scholarly journals Toward Unified pH of Saline Solutions

Water ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 2522
Author(s):  
Silvie Lainela ◽  
Ivo Leito ◽  
Agnes Heering ◽  
Gaëlle Capitaine ◽  
Bárbara Anes ◽  
...  

Fluctuations of pH in coastal systems are generally surveyed through potentiometric pH measurements. A new concept of a unified pH scale was introduced with the great advantage of enabling comparability of absolute values, pHabs, pertaining to any medium. Using water as an anchor solvent, yielding pHabsH2O, enables referencing the pHabs values to the conventional aqueous pH scale. The current work aims at contributing to implement pHabsH2O to saline solutions. To this purpose, differential potentiometric measurements, with a salt bridge of ionic liquid [N2225][NTf2], were carried out aiming at overcoming problems related to residual liquid junction potentials that affect the quality of such measurements. The ability to measure pHabsH2O with acceptable uncertainty was evaluated using Tris-Tris·HCl standard buffer solutions prepared in a background matrix close to the characteristics of estuarine systems (salinity of 20) as well as with NaCl solutions with ionic strength between 0.005 and 0.8 mol kg−1. The present study shows that for high ionic strength solutions, such as seawater, challenges remain when addressing the assessment and quantification of ocean acidification in relation to climate change. Improvements are envisaged from the eventual selection of a more adequate ionic liquid.

1988 ◽  
Vol 41 (10) ◽  
pp. 1523 ◽  
Author(s):  
A Berne ◽  
O Popovych

Transfer activity coefficients of the tetraalkylammonium ions, logmγR, where R+ = Me4N+, Et4N+, Pr4N+ and Bu4N+, and of the picrate ion, logmγPic, between pairs of dipolar aprotic solvents, S1 → S2, were evaluated by combining the e.m.f . of cells Ag(cryst.)|AgClO4|RX|AgClO4|Ag( cryst .)�������������������������������� S1 ������ S2with the calculated liquid-junction potentials, Ej. The salt-bridge electrolyte RX was RClO4 and R Pic for the determinations of logmγR and logmγPic, respectively, and the solvents were: acetonitrile ( MeCN ), N,N- dimethylformamide (HCONMe2), dimethyl sulfoxide (Me2SO) and propylene carbonate ( pcar ). The logmγR values showed a systematic variation with the AgClO4 concentration, apparently caused by the concentration dependence of the solvent component of the liquid-junction potential, Ej,s, neglected in the calculations. However, the above concentration dependence was virtually eliminated from the values of logmγPic when they were calculated with the aid of our concentration-dependent logmγR data. For a number of our cells it was possible to evaluate the Ej,s, with the aid of literature data. The solvent component of Ej was found to be appreciable and varied both with the AgClO4 and the RX concentration. The Ej,s, was particularly large for cells containing pcar , with a maximum of -172 mV for the pcar | MeCN junction.


2016 ◽  
Vol 15 ◽  
pp. 163-171
Author(s):  
M. G. Shcherbakovskiy

The article discusses the reasonsfor an expert to participate in legal proceedings. The gnoseological reason for that consists of the bad quality of materials subject to examination that renders the examination either completely impossible or compromises objective, reasoned and reliable assessment of the findings. The procedural reason consists ofa proscription for an expert to collect evidence himself or herself. The author investigates into the ways of how an expert can participate in legal proceedings. If the defense invites an expert to participate in the proceedings, then it is recommended that his or her involvement should be in the presence of attesting witnesses and recorded in the protocol. In the course of the legal proceedings an expert has the following tasks: adding initial data, acquiring new initial data, understanding the situation of the incident, acquiring new objects to be studied, including samples for examination. An expert’s participation in legal proceedings differs from the participation of a specialist or an examination on the scene of the incident. The author describes the tasks that an expert solves in the course of legal proceedings, the peculiarities ofan investigation experiment practices, the selection of samples for an examination, inspection, interrogation.


2019 ◽  
Vol 9 (01) ◽  
pp. 47-54
Author(s):  
Rabbai San Arif ◽  
Yuli Fitrisia ◽  
Agus Urip Ari Wibowo

Voice over Internet Protocol (VoIP) is a telecommunications technology that is able to pass the communication service in Internet Protocol networks so as to allow communicating between users in an IP network. However VoIP technology still has weakness in the Quality of Service (QoS). VOPI weaknesses is affected by the selection of the physical servers used. In this research, VoIP is configured on Linux operating system with Asterisk as VoIP application server and integrated on a Raspberry Pi by using wired and wireless network as the transmission medium. Because of depletion of IPv4 capacity that can be used on the network, it needs to be applied to VoIP system using the IPv6 network protocol with supports devices. The test results by using a wired transmission medium that has obtained are the average delay is 117.851 ms, jitter is 5.796 ms, packet loss is 0.38%, throughput is 962.861 kbps, 8.33% of CPU usage and 59.33% of memory usage. The analysis shows that the wired transmission media is better than the wireless transmission media and wireless-wired.


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