A portable six-wheeled mobile robot with reconfigurable body and self-adaptable obstacle-climbing mechanisms

Mobile robots can replace rescuers in rescue and detection missions in complex and unstructured environments and draw the interest of many researchers. This paper presents a novel six-wheeled mobile robot with a reconfigurable body and self-adaptable obstacle-climbing mechanisms, which can reconfigure itself to three locomotion states to realize the advantages of terrain adaptability, obstacle crossing ability and portability. Design criteria and mechanical design of the proposed mobile robot are firstly presented, based on which the geometry of the robot is modelled and the geometric constraint, static conditions and motion stability condition for obstacle crossing of the robot are derived and formulated. Numerical simulations are then conducted to verify the geometric passing capability, static passing capability and motion stability and find feasible structure parameters of the robot in obstacle crossing. Further, a physical prototype of the proposed mobile robot is developed and integrated with mechatronic systems and remote control. Using the prototype, field experiments are carried out to verify the feasibility of the proposed design and theoretical derivations. The results show that the proposed mobile robot satisfies all the criteria set and is feasible for applications in disastrous rescuing scenarios.

The Structure and Compression of Medical Compression Stockings

This paper lays out standards of compression stockings and their classification into classes. The analysis of knitted fabric structure parameters, elongation and compression of moderate- and high-compression stockings was conducted. Stocking compression on specific parts of the stocking leg was measured on three sizes of a wooden leg model. For moderate-compression stockings, compression above the ankle was 32 hPa. For high-compression stockings, compression above the ankle was 60 hPa. Both groups of the analyzed compression stockings were made on modern one-cylinder hosiery automats. The legs of the stockings were made in single inlaid jersey 1 + 1. Both yarns were elastane covered. The finer yarn formed loops and its knitting into a course was significantly larger than in the other yarn, which was much coarser and does not form loops but “lay the weft in a bent way”. The smallest elongation of knitted fabric was above the ankle, where the highest compression was achieved, while the largest elongation was under the crotch, where the stocking leg exerted the smallest compression on the surface. The leg of the compression stocking acted as a casing that imposed compression on the leg and often reinforced it to be able to sustain compression loads.

Synthesis, Characterization and DFT Calculations of a Novel Pyrazole Derivative 4-(1-Phenyl-5-(p-Tolyl)-2,5-Dihydro-1H-Pyrazol-3-Yl)Benzo[c][1,2,5]Oxadiazole

s Heterocyclic compounds like pyrazoline was synthesized along to the reaction of phenyl hydrazine hydrochloride with 3-(benzo [c][1,2,5] oxadiazol-4-yl)-1-phenylprop-2-en-1-one undergoing in reflux condition. This compound going to begood yields.A thoroughly fresh compound wasindicating by IR, 1H, and 13C elemental analysis. Stimulate the calculated HOMO/LUMO, MEP and mulliken population analysis and NLO was compare to the experimental analysis of this data. The optimized theoretical structure parameters betide collate to the satisfied assent with the experimental structure. Keywords: Pyrazoline, Heterocycles, NLO, HOMO/LUMO, Optimized structure, Mulliken charges. Graphical Abstract

Single-polarization single-mode hollow-core negative curvature fiber with nested U-type cladding elements

Hollow-core negative curvature fibers (HC-NCFs) have become one of the research hotspots in the field of optical fiber because of its potential applications in the data and energy transmissions. In this paper, a new kind of single-polarization single-mode HC-NCF with nested U-type cladding elements is proposed. To achieve the single-polarization single-mode transmission, we use two different silica tube thicknesses that satisfy the resonance and anti-resonance conditions on the U-type cladding elements and the cladding tubes, respectively. Besides, the elliptical elements are introduced to achieve good single-mode performance. By studying the influences of the structure parameters on the propagation characteristics, the optimized structure parameters are obtained. The simulation results show that when the wavelength is located at 1550 nm, the single-polarization single-mode transmission is achieved, along with the polarization extinction ratio of 25749 and minimum high-order mode extinction ratio of 174. Furthermore, the confinement loss is only 0.0015 dB/m.

HYPERFINE STRUCTURE PARAMETERS FOR COMPLEX ATOMS WITHIN RELATIVISTIC MANY-BODY PERTURBATION THEORY

The calculational results for the hyperfine structure (HFS) parameters for the Mn atom (levels of the configuration 3d64s) and the results of advanced calculating the HFS constants and nuclear quadrupole moment for the radium isotope are obtained on the basis of computing within the relativistic many-body perturbation theory formalism with a correct and effective taking into account the exchange-correlation, relativistic, nuclear and radiative corrections. Analysis of the data shows that an account of the interelectron correlation effects is crucial in the calculation of the hyperfine structure parameters. The fundamental reason of physically reasonable agreement between theory and experiment is connected with the correct taking into account the inter-electron correlation effects, nuclear (due to the finite size of a nucleus), relativistic and radiative corrections. The key difference between the results of the relativistic Hartree-Fock Dirac-Fock and many-body perturbation theory methods calculations is explained by using the different schemes of taking into account the inter-electron correlations as well as nuclear and radiative ones.

A time-varying reliability-based robust design method considering overall efficiency of axial piston pump

Axial piston pumps (APPs) are the core energy conversion components in a hydraulic transmission system. Energy conversion efficiency is critically important for the performance and energy-saving of the pumps. In this paper, a time-varying reliability design method for the overall efficiency of APPs was established. The theoretical and practical instantaneous torque and flow rate of the whole APP were derived through comprehensive analysis of a single piston-slipper group. Moreover, as a case study, the developed model for the instantaneous overall efficiency was verified with a PPV103-10 pump from HYDAC. The time-variation of reliability for the pump was revealed by a fourth-order moment technique considering the randomness of working conditions and structure parameters, and the proposed reliability method was validated by Monte Carlo simulation. The effects of the mean values and variance sensitivity of random variables on the overall efficiency reliability were analyzed. Furthermore, the optimized time point and design variables were selected. The optimal structure parameters were obtained to meet the reliability requirement and the sensitivity of design variables was significantly reduced through the reliability-based robust design. The proposed method provides a theoretical basis for designers to improve the overall efficiency of APPs in the design stage.

Permeable Asphalt Hydraulic Conductivity and Particulate Matter Separation With XRT

Permeable asphalt (PA) is a composite material with an open graded mix design that provides a pore structure facilitating stormwater infiltration. PA is often used as a wearing course for permeable pavements and on roadways to reduce aquaplaning and noise pollution. The pore structure functions as a filter promoting particulate matter (PM) separation. The infiltrating flow characteristics are predominately dependent on pore diameter and pore interconnectivity. X-Ray microTomography (XRT) has been successfully used to estimate these parameters that are otherwise difficult to obtain through conventional gravimetric methods. The pore structure parameters allow modeling of hydraulic conductivity (k) and filtration mechanisms; required to examine the material behavior for infiltration and PM separation. Pore structure parameters were determined through XTR for three PA mixtures. The Kozeny-Kovàv model was implemented to estimate k. PM separation was tested using a pore-to-PM diameter categorical model. This filtration mechanism model was validated with data using rainfall simulation. The filtration model provided a good correlation between measured and modeled data. The identification of filtration mechanisms and k facilitate the design and evaluation of permeable pavement systems as a best management practice (BMP) for runoff volume and flow as well as PM and PM-partitioned chemical separation.