45 research outputs found
Thermodynamically Traceable Calorimetric Results for Aqueous Sodium Chloride Solutions from T = (273.15 to 373.15) K up to the Saturated Solutions: Part 1—The Quantities Associated with the Partial Molar Enthalpy
No full textPublisher Copyright: © 2023, The Author(s).The three-parameter extended Hückel equations with parameters B, b 1, and b 2 have recently been successfully tested against existing vapor pressure, electrochemical, and solubility data for aqueous NaCl solutions at temperatures from (273 to 373) K (Partanen and Partanen in J. Chem. Eng. Data 65:5226–5239, 2020). In the present study, we extend this model to the apparent and partial molar enthalpy data of these solutions. The enthalpy equations were determined using a new calculation method that gives practically the same results as that used in another previous study (Partanen et al. in J. Chem. Eng. Data 62:2617–2632, 2017), but the new method is much simpler. In the previous enthalpy study, dilute NaCl solutions up to m = 0.2 mol⋅kg−1 were considered in the range from T = 273 to 353 K. Following the success of the three-parameter extended Hückel model within the whole concentration range at various temperatures, we tabulate new values for relative apparent and partial molar enthalpies for NaCl solutions at rounded molalities. The resulting values are extensively tested against the literature ones. The best agreement is obtained for temperatures below 288 K and between 313 and 353 K. Elsewhere, at least a reasonable agreement is obtained. As no enthalpy or heat capacity data were used in the estimation of our model’s parameters and as the model has excelled in explaining other high-precision thermodynamic data, we argue that the recommended enthalpy values should be preferred even for the temperatures where the agreement is only reasonable due to potential problems associated with the literature values. These problems are also considered in the study.Peer reviewe
Thermodynamically Traceable Calorimetric Results for Dilute Aqueous Potassium Chloride Solutions at Temperatures from (273.15 to 373.15) K. Part 1. The Quantities Associated with the Partial Molar Enthalpy
No full textIn our previous study (Partanen,
J. I.; Partanen, L. J.; Vahteristo,
K. P., J. Chem. Eng. Data 2019, 64, 16–33), we presented a fully traceable two-parameter
Hückel equation with parameters B and b1 for activity and osmotic coefficients in dilute
KCl(aq) in the temperature range of (273.15 to 383.15) K. This equation
applies within experimental error to almost all thermodynamic data
in the literature at least up to a molality of 0.2 mol·kg–1. In our Hückel model, parameter B is treated as a constant, whereas parameter b1 depends quadratically on the temperature. In the present
study, the same model is applied to the molar enthalpies of the components
in KCl solutions. No new parameter estimations are necessary for the
treatment of these calorimetric data. We also extend now the previous
enthalpy results for dilute NaCl solutions (see Partanen, J. I.; Partanen,
L. J.; Vahteristo, K. P., J. Chem. Eng. Data 2017, 62, 2717–2632) up to 373 K because
in that study the treatment of calorimetric data was limited only
up to 353 K. In a future publication (Part 2 of this study), it will
be shown that this Hückel model applies additionally well to
the heat-capacity literature available for dilute KCl solutions. Here,
we also consider a second parametrization of the Hückel equation
for KCl solutions obtained in a previous work (Partanen, J. I., J. Chem. Eng. Data 2016, 59, 286–306). This is seen to apply better to enthalpy data
in less dilute KCl solutions up to the saturated solutions in the
range of (298 to 303) K. However, the alternative parametrization
is not fully traceable and not as accurate as our primary one. Following
the success of these Hückel models, we supplement the thermodynamic
tables for KCl solutions with the relative apparent and partial molar
enthalpies of KCl in these solutions from (273.15 to 373.15) K. We
also give here the values of these quantities for NaCl in dilute aqueous
NaCl solutions at 373.15 K. We have good reason to believe that the
new tables contain the most reliable values available for the enthalpy
quantities of dilute NaCl and KCl solutions
