We extend the Feynman derivation of the Maxwell-Lorentz equations to the case in which coordinates do not commute, adding significantly to previous results. New dynamics is pinned down precisely at the level of the homogeneous equations and of the Lorentz force, for which a complete derivation is given for the first time. A more general approach is introduced to allow navigation among inequivalent starting points for the Feynman procedure.

In this paper, we introduce a class of generalized Sylvester matrix equations, which is frequently used in control systems. The presented matrix equation is the generalization of classical equations and the general form of previous generalizations in this field. By using the Kronecker product of matrices, we propose a method for solving the introduced matrix equations. To support the presented matrix equations and provided solution, we investigate some practical examples, such as a double inverted pendulum and two–link robot arm with two fractional dampers.

In this paper, we investigate the stationary entanglement dynamics between the neighboring subsystems using an opto-electro-mechanical system, in which the mechanical resonator simultaneously coupled to both microwave and optical cavities through the plate of capacitor coupling process. Under the linearization approximation, the dynamics of the entanglement is quantifying by using logarithmic negativity. Our numerical simulation exhibits a sharing bipartite entanglement with optical cavitymechanical, microwave cavity-mechanical, and optical cavity-microwave modes. We further show that there is an entanglement between the optical cavity and microwave modes despite the lack of direct coupling with these modes and optical cavity. Thus, an effective interaction between the optical cavity-microwave cavity mediated by the mechanical resonator, and therefore microwave entanglement is efficiently generated. Such a hybrid electro-optomechanics system can serve as a promising platform to control the follow of light in the Nano-Photonic structure and framework for the optomechanical information transfer between the microwave and optical cavities.

The tensor Feynman amplitudes are reduced to scalar integrals by a procedure of Passarino and Veltman. We provide an alternative approach based on the causal formalism.

Understanding the principles of morphogenesis is indispensable for developing effective strategies to build living tissues in the laboratory. Tissue fusion is essential in bioprinting, an emergent technique based on computer-controlled delivery of multicellular building blocks and supportive hydrogels. The objective of this work was to predict the time course of the fusion of multicellular systems. Computational methods, including Lattice Boltzmann models, proved to be able to simulate in vitro morphogenesis. Here, a Hermite Lattice Boltzmann (HLB) model was used to simulate the sidewise fusion of contiguous cylinders made of cohesive cells in a hydrogel. Fusion eventually gave rise to a tubular construct, in qualitative agreement with 3D tissue printing experiments. Also, the HLB model accounted for the experimentally observed spontaneous rounding of irregular tissue fragments. Our numerical code was based on parallel computing, implemented using the Compute Unified Device Architecture (CUDA) libraries on nVidia M2090 Graphics Processing Unit blades, on lattices of up to 4096 × 4096 nodes. Importantly, the CUDA implementation was about 20 times faster than the parallel computation code written using the Portable, Extensible Toolkit for Scientific Computation (PETSc), running on a cluster of 32 central processing units. In conclusion, the CUDA version of the HLB model can be employed to simulate the post-printing evolution of bioprinted tissue constructs.

The current design of the CBM-TOF inner wall is based on doublestack multi-strip, multi-gap resistive plate counters (MSMGRPCs) with 2 x 5 gas gaps, equipped with low resistivity glass electrodes. Three types of MSMGRPC, with different granularity as a function of polar angle are used for a full coverage of the active area of the inner wall. A MSMGRPC prototype with the highest granularity of the CBM-TOF wall and 200 µm gap size was tested in the Detector Laboratory of Hadron Physics Department of IFIN-HH with cosmic rays and ⁶⁰Co radioactive source. The obtained performances in terms of time resolution, efficiency and its uniformity across the active area of the detector are reported in this paper.

In this work we make further studies of the quadruple-quadruple interaction used in shell model calculations.Whereas in a previous work we adjusted the single particle energies so as to obtain the rotational spectrum of the Elliott model, we here vary the single particle energies and examine the various spectral shapes that evolve.

The pulsed-plasma coatings were fabricated by electro-thermal axial plasma accelerator applying the cathodes made of graphite, tungsten, steel AISI 1020, steel T1 and 28 wt.%Cr cast iron. The coating thickness increases as the melting point of the cathode decreases. The usage of Cr (W)-rich cathode results in high amount of retained austenite leading to cracks under the coating crystallization.

