Molar mass distribution

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Dispersity effects in polymer self assemblies : a matter of hierarchical control

Dispersity effects in polymer self assemblies : a matter of hierarchical control

chemical interaction with the SEC column, as opposed to its molar mass. Typically, the distribution of retention times is transformed mathematically into a distribution of molar masses by use of a series of calibrants of known narrow molar mass distributions, however one must consider the similarity of the solution behavior between the sample polymer and the calibrant standard. More accurate results can be obtained by use of a multi-detector SEC setup that employs the use of a multi-angle light scattering (MALS) and/or an intrinsic viscosity detector in conjunction with a refractive index (RI) or ultraviolet (UV) detector. For additional information regarding SEC, the reader is referred to the following text. 1 Additionally, more advanced techniques employing 2D chromatography, such as SEC coupled to an affinity column, or liquid chromatography under critical conditions of absorption, coupled to information rich detectors such as those discussed above, as well as FT-IR or NMR spectroscopy, or ESI-ToF and MALDI-ToF MS exist. 2 These advanced techniques can give information on not only length but also compositional dispersity, and can even decipher polymer chains of identical length that vary only in their end group.
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Polyurea microcapsules from isocyanatoethyl methacrylate copolymers

Polyurea microcapsules from isocyanatoethyl methacrylate copolymers

The synthesis of two types of isocyanate side chain containing copolymers, poly(methyl methacrylate-co-isocyanatoethyl methacrylate) (P(MMA-co-IEM)) and poly(benzyl methacrylate-co- isocyanatoethyl methacrylate) (P(BnMA-co-IEM)), which were synthesized by Cu(0)-mediated radical polymerization, is reported. Polymerization proceeded to high conversion giving polymers of relatively narrow molar mass distributions. The incorporation of the bulky aromatic groups in the latter copolymer rendered it sufficiently stable towards hydrolysis and enabled the isolation of the product and its characterization by 1 H and 13 C NMR, and FTIR spectroscopy and SEC. Both P(MMA-co-
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Determination of the Molar Mass of Surface-Grafted Weak Polyelectrolyte Brushes using Force Spectroscopy

Determination of the Molar Mass of Surface-Grafted Weak Polyelectrolyte Brushes using Force Spectroscopy

to simultaneously carry out polymerization on the surface and in bulk solution under the same conditions. For this approach, one assumes that both the free and grafted polymer chains have similar molar mass and dispersity. Recently, it has been pointed out that polymers synthesized in bulk solution have a greater growth rate and a narrower molar mass distribution than those initiated from a flat substrate [25]. It has, however, been possible to characterize the molar mass from the growth of polymer from a ÔfreeÕ initiator [26]. Another possibility is to remove the polymer from the surface and perform GPC on the degrafted polymer [25, 27]. This technique is restricted to the growth of polymers on small colloidal surfaces because of the need for a large surface area to permit the retrieval of sufficient polymer for the subsequent GPC analysis. Nevertheless, a different approach to effectively characterize the molar mass of surface-anchored polymers is required.
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Study and optimization of a CAD/CFD model for valveless pulsejets

Study and optimization of a CAD/CFD model for valveless pulsejets

The method introduced in this paper aims to find a feasible method to evaluate the static thrust of a “ valveless ” pulsejet, starting from a CAD model. CFD (Computational Fluid Dynamic) simulation and golden section were used for this purpose. Even for new pulsejet designs, it is possible to evaluate the pulsating frequency from equations available in literature or with a mono-dimensional pressure wave model. Then the combustion energy should be introduced in the engine. In this CFD model, the heat flow due to the combustion is simulated through the application of a pulsating flow of hot gases through the walls of the combustion chamber. To minimize the error of this added flow, a stoichiometric combustion of pure oxygen is introduced. The temperature value of the hot gases was optimized with the Golden Section Method in order to obtain the same experimental results of the Department of Aerospace Engineering of California Polytechnic State University, San Luis Obispo [2]. In this way, it is possible to evaluate the performance of a new design of different geometry and size. In fact, a flow with the same temperature can be introduced through the wall of the combustion chamber. The mass flow rate can be trimmed to obtain a mass balance between the incoming and the outgoing gases. In this way, the thrust can be calculated. The fuel type is not very influent for pulsejet performance.
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The field white dwarf mass distribution

