Absence Of Charge Research Articles

Strong cosmic censorship in de Sitter spacetimes with dark matter

After imposing the weak energy condition on dark matter, we find that even in the absence of charge, a spherically symmetric de Sitter black hole with perfect fluid dark matter may still possess a Cauchy horizon. This paper investigates the stability of the Cauchy horizon in such a black hole under perturbations from a massless scalar field. Through numerical calculations of the massless scalar field's quasinormal modes, we discover that in this spacetime, when the black hole approaches extremality, i.e., when the dark-matter parameter b approaches its maximum value bmax, the Strong Cosmic Censorship (SCC) conjecture may be violated. This is the first instance of classical SCC violation observed in a spherically symmetric, uncharged black hole. Additionally, we explore the region of SCC violation within the parameter space ΛM2−b/bmax. Our findings indicate that as the cosmological constant increases, the violation region initially expands and then contracts.

Extending Anisotropic Interiors admitting Vanishing Complexity in Charged f (R, T) Theory

AbstractThis paper extends the definition of the complexity factor for a charged self‐gravitating structure in the background of gravity. For this purpose, the modified Einstein‐Maxwell field equations and the mass function in terms of interior charge are calculated corresponding to a static sphere. The Reissner‐Nordström exterior spacetime and match it with the spherical interior at the hypersurface to determine the junction conditions are adopted then. The curvature tensor is also decomposed orthogonally, resulting in several scalar functions. Only encompasses all the required parameters and fulfills the proposed criteria to be the complexity factor for the considered setup is noticed. Moreover, some constraints to minimize the degrees of freedom in the field equations are chosen. To achieve this, complexity‐free constraint with four additional conditions depending on the matter sector that lead to different models is employed. The stability of the developed models is also analyzed in the presence and absence of charge through the standard model by varying the values of the model parameter . The presence of charge in compact models corresponding to , a polytropic and a linear equation of state make them stable for specific values of is concluded.

Особенности межмолекулярного взаимодействия в нефтяных дисперсных системах

Oil, gas condensates, oil products present a complex colloidal-dispersed system which often demonstrates the abnormally changing properties when external conditions change. Mixing the petroleum products can be accompanied by a non-linear behavior accompanied by synergistic and antagonistic effects. Understanding of the oil and oil products as oil dispersed systems, the specific features of intermolecular interaction largely clarify their behavior, changes in properties, chemistry and mechanism of reactions occurring in them. Petroleum systems are polydisperse, in which the components can coexist in different aggregate states, and the size of the dispersed phase can vary over a wide range. They consist of diverse compounds that differ in properties, structure, shapes and sizes of molecules. Due to the variety of components that make up oil disperse systems the intermolecular interactions determine such a feature of the behavior of oil systems as the phenomenon of self-organization and structuring, which manifest themselves when external influences change and are sensitive to them. They are characterized by the absence of charge and a minimum of charge-polarization interactions of molecules, and intermolecular interactions are largely determined by the presence of paramagnetic molecules. The uncompensated spin of macromolecular compounds due to the steric obstacles, a homolytic dissociation, and the presence of microelement compounds ensure the paramagnetism of petroleum dispersed systems. This leads to developing the stable associative combinations and the formation of complex structural units capable of redistributing components and layers between phases under the influence of external effects. Comprehensive analysis and unanimity of views on the physical and chemical interactions of the components of oil systems leading to a change in their structure, open up fundamentally new opportunities for intensifying processes in the practice of production, transportation and processing of hydrocarbon raw materials and the use of petroleum products, and also allow predicting the behavior of oil systems in processes which they are participating.

Page curve and phase transition in deformed Jackiw–Teitelboim gravity

We consider the entanglement island in a deformed Jackiw–Teitelboim black hole in the presence of the phase transition. This black hole has the van der Waals–Maxwell-like phase structure as it is coupled with a Maxwell field. We study the behavior of the Page curve of this black hole by using the island paradigm. In the fixed charge ensemble, we discuss different situations with different charges that influence the system’s phase structure. There is only a Hawking–Page phase transition in the absence of charges, which leads to an unstable small black hole. Hence, the related Page curve does not exist. However, a van der Waals–Maxwell-like phase transition occurs in the presence of charges. This yields three black hole solutions. The Page curve of the middle size black hole does not exist. For the extremal black hole, the Page time approaches zero in the phase transition situation but becomes divergent without the phase transition. In a word, we study the Page curve and the island paradigm for different black hole phases and in different phase transition situations.