Thermodynamically Traceable Calorimetric Results for Dilute Aqueous Potassium Chloride Solutions at Temperatures from 273.15 to 373.15 K. Part 2. The Quantities Associated with the Partial Molar Heat Capacity
No full textIn previous articles (Partanen et al. J. Chem. Eng. Data 2019, 64, 16-33 and Partanenet al. J. Chem. Eng. Data 2019, 64, 2519-2535), we presented traceable and transparent two-parameter Hückel equations (with parameters B and b1) for the activity coefficients of the salt and for the osmotic coefficients of water in aqueous KCl solutions in the temperature range of 273.15-383.15 K. The latter article is the first part (Part 1) of the calorimetric study. We showed in these articles that our equations for these solutions explain within experimental error the literature data on almost all thermodynamic quantities including the partial molar enthalpies at least up to a molality of 0.2 mol·kg-1 and up to 373 K. In this model, parameter B is regarded as a constant but parameter b1 has a quadratic temperature dependence. No calorimetric data were needed in the parameter estimation. In the second part (Part 2) of the calorimetric study, now, the results obtained for the heat capacity quantities of KCl (aq.) are considered. We show here that all heat capacity literature available for KCl solutions at least up to 0.5 mol·kg-1 is possible to explain within experimental error using exactly the same Hückel equations as those considered previously in our studies for dilute KCl solutions from 273 to 373 K. Because of the success of the used model, we supplement the existing thermodynamic tables with new values for the relative apparent and partial molar heat capacities for KCl solutions. It is likely that the new tables contain the most reliable values available for these heat capacity quantities.Peer reviewe
A Guided Inquiry Learning Design for a Large-Scale Chemical Thermodynamics Laboratory Module
No full textPublisher Copyright: © 2022 The Author. Published by American Chemical Society and Division of Chemical Education, Inc.In this action research study, I propose a guided inquiry alternative to the traditional physical chemistry laboratory module where the equilibrium constant of acetic acid is determined conductometrically. I complement the guided inquiry structure with a 360° feedback support framework for the preparation and assessment of a laboratory report. The new laboratory module showed great promise, improving both report marks and student experiences. Diligent training of teaching assistants, ample availability of formative feedback, and reservation of sufficient time for the guided inquiry activities were identified as key contributors for the success of the module.Peer reviewe
Kulttuurihistoriallisten arkistoaineistojen elinkaarta läpivalaisemassa
No full textArvio teoksesta Hupaniittu, Outi & Ulla-Maija Peltonen toim. Arkistot ja kulttuuriperintö. Suomalaisen Kirjallisuuden Seura. 2021. 263 s. ISBN 978-951- 858-282-6.nonPeerReviewe
Yksityisarkistojen kriittistä tarkastelua
No full textArvio teoksesta Karhu, Hanna, Katri Kivilaakso & Viola Parente-Čapková, toim. Tutkimuspolkuja yksityisarkistoihin. Aineistot historian, kulttuurin ja kirjallisuuden tutkimuksessa. SKS. 2024. 443 s. ISBN 978-951-858-876-7.nonPeerReviewedei tietoa saavutettavuudestaunknown accessibilit
Traceable Values for Activity and Osmotic Coefficients in Aqueous Sodium Chloride Solutions at Temperatures from 273.15 to 373.15 K up to the Saturated Solutions
No full textWe present traceable three-parameter extended Hückel equations for the activity coefficient of sodium chloride and for the osmotic coefficient of water in aqueous NaCl solutions from 273.15 to 373.15 K. In this temperature range, our equations seem to apply within experimental error to all thermodynamic data available for these solutions up to the molality of the saturated solution. Our previous studies (J. Chem. Eng. Data 2017, 62, 2617-2632 and 2019, 64, 16-33) showed that, from 273.15 to 373.15 K, two-parameter Hückel equations can successfully explain the literature results of electrochemical, isopiestic, and cryoscopic measurements at least up to a molality of 0.2 mol·kg-1. The model recommended in this study employs the values of our previous two-parameter model for the ion-size parameter in