The field white dwarf mass distribution

Young and massive star clusters are ideal for studying the high- mass IMF since they still include bright intermediate-mass stars (1.5 M / M 8). However, the vast majority of these stars that were ever born in the local galaxy group are now white dwarfs. While these faint remnants can not be observed to the same dis- tances as their progenitors, the field white dwarf mass distribution could still provide information about the IMF of local populations, such as the Galactic disc and halo. Current white dwarf samples are small for Galactic halo studies, but Gaia (Carrasco et al. 2014) and Euclid (Laureijs et al. 2011) will soon present unprecedented op- portunities. Furthermore, the mass distribution of degenerate stars presents unique constraints on the population of white dwarf merg- ers, which could be one of the evolution channel linked to SN Ia (see e.g. Dan et al. 2015) as well as high-field magnetic white dwarfs (B > 1 MG; Tout, Wickramasinghe & Ferrario 2004; Tout et al. 2008; Garc´ıa-Berro et al. 2012; Wickramasinghe, Tout & Ferrario 2014). Extensive studies have also been dedicated to using white dwarf masses and cooling ages to derive the SFH (Tremblay et al. 2014) and IFMR (see e.g. Weidemann 2000; Catal´an et al. 2008;
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Molar Mass Version of the Ideal Gas Law Points to a Very Low Climate Sensitivity

Molar Mass Version of the Ideal Gas Law Points to a Very Low Climate Sensitivity

on planetary bodies with a thick atmosphere. Usually, the Stefan Boltzmann (S-B) black body law is used to provide the effective temperature, then debate arises about the size or relevance of additional factors such as the greenhouse effect. Here is presented a simple and reliable method of calculating the average near surface atmospheric temperature on planetary bodies which possess a surface atmospheric pressure of over 10kPa. This method requires knowledge of the gas constant and only three variable gas parameters; average near- surface atmospheric pressure, average near surface atmospheric density and the mean molar mass of the atmosphere.
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Determination of the molar mass of surface-grafted weak polyelectrolyte brushes using force spectroscopy

Determination of the molar mass of surface-grafted weak polyelectrolyte brushes using force spectroscopy

The molar mass of comb PDMAEMA has been determined by both GPC and SMFS methods at pH 7. As for the SMFS approach, over 100 force curves were acquired for each sample, and then processed following the methodology described in the experimental section to estimate the number averaged molar mass of PDMAEMA comb grafted on a silicon surface. Subsequently, comparison was made between the molar mass of the PDMAEMA arms of the graft copolymer acquired by SMFS and GPC, which is presented in Fig. 3 [38]. It was found that the GPC and SMFS results align remarkably well over the entire range of chain lengths. The two different sets of results show a similar distribution of M w , with the peak position in the region of 51 kDa, even though GPC curve exhibits a definite tail in the higher molar mass region, which is not observed in the force measurement. While the GPC curve indicates an average M n of 58.7 kDa (D = 1.17),
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Modelling of down-draft gasification of biomass - An integrated pyrolysis, combustion and reduction process

Modelling of down-draft gasification of biomass - An integrated pyrolysis, combustion and reduction process

A gasification model is developed and implemented in Matlab to simulate a downdraft gasifier using wood as feedstock. The downdraft gasifier was conceptually divided into three zones: the pyrolysis zone, the combustion/oxidation zone and the reduction zone. A typical tar composition and its mole fraction, as reported in the literature was supplied as an input parameter in the model. The concentration of syngas and profiles of temperature along the reduction zone length were obtained by solving the mass and energy balances across each control volume and taking into account the rate of formation/consumption of the species according to different gasification kinetics. The simulation results from the model agreed closely with the experimental results. The syngas concentration was found to be about 1.1%, 17.3%, 22.8%, 9.0% and 49.8% for CH 4 , H 2 , CO, CO 2 , and N 2 respectively and the
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ap-chemistry-2017-exam-frq-scoring-guidelines.pdf

ap-chemistry-2017-exam-frq-scoring-guidelines.pdf

(b) Glycerol (molar mass 92.09 g/mol) has been suggested for use as an alternative fuel. 1 point is earned for the correct mass of glycerol. Assume that all the heat released by the co[r]