A new class of charged spherically symmetric and static superdense star configurations

In this paper, we have obtained a new family of interior solutions of the Einstein–Maxwell field equations in general relativity for static, spherically symmetric distribution of charged fluid. The electric density is assumed to be [Formula: see text] where [Formula: see text] is a positive constant. The solution is well behaved for a wide range of [Formula: see text] hence, it is suitable for modeling a superdense star. The surface density is assumed to be [Formula: see text], for the validation of the solution set present, a comparison has also been made with the stars EXO 1785-248, SMC X-1, Her X-1, 4U 1538-52. For these particular stars, the maximum value of surface redshift is obtained to be 0.3251 for the star EXO 1785-248 and the minimum value is obtained as 0.2027 for the star Her X-1. We subject our solution to rigorous physical viability tests. In the absence of charge, we obtain the regular and well-behaved sixth model of Durgapal.

Wormlike micelles of CTAB with phenols and with the corresponding phenolate derivatives - When hydrophobicity and charge drive the coacervation

HypothesisHydrophobicity and the presence or absence of charge in phenol derivatives are relevant on the rheology and phase behavior when they are assembled with a cationic surfactant, forming wormlike micelles. The incorporation of phenols with a greater number of rings into the micellar palisade is entropically favored, but a solubilization limit or coacervation are two paths followed by the solutions, depending on the electrical nature of the aromatic co-solutes. ExperimentsThe investigations were carried out with systems formed by a fixed concentration of hexadecyltrimethylammonium bromide (CTAB) and increasing concentrations of neutral phenols (1-naphthol, 2-naphthol, 2,3-dihydroxynaphthalene and R and S-binol) and with their corresponding phenolate derivatives. The monophasic limits of the systems were established, as well as their linear and non-linear rheology. The structural investigation of the coacervates formed with the phenolates were done using SAXS and Cryo-TEM. FindingsThe zero-shear viscosity of the solutions reaches maxima values close to the solubility limit of the aromatics, which depends on the numbers of rings and hydroxyl groups (position and number). However, when the correspondent ionized phenols were investigated, beyond the maxima values for the zero-shear viscosity, liquid–liquid biphasic systems are formed, in which the upper phase contains a coacervate, associated with branched wormlike micelles. However, when the ratio between phenolate and CTAB is around 3:1 the coacervate evolves to a lamellar structure.

The results of a study on the development of a constructive and technological device for protect-ing water intakes of irrigation systems from blue-green algae

The article presents the information of the conducted experimental studies on the development of a constructive and technological device for the protection of water intakes of irrigation systems from blue-green algae. The purpose of this experiment was to determine the charge sign of large colonies of cyanobacteria. During the experiments, it was found that colonies of "living" cyanobacteria have a negative charge sign, since they detected a characteristic movement towards the anode, and colonies of "dead" algae showed no characteristic movement towards the anode or cathode, which indicates the absence of charge. Research on the development of a constructive and technological device for protecting water intakes of irrigation systems from blue-green algae was carried out in three stages: trial coagulation in laboratory conditions; filtration using ruffs in laboratory conditions; field studies at the pilot plant. In conclusion, a new technological and design method of improving the aquatic ecosystem, in the form of a water intake and treatment facility, is proposed. The introduction of the developed constructive and technological device for protecting irrigation system intakes from blue-green algae will give the operation mode of sprinkler machines stability, significantly reduce energy consumption for pumping irrigation water during the flowering of reservoirs, increase soil fertility, which will eventually increase crop yields and generally improve the functionality of the reclamation system.

Gelation of Gelatin: An Introduction to the Physics of Gels by Means of Rheological Investigations

Gels are common materials in our everyday life: in food products, in cosmetics and in health care. Among the most common and useful gels are gelatin based gels which are obtained through denaturation and hydrolysis of collagen, an important structural protein in animals [1]. Depending on the extraction in acidic or basic media one can distinguish between gelatin A and gelatin B respectively. Gelatin A has an alkaline isoelectric point and gelatin B has an isoelectric point close to 5. The isoelectric point of a protein corresponds to the pH value where the protein does not migrate in the presence of an electric field, meaning not the absence of charges but an equal amount of positive and negative charges.

