads". Physics Teacher 53, nr 1 (styczeń 2015): 38–40. http://dx.doi.org/10.1119/1.4904242.

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Chatree, Kamonwan, i Albert Schulte. "Dip-coated carbon nanotube surface deposits as stable, effective response enhancers in pencil lead electrode voltammetry". RSC Advances 13, nr 46 (2023): 32672–80. http://dx.doi.org/10.1039/d3ra05688k.

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Presented is a simple and sustainable tactic for the adaptation of low-cost pencil lead electrodes with a carbon nanotube deposit that markedly enhances their electrochemical redox response as sensors for voltammetry and amperometry.

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