scholarly journals Pyrite (FeS2)-supported ultrafiltration system for removal of mercury (II) from water

2021 ◽  
Author(s):  
Dong Suk Han ◽  
Kawsher M. D. Solayman ◽  
Ho Kyong Shon ◽  
Ahmed Abdel-Wahab
Keyword(s):  
Membrane Filter ◽  
Pyrite Surface ◽  
Ph Change ◽  
Filtration Process ◽  
Sem Images ◽  
Flux Decline ◽  
Cake Layer ◽  
Water Effects ◽  
Almost All ◽  
Over Time

AbstractThis study investigated the Hg(II) removal efficiencies of the reactive adsorbent membrane (RAM) hybrid filtration process, a removal process that produces stable final residuals. The reaction mechanism between Hg(II) and pyrite and the rejection of the solids over time were characterized with respect to flux decline, pH change, and Hg and Fe concentration in permeate water. Effects of the presence of anions (Cl−, SO42−, NO3−) or humic acid (HA) on the rejection of the Hg(II)-contacted pyrite were studied. The presence of both HA and Hg(II) increased the rate of flux decline due to the formation of irreversible gel-like compact cake layers as shown in the experimental data and modeling related to the flux decline and the SEM images. Stability experiments of the final residuals retained on the membrane using a thiosulfate solution (Na2S2O3) show that the Hg(II)-laden solids were very stable due to little or no detection of Hg(II) in the permeate water. Experiment on the possibility of continuously removing Hg(II) by reusing the Hg/pyrite-laden membrane shows that almost all Hg(II) was adsorbed onto the pyrite surface regardless of the presence of salts or HA, and the Hg(II)-contacted pyrite residuals were completely rejected by the DE/UF system. Therefore, a membrane filter containing pyrite-Hg(II) could provide another reactive cake layer capable of further removal of Hg(II) without post-chemical treatment for reuse.

Globalization and interconfessional communications

2001 ◽  
pp. 13-17
Author(s):  
Serhii Viktorovych Svystunov
Keyword(s):  
21St Century ◽  
Global Economy ◽  
Modern World ◽  
The World ◽  
Target Set ◽  
Almost All ◽  
Over Time ◽  
Rapid Appearance

In the 21st century, the world became a sign of globalization: global conflicts, global disasters, global economy, global Internet, etc. The Polish researcher Casimir Zhigulsky defines globalization as a kind of process, that is, the target set of characteristic changes that develop over time and occur in the modern world. These changes in general are reduced to mutual rapprochement, reduction of distances, the rapid appearance of a large number of different connections, contacts, exchanges, and to increase the dependence of society in almost all spheres of his life from what is happening in other, often very remote regions of the world.

scholarly journals The Scenario of a Pandemic Spread of the Coronavirus SARS-CoV-2 is Based on a Statistical Fallacy

2020 ◽  
Author(s):  
Christof Kuhbandner
Keyword(s):  
Apparent Increase ◽  
Rapid Spread ◽  
Almost All ◽  
Over Time ◽  
Coronavirus Infections

In view of the rapidly increasing numbers of reported new coronavirus infections, many speak of an upcoming pandemic. However, since the number of conducted coronavirus tests has rapidly increased over time as well, the apparent increase in infections may actually reflect increased testing, rather than a rapid spread of the coronavirus. To examine this issue, data from Austria, Belgium, France, Germany, Italy, and USA were analyzed. In all countries, the rapid increase in reported new infections was largely attributable to the rapid increase in conducted tests. Statistically controlling for the increased amount of testing revealed that the increases in reported infections dramatically overestimate the true increases in every country. According to the estimated true courses of new infections, the increases were initially much smaller, and the courses of new infections have already flattened or are even decreasing since the beginning of calendar week 13 (March 23) in almost all countries. The courses of reported new infections and deaths started to increase almost simultaneously in every country, which further confirms that the increases in reported new infections reflect effects of increased testing. These results indicate that the scenario of a coronavirus pandemic is based on a statistical fallacy.<br>

scholarly journals Alleviation of Ultrafiltration Membrane Fouling by ClO2 Pre-Oxidation: Fouling Mechanism and Interface Characteristics

