Analysis of Fractional Viscoelastic Material With Mechanical Parameters Dependent on Random Temperature

2017 ◽  
Vol 3 (3) ◽  
Author(s):  
G. Alotta ◽  
N. Colinas-Armijo
Keyword(s):  
Epoxy Resin ◽  
Viscoelastic Material ◽  
Viscoelastic Model ◽  
Polymeric Materials ◽  
Random Variable ◽  
The Other ◽  
Mechanical Parameters ◽  
Simple Method ◽  
Different Temperatures ◽  
Probability Density Function Pdf

It is well known that mechanical parameters of polymeric materials, e.g., epoxy resin, are strongly influenced by the temperature. On the other hand, in many applications, the temperature is not known exactly during the design process and this introduces uncertainties in the prevision of the behavior also when the stresses are deterministic. For this reason, in this paper, the mechanical behavior of an epoxy resin is characterized by means of a fractional viscoelastic model at different temperatures; then, a simple method to characterize the response of the fractional viscoelastic material at different temperatures modeled as a random variable with assigned probability density function (PDF) subjected to deterministic stresses is presented. It is found that the first- and second-order statistical moments of the response can be easily evaluated only by the knowledge of the PDF of the temperature and the behavior of the parameters with the temperature. Comparison with Monte Carlo simulations is also performed in order to assess the accuracy and the reliability of the method.

The Tradition of Religious Books (Kitabs) Printing: Case Study of the Production and Reproduction of Religious Books (Kitabs) in Cianjur and Sukabumi, West Java, Indonesia

2020 ◽  
Vol 17 (2) ◽  
pp. 291-320
Author(s):  
Asep Saefullah
Keyword(s):  
Data Collection ◽  
Screen Printing ◽  
The Other ◽  
West Java ◽  
Simple Method ◽  
Original Essays ◽  
Printed Books ◽  
Religious Books ◽  
Living Tradition

Tulisan ini membahas fenomena penyebaran kitab-kitab cetak keaga­maan di Jawa Barat, khususnya di Sukabumi dan Cianjur. Jenis kitab ini biasanya menggunakan tulisan Arab dengan bahasa Sunda dan menggu­nakan aksara Pegon. Kitab-kitab cetak dari jenis-jenis itu diproduksi dan direproduksi, dan masih digunakan sampai hari ini. Oleh karena itu, fenomena ini dapat disebut sebagai “living tradition”. Pengumpulan data dilakukan dengan melacak dan merekam kitab-kitab yang diproduksi (disalin atau dikarang) dan direproduksi (dicetak atau digandakan) dengan metode seder­hana, yakni fotocopi dan pencetakan tradisional seperti stensil, sablon, dan "cetak toko". Tulisan ini bertujuan untuk memetakan dan merevisi kategorisasi kitab-kitab tersebut dari kajian terdahulu berdasarkan jenis karya, seperti karangan asli, tuqilan, terjemahan, syarḥ (penjelasan), khulasah (ringkasan) yang lain, dan juga berdasarkan bahasa dan aksara yang digunakan. Selain itu, tulisan ini juga mengamati lembaga-lembaga atau individu-individu yang masih mereproduksi buku-buku (kitab-kitab) keagamaan sederhana seperti perusahaan percetakan atau pesantren yang menerbitkan kitab-kitab tersebut. Pada akhir artikel ini, ada beberapa saran dalam upaya untuk melestarikan kitab-kitab cetak dan karya-karya tersebut.Kata kunci: kitab, jenis karya, pencetakan tradisional, Sunda, Pegon, Jawa Barat This paper discusses the phenomenon of the spreading of religious printed books (kitabs) in West Java, especially in Sukabumi and Cianjur, which are characterized by the use of Arabic writing in Sundanese (or known as Pegon script). The printed books (Kitabs) of those types are produced and reproduced, and are still used to this day. Therefore, this phenomenon can be called as a “living tradition”. Data collection was conducted by tracing and recording religious books (kitabs) that are pro-duced (rewritten or compossed) and reproduced (printed or duplicated) with a simple method, known as photocopying and traditional printing such as stencils, screen printing, and “shop printing”. This paper aims to map and revise the categorization of these Kitabs from previous studies based on the types of works including original essays, tuqilan (quotations), translation, sharh (explanation), khulaṣah (summary), or the other, and also based on the language and the script used. In addition, this paper also observes the institutions or individuals that are still reproducing these printed religious books such as the printing company or pesantren that publish such kitabs. At the end of this article, there are some suggestions in attempts to preserve those printed kitabs and the works.Keywords: Kitabs, type of work, traditional printing, Sunda, Pegon, West Java

scholarly journals The Respiration of some Planktonic copepods II. The Effect Of Temperature

