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Constant-composition codes are a subclass of constant weight codes. When $d\geq 4$ , the problem of determining the maximum size of a constant-composition code for general parameters is much less understood. In this correspondence, we give a new construction for constant-composition codes with techniques in additive number theory. Moreover, we provide a new connection between constant-composition codes and linear block codes with certain properties. It turns out that when $d\geq 4$ our new lower bounds improve the one by Ding (2008) substantially.

In this paper, we consider the scatter of the laminar flame front velocities caused both by an error in the composition of the combustible mixture and by artificial initial disturbances. It is shown how the configuration of the initial perturbations of an initially flat front of a laminar flame in a gas mixture with the constant composition affects the velocity spread of expanding spherical flames. The effect of the error in the composition of the combustible mixture on the parameters that determine the flame front velocity was analyzed from the literature data on the spread of the flame propagation velocity. These parameters were recalculated for the possible variation in the mixture composition obtained based on the data on the accuracy of the equipment used in the experiments.

The production of struvite (MgNH4PO4·6H2O) from dairy lagoon wastewater (DW) improves phosphorus (P) resource sustainability and reduces the rate of deposition of P into surface waters. Struvite fo...

Feed is one of the important factor that affect livestock productivity, so the availability of good quality feed is a requirement for livestock development in an area. In the tropical area, providing forage as a crucial feed for ruminants was hampered by fluctuating seasons. Likewise, the availability of agricultural waste as an alternative source of feed material experiences the same constraints, easily damaged, and bulky (voluminous). Therefore, feed processing technology is needed so that it is become durable, easily stored, and easily provided for livestock. One way to overcome this is to utilize technology for making wafers. Information regarding technology for making animal feed wafers in Indonesia is still limited. This paper reviews a number of studies that discuss the development of wafer processing technology, types of wafers, the main components of wafer compilers, wafer manufacturing processes, reactions that occur during wafer manufacturing, nutrient quality of various wafers, and the results of research on the use of wafers for feed livestock. Wafers are feeds that are processed using heat and pressure, so that a solid, compact, and high density product is formed. Feed wafer technology is a modification of cube and block feed. Wafers are divided into feed wafers, feed supplement wafers, and complete feed wafers. Feed wafers can be used instead of concentrates. Feed supplement wafers are high in energy and protein. Complete feed wafers contain energy, protein, fiber, and complete minerals that have been adapted to the daily nutritional needs of livestock. Feed wafer processing technology can be one of the strategies to provide feed with a constant composition of nutrients throughout the season and increase production and feed efficiency.

We present the adsorption data of CO2, CH4, and N2 ternary mixtures on anthracite from 293.15 to 353.15 K and pressures up to 7 MPa obtained via a volumetric method. The experimental data are given at different conditions, and simple analysis is made. The results show that the excess adsorption capacity of the CO2/CH4/N2 mixture and its component gases decreases linearly with the increase of temperature for constant composition. The total adsorption capacity is between pure CO2 and pure N2 in the entire pressure range. The effect of total pressure on total adsorption capacity is mainly influenced by the CO2 mole fraction in the feed gas. However, the adsorption capacities of CH4 and N2 decrease, and CO2 presents a maximum with the decrease in total pressure. For the feed gases of 10% CH4 and 16% CO2, the total adsorption capacity increases when the ratio of CO2 and CH4 increases, respectively, and the increasing magnitudes for 10% CH4 are larger than that of 16% CO2. The obtained experimental data are in agreement with the extended three-parameter Ono-Kondo model.

This chapter introduces the PVT challenges of gas injection. First, the phase diagram of various gases, oil samples and mixtures of oil and gas are investigated. In the next part, the important PVT experiments are discussed in details. These experiments consist of CCE (constant composition expansion), DL (differential liberation), CVD (constant volume depletion), flash separation and swelling test. Some calculation must be considered for designing the gas injection process as it is discussed in Sect. 2.4. In Sects. 2.5, 2.6 and 2.7, three cases are studied about change of phase behavior due to gas injection, MMP calculation of gas injection and asphaltene precipitation due to gas injection, respectively. The optimum design of gas injection and PVT challenges associated with gas injection are presented in Sects. 2.8 and 2.9, respectively.