Membranes ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 78
Author(s):  
Bin Liu ◽  
Meng Wang ◽  
Kaihan Yang ◽  
Guangchao Li ◽  
Zhou Shi
Keyword(s):  
Natural Water ◽  
Membrane Fouling ◽  
Interaction Force ◽  
Interfacial Free Energy ◽  
Fouling Control ◽  
Membrane Flux ◽  
Flux Decline ◽  
Interface Characteristics ◽  
Cake Layer ◽  
Free Energy Analysis

In order to alleviate membrane fouling and improve removal efficiency, a series of pretreatment technologies were applied to the ultrafiltration process. In this study, ClO2 was used as a pre-oxidation strategy for the ultrafiltration (UF) process. Humic acid (HA), sodium alginate (SA), and bovine serum albumin (BSA) were used as three typical organic model foulants, and the mixture of the three substances was used as a representation of simulated natural water. The dosages of ClO2 were 0.5, 1, 2, 4, and 8 mg/L, with 90 min pre-oxidation. The results showed that ClO2 pre-oxidation at low doses (1–2 mg/L) could alleviate the membrane flux decline caused by humus, polysaccharides, and simulated natural water, but had a limited alleviating effect on the irreversible resistance of the membrane. The interfacial free energy analysis showed that the interaction force between the membrane and the simulated natural water was also repulsive after the pre-oxidation, indicating that ClO2 pre-oxidation was an effective way to alleviate cake layer fouling by reducing the interaction between the foulant and the membrane. In addition, ClO2 oxidation activated the hidden functional groups in the raw water, resulting in an increase in the fluorescence value of humic analogs, but had a good removal effect on the fluorescence intensity of BSA. Furthermore, the membrane fouling fitting model showed that ClO2, at a low dose (1 mg/L), could change the mechanism of membrane fouling induced by simulated natural water from standard blocking and cake layer blocking to critical blocking. Overall, ClO2 pre-oxidation was an efficient pretreatment strategy for UF membrane fouling alleviation, especially for the fouling control of HA and SA at low dosages.

Natural History Wet Collections: Observations on PH Readings from the Use of Different Ethanol and Label Types

2019 ◽  
Vol 33 (1) ◽  
pp. 7-17
Author(s):  
Ximo Mengual ◽  
France Gimnich ◽  
Hannah Petersen ◽  
Jonas J. Astrin
Keyword(s):  
Natural History ◽  
Tissue Samples ◽  
Daily Work ◽  
Starting Point ◽  
Good Starting Point ◽  
Research Questions ◽  
Almost All ◽  
Changes Over Time ◽  
Fluid Preservation ◽  
Over Time

Abstract We examined the effects of different types of specimen labels and tags on pH of different concentrations of ethanol typically used for fluid preservation in natural history collections. Labels were immersed in three different concentrations of ethanol, 96% pure undenatured ethanol (EtOH), 96% EtOH denatured with methyl-ethyl ketone (MEK), and 99.8% pure undenatured EtOH, with or without the presence of insect specimens, and the solutions were evaluated after 26 months for changes over time in pH reading. In general, pH readings of all label trials with 96% and 99.8% ethanol increased over time, except for trials of denatured alcohol, which demonstrated lower pH readings in almost all treatments, regardless of label type. Samples that contained labels with ordinary, nonstandardized, not explicitly acid-free printing paper had higher pH readings compared after the trial. Our observations are a good starting point for further experiments to answer research questions related to chemical interactions with labels in ethanol-preserved specimens, including tissue samples for molecular analyses, which can guide collection staff in their daily work.

“We Begin 300 Metres Behind the Starting Line”

2021 ◽  
Vol 11 (2) ◽  
Author(s):  
Sara Hosseini-Nezhad ◽  
Saba Safdar ◽  
Lan Anh Nguyen Luu
Keyword(s):  
International Students ◽  
Well Being ◽  
Psychosocial Adaptation ◽  
Structured Interviews ◽  
One Year ◽  
Iranian Students ◽  
Almost All ◽  
The Impact ◽  
Longitudinal Qualitative Research ◽  
Over Time

This longitudinal qualitative research aimed to investigate the psychosocial adaptation trajectory of Iranian international students in Hungary and the challenges they encountered. Semi-structured interviews were conducted at seven-month to one-year intervals with 20 Iranian students; inductive content analysis was utilized to analyze the interview transcripts. Three topics were identified: (1) visa and banking challenges, (2) the impact of the currency crisis in Iran on mental health, and (3) positive and negative changes in psychological well-being over time. The results revealed that almost all students’ well-being improved over time, despite facing challenges related to visas, banking, and Iran’s recent economic crisis (specifically, the drastic plunge of the Iranian currency).