1953 ◽  
Vol 31 (3) ◽  
pp. 447-460 ◽  
Author(s):  
D. T. Gauld ◽  
J. E. G. Raymont
Keyword(s):  
Respiratory Rate ◽  
The Body ◽  
The Other ◽  
Effect Of Temperature ◽  
Acartia Clausi ◽  
Temora Longicornis ◽  
Different Temperatures ◽  
Planktonic Copepods ◽  
The Difference ◽  
The Relationship

The respiratory rates of three species of planktonic copepods, Acartia clausi, Centropages hamatus and Temora longicornis, were measured at four different temperatures.The relationship between respiratory rate and temperature was found to be similar to that previously found for Calanus, although the slope of the curves differed in the different species.The observations on Centropages at 13 and 170 C. can be divided into two groups and it is suggested that the differences are due to the use of copepods from two different generations.The relationship between the respiratory rates and lengths of Acartia and Centropages agreed very well with that previously found for other species. That for Temora was rather different: the difference is probably due to the distinct difference in the shape of the body of Temora from those of the other species.The application of these measurements to estimates of the food requirements of the copepods is discussed.

Are membrane properties essential for the circadian rhythm of Gonyaulax?

1984 ◽  
Vol 247 (2) ◽  
pp. R250-R256
Author(s):  
H. G. Scholubbers ◽  
W. Taylor ◽  
L. Rensing
Keyword(s):  
Circadian Rhythm ◽  
Phase Shift ◽  
Fluorescence Polarization ◽  
The Other ◽  
Membrane Properties ◽  
Response Curves ◽  
Whole Cells ◽  
Different Temperatures ◽  
Free Running ◽  
Free Running Period

Membrane properties of whole cells of Gonyaulax polyedra were measured by fluorescence polarization. Circadian changes of fluorescence polarization exist in exponentially growing cultures. They show an amplitude larger than that of stationary cultures, indicating that a part of the change is due to or amplified by an ongoing cell cycle. Measurements of parameters of the circadian glow rhythm were analyzed for possible correlation with the membrane data. Considerable differences (Q10 = 2.5-3.0) in fluorescence polarization were found in cultures kept at different temperatures ranging from 15 to 27.5 degrees C. The free-running period length at different temperatures, on the other hand, differed only slightly (Q10 = 0.9-1.1). Stationary cultures showed higher fluorescence polarization compared with growing cultures, whereas the free-running period lengths did not differ in cultures of various densities and growth rates. Temperature steps of different sign changed the fluorescence polarization slightly in different directions. The phase shift of 4-h pulses (-5, -9, +7 degrees C) resulted in maximal phase advances of 4, 6, and 2 h, respectively. The phasing of the phase-response curves was identical in all these experiments, a finding not to be expected if the pulses act via the measured membrane properties. Pulses of drugs that change the fluorescence polarization (e.g., chlorpromazine and lidocaine) did not or only slightly phase-shift the circadian rhythm.

scholarly journals An enquiry concerning the nature of heat, and the mode of its communication

1832 ◽  
Vol 1 ◽  
pp. 139-147
Keyword(s):  
Principal Part ◽  
Cylindrical Vessel ◽  
The Other ◽  
Metallic Surface ◽  
Previous Trial ◽  
Flat Surfaces ◽  
Different Temperatures ◽  
The One ◽  
Quantity Of Heat

The importance of the investigation here entered into,—inasmuch as it applies to most of the operations of nature as well as art,—appears so manifest, that we shall not recapitulate what the author advances on that subject. Before he proceeds to the detail of his experiments for the purpose of computing the emissions of heat from various bodies under a variety of circumstances, he finds it necessary to premise a minute description of the principal part of the apparatus he contrived for his purpose. This instrument consists of a hollow cylindrical vessel of brass, four inches long, and as many in diameter. It is closed at both ends; but has at one end a cylindrical neck about eight-tenths of an inch in diameter, by which it is occasionally filled with water of different temperatures, and through which also a thermometer, constructed for the purpose, is occasionally introduced, in order to ascertain the changes of temperature in the fluid. As it was in the first instance only meant to observe the quantity of heat that escapes through the sides of the vessel, two boxes were contrived, filled and covered with non-conducting substances, such as eiderdown, fur, &c., which were fitted to the two ends or flat surfaces of the cylinder. Six of these instruments, with proper stands, and auxiliary implements of obvious construction, were prepared for the sake of comparative experiments. A previous trial was made with two of the cylinders, the vertical polished sides of the one being naked, and those of the other covered with one thickness of fine white Irish linen, strained over the metallic surface. Here it was found, contrary to expectation, that in a certain space of time the covered cylinder had lost considerably more heat than the naked one.

