Properties of n-alcohol + n-alkane mixtures

1977 ◽  
Vol 30 (1) ◽  
pp. 43 ◽  
Author(s):  
F Smith
Keyword(s):  
P Systems ◽  
Effect Of Temperature ◽  
P System ◽  
Range Data ◽  
Free Energies ◽  
Dipole Term ◽  
Partial Molar Enthalpies ◽  
Refined Estimate ◽  
Two Parameters ◽  
Latent Heats

The total polar contributions (AP) to three properties [infrared absorbance, mixing enthalpies (HM) and excess free energies (GE)] of alcohol + alkane (alp) systems are separated into a direct hydrogenbond contribution ( AB) from the formation of isolated imers and a dipole-dipole contribution (AD) resulting from dipolar correlation between these transient imers. Dilute concentration range data giving the AB contributions to these properties were found dependent only on OH group concentration (c) and are used to show the serious inadequacies of previous theories. A new proposed association model having only two parameters, that are fixed for all systems, does give good results for the AB contributions and further is quite compatible with the effect of temperature change and with the n.m.r. chemical shift (ε) and apparent mean square dipole moment (p2) data that are also studied. Thus association theory has been made quantitative for the AB contributions to three properties of a/p systems and the approach given for deriving models appears capable of wider application. The model was used to extrapolate the AB contributions into the concentrated alcohol range to thus give the AD contributions by difference. The latter are then shown to be the origin of the distinctive behaviour shown by lower alcohols in their pure and binary mixture properties either with alkanes or with other alcohols where for the latter the principle of congruence is shown to be completely misleading. Two contributions (Ag and AD) explain the different c dependence shown by the i.r., HM and the δ data for a/p systems and, qualitatively, the HM data for alcohol+alcohol systems while the existence of a significant dipole term is strongly supported by the remarkable similarities found between the p2(c) data and the derived dipole-dipole contribution to the entropy of a/p systems. A method is given for predicting latent heats and partial molar enthalpies of higher alcohols from the HM data for one a/p system and a refined estimate is made of the enthalpy of formation of a hydrogen bond. Polar structure and non-linear dielectric effects are also discussed.

Chemical equilibrium and chemical kinetics

2018 ◽  
Author(s):  
Dennis Sherwood ◽  
Paul Dalby
Keyword(s):  
Free Energy ◽  
Equilibrium Constant ◽  
Gibbs Free Energy ◽  
Chemical Kinetics ◽  
Chemical Equilibrium ◽  
First Principles ◽  
Effect Of Temperature ◽  
Total System ◽  
Free Energies

Building on the previous chapter, this chapter examines gas phase chemical equilibrium, and the equilibrium constant. This chapter takes a rigorous, yet very clear, ‘first principles’ approach, expressing the total Gibbs free energy of a reaction mixture at any time as the sum of the instantaneous Gibbs free energies of each component, as expressed in terms of the extent-of-reaction. The equilibrium reaction mixture is then defined as the point at which the total system Gibbs free energy is a minimum, from which concepts such as the equilibrium constant emerge. The chapter also explores the temperature dependence of equilibrium, this being one example of Le Chatelier’s principle. Finally, the chapter links thermodynamics to chemical kinetics by showing how the equilibrium constant is the ratio of the forward and backward rate constants. We also introduce the Arrhenius equation, closing with a discussion of the overall effect of temperature on chemical equilibrium.

scholarly journals Novel Numerical Spiking Neural P Systems with a Variable Consumption Strategy

Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 549
Author(s):  
Xiu Yin ◽  
Xiyu Liu ◽  
Minghe Sun ◽  
Qianqian Ren
Keyword(s):  
Production Functions ◽  
P Systems ◽  
P System ◽  
Computing Device ◽  
Spiking Neural P Systems ◽  
Distributed Parallel Computing ◽  
Production Values ◽  
Novel Variant ◽  
Turing Universality ◽  
Variable Consumption