Digital Transformation of E-Commerce Services and Cybersecurity for Modernizing the Banking Sector of Pakistan

2021 ◽  
pp. 373-403
Author(s):  
Tansif Ur Rehman
Keyword(s):  
Intellectual Property ◽  
Mobile Devices ◽  
Banking Sector ◽  
Digital Transformation ◽  
Financial Data ◽  
Digital Data ◽  
Sensitive Data ◽  
Medical Institutions ◽  
Almost All ◽  
Over Time

The practice of protecting computers, websites, mobile devices, electronic services, networks, and digital data from malicious attacks is known as cybersecurity. Since political, military, private, financial, and medical institutions collect, process, and maintain massive volumes of data on computers and other devices, cybersecurity is critical. Sensitive data, such as intellectual property, financial data, personal records, or other forms of data, can make up a large amount of the data. Improper access or disclosure to that data can have profound implications. Technology has undoubtedly made a significant change in every aspect of life in Pakistan, whether it is a financial or non-financial sphere. Technology's usage is thoroughly utilized by banks worldwide. They have started adopting it frequently because of the immense need to achieve goals and satisfy customer needs more efficiently. Almost all leading banks have now provided e-commerce facilities. Over time, more and more services and facilities are offered to bank customers conveniently via e-commerce products.

Idolatry

2018 ◽  
Author(s):  
Stephen Fowl
Keyword(s):  
Daily Life ◽  
Central Place ◽  
Ancient World ◽  
The Bible ◽  
Activities Of Daily Life ◽  
The Face ◽  
The One ◽  
Almost All ◽  
Over Time ◽  
The Invisible

The use of material images of various gods (idols) in religious worship has a long history and a central place in the polytheistic religions of the ancient world. The worship of these gods is strictly prohibited in Judaism, Christianity and Islam. This practice is generally referred to as idolatry. In addition, the making of images of the one God along with the use of such images in worship is also considered idolatry within these three monotheistic faiths. In the ancient societies within which Judaism, Christianity and, later, Islam emerged, almost all aspects of life were touched by the presence of idols. For a Jew (particularly in the diaspora) or a Christian to faithfully negotiate one’s way through the activities of daily life in such a world required sustained attentiveness and resolve. Over time, idolatry became more generally and metaphorically associated with ideas, motivations, beliefs and commitments that draw believers’ attention away from God. In some instances in Christianity, idolatry simply becomes a synonym for sin. Although it is not common today for Jews, Christians or Muslims to worship fabricated images of their own or other gods, some of the ongoing philosophical and theological issues concern how God’s creation can manifest the invisible God. In what ways, if any, can the created world mediate God truthfully to humans? Can such things as icons be instrumental in the worship of the one God without that worship being idolatrous? In recent French phenomenological writing, some of these issues receive attention. Although these concerns may seem distant from those of the Bible and Quran, they share a common recognition that idolatry stems from a failure of attentiveness, an inability or unwillingness to focus one’s attention and desire upon God in the face of myriad distractions.

scholarly journals EFFECT OF STERILIZATION BY HEATING IN THE PRESENCE OF BACTERICIDE AND BACTERIAL FILTERED MEMBRANE ON THE STABILITY OF EYE DROPS CONTAINING 0.5% CHLORAMPHENICOL AT VARIOUS pH

2019 ◽  
pp. 103-109
Author(s):  
SRI AGUNG FITRI KUSUMA ◽  
MARLINE ABDASSAH
Keyword(s):  
Room Temperature ◽  
Membrane Filter ◽  
Storage Period ◽  
Eye Drops ◽  
Percentage Reduction ◽  
Ph Change ◽  
Sterilization Method ◽  
Filter Membrane ◽  
The Stability ◽  
Antibacterial Potential