the original Debye-Hückel equation, B, and for the coefficient of the linear term with respect to the molality, b1. In addition, it includes a quadratic term with respect to the molality with the coefficient b2. Both b1 and b2 are quadratically dependent on temperature. With the introduction of b2, our model is able to explain the existing vapor pressure, electrochemical, and solubility data from 273.15 to 373.15 K up to the saturated solution. A comparison with the most important literature values for the activity and osmotic coefficients revealed that the agreement is always at least satisfactory, but is best for temperatures below 363 K. On the basis of these results, our activity and osmotic coefficients are the most reliable values for these thermodynamic quantities so far. We propose this is true also for the values from 363 to 373 K.Peer reviewe
Corrigendum to: Consensus framework for conducting phase I/II clinical trials for children, adolescents, and young adults with pediatric low-grade glioma: Guidelines established by the International Pediatric Low-Grade Glioma Coalition Clinical Trial Working Group
No full textThis is a corrigendum to: Sabine Mueller, Jason Fangusaro, Arzu Onar Thomas, Thomas S Jacques, Pratiti Bandopadhayay, Peter de Blank, Roger J Packer, Maryam Fouladi, Antoinette Schouten van Meeteren, David Jones, Arie Perry, Yoshiko Nakano, Darren Hargrave, David Riedl, Nathan J Robison, Marita Partanen, Michael J Fisher, Olaf Witt, Consensus framework for conducting phase I/II clinical trials for children, adolescents, and young adults with pediatric low-grade glioma: Guidelines established by the International Pediatric Low-Grade Glioma Coalition Clinical Trial Working Group, Neuro-Oncology, 2023;, noad227, https://doi.org/10.1093/neuonc/noad227.
In the originally published version of this manuscript, there was an error in the spelling of author Nathan J Robison’s name. This has been corrected
Morphologic and functional correlates of synaptic pathology in the cathepsin D knockout mouse model of congenital neuronal ceroid lipofuscinosis
No full textMutations in the cathepsin D (CTSD) gene cause an aggressive neurodegenerative disease (congenital neuronal ceroid lipofuscinosis) that leads to early death. Recent evidence suggests that presynaptic abnormalities play a major role in the pathogenesis of CTSD deficiencies. To identify the early events that lead to synaptic alterations, we investigated synaptic ultrastructure and function in presymptomatic CTSD knockout (Ctsd) mice. Electron microscopy revealed that there were significantly greater numbers of readily releasable synaptic vesicles present in Ctsd mice than in wild-type control mice as early as postnatal day 16. The size of this synaptic vesicle pool continued to increase with disease progression in the hippocampus and thalamus of the Ctsd mice. Electrophysiology revealed a markedly decreased frequency of miniature excitatory postsynaptic currents (mEPSCs) with no effect on paired-pulse modulation of the evoked excitatory post synaptic potentials in the hippocampus of Ctsd mice. The reduced mEPSCs frequency was observed before the appearance of epilepsy or any morphologic sign of synaptic degeneration. Taken together, these data indicate that CTSD is required for normal synaptic function and that a failure in synaptic trafficking or recycling may bean early and important pathologic mechanism in Ctsd mice; these presynaptic abnormalities may initiate synaptic degeneration in advance of subsequent neuronal loss
A Guided Inquiry Learning Design for a Large-Scale Chemical Thermodynamics Laboratory Module
No full textIn this action research study, I propose a guided inquiry
alternative
to the traditional physical chemistry laboratory module where the
equilibrium constant of acetic acid is determined conductometrically.
I complement the guided inquiry structure with a 360° feedback
support framework for the preparation and assessment of a laboratory
report. The new laboratory module showed great promise, improving
both report marks and student experiences. Diligent training of teaching
assistants, ample availability of formative feedback, and reservation
of sufficient time for the guided inquiry activities were identified
as key contributors for the success of the module
