Stretching necklaces

Polyelectrolytes in poor solvents show a necklace structure where collapsed polymer pearls are linked to stretched strings. In the present paper the elasticity of such chains is studied in detail. Different deformation regimes are addressed. The first is the continuous regime, where many pearls are present. A continuous force extension relation ship is calculated. The main contribution comes from the tension balance and the electrostatic repulsion of consecutive pearls. The main correction term stems from the finite size of the pearls, which monitors their surface energy. For a finite amount of pearls discontinuous stretching is predicted. Finally counterion effects are discussed qualitatively.Comment: to appear in European Phys. Journal E (soft matter

Pearl oyster farming and pearl production

Natural pearls were the oldest gems known to mankind. Long before man discovered the diamond and other precious stones, pearls were considered to be the first precious gem. The Vedas of India, the Bible and the Quran make several reference of pearls as objects of adoration and worship. The natural pearls of the Gulf of Mannar and the Persian Gulf enjoyed very good reputation in the world trade from the time immemorial. The Gulf of Mannar pearls are famous throughout the world as 'Orient Pearls'

Onshore [land Based] Culture of Pearl Oysters for Pearl Production

Marine pearls are precious and are the most attractive objects of adoration. Pearls are most revered biological products from time lmmemorial. Pearls have been extolled as a metaphor of life for virtue, love, wisdom and justice, spirituality and righteousness. The occurrence and use of pearls have a history more ancient and more fascinating than any other precious objects

Spatiogram features to characterize pearls in paintings

Objective characterization of jewels in paintings, especially pearls, has been a long lasting challenge for art historians. The way an artist painted pearls reflects his ability to observing nature and his knowledge of contemporary optical theory. Moreover, the painterly execution may also be considered as an individual characteristic useful in distinguishing hands. In this work, we propose a set of image analysis techniques to analyze and measure spatial characteristics of the digital images of pearls, all relying on the so called spatiogram image representation. Our experimental results demonstrate good correlation between the new metrics and the visually observed image features, and also capture the degree of realism of the visual appearance in the painting. In that sense, these results set the basis in creating a practical tool for art historical attribution and give strong motivation for further investigations in this direction

Marine pearl production

Pearls are harvested manually. Oysters are opened and pearls are squeezed out. In case 9,500 reuse, the pearls are removed carefully by opening the pearl- sac through the gonad without damaging it. The harvested pearls are washed in distilled water polished in refined salt and again washed in distilled wate

Evaluation of enamel pearls by cone-beam computed tomography (CBCT)

Objective: The aim of this study was to evaluate the frequency of enamel pearls according to population, sex and tooth groups on Cone-Beam Computed Tomography (CBCT) or Dental Volumetric Tomography (DVT) scans of patients, retrospectively. Study Design: In this study, 15185 teeth belonging to 768 patients, 430 female and 338 male, was performed cross-sectional examination by CBCT. The volumetric Computed Tomography used in the study is Newton FP based on flat-panel. The data were analyzed with Pearson chi-squared test. Results: Enamel pearls were detected in 36 subjects (4.69%). Of these enamel pearls, 19 were detected in male and 17 were in male. There was no statistically a significant association between prevalence of enamel pearls and sex. All of enamel pearls were detected in molar teeth, for prevalence 0.83%. Conclusion: All of enamel pearls are found upper and lower molar teeth, especially the most commonly in maxillary second and third molars. © Medicina Oral S. L

Hatchery production of Black-lip pearl oyster spat in the Andaman and Nicobar Islands: a success story

The lustrous black pearls produced by the black-lip pearl oysler Pinctada margaritifera in the inner surface its two shells have become one of the most valuable pearls on earth with prices ranging from a minimum of 100 US$and to a maximum of 10,000 US$ per pearl, in the case of those at exceptional and rare quality. Through the production of black pearls from Pinctada margaritifera, the island country of Tahili became the global leader in this business controlling 28.8% of the world market