Calculation method for sound insulation of lightweight enclosures at low frequencies

The objects of the study are lightweight enclosing structures (partitions) located between the premises of buildings. The surface density of lightweight fences lies in the range of 20 < μ < 100 kg/m2. The elaboration of methods for calculating the sound insulation of lightweight enclosures, taking into account geometric and physical and mechanical parameters, is an urgent task for building acoustics. The studies are carried out on the basis of the theory of self-consistency of wave fields with account of the resonant and inertial sound transmission through the enclosures. The article presents the results of theoretical studies of sound insulation of lightweight enclosing structures in the frequency range from 50 Hz to 5000 Hz. It was proposed to divide the generalized frequency characteristic of the sound insulation of lightweight enclosing structures into two ranges, the boundary between which is determined by the geometric sizes of the fence. Based on the theory of self-consistency of wave fields, a method was developed for calculating the sound insulation of lightweight enclosing structures in the frequency range above the threshold frequency of sound field diffuseness in the plane of the enclosing structure and below the threshold frequency. The method enables calculating the sound insulation of lightweight enclosures, the threshold frequencies of the areas of resonant sound transmission, as well as the frequency characteristics of the coefficients of resonant and inertial sound transmission. The implementation of this method is considered on the example of a lightweight frame-sheathing partition with anti-resonance panels. The authors obtained theoretical frequency characteristics of the coefficients of sound transmission through a lightweight frame-sheathing partition and the frequency characteristics of the sound insulation of the partition in the calculated frequency range

STATISTICAL MODEL OF AERODYNAMIC IMPACT ON THE LARGE-SPAN COVERAGE

The aim of the study was to study the possibility of using the Dirichlet distribution as a statistical model of the process of dynamic interaction of large-span structures with aerodynamic load. As an object of research, a model of a hangar building was chosen for the maintenance of two AirbusA-380 aircraft at a scale of 1: 500 blown in a wind tunnel at five directions of wind flow at angles of 0 °, 30 °, 45 °, 60 °, 90 ° to the front of the structure ... It is shown that the statistical model of the Dirichlet distribution has sufficient flexibility and realism and compares favorably with the models built on the basis of the normal distribution, beta distribution, gamma distribution and Poisson distribution when describing the processes of intense dynamic interaction of wind load with structural elements. The problem of finding an integral assessment of the state of the processes of interaction of the wind load with the hangar building for the maintenance of two aircraft was reduced to calculating the self-organization parameter of the distribution over the surface of the building model of the aerodynamic coefficients, which was taken as the ratio of the total weighted amount of the Dirichlet models detected in the analyzed numerical series of the registered signal i-th dimension with negative external entropy to the total weighted number of Dirichlet models with positive external entropy. The study showed that the dimensionless informational and statistical indicator of self-organization makes it possible from a unified standpoint to assess the states that differ from each other in terms of external signs, the processes of interaction and their dynamics. The integral indicator can be used to rank the efficiency of operating systems and can be useful in assessing the state of the processes of dynamic interaction of the operating pressure and objects and structures of various shapes and purposes

High-resolution label-free 3D mapping of extracellular pH of single living cells

Abstract: Dynamic mapping of extracellular pH (pHe) at the single-cell level is critical for understanding the role of H+ in cellular and subcellular processes, with particular importance in cancer. While several pHe sensing techniques have been developed, accessing this information at the single-cell level requires improvement in sensitivity, spatial and temporal resolution. We report on a zwitterionic label-free pH nanoprobe that addresses these long-standing challenges. The probe has a sensitivity > 0.01 units, 2 ms response time, and 50 nm spatial resolution. The platform was integrated into a double-barrel nanoprobe combining pH sensing with feedback-controlled distance dependance via Scanning Ion Conductance Microscopy. This allows for the simultaneous 3D topographical imaging and pHe monitoring of living cancer cells. These classes of nanoprobes were used for real-time high spatiotemporal resolution pHe mapping at the subcellular level and revealed tumour heterogeneity of the peri-cellular environments of melanoma and breast cancer cells

Electrochemical Nanoprobes for Single-Cell Analysis

The measurement of key molecules in individual cells with minimal disruption to the biological milieu is the next frontier in single-cell analyses. Nanoscale devices are ideal analytical tools because of their small size and their potential for high spatial and temporal resolution recordings. Here, we report the fabrication of disk-shaped carbon nanoelectrodes whose radius can be precisely tuned within the range 5–200 nm. The functionalization of the nanoelectrode with platinum allowed the monitoring of oxygen consumption outside and inside a brain slice. Furthermore, we show that nanoelectrodes of this type can be used to impale individual cells to perform electrochemical measurements within the cell with minimal disruption to cell function. These nanoelectrodes can be fabricated combined with scanning ion conductance microscopy probes, which should allow high resolution electrochemical mapping of species on or in living cells