Let $$v \equiv 4 \pmod 6$$ and $$v\ge 4$$ . A canonical Kirkman packing design of order v, denoted by $$\hbox {CKPD}(v)$$ , is a resolvable packing with $$r=(v-4)/2$$ parallel classes such that (i) each parallel class consists of a size 4 block and $$(v- 4)/3$$ triples; (ii) the leave consists of the union of $$(v- 4)/2$$ vertex-disjoint edges and a $$K_4$$ with no vertices in common with those edges. A canonical Kirkman packing design is said to be doubly resolvable if there exist a pair of orthogonal resolutions. A doubly resolvable packing design is the generalization of the Kirkman square, which is inextricably bound up with the existence of some constant weight codes such as constant composition codes and permutation codes, etc. In this paper, we establish the spectra of doubly resolvable $$\hbox {CKPD}(v)\hbox {s}$$ with 36 possible exceptions for v. As its direct application, a class of permutation codes are obtained.

X-ray spectra of glass of the sodium-borate system are obtained by the method of X-ray diffractometry. Using the proposed processing of these spectra, the smallest elements of the sodium–borate glass structure (constant stoichiometry groups, CSGs), which unambiguously determine their properties, are determined. The method for determining the smallest elements of the glass structure consists of comparing the glass contours with the known contour of a glass of a stoichiometric composition.

A concept of good overlarge set of disjoint packing triple systems (OLPTS) is introduced in order to characterize a ternary constant-composition code with weight four, distance three and the composition [ 3 , 1 ] . A recursive construction for good OLPTSs via fan designs is also given. 4-cycle free one-factorizations of the complete graphs are also used to construct optimal ternary constant-composition codes with weight four distance three and the composition [ 2 , 2 ] . Consequently, a few infinite classes of optimal ternary constant-composition codes with weight four and distance three are obtained.

In this paper, on one hand, a class of linear codes with one or two weights is obtained. Based on these linear codes, we construct two classes of constant composition codes, which includes optimal constant composition codes depending on LVFC bound. On the other hand, a class of constant composition codes is derived from known linear codes., 13pages

We analyse trends in average wage growth in New Zealand from 1997 to 2015, focusing on the contributions of within‐group wage growth and employment compositional changes, and whether there have been secular or cyclical changes in these contributions. Real wage growth was mildly pro‐cyclical over the period, and has been weaker during the recovery from the global financial crisis. We estimate that within‐group wage growth dominated aggregate wage growth, and compositional changes provided only trivial contributions. Furthermore, within‐group wage growth is primarily from constant composition wage growth, contributing on average 0.9 per cent to annual wage growth, while improvements in observable human capital characteristics of workers contributed 0.4 per cent on average.

Probabilistic amplitude shaping&mdash, implemented through a distribution matcher (DM)&mdash, is an effective approach to enhance the performance and the flexibility of bandwidth-efficient coded modulations. Different DM structures have been proposed in the literature. Typically, both their performance and their complexity increase with the block length. In this work, we present a hierarchical DM (Hi-DM) approach based on the combination of several DMs of different possible types, which provides the good performance of long DMs with the low complexity of several short DMs. The DMs are organized in layers. Each upper-layer DM encodes information on a sequence of lower-layer DMs, which are used as &ldquo, virtual symbols&rdquo, First, we describe the Hi-DM structure, its properties, and the encoding and decoding procedures. Then, we present three particular Hi-DM configurations, providing some practical design guidelines, and investigating their performance in terms of rate loss and energy loss. Finally, we compare the system performance obtained with the proposed Hi-DM structures and with their single-layer counterparts: a 0.19dB SNR gain is obtained by a two-layer Hi-DM based on constant composition DMs (CCDM) compared to a single-layer CCDM with same complexity, a 0.12dB gain and a significant complexity reduction are obtained by a Hi-DM based on minimum-energy lookup tables compared to a single-layer DM based on enumerative sphere shaping with same memory requirements.