A novel variant of NSN P systems, called numerical spiking neural P systems with a variable consumption strategy (NSNVC P systems), is proposed. Like the spiking rules consuming spikes in spiking neural P systems, NSNVC P systems introduce a variable consumption strategy by modifying the form of the production functions used in NSN P systems. Similar to the delay feature of the spiking rules, NSNVC P systems introduce a postponement feature into the production functions. The execution of the production functions in NSNVC P systems is controlled by two, i.e., polarization and threshold, conditions. Multiple synaptic channels are used to transmit the charges and the production values in NSNVC P systems. The proposed NSNVC P systems are a type of distributed parallel computing models with a directed graphical structure. The Turing universality of the proposed NSNVC P systems is proved as number generating/accepting devices. Detailed descriptions are provided for NSNVC P systems as number generating/accepting devices. In addition, a universal NSNVC P system with 66 neurons is constructed as a function computing device.

scholarly journals Torrefaction of Napier Grass and Oil Palm Petiole Waste Using Drop-type Pyrolysis Reactor

2021 ◽  
Author(s):  
Syazmi Zul Arif Hakimi Saadon ◽  
Noridah Osman ◽  
Moviin Damodaran ◽  
Shan En Liew
Keyword(s):  
Residence Time ◽  
Oil Palm ◽  
Waste Product ◽  
Calorific Value ◽  
Napier Grass ◽  
Effect Of Temperature ◽  
Energy Yield ◽  
Pyrolysis Reactor ◽  
Parameter Ranges ◽  
Two Parameters

Abstract Interest in torrefaction has improved along the recent years and it has been studied extensively as a mean of preparing solid fuels. Biomass to be considered as a renewable source of energy must endeavor improvement continuously and where it is more sustainable going forward in which can come from waste product, wild and cultivated plant. The aim of this study is to investigate the effect of temperature and residence time of wild Napier grass and Oil palm petiole from waste. The torrefied samples were derived by pyrolysis reactor mimicking torrefaction procedure. The temperature parameter ranges between 220 and 300 ℃ while residence time parameter is from 10 minutes to 50 minutes of reaction. It was found that as temperature and time increasing, moisture content and amount of O and H atoms decreases as well as both mass and energy yield, but calorific value and the energy density increase along with both two parameters. Between the two parameters, the temperature variation shows more significant changes to the torrefied samples as compared time. The optimized temperature and time are found to be 260 ℃ and 30 minutes, respectively. Remarkably, the usage of pyrolyzer as torrefaction reaction has proved to be a good option since they share similar characteristics while can also produce product with similar properties reflecting torrefaction process.

scholarly journals Effect of Temperature on the Tribological Properties of Selected Thermoplastic Materials Cooperating with Aluminium Alloy

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7318
Author(s):  
Anita Ptak ◽  
Paula Taciak ◽  
Wojciech Wieleba
Keyword(s):  
Aluminium Alloy ◽  
Contact Pressure ◽  
Tribological Properties ◽  
Polymer Materials ◽  
Effect Of Temperature ◽  
Test Results ◽  
Friction Process ◽  
Before And After ◽  
Pin On Disc ◽  
Two Parameters

This article concerns the tribological properties of three selected polymer materials: polyamide PA6, polyethylene PE-HD and polyetheretherketone composite PEEK/BG during sliding against aluminium alloy EN AW-2017A in the presence of hydraulic oil HLP 68. The tests were carried out under contact pressure p of 3.5–11 MPa at ambient temperature T ranging from −20 °C to +20 °C. The dependence of kinetic friction coefficient μk on the two parameters was determined through tribological tests carried out using a pin-on-disc tribometer. A five-level central composite rotatable design (CCRD) was adopted for the experiment. All the test results were statistically analysed. The microhardness of the surface of the polymeric material was measured before and after the friction process. The surface was also examined under SEM. Temperature and contact pressure have been found to have a significant effect on the tribological properties of the tested sliding pairs. Relative to the applied friction conditions, the surfaces after friction showed rather heavy signs of wear.

Effect of Temperature on Tool Wear During Milling of Ti64

2021 ◽  
Vol 143 (7) ◽  
Author(s):  
Q. Lagarde ◽  
V. Wagner ◽  
G. Dessein ◽  
M. Harzallah
Keyword(s):  
Tool Wear ◽  
Cutting Temperature ◽  
Cutting Speed ◽  
Effect Of Temperature ◽  
Fundamental Parameter ◽  
Ir Camera ◽  
Radial Depth ◽  
Higher Temperature ◽  
Two Parameters ◽  
Machining Productivity

