The present work aimed to study the efficiency of nanofiltration (NF) and reverse osmosis (RO) process for water recovery from electroplating wastewater and study the factors affecting the performance of two membrane processes. Nanofiltration and reverse osmosis membranes are made from polyamide as spiral wound module. The inorganic materials ZnCl2, CuCl2.2H2O, NiCl2.6H2O and CrCl3.6H2O were used as feed solutions. The operating parameters studied were: operating time, feed concentrations for heavy metal ions, operating pressure, feed flow rate, feed temperature and feed pH. The experimental results showed, the permeate concentration increased and water flux decreased with increase in time from 0 to 70 min. The permeate concentrations increased and flux decreased with increase in feed concentrations from 10 to 300 mg/l. Raising of pressure from 1 to 4 bar, permeate concentration decreased for RO, for NF decreased and then increased at high pressure and increase the flux. The rises of flow rate from 20 to 50 l/h decreased permeate concentration and the flux increase. The rises of temperature from 26 to 40 °C, increased permeate concentration and increased the flux. The rise in pH from 4 to 7, decreased the flux as the pH goes from acidic side towards alkaline. The polyamide nanofiltration membrane had allowed permeation of chromium and copper ions to lower than permissible limits. Nanofiltration membrane had allowed permeation of nickel and zinc ions at low concentration of these ions. The polyamide RO membrane gave a high efficiency for removal of chromium, copper, nickel and zinc and it had allowed permeation of these ions to the lower than permissible limits. The rejection at first three minutes when the feed concentration approximately was constant for chromium in NF and RO, was 99.7% and 99.93%, for copper was 98.43% and 99.33%, for zinc was 97.96% and 99.49%, and for nickel was 97.18% and 99.49% respectively. The maximum recovery for chromium in NF and RO was 71.75% and 48.5%, for copper was 75.62% and 50.68%, for zinc was 80.87% and 54.56%, for nickel was 60.06% and 46.18% respectively. For a mixture of synthetic electroplating wastewater, nanofiltration and reverse osmosis membranes have a high rejection percentage for heavy metal ions. It was obtained pure water and concentrations of less than allowable limits for heavy metals in the case of the mixture.
Precarity means the lack of social and economic networks; a considerable exposure to danger and harm. Minority groups are precariat for they lack rights and full citizenship. Precarity is related, states Judith Butler, with the individual’s performativity, and his ability to perform his gender role. Toni Morrison continually goes to past to retell the history of African Americans. The issues of race, gender and national identity are recurrent in her work. Reading her book Home (2012) evokes the idea of precarity and performativity since the two main characters, Frank and Cee are precarious characters that fail to perform their gender role properly, and eventually are exposed to hazard and harm. This research displays how African American
... Show MoreObjectives: To review the failure rates of molar tubes and the effect of molar tube base design, adhesive type, and bonding technique on the failure rates of molar tubes. Data: The revolution of molar bonding greatly impacted fixed orthodontic appliance treatment by reducing chair-side time and improving patient comfort. Even with the many advantages of molar bonding, clinicians sometimes hesitate to use molar tubes due to their failure rates. Sources: Internet sources, such as Pubmed and Google Scholar. Study selection: studies testing the bond failure rate of molar tubes. Conclusions: The failure rate of the molar tubes can be reduced and the bond strength of the molar tubes can be improved by changing the design of the molar tube base
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In mammals, the kidneys originate in an embryo from the mesoderm through three excretory organs, namely: Pronephros, Mesonephros, and Metanephros. After the formation of Metanephros is completed, the kidneys begin to form nephrogenesis through mesenchymal cells located at the tip of the ureteric bud, that contribute in the formation of glomerulus and Renal tubules. The stages of glomerulus formation in the embryo of albino mice at the age of 14 to 19 days of gestation were studied. It was obtained after the sacrifice of the expectant mother and the kidneys were excised from the embryos and fixed using Aqueous Bouin's solution, Microscopic slices with a thick
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Background: Acute myocardial infarction
(AMI) is one of the most common diagnoses
in hospitalized patients. The stimulus that
initiates the acute inflammatory process in AMI
has not been identified. Conventional risk
factors account only for approximately half of
the patients with clinically apparent
atherosclerosis which can leads to AMI.
Recently a potential link between infectious
agents and atherosclerosis has been suggested
Objective: To find a possible association
between Helicobacter pylori (H. Pylori)
infection and AMI.
Method: We studied the prevalence of antiH. pylori antibodies in 94 patients who were
admitted with the diagnosis of AMI and a
similar number of healthy individuals w
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The research deals with the global ceramic achievement within the international forums in the past decades. As follows، showing and presenting the aesthetic and intellectual values leading to common constants that establish international artistic studies that achieve the purpose of circulation and marketing of artworks. Contemporary global plastic art has witnessed a number of technical and social transformations and changes at the technical and pragmatic levels under the pressure of the changing and accelerating tide towards technical، cognitive، social and cultural concepts.
The second chapter came to the first topic: deliberative and commoditization، and the second topic: the deliberativeness of contemporary global ceramics.
The concept of tolerance is gaining its importance in the midst of an international society suffering from violence, wars and internal and international crises. It is practiced by extremist and extremist forces and movements acting in the name of religion to exclude the different Muslim and non-Muslim people according to the unethical practices and methodologies of Islamic law and reality. , Cultural, civilization .. that distinguish our world today. The society today is suffering from the ideas of the intellectual and aesthetic views of the different ideologically, ethnically, culturally and religiously in the world of the South. This is what the end-of-history thesis of Fukuyama and the clash of civilizations represented to Huntington.
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Crimes are prohibited by law and God Almighty has forbidden them with punishment or punishment.
The punishment is the prescribed punishments that the law has determined in its place and stipulated in the Book of God or the Sunnah of His Prophet, may God bless him and grant him peace.
Ta’zir: These are the punishments that are left to the ruler to assess according to what he sees as preventing corruption on earth and preventing evil. Extrapolation has proven that all the provisions of Islamic Sharia include the interests of the people, and they are based on five matters: what is in it is preserving the religion, what is in it is preserving the soul, and what is in it is preserving the soul. It involves preserving the mind, preserv