The paper presents the research results in the field of TiNiCu shape memory alloys processed by powder metallurgy techniques. The powders mixtures used to synthesize Ti₅₀Ni₃₀Cu₂₀ alloys were obtained by blended constitutive elemental powders or by mechanical alloying of powder mixtures for 10 and 20 hours, respectively. Finally, a subsequent annealing process was carried out, followed by a rapid cooling in ice water. All experiments were performed under 99.9% argon atmosphere. At room temperature, the obtained materials contained monoclinic and orthorhombic martensite type. The structural and thermal investigation of these materials were discussed in view of the potential development of actuators.

We have investigated the antireflective effect of metal nanoparticles on the surface of the solar cell. The antireflection coating on the surface of the solar cell allows a reduction of the reflection losses and an increase of the current generation leading to the increase of the efficiency of solar cells. The obtained results show that the metal nanoparticles can be used to improve the efficiency of the solar cell. The transmittance of the structure achieves about 100% and the reflectance tends to be zero. However, the transverse magnetic mode has the transmittance higher than that of the transverse electric mode due to plasmonic resonance.

Thin ZnSnO films with different thickness deposited on Si substrates by aerosol spray pyrolysis were investigated by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD), atomic force microscopy (AFM) and light microscopy (LM) using depth-sensitive nanoindentation with Berkovich indenter. The values of the Young modulus (E), nanohardness (H), and plasticity index (H/E) of the prepared films were determined according to the Oliver-Pharr method in the diapason of the applied loads of 30–300 mN. The main factors contributing to the nanomechanical properties of film-substrate structures were identified, and the deformation mechanisms of the ZnSnO/Si coated system (CS) under nanoindentation have been revealed.

Long-term variations of ozone and its precursors have been examined in an intra-mountain closed basin during January 1st, 2008 and June 30th, 2017. A complete assessment of surface ozone concentration is given, investigating the ozone cycle, the weekend effect, seasonal and diurnal variability of O₃ and its precursors, photolysis of O₃ and the atmospheric oxidation. The highest hourly concentration of O₃ in the studied period was 163.33 µg/m3. Regarding seasonal O₃ multiannual concentrations, the highest values were measured during spring and summer. The daily hourly concentrations of O₃ in the weekends were higher by 3.55% than those on weekdays, as well as O₃ accumulation rates, yielding 2.19 μg/m³h and 2.11 μg/m³h on weekends and weekdays, respectively. In the Ciuc basin, the NOx-independent contributions value is 42.33 µg/m³, which is equivalent to background O₃ concentrations. O₃ variations are studied through a case study during 2008–2017, taking under consideration one atmospheric stable period, studying the Brunt-Väisälä frequency, the total column of O₃ and the boundary layer height.

In this article, we present a new approach for the classification of soils in different groups based on the proportion of chemical elements contained by them. Firstly, the k-means algorithm is used for clustering purposes, and then the soil samples are redistributed in groups using a genetic algorithm. The application is important for selecting soils of the same type for agricultural use.

This paper shows simulation models for diurnal variation of sub-ionospheric Very Low Frequency (VLF) signals using machine learning approach. Recording of VLF transmitter signals using a ground-based radio receiver provides a beautiful and cost-effective way of monitoring lower ionosphere (D/E regions) in the altitude range (60-90 km). VLF signals respond to the ionization variations due to the Sun and other terrestrial or extra-terrestrial sources. Consequently, it has many applications in remote sensing of the lower ionosphere. Therefore, predicting or simulating the diurnal variation of VLF transmitter signals using past data will help to understand the variability of the ionosphere. Here, the VLF signal from the Indian transmitter VTX (18.2 kHz) received at Kolkata is used for the training, validating, and testing purposes in the machine learning models. Two predictive models, multiple linear regression (MLR) and artificial neural network (ANN) have been built and Pearson correlation coefficients outside the training range are obtained as R=0.94 and R=0.93 respectively for the two models. Variation of the VLF transmitter signal is also calculated using the well-known Long Wave Propagation Capability (LWPC) code coupled with the International Reference Ionosphere (IRI-2016) model and the same is compared with the MLR and ANN model predictions. Both the MLR and ANN models are found to be performing better than the LWPC simulation.