Effects of different pH of 3.5% NaCl solution on steel under zero charge corrosion protection technique

The study is carried out to understand the new corrosion protection technique, non-polarization concept, using current/voltage pulses to achieve a potential of zero charges (Epzc) of the metal-solution interface. As a result, a cost-saving and ecological method has been proposed as a new anti-corrosion method. In the methodology, U-bend samples are immersed in a 3.5% NaCl solution with different pH values. The readings prove the occurrence of electrochemical reaction, absence of charges, and the effect of Epzc. An examination on the ZCCP on low-carbon steel in 3.5% NaCl solution was analyze for 120 hours days. This study is carried out to understand the concept of corrosion behaviour and a new corrosion protection technique which applies non-polarization concept. A U-bend mild steel is used to corrosion effect in various pH values under zero charge protection. Samples were then immersed in 3.5% NaCl solution with different pH values. Electrochemical behaviour of steel sample in 3.5% NaCl solution was analysed by means of Tafel extrapolation. It was found that Ecorr and icorr recorded dissimilar readings at different pH values. As Ecorr rises, icorr drops from pH 6 to pH 9, hence corrosion rate also decreases from pH 6 to pH 9. Zero charge corrosion protection (ZCCP) technique is used to study the efficiency of corrosion protection method in different pH values. Readings of alternating current (IAC) and direct voltage (VDC) are recorded throughout the ZCCP experiment. These readings prove the occurrence of electrochemical reaction, absence of charges and the effect of Epzc.

Water-Soluble Non-Ionic PEGylated Porphyrins: A Versatile Category of Dyes for Basic Science and Applications.

This review arises from the need to rationalize the huge amount of information on the structural and spectroscopic properties of a peculiar class of porphyrin derivatives-the non-ionic PEGylated porphyrins-collected during almost two decades of research. The lack of charged groups in the molecular architecture of these porphyrin derivatives is the leitmotif of the work and plays an outstanding role in highlighting those interactions between porphyrins, or between porphyrins and target molecules (e.g., hydrophobic-, hydrogen bond related-, and coordination-interactions, to name just a few) that are often masked by stronger electrostatic contributions. In addition, it is exactly these weaker interactions between porphyrins that make the aggregated forms more prone to couple efficiently with external perturbative fields like weak hydrodynamic vortexes or temperature gradients. In the absence of charge, solubility in water is very often achieved by covalent functionalization of the porphyrin ring with polyethylene glycol chains. Various modifications, including of chain length or the number of chains, the presence of a metal atom in the porphyrin core, or having two or more porphyrin rings in the molecular architecture, result in a wide range of properties. These encompass self-assembly with different aggregate morphology, molecular recognition of biomolecules, and different photophysical responses, which can be translated into numerous promising applications in the sensing and biomedical field, based on turn-on/turn-off fluorescence and on photogeneration of radical species.

Modified black hole solution with a background Kalb\u2013Ramond field

We study the gravitation effects on a static and spherically symmetric spacetime due to the vacuum expectation value (VEV) of a Kalb–Ramond field. The Kalb–Ramond VEV is a background tensor field which produces a local Lorentz symmetry breaking (LSB) of spacetime. Considering a non-minimal coupling between the Kalb–Ramond (VEV) and the Ricci tensor, we obtain an exact parameterdependent power-law modified black hole. For a particular choice of the LSB parameter, the Lorentz violation produces a solution similar to the Reissner–Nordstrom, despite the absence of charge. The near-horizon geometry is modified by including a new inner horizon and shifting the Schwarzschild horizon. Asymptotically, the usual Minkowski spacetime with a background tensor field is recovered. The vacuum configurations are studied considering the energy conditions and the Lorentz violating source properties. By means of the mercury perihelion test, an upper bound to the local Lorentz violation (LV) is obtained, and its corresponding effects on the black hole temperature is investigated.

