Search results

1

Generation of the vorticity mode by sound in a vibrationally relaxing gas

100%

Perelomova A., Wojda P.

Open Physics

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2012

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vol. 10

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issue 5

1116-1124

EN

The procedure of derivation of a new dynamical equation governing the vorticity mode that is generated by sound, is discussed in detail. It includes instantaneous quantities and does not require averaging over sound period. The resulting equation applies to both periodic and aperiodic sound as the origin of the vorticity mode. Under certain conditions, the direction of streamlines of the vorticity mode may be inverted as compared with that in a fluid with standard attenuation. This reflects an anomalous absorption of sound, when transfer of momentum of the vorticity mode into momentum of sound occurs. The theory is illustrated by a representative example of the generation of vorticity in a vibrationally relaxing gas in the field of periodic weakly diffracting acoustic beam.

2

Efficiency of acoustic heating produced in the thermoviscous flow of a fluid with relaxation

100%

Perelomova A., Pelc-Garska W.

Open Physics

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2010

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vol. 8

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issue 6

855-863

EN

Instantaneous acoustic heating of a fluid with thermodynamic relaxation is the subject of investigation. Among others, viscoelastic biological media described by the Maxwell model of the viscous stress tensor, belong to this type of fluid. The governing equation of acoustic heating is derived by means of the special linear combination of conservation equations in differential form, allowing the reduction of all acoustic terms in the linear part of the final equation, but preserving terms belonging to the thermal mode responsible for heating. The procedure of decomposition is valid for weakly nonlinear flows, resulting in the nonlinear terms responsible for the modes interaction. Nonlinear acoustic terms form a source of acoustic heating in the case of dominative sound, which reflects the thermoviscous and dispersive properties of a fluid. The method of deriving the governing equations does not need averaging over the sound period, and the final governing dynamic equation of the thermal mode is instantaneous. Some examples of acoustic heating are illustrated and discussed, conclusions about efficiency of heating caused by different sound impulses are made.

3

Exercise or Relaxation? Which is More Effective in Improving the Emotional State of Pregnant Women?

100%

Guszkowska M., Sempolska K., Zaremba A., Langwald M.

Human Movement

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2013

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vol. 14

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issue 2

168-174

EN

Purpose The aim of this study was to compare the changes in emotional states in pregnant women after completing a relaxation session and a one-off physical exercise class. Methods. The study included 139 pregnant women between the ages of 22 to 34 years (28.59 ± 2.99 years) in their second and third trimesters of pregnancy who were participating in one of three programs: a progressive relaxation course, a physical exercise program, or a traditional childbirth education program (control group). Emotional states were assessed by McNair, Lorr, and Droppleman’s Profile of Mood States immediately before (pre-test) attending their seventh respective class and then immediately after finishing it (post-test) Results. The pre-test emotional state of participants in all three groups was similar. Post-test, both the exercise and relaxation groups featured significantly improved emotional states, with the changes greater than those of women who attended the prenatal class. Pregnant women who participated in physical exercise were less troubled and tense and characterized by a higher level of vigor than the control group. Conclusions. Physical exercise may be especially helpful in coping with fatigue and feeling tired, while relaxation training is more beneficial for women with elevated levels of anxiety and depression.

4

Thermodynamic and mechanical characterisation of kaolin clay

88%

Hammouda I., Mihoubi D.

Polish Journal of Chemical Technology

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2014

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vol. 16

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issue 1

28-35

EN

This study deals with experimental thermodynamic and rheological characterization of kaolin. Water sorption isotherms of kaolin were determined for three temperatures (30, 50 and 70°C). Desorption isotherms were fitted by using five models (GAB, BET, Henderson modified, Adam and Shove, Peleg) among the most used ones in literature. The GAB model was found to be the most suitable for describing the relationship between equilibrium moisture content and water activity for the whole range of temperature (30-70°C) and relative humidity(0-100%). Desorption enthalpy and entropy were determined. The desorption enthalpy decreases with increasing moisture content. The density and the shrinkage of the material and the Young’s modulus variations as a function of moisture content were determined experimentally. The Young modulus varies between 0.1 MPa and 14 MPa. The viscoelastic parameters of kaolin were also determined by using a series of Prony.

5

Positron Annihilation Studies of the Free Volumes in Nylon12/PVA Films Treated by Supercritical Carbon Dioxide

88%

Li J., Yin C., Zhou Y., Li G., Yeh J.-t., He C.

Acta Physica Polonica A

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2017

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vol. 132

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issue 5

1552-1555

EN

Free volume variations of Nylon12/Polyvinyl alcohol (Nylon12/PVA) blends treated in supercritical carbon dioxide (ScCO₂) were investigated using positron annihilation lifetime spectroscopy. It is found that o-Ps lifetime τ₃ and the corresponding intensity I₃ in Nylon12/PVA decrease with increase of the PVA content. Being treated in ScCO₂ at 50°C and 20 MPa for 1 h, the free volume holes in Nylon12/PVA blends expand to different extents depending on the weight ratio of PVA. After releasing of CO₂, the free volume size decreases as a function of the elapsed time due to the molecular relaxation, and the relaxation time constant depends on the content of PVA in the blends.