Objective: The purpose of this study was to determine a sterile 0.5% chloramphenicol eye drop formula with the best potency of antibacterial by determining the appropriate sterilization method and the supporting pH. Methods: 0.5% chloramphenicol was formulated with 0.01% thimerosal, which act as a bactericide and combines with borate buffer to produce eye drop formulas with variations in pH (6.8, 7.0 and 7.4). All formulas were stored at room temperature for 28 d and were evaluated, including: organoleptic of the preparations, sterility, pH stability, and the antibacterial potency of chloramphenicol in eye drops. Results: All dosage formulas did not undergo photodegradation reactions which were marked by no change in color until the end of the storage period. However, the formula with pH 6.8 which was sterilized by heating in a presence of bactericide, showed the presence of more particulate precipitates than in the pH 6.8 formula which was sterilized using membrane filter bacteria. However, both methods of sterilization produced sterile chloramphenicol eye drops. The preparation using a method of heat sterilization with bactericide decreased the pH greater than the preparation using a sterile bacterial filter sterilization method. C2 preparations at pH 7.0 and sterilized using the bacterial filter membrane sterilization method were more stable because they had the smallest pH change of 0.05 and the percentage reduction in antibacterial potential was smaller at 1.15%. Conclusion: The best treatment for the chloramphenicol eye drop was kept the pH formula at pH 7 and sterilized using bacterial filter membrane sterilization method.

Community-Level Interactions and Disease Dynamics

2021 ◽  
pp. 145-170
Author(s):  
Karen D. McCoy
Keyword(s):  
Local Area ◽  
Community Level ◽  
Disease Dynamics ◽  
Biological Communities ◽  
Natural Systems ◽  
Parasite Communities ◽  
Almost All ◽  
Host Parasite ◽  
Natural Communities ◽  
Over Time

An ecological community includes all individuals of all species that interact within a single patch or local area of habitat. Understanding the outcome of host–parasite interactions and predicting disease dynamics is particularly challenging at this biological scale because the different component species interact both directly and indirectly in complex ways. Current shifts in biodiversity due to global change, and its associated modifications to biological communities, will alter these interactions, including the probability of disease emergence, its dynamics over time, and its community-level consequences. Birds are integral component species of almost all natural communities. Due to their ubiquity and specific life history traits, they are defining actors in the ecology, evolution, and epidemiology of parasitic species. To better understand this role, this chapter examines the relative importance of birds and parasites in natural communities, revisiting basic notions in community ecology. The impact of changes in diversity for disease dynamics, including the debate surrounding dilution and amplification effects are specifically addressed. By considering the intrinsic complexities of natural communities, the importance of combining data from host and parasite communities to better understand how natural systems function over time and space is highlighted. The different elements in each section of the chapter are illustrated with brief, concrete examples from avian species, with a detailed example from marine bird communities in which Lyme disease bacteria circulate.

Three-Dimensional Simulation of Cross-Flow Microfilter Fouling in Tortuous Pore Profiles With Semisynthetic Metalworking Fluids

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
Bingyi Yu ◽  
Shiv G. Kapoor ◽  
Richard E. DeVor
Keyword(s):  
Colloidal Particles ◽  
Three Dimensional ◽  
Particle Trapping ◽  
Collision Model ◽  
Flux Decline ◽  
Cake Layer ◽  
Trapping Model ◽  
Wall Collision ◽  
Dimensional Simulation ◽  
Layer Development

Fouling mechanisms and models for flux decline are investigated with a three-dimensional simulation of the tortuous, verisimilar geometry of an α-alumina microfilter. Reconstruction of the three-dimensional geometry was accomplished from two-dimensional cross-sectional cuts. A wall collision model and a particle trapping model are developed for the investigation of fouling mechanisms. The reconstructed geometry and the two models were used in computational fluid dynamics to simulate metalworking colloidal particles travelling through and becoming trapped in the tortuous pore paths of a microfilter. Results reveal sharp flux decline initiating from partial pore blocking and subdued flux decline transitioning to cake layer development with steady-state flow. This flow behavior is in agreement with experimental data from earlier studies. The inclusion of the wall collision model and particle trapping model enabled the revelation of cake layer development as a fouling mechanism. Additional simulations of microfilters at different particle size distributions were conducted and discussed.

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