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A chemical model for barium oxide depletion from hollow
cathode’s insert

A chemical model for barium oxide depletion from hollow cathode’s insert

Al2O3 BaO CaO diffusion coefficient insert thickness molecular mass mass flow rate number of reactions that produce barium pressure universal gas constant temperature time molar fraction[r]

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1.1

1.1

Recall that no direct conversion is possible between mass and num- ber of particles. You must first convert the given mass to moles by mul- tiplying by the inverse of the molar mass. Then, you can convert moles to the number of representative particles by multiplying by Avogadro’s number. To determine numbers of atoms or ions in a compound, you will need conversion factors that are ratios of the number of atoms or ions in the compound to 1 mol of compound. These are based on the chemical formula. Example Problem 10.9 provides practice in solving this type of problem.
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Prevalence, Distribution, Caries lesion severity and Salivary Characteristics of Molar Incisor Hypomineralization : A Cross Sectional Study

Prevalence, Distribution, Caries lesion severity and Salivary Characteristics of Molar Incisor Hypomineralization : A Cross Sectional Study

morphology and distribution of some inorganic elements in dentin with MIH in permanent first molars. Sixty four tooth sections from 32 children were examined in polarized light. 5 sections were used for Scanning Electron Microscope (SEM) and 10 were used for X-Ray Micro Analysis (XRMA). The XRMA analysis showed a difference in the concentration of elements between dentin below normal and hypomineralised enamel. The authors concluded that the odontoblasts were not affected in cases of MIH, but may be affected by hypocalcemia which was reflected by the presence of interglobular dentin.
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Mass Distribution in Space Time and Conception about Space Time Mass Continuum

Mass Distribution in Space Time and Conception about Space Time Mass Continuum

DOI: 10.4236/ijaa.2018.81007 102 International Journal of Astronomy and Astrophysics The high energy particles are traversing the universe through the cosmic mi- crowave background [17]. This article defines the mass distribution in universe that is the part of space. So matter of radiation is spread out in whole universe.

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GEOPOLYMER BINDER AN APPROACH TOWARDS COMPLETE CEMENT REPLACEMENT

GEOPOLYMER BINDER AN APPROACH TOWARDS COMPLETE CEMENT REPLACEMENT

For instance, NaOH has a molecular weight of 40 hence solution with a concentration of 16 Molar consists of 16 x 40 = 640 grams of NaOH solids per liter of distilled water. Note that the mass of water is the major component in both the alkaline solutions. The mass of NaOH solids was measured as 444 grams per kg of NaOH solution with a Concentration of 16 Molar.

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Production and characterization of two medium-chain-length polydroxyalkanoates by engineered strains of Yarrowia lipolytica

Production and characterization of two medium-chain-length polydroxyalkanoates by engineered strains of Yarrowia lipolytica

(3-OH FA) by a PHA synthase (PhaC), inside the bacte- rial cell in the form of granules that serve as carbon and energy storage compounds [2]. PHA polymers are cat- egorized into subclasses according to the side chain of their monomers: in particular, short-chain-length PHAs (scl-PHA with three to five carbon monomers) and the medium-chain-length PHAs (mcl-PHA with six to four- teen carbon monomers). Copolymers of scl- and mcl- PHA, block copolymers PHA and homopolymers PHA are named based on the monomer arrangements in the polymer chains [3]. The properties of these biopolymers depend on their molar masses and their macromolecu- lar architectures (the side chains of their monomers), [3, 4]. For example, the well-studied scl-PHA, P3HB (poly- 3-hydroxybutyrate), has poor mechanical properties.
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Mouse molar morphogenesis revisited by three dimensional reconstruction  III  Spatial distribution of mitoses and apoptoses up to bell staged first lower molar teeth

Mouse molar morphogenesis revisited by three dimensional reconstruction III Spatial distribution of mitoses and apoptoses up to bell staged first lower molar teeth

Int I D Hiol ~1 679 690 (( 997) 679 Originfll Artidl' Mouse molar morphogenesis revisited by three dimensional reconstruction III Spatial distribution of mitoses and apoptoses up to bell staged first[.]