Abstract In recent years, the development of new, increasingly resistant materials limit machining productivity. This observation is especially true for titanium alloys. The state-of-the-art shows that one of the phenomena responsible for tool wear is temperature. The high temperature is explained by the low thermal conductivity of the alloy and its high mechanical properties. Consequently, high temperatures generated when cutting speeds are increasing lead to very rapid wear phenomena. However in milling, the period during which the insert is not in contact with the material may allow it to cool but its effect is not clearly established. In order to correlate tool wear and cutting temperatures in milling, an experimental bench has been developed. In turning and therefore with a fixed tool, the milling conditions are recreated and allow to measure the temperatures on the cutting face. Two parameters were tested: (i) radial depth, which influences the tooth stress time, and (ii) the cutting speed, which is the fundamental parameter of the cutting temperature. Experimentally, it appears that increasing radial engagement and cutting speed reduces tool life and increases temperatures. However, the phenomenological analysis is not immediate. The relationship between these phenomena is based on a heat balance of the cutting process. The use of an infrared (IR) camera in this problem and a specific analysis method allow observing the temperature gradients on the cutting face making the analysis more robust compared to the thermocouple technic. It thus appears that the increase in radial engagement leads to a higher tool temperature, but the analyses show above all a higher temperature within the insert and therefore more difficult to evacuate.

scholarly journals A Grid-Density Based Algorithm by Weighted Spiking Neural P Systems with Anti-Spikes and Astrocytes in Spatial Cluster Analysis

Processes ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1132
Author(s):  
Deting Kong ◽  
Yuan Wang ◽  
Xinyan Wu ◽  
Xiyu Liu ◽  
Jianhua Qu ◽  
...  
Keyword(s):  
Dimensional Space ◽  
P Systems ◽  
High Dimensional ◽  
P System ◽  
Inhibitory Influence ◽  
Spiking Neural P Systems ◽  
Clustering Approach ◽  
Spatial Cluster Analysis ◽  
Effectiveness And Efficiency ◽  
Real World Datasets

In this paper, we propose a novel clustering approach based on P systems and grid- density strategy. We present grid-density based approach for clustering high dimensional data, which first projects the data patterns on a two-dimensional space to overcome the curse of dimensionality problem. Then, through meshing the plane with grid lines and deleting sparse grids, clusters are found out. In particular, we present weighted spiking neural P systems with anti-spikes and astrocyte (WSNPA2 in short) to implement grid-density based approach in parallel. Each neuron in weighted SN P system contains a spike, which can be expressed by a computable real number. Spikes and anti-spikes are inspired by neurons communicating through excitatory and inhibitory impulses. Astrocytes have excitatory and inhibitory influence on synapses. Experimental results on multiple real-world datasets demonstrate the effectiveness and efficiency of our approach.

Performing Balanced Ternary Logic and Arithmetic Operations with Spiking Neural P Systems with Anti-Spikes

2012 ◽  
Vol 505 ◽  
pp. 378-385 ◽  
Author(s):  
Xian Wu Peng ◽  
Xiao Ping Fan ◽  
Jian Xun Liu
Keyword(s):  
Logic Gates ◽  
P Systems ◽  
P System ◽  
Ternary Logic ◽  
Arithmetic Operations ◽  
Spiking Neural P Systems ◽  
Addition And Subtraction ◽  
Distributed And Parallel Computing ◽  
Computing Models ◽  
Natural Way

Spiking neural P systems are a class of distributed and parallel computing models inspired by P systems and spiking neural networks.Spiking neural P system with anti-spikes can encode the balanced ternary three digits in a natural way using three states called anti-spikes, no-input and spikes. In this paper we use this variant of SN P system to simulate universal balanced ternary logic gates including AND,OR and NOT gate and to perform some basic balanced ternary arithmetic operations like addition and subtraction on balanced ternary integers. This paper provides an applicational answer to an open problem formulated by L.Pan and Gh. Păun.