Content Aware Refresh: Exploiting the Asymmetry of DRAM Retention Errors to Reduce the Refresh Frequency of Less Vulnerable Data

DRAM refresh is responsible for significant performance and energy overheads in a wide range of computer systems, from mobile platforms to datacenters [1] . With the growing demand for DRAM capacity and the worsening retention time characteristics of deeply scaled DRAM, refresh is expected to become an even more pronounced problem in future technology generations [2] . This paper examines content aware refresh , a new technique that reduces the refresh frequency by exploiting the unidirectional nature of DRAM retention errors: assuming that a logical 1 and 0 respectively are represented by the presence and absence of charge, 1 -to- 0 failures are much more likely than 0 -to- 1 failures. As a result, in a DRAM system that uses a block error correcting code (ECC) to protect memory, blocks with fewer 1 s can attain a specified reliability target (i.e., mean time to failure) with a refresh rate lower than that which is required for a block with all 1 s. Leveraging this key insight, and without compromising memory reliability, the proposed content aware refresh mechanism refreshes memory blocks with fewer 1 s less frequently. To keep the overhead of tracking multiple refresh rates manageable, refresh groups—groups of DRAM rows refreshed together—are dynamically arranged into one of a predefined number of refresh bins and refreshed at the rate determined by the ECC block with the greatest number of 1 s in that bin. By tailoring the refresh rate to the actual content of a memory block rather than assuming a worst case data pattern, content aware refresh respectively outperforms DRAM systems that employ RAS-only Refresh, all-bank Auto Refresh, and per-bank Auto Refresh mechanisms by 12, 8, and 13 percent. It also reduces DRAM system energy by 15, 13, and 16 percent as compared to these systems.

Peptide Nucleic Acid-Functionalized Adenoviral Vectors Targeting G-Quadruplexes in the P1 Promoter of Bcl-2 Proto-Oncogene: A New Tool for Gene Modulation in Anticancer Therapy.

The B-cell lymphoma 2 (Bcl-2) gene encodes for an antiapoptotic protein associated with the onset of many human tumors. Several oligonucleotides (ONs) and ON analogues are under study as potential tools to counteract the Bcl-2 expression. Among these are Peptide Nucleic Acids (PNAs). The absence of charges on PNA backbones allows the formation of PNA/DNA complexes provided with higher stability than the corresponding natural DNA/DNA counterparts. To date, the use of PNAs in antigene or antisense strategies is strongly limited by their inability to efficiently cross the cellular membranes. With the aim of downregulating the expression of Bcl-2, we propose here a novel antigene approach which uses oncolytic adenoviral vectors (OAds) as a new cancer cell-targeted PNA delivery system. The ability of oncolytic Ad5D24 vectors to selectively infect and kill cancer cells was exploited to transfect with high efficiency and selectivity a short cytosine-rich PNA complementary to the longest loop of the main G-quadruplex formed by the 23-base-long bcl2midG4 sequence located 52-30 bp upstream of the P1 promoter of Bcl-2 gene. Physico-chemical and biological investigations confirmed the ability of the PNA-conjugated Ad5D24 vectors to load and transfect their PNA cargo into human A549 and MDA-MB-436 cancer cell lines, as well as the synergistic (OAd+PNA) cytotoxic effect against the same cell lines. This approach holds promise for safer chemotherapy because of reduced toxicity to healthy tissues and organs.

Role of hydrophobicity in food peptide functionality and bioactivity

Peptides are important compounds used in the development of functional biomaterials, functional foods and nutraceuticals. The functional and bioactive properties of peptides are directly linked to their structural features, including molecular size, presence or absence of charges, amino acid sequence, hydrophobicity, and hydrophilicity. The role of peptide structures in their bioactivities and functionalities is still emerging. Some bioactive peptides have undesirable taste, which can influence consumer interests in novel peptide-based food applications. In this review, we discussed the role of peptide hydrophobicity in their bioavailability, bioactivity, bitterness property, emulsion stability, aggregation and self-assembly for application in novel food formulations and nutraceutical/ drug delivery.

Stationary solutions from the large D membrane paradigm

It has recently been shown that the dynamics of black holes in large number of dimensions D can be recast as the dynamics of a probe membrane propagating in the background spacetime which solves Einstein equations without matter. The equations of motion of this membrane are simply the statement of conservation of the stress tensor and charge current defined on this membrane. In this paper we obtain the effective equations of motion for stationary membranes in any empty background both in presence and absence of charge. It turns out that the thermodynamic quantities associated with the stationary membranes that satisfy these effective equations also satisfy the first law of black hole thermodynamics. These stationary membrane equations have some interesting solutions such as charged rotating black holes in flat and AdS backgrounds as well as black ring solutions in large D.

