ZnAl2O4/Chitosan Films and Evaluation of the Influence of ZnAl2O4 Filler on the Films Morphology, Structure and Thermal Properties

2014 ◽  
Vol 775-776 ◽  
pp. 692-695
Author(s):  
Pascally M.A. Guerra de Araújo ◽  
P.T.A. Santos ◽  
Ana Cristina Figueiredo de Melo Costa ◽  
Edcleide Maria Araújo
Keyword(s):  
Thermal Stability ◽  
Thermal Properties ◽  
Flat Surface ◽  
Chitosan Film ◽  
The Other ◽  
Other Hand ◽  
Mass Proportion ◽  
Chitosan Films ◽  
Dta Curves

The present work intends to prepare ZnAl2O4/chitosan films with a mass proportion of 3:1and evaluate the influence of the ZnAl2O4 filler on the chitosan films morphology, structure and thermogravimetric properties. The films were characterized by XRD, SEM, TG and FTIR. With the XRD, it has been verified that both the chitosan and the ZnAl2O4/chitosan films presented the chitosan peaks. However, the ZnAl2O4/chitosan film also presented the ZnAl2O4 peaks. Through the SEM, it has been observed that the chitosan film presented a flat surface. On the other hand, the ZnAl2O4/chitosan presented a protruding surface. The TGA/DTA curves of the ZnAl2O4/chitosan film showed an increase in the thermal stability at temperatures greater than 720oC, comparing with the chitosan film.

scholarly journals Preparation and Thermal and Anti-UV Properties of Chitosan/Mica Copolymer

2010 ◽  
Vol 2010 ◽  
pp. 1-6 ◽  
Author(s):  
Yih-Sheng Huang ◽  
Sheng-Haur Yu ◽  
Yea-Ru Sheu ◽  
Kuo-Shien Huang
Keyword(s):  
Experimental Data ◽  
Thermal Stability ◽  
Free Radical ◽  
Physical Properties ◽  
Ammonium Persulfate ◽  
Sodium Bisulfite ◽  
The Other ◽  
Other Hand

This experiment aims to produce a free radical while annoying the oxidizing-reducing reagent of the ammonium persulfate and the sodium bisulfite under nitrogen, then trigger copolymerization between modified-mica and chitosan to prepare a variety of copolymers. This experiment also aims to study the related properties of these copolymer materials. The experimental data shows that the copolymer has more thermal stability and better absorption of UV than chitosan. But the above physical properties will be less if the mica ratio in copolymer is more than 8%. On the other hand, the SEM photo of the microstructure also shows that the modified mica distributes homogeneously on the surface of the film of the copolymer.

Oil Ring Design Influence on Lube Oil Consumption of SI Engines

2004 ◽  
Author(s):  
Andre´ Ferrarese ◽  
Fernando F. Rovai
Keyword(s):  
Thermal Stability ◽  
The Other ◽  
Oil Consumption ◽  
Ring Type ◽  
Full Load ◽  
Sealing Capacity ◽  
Other Hand ◽  
Actual Use ◽  
Si Engines ◽  
Load Conditions

2-piece and 3-piece oil ring designs were tested in dynamometer and vehicles in order to evaluate the ring type influence on lube oil consumption of spark ignited (SI) engines. The dynamometer tests were executed according a typical durability cycle of SI engines. This cycle is predominantly in full load conditions. Under these conditions, 2-piece oil ring design showed lower lube oil consumption than 3-piece. Two different vehicle tests were also run: urban and mountain circuits. The purpose of the urban circuit test was to simulate the actual use of the engine. The mountain circuit was selected to verify the rings behavior under motoring conditions. In vehicle tests, 3-piece showed lower or equivalent oil consumption than 2 piece, which disagreed with the dynamometer tests. This difference can be explained by the better side sealing capacity of the 3-piece oil ring. On the other hand, 2-piece oil rings present better conformability, important for applications with larger bore distortion. So, the most appropriate application of oil ring type depends on the load and speed conditions, in which the engine would predominantly operate. Ring wear and thermal stability are compared using bench and vehicle tests.

