TO THE PROBLEM OF APPLICABILITY OF THE TAMMAN TEMPERATURE CONCEPT TO NANOSIZED OBJECTS: TO THE 160TH ANNIVERSARY OF GUSTAV TAMMAN

Во введении представлен краткий критический обзор имеющихся интерпретаций температуры Таммана, обычно определяемой как T = 0,5T, и температуры Хюттига T = 0,3T, где T - макроскопическое значение температуры плавления материала. Для наночастиц предложено в указанных выше определяющих соотношениях заменить T на температуру плавления малого объекта T, т.е. определить T как 0,5T, а T как 0,3T. В молекулярно-динамических экспериментах на наночастицах Au, осуществленных с помощью LAMMPS, было установлено, что при температуре T=T как в центральной части ГЦК-наночастицы, так и в её поверхностном слое возникают локальные очаги квазикристаллической структуры, которые попеременно идентифицируются программой OVITO то как имеющие кристаллическую структуру, то как не имеющие кристаллической упорядоченности. Однако, вопреки мнению Э. Рукенштейна (1984), при T=T жидкий слой на поверхности кристаллической наночастицы еще не образуется. Вместе с тем в наших молекулярно-динамических экспериментах не обнаружено какое-либо проявление температуры Хюттига T в структуре кристаллических наночастиц Au. The introduction provides a brief critical review of the available definitions and interpretations of the Tamman temperature, usually defined as T = 0,5T, and of the Hüttig temperature T = 0,3T where T is the macroscopic value of the melting point of the material. For a nanoparticle we propose to replace in the above relations T by the melting temperature of the small object T , i.e. to define T as 0,5T and T as 0,3T . In our molecular dynamics experiments on Au nanoparticles, carried out using the LAMMPS program, we found that at the temperature T = T , in both the central part of the fcc nanoparticle (the core) and in its surface layer (the shell), some local species of a quasicrystalline structure appear which are alternately identified either as crystalline or as non-crystalline by the OVITO program. However, contrary to opinion of E. Rukenstein (1984), at T = T , a liquid layer on the surface of the crystalline nanoparticle is not formed yet. However, a liquid-like layer was gradually developed in the course of the further temperature elevation. At the same time, in our molecular dynamics experiments we did not reveal any manifestation of the Huttig temperature T in the structure of crystalline Au nanoparticles reproduced in our molecular dynamics experiments. It is also of interest that in our molecular dynamics experiments the nanoparticle sintering took place not only above the Tammann temperature but below it as well.

Could Pine Wood Nematode (Bursaphelenchus xylophilus) Cause Pine Wilt Disease or Even Establish inside Healthy Trees in Finland Now—Or Ever?

Pine wilt disease (PWD) caused by the pine wood nematode (PWN, Bursaphelenchus xylophilus) can, in suitable conditions, lead to mass mortality of susceptible trees. In the European Union, PWN is a quarantine pest. To support PWN risk management in Finland, we assessed the suitability of the Finnish present and future climate for both PWD and PWN establishment inside susceptible healthy trees. The former was done using the mean summer temperature concept and the latter by relating annual growing degree days to the likelihoods of PWN extinction and establishment inside healthy trees. The likelihoods were derived from the previously published modelling of PWN population dynamics for 139 locations in Germany. Both assessments were conducted using 10 × 10 km resolution climate data from 2000–2019 and Finland-specific climate change projections for 2030–2080. The results indicate that the present Finnish climate is too cool for both PWD and PWN establishment inside healthy trees. Furthermore, even global warming does not appear to turn the Finnish climate suitable for PWD or PWN establishment inside healthy trees by 2080, except under the worst-case representative concentration pathway scenario (RCP8.5). Consequently, giving top priority to PWN when allocating resources for biosecurity activities in Finland might deserve reconsideration.

Effectiveness of Adapted Science Instruction for Teaching Learning of Science Temperature Concept among Students with Visual Impairment

The areas of science and mathematics have traditionally been inaccessible to students with Visual Impairment. Hence it needs adapted materials and instructional methods to understand and perform science experiments by visually impaired. This study aims to study the Effectiveness of Adapted Science Instruction on Leaning of Science Temperature Concept among students with Visual Impairment. The Investigator adapted the Science Temperature concept Activities as per the needs of Students with Visual Impairment. Visually Impaired sample from Grade VI to VIII were trained and effectivess of the Adapted Instruction was found.

Use of Islamic and Local Wisdom Textbook to Train the Religious Character of Prospective Physics Teachers

The research aims to describe the religious character and cognitive competence of physics prospective teachers when they used textbook containing Quranic verses. The Quranic verses were relevant to heat and temperature concept then also relevant to local wisdom of South Kalimantan. The research used to research and development, with the development model of ADDIE. The subjects of this research were 18 students of the 2019/2020 academic year who learned heat and temperature topic in Fundamental of Physics 1 course. The data were obtained through a self-evaluation inventory sheet, observation sheet, and test. The data were analysed quantitatively and qualitatively. The result of the research showed that the religious characters of physics prospective teachers from A1 to A5 domain have average score 4.69 which are in very good category and their cognitive competence of C2 to C6 domain improve quite effectively with average normalised gain 0.68. The conclusion of this research is the textbook can be used to train physics prospective teachers to do religious behaviour.

Fundamental limitations of the mode temperature concept in strongly coupled systems

We theoretically analyze heat exchange between two quantum systems in interaction with external thermostats. We show that in the strong coupling limit the widely used concept of mode temperatures loses its thermodynamic foundation and therefore cannot be employed to make a valid statement on cooling and heating in such systems; instead, the incorrectly applied concept may result in a severe misinterpretation of the underlying physics. We illustrate these general conclusions by discussing recent experimental results reported on the nanoscale heat transfer through quantum fluctuations between two nanomechanical membranes separated by a vacuum gap.

Minimum Net Driving Temperature Concept for Membrane Distillation

In this study, we analyzed the heat requirement of membrane distillation (MD) to investigate the trade-off between the evaporation efficiency and driving force efficiency in a single effect MD system. We found that there exists a non-zero net driving temperature difference that maximizes efficiency. This is the minimum net driving temperature difference necessary for a rational operational strategy because below the minimum net driving temperature, both the productivity and efficiency can be increased by increasing the temperature difference. The minimum net driving temperature has a similar magnitude to the boiling point elevation (~0.5 °C for seawater), and depends on the properties of the membrane and the heat exchanger. The minimum net driving temperature difference concept can be used to understand the occurrence of optimal values of other parameters, such as flux, membrane thickness, and membrane length, if these parameters are varied in a way that consequently varies the net driving temperature difference.

An Exploration of Students’ Mental Models on Heat and Temperature: A Preliminary Study

The mental models are internal representation possessed by students when learning a concept. This study is intended to explore students’ mental models on Heat and Temperature concept. This research was conducted on 11th grade students of Science program (N = 60) at one senior public school in Malang. Data were collected through open-ended questions and analyzed using the SSI method, which consisted of three levels of mental models. Based on the results, most of the students are still at the synthetic level. In addition, some differences of the students in visualizing the state of solid atoms during expansion, direction of heat conduction, and direction of heat convection. The future study is expected to explore the mental models of students in other topics of Physics education and make use of appropriate learning models to increase students’ mental models.