Investigation of the Mechanical and Electromechanical Starting Characteristics of an Asynchronous Electric Drive of a Two-Piston Marine Compressor

In the article, the mechanical and electromechanical starting characteristics of an asynchronous electric drive of a two-piston ship compressor are investigated by a numerical method. A distinctive feature of the operation of the electric drive of a reciprocating compressor is that its load torque changes with a certain frequency. The dependence of the load torque on the shaft of the electric drive of the piston compressor on the angle of rotation is presented in the form of a Fourier series. Moments of inertia are reduced to a single system that performs a rotary motion. Mechanical and electromechanical starting characteristics are constructed. The estimation of the degree of torque pulsations on the shaft is made. It is determined that the compressor has a large amplitude of torque ripple on the shaft, which, in turn, affects the magnitude of the current ripple in the electric drive

High-resolution label-free 3D mapping of extracellular pH of single living cells.

Dynamic mapping of extracellular pH (pHe) at the single-cell level is critical for understanding the role of H+ in cellular and subcellular processes, with particular importance in cancer. While several pHe sensing techniques have been developed, accessing this information at the single-cell level requires improvement in sensitivity, spatial and temporal resolution. We report on a zwitterionic label-free pH nanoprobe that addresses these long-standing challenges. The probe has a sensitivity > 0.01 units, 2 ms response time, and 50 nm spatial resolution. The platform was integrated into a double-barrel nanoprobe combining pH sensing with feedback-controlled distance dependance via Scanning Ion Conductance Microscopy. This allows for the simultaneous 3D topographical imaging and pHe monitoring of living cancer cells. These classes of nanoprobes were used for real-time high spatiotemporal resolution pHe mapping at the subcellular level and revealed tumour heterogeneity of the peri-cellular environments of melanoma and breast cancer cells

High-resolution label-free 3D mapping of extracellular pH of single living cells

Abstract: Dynamic mapping of extracellular pH (pHe) at the single-cell level is critical for understanding the role of H+ in cellular and subcellular processes, with particular importance in cancer. While several pHe sensing techniques have been developed, accessing this information at the single-cell level requires improvement in sensitivity, spatial and temporal resolution. We report on a zwitterionic label-free pH nanoprobe that addresses these long-standing challenges. The probe has a sensitivity > 0.01 units, 2 ms response time, and 50 nm spatial resolution. The platform was integrated into a double-barrel nanoprobe combining pH sensing with feedback-controlled distance dependance via Scanning Ion Conductance Microscopy. This allows for the simultaneous 3D topographical imaging and pHe monitoring of living cancer cells. These classes of nanoprobes were used for real-time high spatiotemporal resolution pHe mapping at the subcellular level and revealed tumour heterogeneity of the peri-cellular environments of melanoma and breast cancer cells

Multiplexed detection of viral antigen and RNA using nanopore sensing and encoded molecular probes.

Acknowledgements: We would like to thank Professor Ruijie Deng for providing the pseudovirus. A.P.I. and J.B.E. acknowledge support from BBSRC grant BB/R022429/1, EPSRC grant EP/V049070/1, and Analytical Chemistry Trust Fund grant 600322/05. This project has also received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement Nos. 724300 and 875525). A.E. and P.G. acknowledge support from the Ministry of Education and Science of the Russian Federation, Agreement No. 075-15-2022-264, unique scientific facility reg. No 2512530. R.R. and Y.K. acknowledge support from Japan Society for the Promotion of Science KAKENHI Grants 21H01770, 22K04890, and World Premier International Research Center Initiative (WPI), MEXT, Japan. Research in the P.C. laboratory is supported by the Francis Crick Institute, which receives its core funding from Cancer Research UK (CC2058), the UK Medical Research Council (CC2058), and the Wellcome Trust (CC2058). This research was funded in whole, or in part, by the Wellcome Trust (CC2058). For the purpose of Open Access, the author has applied a CC BY public copyright licence to any Author Accepted Manuscript version arising from this submission. We acknowledge the UK Health Security Agency and St Mary’s Hospital for providing clinical samples.We report on single-molecule nanopore sensing combined with position-encoded DNA molecular probes, with chemistry tuned to simultaneously identify various antigen proteins and multiple RNA gene fragments of SARS-CoV-2 with high sensitivity and selectivity. We show that this sensing strategy can directly detect spike (S) and nucleocapsid (N) proteins in unprocessed human saliva. Moreover, our approach enables the identification of RNA fragments from patient samples using nasal/throat swabs, enabling the identification of critical mutations such as D614G, G446S, or Y144del among viral variants. In particular, it can detect and discriminate between SARS-CoV-2 lineages of wild-type B.1.1.7 (Alpha), B.1.617.2 (Delta), and B.1.1.539 (Omicron) within a single measurement without the need for nucleic acid sequencing. The sensing strategy of the molecular probes is easily adaptable to other viral targets and diseases and can be expanded depending on the application required