On electrometric titration in fused salts

1956 ◽  
Vol 233 (1195) ◽  
pp. 443-454 ◽  
Keyword(s):  
Molten Salt ◽  
Aqueous Medium ◽  
Effect Of Temperature ◽  
Free Energies ◽  
Ionic Melt ◽  
Fused Salts ◽  
Electrometric Titration

Electrometric titrations have been carried out in molten salt media. An equimolar KNO 3 + NaNO 3 melt was used as solvent, and the following systems were investigated: AgCl, AgBr, AgI, AgCN, Ag(CN) - 2 and Ag 2 CrO 4 . The effect of temperature on the solubility was also studied and heats, free energies and entropies of solution in the melt solvent have been calculated. The process of solution in an ionic melt solvent is discussed. It is suggested that the simple Born theory of solvation is more applicable to a solution in a melt than in an aqueous medium.

scholarly journals ON VARIOUS NOTIONS OF PARALLELISM IN P SYSTEMS

2005 ◽  
Vol 16 (04) ◽  
pp. 683-705 ◽  
Author(s):  
OSCAR H. IBARRA ◽  
HSU-CHUN YEN ◽  
ZHE DANG
Keyword(s):  
Catalytic System ◽  
Fixed Number ◽  
P Systems ◽  
P System ◽  
Catalytic Systems ◽  
Computing Power ◽  
Maximal Subset ◽  
Vector Addition ◽  
Parallel Mode ◽  
Vector Addition System

We consider the following definition (different from the standard definition in the literature) of "maximal parallelism" in the application of evolution rules in a P system G: Let R = {r1, …rk} be the set of (distinct) rules in the system. G operates in maximally parallel mode if at each step of the computation, a maximal subset of R is applied, and at most one instance of any rule is used at every step (thus at most k rules are applicable at any step). We refer to this system as a maximally parallel system. We look at the computing power of P systems under three semantics of parallelism. For a positive integer n ≤ k, define: n-Max-Parallel: At each step, nondeterministically select a maximal subset of at most n rules in R to apply (this implies that no larger subset is applicable). ≤ n-Parallel: At each step, nondeterministically select any subset of at most n rules in R to apply. n-Parallel: At each step, nondeterministically select any subset of exactly n rules in R to apply. In all three cases, if any rule in the subset selected is not applicable, then the whole subset is not applicable. When n = 1, the three semantics reduce to the Sequential mode. We focus on two popular models of P systems: multi-membrane catalytic systems and communicating P systems. We show that for these systems, n-Max-Parallel mode is strictly more powerful than any of the following three modes: Sequential, ≤ n-Parallel, or n-Parallel. For example, it follows from the result in [9] that a maximally parallel communicating P system is universal for n = 2. However, under the three limited modes of parallelism, the system is equivalent to a vector addition system, which is known to only define a recursive set. These generalize and refine the results for the case of 1-membrane systems recently reported in [3]. Some of the present results are rather surprising. For example, we show that a Sequential 1-membrane communicating P system can only generate a semilinear set, whereas with k membranes, it is equivalent to a vector addition system for any k ≥ 2 (thus the hierarchy collapses at 2 membranes - a rare collapsing result for nonuniversal P systems). We also give another proof (using vector addition systems) of the known result [8] that a 1-membrane catalytic system with only 3 catalysts and (non-prioritized) catalytic rules operating under 3-Max-Parallel mode can simulate any 2-counter machine M. Unlike in [8], our catalytic system needs only a fixed number of noncatalysts, independent of M. A simple cooperative system (SCO) is a P system where the only rules allowed are of the form a → v or of the form aa → v, where a is a symbol and v is a (possibly null) string of symbols not containing a. We show that a 9-Max-Parallel 1-membrane SCO is universal.

The computational power of timed P systems with active membranes using promoters

2018 ◽  
Vol 29 (5) ◽  
pp. 663-680 ◽  
Author(s):  
YUEGUO LUO ◽  
HAIJUN TAN ◽  
YING ZHANG ◽  
YUN JIANG
Keyword(s):  
P Systems ◽  
P System ◽  
Computational Power ◽  
Computable Set ◽  
Complete Problem ◽  
Active Membranes ◽  
New Variant ◽  
Uniform Solution ◽  
Bioinspired Computing ◽  
Computing Models

P systems with active membranes are a class of bioinspired computing models, where the rules are used in the non-deterministic maximally parallel manner. In this paper, first, a new variant of timed P systems with active membranes is proposed, where the application of rules can be regulated by promoters with only two polarizations. Next, we prove that any Turing computable set of numbers can be generated by such a P system in the time-free way. Moreover, we construct a uniform solution to the$\mathcal{SAT}$problem in the framework of such recognizer timed P systems in polynomial time, and the feasibility and effectiveness of the proposed system is demonstrated by an instance. Compared with the existing methods, the P systems constructed in our work require fewer necessary resources and RS-steps, which show that the solution is effective toNP-complete problem.

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