Copolymerization of Ethylene/Diene with Different Metallocene Catalysts

2006 ◽  
Vol 61 (11) ◽  
pp. 1426-1432 ◽  
Author(s):  
Maria de Fátima Vieira Marques ◽  
Fernanda Constantino Rocha ◽  
Narda Juárez Soto
Keyword(s):  
Catalytic Activity ◽  
Thermal Properties ◽  
Reaction Time ◽  
Polymerization Rate ◽  
The Other ◽  
Copolymer Composition ◽  
Metallocene Catalysts ◽  
Ethylene Pressure ◽  
Other Hand ◽  
Catalyst Type

Copolymerizations of ethylene and 1,7-octadiene were carried out employing homogeneous catalysts Cp2ZrCl2, Ph2C(Flu,Cp)ZrCl2 and Et(Ind)2ZrCl2, and methylaluminoxane as cocatalyst. The polymerization characteristics, such as catalytic activity, polymerization rate, copolymer composition, and thermal properties were examined in relation to the catalyst type. Different comonomer concentrations were employed, and the reaction time was varied, ranging from 1 h up to 4 h, at 90°C and at 0.5 bar ethylene pressure. The results showed that the catalyst Cp2ZrCl2 was more efficient than Et(Ind)2ZrCl2 in the preparation of high diene content ethylene/1,7-octadiene copolymers. On the other hand, Et(Ind)2ZrCl2 and Ph2C(Flu,Cp)2ZrCl2 catalysts produced low insaturation content but possibly formed cyclic structures and crosslinking.

Studies on metal hydroxy compounds. VII. Thermal analyses of copper derivatives

1969 ◽  
Vol 47 (12) ◽  
pp. 2185-2190 ◽  
Author(s):  
P. Ramamurthy ◽  
E. A. Secco
Keyword(s):  
Thermal Stability ◽  
Thermal Analyses ◽  
General Pattern ◽  
The Other ◽  
Other Hand ◽  
Hydroxy Compounds ◽  
Initial Mode

Copper basic halide compounds have been studied by thermogravimetric and differential thermal analyses. This study reveals the general pattern of thermal stability observed for cadmium and zinc basic halides.The initial mode of decomposition varied within the copper group. The iodides, bromides, and chlorides all decomposed via dehydroxylation and in this way resembled the Cd and Zn basic halides. The copper basic fluorides, on the other hand, decomposed by simultaneous dehydroxylation and dehydrofluorination which is in distinct contrast to the Cd and Zn basic fluorides.

High-Performance Polyesters: Synthesis, Characterization, and Properties of Poly(P-Oxybenzoate)

2020 ◽  
Vol 992 ◽  
pp. 380-385
Author(s):  
A.I. Akhmetshina ◽  
L.K. Karimova ◽  
R.Ya. Deberdeev
Keyword(s):  
Thermal Stability ◽  
Molecular Weight ◽  
Thermal Properties ◽  
Ir Spectroscopy ◽  
High Performance ◽  
The Other ◽  
Transesterification Method

Poly (p-oxybenzoate) samples were synthesized via the esterification and the transesterification reactions. The structure of the obtained target products was investigated by IR spectroscopy and has revealed that these substances were oligomers. The transesterification method has facilitated the synthesis of higher molecular weight grades of the polymer. This resulted in enhanced thermal properties of polyester synthesized by transesterification (up to 340 °C). The other specimen has performed thermal stability up to 320 °C.

scholarly journals Influence of Al addition on the thermal stability and mechanical properties of Fe76.5-xCu1Si13.5b9Alx amorphous alloys

2012 ◽  
Vol 48 (1) ◽  
pp. 45-51 ◽  
Author(s):  
Y.Y. Sun ◽  
M. Song
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Amorphous Alloys ◽  
Melt Spinning ◽  
The Other ◽  
Al Content ◽  
Amorphous Ribbons ◽  
Other Hand ◽  
Al Addition

This paper fabricated Fe76.5-xCu1Si13.5B9Alx (x=0,1,2,3,5,7 at.%) amorphous ribbons using singleroller melt-spinning method. The effect of Al content on the thermal stability and mechanical properties was investigated. The results indicated that Al addition have little effect on the amorphous formation ability of the alloys. On the other hand, increasing the Al content can substantially increase Tx2, which corresponds to the crystallization of Fe borides. Nanoindentation tests indicated that hardness of the alloys increase slightly with increasing the Al content, and Young?s modulus has a complicated relationship with the Al content.

scholarly journals THE SPECIFIC HEAT AND THE HEAT OF COMPRESSION OF HUMAN RED CELLS, SICKLED RED CELLS, AND PARACRYSTALLINE RAT RED CELLS