A strong converse bound for constant composition codes of the form $P_{e}^{(n)} \geq 1- A n^{-0.5(1-E_{sc}'(R,W,p))} e^{-n E_{sc}(R,W,p)}$ is established using the Berry-Esseen theorem through the concepts of Augustin information and Augustin mean, where $A$ is a constant determined by the channel $W$, the composition $p$, and the rate $R$, i.e., $A$ does not depend on the block length $n$., Comment: 7 pages

The K2NixCo(1-x)(SO4)2·6H2O (KCNSH) mixed crystals were grown from solutions of different composition by the temperature difference technique with continuous solution feeding. The schemes of the solution supply and condensate extraction were calculated, which allowed maintaining the constant composition of the crystals. The real structure and optical properties of the crystals obtained were studied. The experimental samples of optical filters were made from KCNSH mixed crystals and their optical characteristics had been studied. Their high optical quality is shown.

Calcification is among the principal causes of biological heart valve substitute failure. Glycosaminoglcans (GAGs) are negatively charged molecules, possessing anticoagulation and anti-inflammatory activity that make them a potential solution against calcification. In the present work, the anticalcification potential of heparin was investigated under constant supersaturation conditions with respect to hydroxyapatite (Ca 5 (PO 4 ) 3 OH; HAP). Heparin concentration in the supersaturated solutions was in the range between 0.25 and 3 ppm, at pH 7.40 and 37 °C. Heparin showed inhibitory activity, which was attributed to adsorption at the active crystal growth centres. Heparin concentration as low as ca. 50 μM, reduced the rate of HAP crystal growth by more than 80%, while further increase (up to 200 μM) failed to completely inhibit the process beyond 90%. Heparin uptake studies at equilibrium conditions and analysis of the kinetics data in the presence of heparin, strongly suggest that the inhibition is due to the adsorption of heparin onto the HAP crystals, which resulted in the poisoning of the active growth sites.

The Johnson-type upper bound on the maximum size of a code of length $n$, distance $d=2w-1$ and constant composition ${\overline{w}}$ is $\lfloor\dfrac{n}{w_1}\rfloor$, where $w$ is the total weight and $w_1$ is the largest component of ${\overline{w}}$. Recently, Chee et al. proved that this upper bound can be achieved for all constant-composition codes of sufficiently large lengths. Let $N_{ccc}({\overline{w}})$ be the smallest such length. The determination of $N_{ccc}({\overline{w}})$ is trivial for binary codes. This paper provides a lower bound on $N_{ccc}({\overline{w}})$, which is shown to be tight for all ternary and quaternary codes by giving new combinatorial constructions. Consequently, by refining method, we determine the values of $N_{ccc}({\overline{w}})$ for all $q$-ary constant-composition codes provided that $3w_1\geq w$ with finite possible exceptions., Comment: 11 pages

The solid-phase equilibria and thermodynamic properties of an As–Se system are studied using the electromotive force (EMF). The existence of compounds As2Se3, AsSe, and As4Se3 in a system with near constant composition is confirmed. The relative partial molar functions, standard Gibbs free energies, enthalpies of formation, and standard entropies of As in the alloys are calculated using EMF measurements.

A high-Ge-content Si1–yGey/compositionally graded Si1–xGex-stacked structure grown on Si(001) is now considered to be an important platform for the realization of advanced nanometer-scale complementary metal oxide semiconductor devices with high-mobility channel materials, such as III–V materials and Ge, and monolithically integrated photonic modules. The performance of such advanced devices is critically influenced by crystalline inhomogeneity in the stacked structure; therefore, precise characterization of the crystallinity is important. In particular, the development of a characterization method not only for in-plane crystallinity but also for in-depth crystallinity is strongly required. This is because the crystalline quality of the constant composition Si1–yGey is sensitively dependent on that of the compositionally graded Si1–xGex layers underneath. Here, we have demonstrated in-depth tomographic mapping of a high-Ge-content Si1–yGey/compositionally graded Si1–xGex-stacked structure using position-d...

