Wilhelm Sunde Lie, Ingve Simonsen, Paul Gunnar Dommersnes
Turbulence is most commonly associated with high Reynolds number flow, however the framework of turbulent dynamics has been conceptually extended to many other fields, such as magnetohydrodynamic turbulence, elastic wave turbulence in solids, and more recently to low Reynolds number active turbulence in biological fluids. Here we report a form of solid turbulent dynamics in a self-propelled two-dimensional elastic sheet. We show numerically that the polar ordering dynamics in the active elastic solid model (AES) exhibit hallmark features of turbulent dynamics: power-law scaling of the energy spectrum and non-Gaussian statistics of velocity increments. However, there is no energy cascade, in line with previous findings for active turbulence in fluids. These results extend the concept of active turbulence to solid-state active matter, and can be important for understanding collective dynamics in biological active solids such as bacterial colonies and epithelial cell layers.
Piotr Gruza, Leszek Aleksander Kołodziejczyk, Mateusz Łełyk
It was shown by Visser that Peano Arithmetic has the property that any two bi-interpretable extensions of it (in the same language) are equivalent. Enayat proposed to refer to this property of a theory as tightness and to carry out a more systematic study of tightness and its stronger variants that he called neatness and solidity. Enayat proved that not only $\mathrm{PA}$, but also $\mathrm{ZF}$ and $\mathrm{Z}_2$ are solid. On the other hand, it was shown in later work by a number of authors that many natural proper fragments of those theories are not even tight. Enayat asked whether there is a proper solid subtheory of the theories listed above. We answer that question in the case of $\mathrm{PA}$ by proving that for every $n$, there exist both a solid theory and a tight but not neat theory strictly between $\mathrm{I}Σ_{n}$ and $\mathrm{PA}$. Moreover, the solid subtheories of $\mathrm{PA}$ can be required to be unable to interpret $\mathrm{PA}$. We also obtain some other separations between properties related to tightness, for example by giving an example of a sequential theory that is neat but not semantically tight in the sense of Freire and Hamkins.
Abdur Rab Dhruba, Kazi Nabiul Alam, Md. Shakib Khan
et al.
The environment, especially water, gets polluted due to industrialization and urbanization. Pollution due to industrialization and urbanization has harmful effects on both the environment and the lives on Earth. This polluted water can cause food poisoning, diarrhea, short-term gastrointestinal problems, respiratory diseases, skin problems, and other serious health complications. In a developing country like Bangladesh, where ready-made garments sector is one of the major sources of the total Gross Domestic Product (GDP), most of the wastes released from the garment factories are dumped into the nearest rivers or canals. Hence, the quality of the water of these bodies become very incompatible for the living beings, and so, it has become one of the major threats to the environment and human health. In addition, the amount of fish in the rivers and canals in Bangladesh is decreasing day by day as a result of water pollution. Therefore, to save fish and other water animals and the environment, we need to monitor the quality of the water and find out the reasons for the pollution. Real-time monitoring of the quality of water is vital for controlling water pollution. Most of the approaches for controlling water pollution are mainly biological and lab-based, which takes a lot of time and resources. To address this issue, we developed an Internet of Things (IoT)-based real-time water quality monitoring system, integrated with a mobile application. The proposed system in this research measures some of the most important indexes of water, including the potential of hydrogen (pH), total dissolved solids (TDS), and turbidity, and temperature of water. The proposed system results will be very helpful in saving the environment, and thus, improving the health of living creatures on Earth.
Mingjun Ying, Dipankar Shakya, Hitesh Poddar
et al.
In this paper, we expand upon a new metric called the Waste Factor ($W$), a mathematical framework used to evaluate power efficiency in cascaded communication systems, by accounting for power wasted in individual components along a cascade. We show that the derivation of the Waste Factor, a unifying metric for defining wasted power along the signal path of any cascade, is similar to the mathematical approach used by H. Friis in 1944 to develop the Noise Factor ($F$), which has since served as a unifying metric for quantifying additive noise power in a cascade. Furthermore, the mathematical formulation of $W$ can be utilized in artificial intelligence (AI) and machine learning (ML) design and control for enhanced power efficiency. We consider the power usage effectiveness (PUE), which is a widely used energy efficiency metric for data centers, to evaluate $W$ for the data center as a whole. The use of $W$ allows easy comparison of power efficiency between data centers and their components. Our study further explores how insertion loss of components in a cascaded communication system influences $W$ at 28 GHz and 142 GHz along with the data rate performance, evaluated using the consumption efficiency factor (CEF). We observe CEF's marked sensitivity, particularly to phase shifter insertion loss changes. Notably, CEF variations are more prominent in uplink transmissions, whereas downlink transmissions offer relative CEF stability. Our exploration also covers the effects of varying User Equipment (UE) and Base Station (BS) deployment density on CEF in cellular networks. This work underscores the enhanced energy efficiency at 142 GHz, compared to 28 GHz, as UE and BS numbers escalate.