Investigation of changes in physical and mechanical parameters of biodegradable polymer films during composting

2021 ◽  
pp. 40-43
Author(s):  
Дмитрий Михайлович Мяленко
Keyword(s):  
Lactic Acid ◽  
Environmental Protection ◽  
Biodegradable Polymer ◽  
Polymeric Materials ◽  
Mechanical Parameters ◽  
Ecological Situation ◽  
Plant Materials ◽  
Foreign Countries ◽  
Hydrolysis Of ◽  
Aliphatic Biopolymer

Вопросы защиты окружающей среды и улучшения экологической обстановки приобретают глобальный характер. Количество производимых в России и зарубежных странах синтетических полимерных материалов постоянно увеличивается, что заставляет задуматься о подходах к разработке современных биоразлагаемых полимерных материалов из полностью возобновляемого растительного сырья. Один из таких материалов - это линейный алифатический биополимер, полученный путем гидролиза молочной кислоты: полилактид (PLA). В данной статье представлены результаты исследований способности к биоразложению полимерных материалов на основе PLA при их компостировании в течение 3 мес. The issues of environmental protection and improvement of the ecological situation are becoming global in nature. The number of synthetic polymeric materials produced from Russia and foreign countries is constantly increasing, which makes us think about approaches to the development of modern biodegradable polymeric materials from completely renewable plant materials. One such material is a linear aliphatic biopolymer made by hydrolysis of lactic acid: polylactide (PLA). This article presents the results of studies on the biodegradability of PLA-based polymeric materials when composted for 3 months.

scholarly journals Investigation of Fatigue Behavior of ABS and PC-ABS Polymers at Different Temperatures

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1818
Author(s):  
Andrea Mura ◽  
Alessando Ricci ◽  
Giancarlo Canavese
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
Working Condition ◽  
Fatigue Behavior ◽  
Polymeric Materials ◽  
Cyclic Loads ◽  
Structural Components ◽  
Working Temperature ◽  
Different Temperatures ◽  
Positive Effect

Plastics are widely used in structural components where cyclic loads may cause fatigue failure. In particular, in some applications such as in vehicles, the working temperature may change and therefore the strength of the polymeric materials. In this work, the fatigue behavior of two thermoplastic materials (ABS and PC-ABS) at different temperatures has been investigated. In particular, three temperatures have been considered representing the working condition at room temperature, at low temperature (winter conditions), and high temperature (summer conditions and/or components close to the engine). Results show that high temperature have big impact on fatigue performance, while low temperatures may also have a slight positive effect.

Sintering Temperature Effect on Hardness of Self-Synthetisized Porcelain Made from Natural Sumatran Sand without Kaolin

2018 ◽  
Vol 782 ◽  
pp. 227-232
Author(s):  
Sianny Surya Putri Kurnia ◽  
Dede Taufik ◽  
Veni Takarini ◽  
Zulia Hasratiningsih
Keyword(s):  
Temperature Effect ◽  
Potassium Salt ◽  
Sintering Temperature ◽  
The Self ◽  
The Other ◽  
P Value ◽  
Natural Sand ◽  
Average Hardness ◽  
Different Temperatures ◽  
Statistic Result

Dental porcelain is one of the indirect restoration material with excellent aesthetic properties,on the other hand porcelain hardness frequently causing excessive wear of antagonist teeth. This study aiming to evaluate the effect of sintering temperature on the self-synthesized porcelain hardness. In this experiment, 25 porcelain samples were synthesized using Sumatran sand from Pangaribuan and Belitung regions, with the composition of 65 wt% Pangaribuan feldspar, 25 wt% Belitung silica and 10 wt% potassium salt. The samples were sintered in five different temperatures, which were 1110°C (A), 1120°C (B), 1130°C (C), 1140°C (D), and 1150°C (E). These samples were then invested on 5cm diameter resin each. The hardness was tested using Zwick Roell ZHμ Micro Vickers with 900 gram load for 15 seconds in 5 different indented areas for each sample. The result shows average hardness of 435.8 VHN (A), 461.0 VHN (B), 472.0 VHN (C), 487.6 VHN (D), and 528.7 VHN (E), which were increasing as the sintering temperature increased. Statistic result shows that sintering temperature significantly affected the hardness value of the porcelain (p value < 0.05). In conclusion sintering temperature affects the hardness of self-synthesized porcelain made from Sumatran natural sand without kaolin, although the average hardness of self-synthesized porcelain is still higher than average hardness of teeth enamel.