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Extraction-Chromogenic Systems Containing Iron(III), 4-(2-Thiazolylazo)resorcinol and Ditetrazolium Salts

Extraction-Chromogenic Systems Containing Iron(III), 4-(2-Thiazolylazo)resorcinol and Ditetrazolium Salts

of distribution (K D ) describing eq. 2 were calculated by the formula K D =E/(1-E), where E is determined by MP-AES at the optimum extraction conditions (as described above). The attempts to determine these constants spectrophotometrically by comparison of the absorbance values obtained after single (A 1 ) and triple (A 3 ) extractions in equal final volumes 26-28 were

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Producing Renewable Biodiesel Fuel Using the Transesterification Process

Producing Renewable Biodiesel Fuel Using the Transesterification Process

stand the interactions between these manufacturing variables [6]. The statistical analysis system for a factorial design of three factors applied in this analysis of the transesterification process was designed, and the coded le- vels (+1 - −1) of the manufacturing variables are tabulated in Table 2. A mere 15 experimental runs was enough for this type of analysis. The three manufacturing variables (or factors) chosen in this study were the reaction time (X 1 ), the mass fraction of NaOH in methanol (X 2 ) and the molar ratio of methanol to palm oil (X 3 ). The

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Dissolution characteristics of anti cancer drug Cytarabine

Dissolution characteristics of anti cancer drug Cytarabine

1.2, the heat adsorption increases as the cytarabine quality increases, but the molar enthalpy remains constant, therefore the average of molar enthalpy calculated under different mass can be used as the infinite dilution molar enthalpy of cytarabine in saline or citric acid. Obviously, the relationship between different mass of cytarabine and thermal effect can be represented in Figure 3.4, and the molar enthalpy can be calculated as -5.408 kJ·mol -1 and -20.058 kJ·mol -1 , respectively.

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Allscher, Thorsten
  

(2011):


	Carbohydrate-Metal Chemistry: Complexes of Palladium(II) and their Characterization via NMR Spectroscopy and X-Ray Crystallography.


Dissertation, LMU München: Fakultät für Chemie und Pharmazie

Allscher, Thorsten (2011): Carbohydrate-Metal Chemistry: Complexes of Palladium(II) and their Characterization via NMR Spectroscopy and X-Ray Crystallography. Dissertation, LMU München: Fakultät für Chemie und Pharmazie

The 2:1:1 molar Pd-en/polyol/H + ratio used for glycerol was only applicable to the tetritols, and had to be altered to 3:1:1.5 for the pentitols and to 4:1:2 for the hexitols. For the three pentitols, some rules may be recognized. Hence, if a threo-connection was available, it was part of a chelate ring. Thus arabitol formed the 1κO 1 ,1:2κ 2 O 2 ,2κO 3 chelate by its only terminal/threo pair of diol functions and not 1κO 3 ,1:2κ 2 O 4 ,2κO 5 (an erythro/terminal pair of diols) or 1κO 2 ,1:2κ 2 O 3 ,2κO 4 (a threo/erythro pair). Xylitol allowed the exclusion of erythro- diol-binding both in its 1,2,3-terminal/threo pair (symmetrically equivalent with the 3,4,5- threo/terminal site) as well as for the prevailing 2,3,4-threo/threo bonding, as Table 2.17 shows. Signals of a higher-metalated species were assigned for ribitol and xylitol. In these species, the new μ-triolato-binding mode was accompanied by the well-known formation of a five-membered chelate ring. The meso-hexitols—allitol and dulcitol—exhibited the attempted bonding pattern, too, whereas the C 1 -symmetric D -sorbitol showed spectra that were too
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