Uniform constant composition (UCC) codes are introduced, which are p-ary constant composition codes with block length mp where each p-ary symbol appears exactly m times in each codeword, being m a positive integer and p a prime. UCC codes are derived from a new class of p-ary repeated-root cyclic codes and two constructions are presented. Both constructions are at least asymptotically optimal with increasing p when compared with known best bounds for constant composition codes.

The results of studying the composition of arsenic trisulphide (As2S3) films obtained by adding finely dispersed copper or silver powders to the starting materials for sputtering or by using triple compositions As–S–As and As–S–Cu are presented. The issues of preserving the composition of the films obtained and the degree of their purity are discussed.

A judicious application of the Berry-Esseen theorem via the concepts of Augustin information and mean is demonstrated to be sufficient for deriving the sphere packing bound with a prefactor that is $\Omega \left( {{n^{ - 0.5\left( {1 - E_{sp}^\prime \left( {R,W,p} \right)} \right)}}} \right)$ for the constant composition codes. The resulting non-asymptotic bounds have definite approximation error terms.

In this paper, we establish an interesting duality between two different quantum information-processing tasks, namely, classical source coding with quantum side information, and channel coding over c-q channels. The duality relates the optimal error exponents of these two tasks, generalizing the classical results of Ahlswede and Dueck. We establish duality both at the operational level and at the level of the entropic quantities characterizing these exponents. For the latter, the duality is given by an exact relation, whereas for the former, duality manifests itself in the following sense: an optimal coding strategy for one task can be used to construct an optimal coding strategy for the other task. Along the way, we derive a bound on the error exponent for c-q channel coding with constant composition codes which might be of independent interest., Comment: 35 pages

Saddlepoint approximations to the error probability are derived for multiple-cost-constrained random coding ensembles where codewords satisfy a set of constraints. Constant-composition inputs over a binary symmetric channel are studied as a particular case. For codewords with equiprobable empirical distribution, the analysis recovers the same error exponent and pre-exponential polynomial decay as the uniform i.i.d. ensemble and provides an explicit formula for the loss in prefactor (third-order term) incurred by the constant-composition ensemble.

The knowledge of specific mass of drilling fluids are of great importance in defining the characteristics of them during drilling wells. In the present work, the specific mass of distilled water was carried out in a PVT (Pressure-Volume-Temperature) cell using the Constant Composition Expansion procedure under high pressure and high temperature. Results showed a good agreement with literature valures.

For classical discrete systems with constant composition (typically referred to substitutional alloys) under thermodynamically equilibrium state, macroscopic structure should in principle depend on temperature and many-body interaction through Boltzmann factor, exp(-bE). Despite this fact, our recently find that (i) thermodynamic average for structure can be characterized by a set of special microscopic state whose structure is independent of energy and temperature, and (ii) bidirectional-stability character for thermodynamic average between microscopic structure and potential energy surface is formulated without any information about temperature or many-body interaction. These results strongly indicates the significant role of configurational geometry, where anharmonicity in structural degree of freedom (ASDF) that is a vector field on configuration space, plays central role, intuitively corresponding to nonlinearity in thermodynamic average depending only on configurational geometry. Although ASDF can be practically drawn by performing numerical simulation based on such as Monte Carlo simulation, it is still unclear how its entire character is dominated by geometry of underlying lattice. We here show that by applying the limit in tropical geometry (i.e., tropical limit) with special scale-transformation to discrete dynamical system for ASDF, we find tropical relationships between how nonlinearity in terms of configurational geometry expands or shrinks and geometric information about underlying lattice for binary system with a single structural degree of freedom (SDF). The proposed tropical limit will be powerful procedure to simplify analyzation of complicated nonlinear character for thermodynamic average with multiple SDF systems., Comment: 5 pages, 3 figures (More accurate expression for series expansion is applied)

An algorithm of distribution matching which could be effectively implemented for short block lengths of around 100 bit or less is proposed, enabling better performance than the constant composition schemes with the same block lengths.