IV. On the expansion by heat of metals and alloys

1867 ◽  
Vol 15 ◽  
pp. 220-222
Keyword(s):  
Specific Gravity ◽  
Metals And Alloys ◽  
The Body ◽  
The Other ◽  
Different Temperatures ◽  
The Mean

In a paper “ On the Expansion by Heat of Water and Mercury” *, a method of determining the expansion of bodies is described, by which good results can be obtained with comparatively small quantities of the substances to be experimented with. This method, that of weighing the body in water at different temperatures, has been employed for the present research. The results obtained are given in the following Tables:— From the above the following conclusion is drawn-namely, that just as it may be said that the specific gravity of an alloy is approximately equal to the mean specific gravities of the component metals , so also from the foregoing we may deduce that the volume which an alloy will occupy at any temperature between 0° and 100° is approximately equal to the mean of the volumes o f the component metals at the same temperature, or, in the other words, the cubical or linear coefficients o f expansion by heat of an alloy between 0° and 100° are approximately equal to the mean of the cubical or linear coefficients of expansion by heat o f the component metals .

scholarly journals The use of ceiling temperature and reactivation in the isolation of pox virus hybrids

1964 ◽  
Vol 62 (2) ◽  
pp. 133-140 ◽  
Author(s):  
K. R. Dumbell ◽  
H. S. Bedson
Keyword(s):  
Active State ◽  
The Other ◽  
Detailed Account ◽  
Parental Virus ◽  
Simple Method ◽  
Ceiling Temperature ◽  
Temperature Heat

A simple method for the isolation of pox virus hybrids on the C.A.M. has been described. One parental virus was used as a heat-inactivated suspension. The other parent was used in the active state, but at a temperature higher than its ceiling temperature. Under these conditions the inactive parent was reactivated so that pocks resulted only from the cells infected with both parental viruses. Many of these pocks were unlike those of either parent. Such lesions were found to contain a high proportion of hybrids. In these experiments, alastrim was crossed with rabbit pox and variola major with cowpox.The term ‘heat-tethered’ has been used to describe virus whose intracellular cycle of development has been arrested by incubation at too high a temperature. Heat-tethered virus has interesting properties and two of these have been described. When the temperature is lowered, heat-tethered virus will start to grow again. Its reactivating potential has been mentioned above. A more detailed account of the properties of heat-tethered virus is being prepared.

scholarly journals A simple method of suspending implant wear particles for more physiological modelling of cell-particle interactions in vitro

2021 ◽  
Author(s):  
Christine Poon
Keyword(s):  
Wear Debris ◽  
Culture Media ◽  
Polymeric Materials ◽  
Wear Particle ◽  
Physicochemical Characteristics ◽  
Wear Particles ◽  
Simple Method ◽  
Implant Wear

AbstractArthroplasty implants e.g. hip, knee, spinal disc sustain relatively high compressive loading and friction wear, which lead to the formation of wear particles or debris between articulating surfaces. Despite advances in orthopaedic materials and surface treatments, the production of wear debris from any part of a joint arthroplasty implant is currently unavoidable. Implant wear debris induces host immune responses and inflammation, which causes patient pain and ultimately implant failure through progressive inflammation-mediated osteolysis and implant loosening, where the severity and rate of periprosthetic osteolysis depends on the material and physicochemical characteristics of the wear particles. Evaluating the cytotoxicity of implant wear particles is important for regulatory approved clinical application of arthroplasty implants, as is the study of cell-particle response pathways. However, the wear particles of polymeric materials commonly used for arthroplasty implants tend to float when placed in culture media, which limits their contact with cell cultures. This study reports a simple means of suspending wear particles in liquid medium using sodium carboxymethyl cellulose (NaCMC) to provide a more realistic proxy of the interaction between cells and tissues to wear particles in vivo, which are free-floating in synovial fluid within the joint cavity. Low concentrations of NaCMC dissolved in culture medium were found to be effective for suspending polymeric wear particles. Such suspensions may be used as more physiologically-relevant means for testing cellular responses to implant wear debris, as well as studying the combinative effects of shear and wear particle abrasion on cells in a dynamic culture environments such as perfused tissue-on-chip devices.

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