1955 ◽  
Vol 38 (5) ◽  
pp. 575-580 ◽  
Author(s):  
Eric Ponder
Keyword(s):  
Thermal Properties ◽  
Specific Heat ◽  
Crystallization Process ◽  
Red Cells ◽  
The Other ◽  
Red Cell ◽  
X Ray Diffraction ◽  
X Ray ◽  
Other Hand ◽  
Human Red Cells

The investigation of two thermal properties of red cells throws some light on whether sickling is a process involving the crystallization of a relatively insoluble hemoglobin. These properties are the specific heat and the heat of compression, both of which would be expected to become numerically less if the hemoglobin of the red cell were to crystallize. In the case of paracrystalline rat red cells, which give spacings at 45 A and 58 A by x-ray diffraction, the specific heat is reduced to 85 per cent of that of the normal red cells, and the heat of compression is only about 75 per cent of that found for the normal red cell. In the case of the red cell sickled by a reduction of the O2 tension, the specific heat and the heat of compression are substantially the same as found for the normal red cell. This is an argument against sickling being the result of a crystallization process, and supports the observation that sickled cells do not give x-ray spacings. The result is compatible, on the other hand, with sickling being the result of the formation of an oriented and birefringent gel.

A study of cometary eruptions through OH radio-lines

1999 ◽  
Vol 173 ◽  
pp. 249-254
Author(s):  
A.M. Silva ◽  
R.D. Miró
Keyword(s):  
Short Duration ◽  
Growth Curves ◽  
The Other ◽  
Initial Mass ◽  
Radio Lines ◽  
Other Hand ◽  
Sudden Rise

AbstractWe have developed a model for theH2OandOHevolution in a comet outburst, assuming that together with the gas, a distribution of icy grains is ejected. With an initial mass of icy grains of 108kg released, theH2OandOHproductions are increased up to a factor two, and the growth curves change drastically in the first two days. The model is applied to eruptions detected in theOHradio monitorings and fits well with the slow variations in the flux. On the other hand, several events of short duration appear, consisting of a sudden rise ofOHflux, followed by a sudden decay on the second day. These apparent short bursts are frequently found as precursors of a more durable eruption. We suggest that both of them are part of a unique eruption, and that the sudden decay is due to collisions that de-excite theOHmaser, when it reaches the Cometopause region located at 1.35 × 105kmfrom the nucleus.

Closing the GAP—A 5Å Scanning Microscope

1969 ◽  
Vol 27 ◽  
pp. 6-7
Author(s):  
A. V. Crewe
Keyword(s):  
Normal Form ◽  
The Other ◽  
Resolving Power ◽  
Scanning Microscope ◽  
Conventional Microscope ◽  
Other Hand ◽  
Closing The Gap ◽  
Thermal Sources ◽  
Better Than ◽  
Transmission Microscope

We have become accustomed to differentiating between the scanning microscope and the conventional transmission microscope according to the resolving power which the two instruments offer. The conventional microscope is capable of a point resolution of a few angstroms and line resolutions of periodic objects of about 1Å. On the other hand, the scanning microscope, in its normal form, is not ordinarily capable of a point resolution better than 100Å. Upon examining reasons for the 100Å limitation, it becomes clear that this is based more on tradition than reason, and in particular, it is a condition imposed upon the microscope by adherence to thermal sources of electrons.

Life Beyond 1MeV

1980 ◽  
Vol 38 ◽  
pp. 30-33
Author(s):  
K.H. Westmacott
Keyword(s):  
Electron Microscopy ◽  
Past Experience ◽  
The Other ◽  
Good Case ◽  
Other Hand ◽  
The U.S

Life beyond 1MeV – like life after 40 – is not too different unless one takes advantage of past experience and is receptive to new opportunities. At first glance, the returns on performing electron microscopy at voltages greater than 1MeV diminish rather rapidly as the curves which describe the well-known advantages of HVEM often tend towards saturation. However, in a country with a significant HVEM capability, a good case can be made for investing in instruments with a range of maximum accelerating voltages. In this regard, the 1.5MeV KRATOS HVEM being installed in Berkeley will complement the other 650KeV, 1MeV, and 1.2MeV instruments currently operating in the U.S. One other consideration suggests that 1.5MeV is an optimum voltage machine – Its additional advantages may be purchased for not much more than a 1MeV instrument. On the other hand, the 3MeV HVEM's which seem to be operated at 2MeV maximum, are much more expensive.

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