ABSTRACT Local authorities in Palestine are the service providers for solid waste management. Given that the organic fraction is the largest in municipal solid waste, and with ineffective management policies, the study of attitudes and behavioral aspects of personnel involved are very-important parameters in developing an effective waste management system and assisting policymakers in rectifying these policies. This study aims to assess the attitude of local authorities (LAs) in the southern West Bank of Palestine towards organic municipal solid waste composting and the factors that affect their attitude. The data was gathered via a structured questionnaire from all local authorities in the study area. The results showed that the local authorities’ attitude toward organic solid waste composting is low and can be considered dissatisfactory since only 36.5% of the local authorities are planning for composting compared to 63.5% who are not. The results also showed that municipal solid waste composting is significantly affected by nine factors, including financial capacity, proper machinery, enough refuse collection vehicles to collect solid waste fractions separately, availability of area of land to be used for composting, familiarity with composting systems, staff previous-experience in compost production, acceptance of the rapid composting system, staff training in compost production, and believe that solid waste composting is within the LAs’ responsibility. Implications: The generation of municipal solid waste is growing continuously due to the population growth leading to increased methane emissions, adding more pressure on the landfills which are facing political and social restrictions for expansion in Palestine. In addition, there are severe restrictions imposed on the import of chemical fertilizers. Therefore, composting the organic fractions of solid waste can, to a large extent, extend the life of the landfills and compensate for the shortage of fertilizers in the market. Moreover, it will encourage organic farming and reduce methane emissions as well. Further, it can contribute to achieve the objective of the national strategy on solid waste management.
Huge amount of wastes are being generated, and even though the incineration process reduce the mass of wastes to a large extent, large amount of residues are still remain. The sustainable development of the system should decrease the waste-to-energy ratio continuously through the planned reuse of materials. This paper reviews the existing studies on recycling municipal and construction solid waste for the manufacture of Geo polymer composites. The principal findings of this work reveal that municipal and construction solid waste could be successfully used into Geo polymer composites as an alternative in the forms of precursor, aggregate, additive, reinforcement fibres, or filling material. Additionally, the results indicate that although the inclusion of such waste might depress some attributes of Geo polymer composites, proper proportion design and suitable treatment technique could solve these detrimental effects. Finally, a brief discussion is provided to identify the important needs in the future research and development for promoting the utilization of solid waste materials in the forthcoming sustainable geo polymer industry. In summary, this work offers guidance for a greener approach to building – scoring favourably in environmental performance for being relevant to resource conservation, landfill diversion, and waste recycling.
 Keywords: Construction materials, Geo polymer composite, Municipal solid waste, Construction solid waste, Sustainability.
Ashok Bhandari, Alexandar P. Rollings, Levi Ratto
et al.
Alkali atoms trapped in solid hydrogen matrices have demonstrated ultralong electron spin coherence times, and are promising as quantum sensors. Their spin coherence is limited by magnetic noise from naturally-occurring orthohydrogen molecules in the parahydrogen matrix. In the gas phase, the orthohydrogen component of hydrogen can be converted to parahydrogen by flowing it over a catalyst held at cryogenic temperatures, with lower temperatures giving a lower orthohydrogen fraction. In this work, we use a single cryostat to reduce the orthohydrogen fraction of hydrogen gas and grow a solid matrix from the resulting high-purity parahydrogen. We demonstrate operation of the catalyst down to a temperature of 8 K, and we spectroscopically verify that orthohydrogen impurities in the resulting solid are at a level < 1e-6. We also find that, at sufficiently low temperatures, the cryogenic catalyst provides isotopic purification, reducing the HD fraction.
Bryan Tan, Benjamin Mariano, Shuvendu K. Lahiri
et al.
As smart contracts gain adoption in financial transactions, it becomes increasingly important to ensure that they are free of bugs and security vulnerabilities. Of particular relevance in this context are arithmetic overflow bugs, as integers are often used to represent financial assets like account balances. Motivated by this observation, this paper presents SolType, a refinement type system for Solidity that can be used to prevent arithmetic over- and under-flows in smart contracts. SolType allows developers to add refinement type annotations and uses them to prove that arithmetic operations do not lead to over- and under-flows. SolType incorporates a rich vocabulary of refinement terms that allow expressing relationships between integer values and aggregate properties of complex data structures. Furthermore, our implementation, called Solid, incorporates a type inference engine and can automatically infer useful type annotations, including non-trivial contract invariants. To evaluate the usefulness of our type system, we use Solid to prove arithmetic safety of a total of 120 smart contracts. When used in its fully automated mode (i.e., using Solid's type inference capabilities), Solid is able to eliminate 86.3% of redundant runtime checks used to guard against overflows. We also compare Solid against a state-of-the-art arithmetic safety verifier called VeriSmart and show that Solid has a significantly lower false positive rate, while being significantly faster in terms of verification time.