6

Pre-stress losses in FRP pre-stressed reinforced concrete – subject overview

75%

Przygocka M., Kotynia R., Przygocka M., Kotynia R.

Archives of Civil Engineering

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2018

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vol. 64

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issue 4-II

7

Comparison of the Stress Relaxation of Biodegradable Surgical Threads Made of Mg and Zn Alloys and Some Commercial Synthetic Materials

75%

Milenin A., Kustra P., Wróbel M., Paćko M., Byrska-Wójcik D.

Archives of Metallurgy and Materials

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2019

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vol. 64

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issue 3

8

The assessment of the influence of styrene-butadiene-styrene copolymer on the selected rheological properties characterising durability of modified bitumens used in road pavements

75%

Mielczarek M., Dziadosz S., Słowik M., Bilski M., Mielczarek M., Dziadosz S., Słowik M., Bilski M.

Bulletin of the Polish Academy of Sciences: Technical Sciences

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2020

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issue 6

9

Virtual reality among dental patients – cross-sectional, questionnaire, pilot study

63%

Ledwoń A., Dębski P., Jędrusik P., Skucha-Nowak M., Mikusek J.

Annales Academiae Medicae Silesiensis

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2023

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issue 78

41-48

PL

WSTĘP: Strach przed wizytą stomatologiczną jest poważnym problemem zarówno u dzieci, jak i u pacjentów dorosłych. Często staje się on przyczyną unikania wizyt, co może skutkować pogorszeniem nie tylko zdrowia jamy ustnej, lecz także całego organizmu. Istnieje wiele metod mających na celu zrelaksowanie i uspokojenie pacjenta przed samą wizytą oraz w jej trakcie. Wykorzystanie wirtualnej rzeczywistości stanowi jedną z nich. MATERIAŁ I METODY: Badanie pilotażowe przeprowadzono w grupie 100 dorosłych pacjentów, podczas gdy oczekiwali na wizytę stomatologiczną w poczekalni. Ankietowani wypełniali dobrowolny kwestionariusz wielokrotnego wyboru składający się z czterech pytań. WYNIKI: Wyniki pokazują, że najczęściej wybieranymi odpowiedziami były projekcja krajobrazów (40%) oraz interaktywny spacer, np. po plaży, lub trekking w górach (35%). Nie zaobserwowano różnic w zależności od płci. Zarówno mężczyźni, jak i kobiety najczęściej wybierali projekcję krajobrazów. Zdecydowana większość ankietowanych (87%) była skłonna skorzystać z dystrakcji z wykorzystaniem wirtualnej rzeczywistości podczas wizyty stomatologicznej. Pozostałe 13% pacjentów nie chciało w ogóle korzystać z wirtualnej rzeczywistości, niezależnie od proponowanego materiału audiowizualnego. WNIOSKI: Większość pacjentów była optymistycznie nastawiona do skorzystania z wirtualnej rzeczywistości podczas wizyty stomatologicznej. Najczęściej wybierane odpowiedzi były związane ze spokojnymi oraz relaksującymi materiałami niż z grami czy quizami. Badanie wskazuje, że pacjenci stomatologiczni są skłonni korzystać z nowoczesnych technologii w walce z dentofobią.

EN

INTRODUCTION: Anxiety preceding dental appointment is a common problem among both children and adult patients. It is frequently the reason of avoiding visits what often results in poor oral health and deterioration of general well-being. There is a number of methods regarding patients’ relaxation as well prior the appointment as amid one, virtual reality among them. MATERIAL AND METHODS: The study was carried out among 100 adult dental patients while they waited for their appointment in the waiting room. Interviewees completed the multiple-choice, uncompelled questionnaire containing four questions. RESULTS: The results show that the most frequently chosen answer was projection of landscapes (40%) or an interactive journey like beach walk or mountain trekking (35%). No differences were observed between men and woman, in both groups projection of landscapes was the most common answer. The vast majority of interviewees (87%) was willing to try virtual reality during dental treatment while the remaining 13% did not want to experience virtual reality at all. CONCLUSIONS: Most of the participants were eager to try virtual reality amid dental appointment and they rather chose calm and relaxing contend instead of interactive quizzes or games. It is promising that dental patients are willing to be ready to try out innovative technologies in the fight against dental anxiety.

Refine search results

Generation of the vorticity mode by sound in a vibrationally relaxing gas

Efficiency of acoustic heating produced in the thermoviscous flow of a fluid with relaxation

Exercise or Relaxation? Which is More Effective in Improving the Emotional State of Pregnant Women?

Thermodynamic and mechanical characterisation of kaolin clay

Positron Annihilation Studies of the Free Volumes in Nylon12/PVA Films Treated by Supercritical Carbon Dioxide

Pre-stress losses in FRP pre-stressed reinforced concrete – subject overview

Comparison of the Stress Relaxation of Biodegradable Surgical Threads Made of Mg and Zn Alloys and Some Commercial Synthetic Materials

The assessment of the influence of styrene-butadiene-styrene copolymer on the selected rheological properties characterising durability of modified bitumens used in road pavements

Virtual reality among dental patients – cross-sectional, questionnaire, pilot study