Co-Crystallization of Achiral Components into Chiral Network by Supramolecular Interactions: Coordination Complexes – Organic Radical

Co-crystallization is an important aspect of crystal engineering that has found major applications in the development and manufacture of pharmaceutical drugs but is rarely invoked in the development of magnetic materials. Co-crystals have been serendipitously obtained instead of the usual coordination polymers from the organic radical, 2,2-pentamethylene-4,4,5,5-tetramethylimidazolidine-l-oxyl, and coordination complexes, cis-MII(hfac)2(H2O)2, where M = Co or Mn and hfac = hexafluoroacetylacetonato. The extensive intramolecular H-bond is the cause for the segregation of the two entities but the supramolecular interactions between these two neutral building blocks resulted in a rare chiral co-crystal system. The directional properties of the supramolecular interactions, N–O···OH2, N–H···OH2, N–O···CH3, N–O···CH2, F···CH3, and F···CH2, have been identified as working in tandem to generate the chirality from achiral components in achiral solvents. The absence of charge or proton transfer as suggested by X-ra...

Nonlinear time-harmonic Maxwell equations in domains

The search for time-harmonic solutions of nonlinear Maxwell equations in the absence of charges and currents leads to the elliptic equation $$\begin{aligned} \nabla \times \left( \mu (x)^{-1}\nabla \times u\right) - \omega ^2\varepsilon (x)u = f(x,u) \end{aligned}$$ for the field $$u:\Omega \rightarrow \mathbb {R}^3$$ in a domain $$\Omega \subset \mathbb {R}^3$$ . Here, $$\varepsilon (x) \in \mathbb {R}^{3\times 3}$$ is the (linear) permittivity tensor of the material, and $$\mu (x) \in \mathbb {R}^{3\times 3}$$ denotes the magnetic permeability tensor. The nonlinearity $$f:\Omega \times \mathbb {R}^3\rightarrow \mathbb {R}^3$$ comes from the nonlinear polarization. If $$f=\nabla _uF$$ is a gradient, then this equation has a variational structure. The goal of this paper is to give an introduction to the problem and the variational approach, and to survey recent results on ground and bound state solutions. It also contains refinements of known results and some new results.

On cracking of charged anisotropic polytropes

Recently in [1], the role of electromagnetic field on the cracking of spherical polytropes has been investigated without perturbing charge parameter explicitly. In this study, we have examined the occurrence of cracking of anisotropic spherical polytropes through perturbing parameters like anisotropic pressure, energy density and charge. We consider two different types of polytropes in this study. We discuss the occurrence of cracking in two different ways (i) by perturbing polytropic constant, anisotropy and charge parameter (ii) by perturbing polytropic index, anisotropy and charge parameter for each case. We conclude that cracking appears for a wide range of parameters in both cases. Also, our results are reduced to [2] in the absence of charge.

Bioavailability studies and anticancer properties of malvidin based anthocyanins, pyranoanthocyanins and non-oxonium derivatives.

In this study, the gastric transport efficiency of malvidin-3-glucoside and several derivatives was assayed on the MKN-28 cell model. The transport efficiency was found to increase for all compounds with the incubation time. Pyranoanthocyanins may slightly impair transport efficiency levels in comparison with native anthocyanins. Among the pyranoanthocyanin derivatives the presence of the carbonyl group and the absence of charge were important for the transport efficiency percentage of oxovitisin and apparently compensated the negative effect associated with the additional ring. Moreover, the antiproliferative properties of these compounds in the MCF-7 cancer cell line were assayed, oxovitisin being the most effective compound in inhibiting the proliferation of MCF-7 cells. Also, a kinetic incorporation of oxovitisin was assayed revealing that this pyranoanthocyanin is quickly incorporated into cells. This study confirms the importance of the natural micro-oxidative processes that occur during the ageing of anthocyanin-containing food and their impact on their bioavailability and bioactivity properties.

Disposable Plasmonics: Plastic Templated Plasmonic Metamaterials with Tunable Chirality.

Development of low-cost disposable plasmonic substrates is vital for the applicability of plasmonic sensing. Such devices can be made using injection-molded templates to create plasmonic films. The elements of these plasmonic films are hybrid nanostructures composed of inverse and solid structures. Tuning the modal coupling between the two allows optimization of the optical properties for nanophotonic applications.