Q. Arifianti, M. R. Abidin, E. F. Nugrahani
et al.
To utilize the municipal solid waste (MSW), PT Semen Indonesia has a program to convert waste into three useful products. One of the product is named Refuse Derived Fuel (RDF). The RDF has claimed that it had a caloric value about 5178 kcal/kg. However, currently, RDF could not be used for the combustion process in the cement kiln since RDF has higher moisture content and lower caloric value. In this research, a solar dryer with greenhouse type is designed to reduce the moisture content. The performance is tested using two variations and compared to the conventional method. The variations are a solar dryer with one fan and with no fan. The general results show that variation with one fan has the highest drying rate among all. There is a significant reduction of moisture content after drying process using a solar dryer. The moisture content could be reduced to 16.25 % and 17 % using one fan and no fan, respectively. Furthermore, variation with 1 fan has higher solar dryer efficiency than that of one fan.
We determine the solid hull and solid core of weighted Banach spaces $H_v^\infty$ of analytic functions $f$ such that $v|f|$ is bounded, both in the case of the holomorphic functions on the disc and on the whole complex plane, for a very general class of radial weights $v$. Precise results are presented for concrete weights on the disc that could not be treated before. It is also shown that if $H_v^\infty$ is solid, then the monomials are an (unconditional) basis of the closure of the polynomials in $H_v^\infty$. As a consequence $H_v^\infty$ does not coincide with its solid hull and core in the case of the disc. An example shows that this does not hold for weighted spaces of entire functions.
Solid inflation is a cosmological model where inflation is driven by fields which enter the Lagrangian in the same way as body coordinates of a solid matter enter the equation of state, spontaneously breaking spatial translational and rotational symmetry. We construct a simple generalization of this model by adding a scalar field with standard kinetic term to the action. In our model the scalar power spectrum and the tensor-to-scalar ratio do not differ from the ones predicted by the solid inflation qualitatively, if the scalar field does not dominate the solid matter. The same applies also for the size of the scalar bispectrum measured by the non-linearity parameter, although our model allows it to have different shapes. The tensor bispectra predicted by the two models do not differ from each other in the leading order of the slow-roll approximation. In the case when contribution of the solid matter to the stress-energy tensor is much smaller than the contribution from the scalar field, the tensor-to-scalar ratio and the non-linearity parameter are amplified by factors $ε^{-1}$ and $ε^{-2}$ respectively.
Sumit Kumar Birwa, G. Rajalakshmi, Rama Govindarajan
et al.
We study experimentally the collision between a sphere falling through a viscous fluid, and a solid plate below. It is known that there is a well-defined threshold Stokes number above which the sphere rebounds from such a collision. Our experiment tests for direct contact between the colliding bodies, and contrary to prior theoretical predictions, shows that solid-on-solid contact occurs even for Stokes numbers just above the threshold for rebounding. The dissipation is fluid-dominated, though details of the contact mechanics depend on the surface and bulk properties of the solids. Our experiments and a model calculation indicate that mechanical contact between the two colliding objects is generic and will occur for any realistic surface roughness.
The Cellular Automaton (CA) modeling and simulation of solid dynamics is a long-standing difficult problem. In this paper we present a new two-dimensional CA model for solid dynamics. In this model the solid body is represented by a set of white and black particles alternatively positioned in the $x$- and $y$- directions. The force acting on each particle is represented by the linear summation of relative displacements of the nearest-neighboring particles. The key technique in this new model is the construction of eight coefficient matrices. Theoretical and numerical analyses show that the present model can be mathematically described by a conservative system. So, it works for elastic material. In the continuum limit the CA model recovers the well-known Navier equations. The coefficient matrices are related to the shear module and Poisson ratio of the material body. Compared with previous CA model for solid body, this model realizes the natural coupling of deformations in the $x$- and $y$- directions. Consequently, the wave phenomena related to the Poisson ratio effects are successfully recovered. This work advances significantly the CA modeling and simulation in the field of computational solid dynamics.
One of the key differences between normal neutron and (bare) quark stars is relevant to the fact that the former are gravitationally bound while the latter self-confined unless their masses approach the maximum mass. This difference results in the possibility that quark stars could be very low massive whereas neutron stars cannot. Mountains could also be build on quark stars if realistic cold quark matter is in a solid state, and an alternative estimation of the mountain building is present. As spinning compact objects with non-axisymmetric mass distribution will radiate gravitational waves, the equations of states of pulsars could be constraint by the amplitude of gravitational waves being dependent on the heights of mountains. We then estimate the maximum mountains and thus quadrupole moment on solid quark stars, to be consistent with that by Owen (2005) if the breaking strain is 0.1, addressing that a solid quark star with mass < 10^{-2} Msun could be `potato-like'. We estimate the gravitational wave amplitude of solid quark stars with realistic mountains to be order of h0 ~ 10^{-27}.