For substitutional alloys typically referred to as classical discrete systems under constant composition, a set of microscopic states dominantly contributing to thermodynamically equilibrium struct...

In the present paper, by generalizing the definition of the zero-difference balanced (ZDB) function to be the G-ZDB function, several classes of G-ZDB functions are constructed based on properties of cyclotomic numbers. Furthermore, some special constant composition codes are obtained directly from G-ZDB functions.

Information regarding the sulfur content of the coal is required not only in metallurgy but also when burning coal as a fuel. The traditional method of determining the sulfur content of coal is unsuitable for large-scale monitoring of processes because it is laborious and not sufficiently reliable. Nuclear-physics methods are free of those problems. However, satisfactory precision of the results is only possible with relatively constant composition of the coal or when the matrix effect due to fluctuations in the composition is taken into account. In the present work, the composition of coal is studied by correlation and regression analysis of the ash composition in coal from different deposits. The correlation coefficients between the main ash components (Al2O3, SiO2, SO3, CaO, and Fe2O3) are calculated. For the example, of coal from Kazakhstan and the Minusinsk Basin, statistically significant correlations are established between the contents of sulfur and calcium in the coal; the correlation coefficient is 0.75–0.93. No significant and consistent correlations are found between other ash components. These findings permit optimal development of nuclear-physics methods of monitoring the sulfur content of coal—specifically, in improving the precision of the analysis by taking account of the matrix effect due to redistribution of the mineral components.

For a classical discrete system under constant composition, the macroscopic structure in a thermodynamically equilibrium state can be typically determined through the so-called canonical average, i...

A variant of successive decoding for asynchronous multiple access channel is introduced involving constant composition codebooks and maximal mutual information decoder. This admits to improve known achievability results to universal achievability, complemented by error exponents. A further result is that when synchronization is available, a deliberate shifting of the starting times of codewords (controlled asynchronism) combined with successive decoding offers a substitute for techniques of rate splitting and time sharing.

Uniform constant composition codes are particular cases of constant composition codes, where every symbol of the alphabet appears λ times in the codewords. A construction of optimal uniform constant composition codes with no restrictions over the alphabet is presented.

A robust numerical scheme for the calculation of constant composition (isoplethic) phase diagrams of complex multicomponent mixtures is presented. The scheme refers to the sequential calculation of the phase envelope of a mixture by guiding the estimation for the equilibrium curve via the introduction of a “spring” that sets the slope value of the modified tangent plane distance with respect to either temperature or pressure. A simple variation of the proposed method allows direct estimation of the Cricondentherm and/or Cricondenbar points, thus avoiding the calculation of the entire phase diagram. Extensive tests of the proposed scheme for different types of phase diagrams, using both cubic and higher-order equations of state are presented. © 2015 American Institute of Chemical Engineers AIChE J, 62: 868–879, 2016

The effects of 1% tin (Sn) addition on the densification of pre-alloyed and pre-mixed W-brass composites were carried out. The green compacts were produced with the pressure of 350MPa and sintered at the temperature of 800°C, 920°C and 1000°C. The Sn addition is aimed at inhibiting the dezincification (selective removal of zinc from an alloy) of the brass component by the elimination of pores and enhances densification. The hardness of the composites increased with increase in temperature, the densification was low at both temperatures while the electrical conductivity remains constant as a result of constant composition in both pre-alloyed and pre-mixed composites. The microstructures revealed pores, which might be as a result of zinc evaporation.