A two-stage traveling-wave thermoacoustic electric generator with loudspeakers as alternators

This paper presents the design, construction and tests of a traveling-wave thermoacoustic electric generator. A two-stage travelling-wave thermoacoustic engine converts thermal energy to acoustic power. Two low-impedance linear alternators (i.e., audio loudspeakers) were installed to extract and convert the engine’s acoustic power to electricity. The coupling mechanism between the thermoacoustic engine and alternators has been systematically studied numerically and experimentally, hence the optimal locations for installing the linear alternators were identified to maximize the electric power output and/or the thermal-to-electric conversion efficiency. A ball valve was used in the loop to partly correct the acoustic field that was altered by manufacturing errors. A prototype was built based on this new concept, which used pressurized helium at 1.8 MPa as the working gas and operated at a frequency of about 171 Hz. In the experiment, a maximum electric power of 204 W when the hot end temperature of the two regenerators reaches 512℃ and 452℃, respectively. A maximum thermal-to-electric efficiency of 3.43% was achieved when the hot end temperature of the two regenerators reaches 597℃ and 511℃, respectively. The research results presented in this paper demonstrate that multi-stage travelling-wave thermoacoustic electricity generator has a great potential for developing inexpensive electric generators

Size and temperature effects on the viscosity of water inside carbon nanotubes

The influences of the diameter (size) of single-walled carbon nanotubes (SWCNTs) and the temperature on the viscosity of water confined in SWCNTs are investigated by an "Eyring-MD" (molecular dynamics) method. The results suggest that the relative viscosity of the confined water increases with increasing diameter and temperature, whereas the size-dependent trend of the relative viscosity is almost independent of the temperature. Based on the computational results, a fitting formula is proposed to calculate the size- and temperature- dependent water viscosity, which is useful for the computation on the nanoflow. To demonstrate the rationality of the calculated relative viscosity, the relative amount of the hydrogen bonds of water confined in SWCNTs is also computed. The results of the relative amount of the hydrogen bonds exhibit similar profiles with the curves of the relative viscosity. The present results should be instructive for understanding the coupling effect of the size and the temperature at the nanoscale

The Application of Carbon Fiber Composites in Cryotank

To meet the design goal for lightweighting the next-generation launch vehicles, carbon fiber reinforced polymeric-based composites are being explored for cryogenic fuel tank applications. The applications of carbon fiber composites in liquid hydrogen (LH2) and liquid oxygen (LOX) fuel tanks were introduced in this chapter. The materials, processing, and design of DC-XA LH2 tank, X-33 LH2 tank, SLI LH2 tank, and CCTD Program tank were discussed. Lockheed Martin LOX tank and Space X LOX tank were introduced. Technology development, materials development, and development trend of cryogenic fuel tanks were discussed. Thin-ply hybrid laminates and out-of-autoclave tanks are projected for future space missions

Ruscogenin alleviates palmitic acid-induced endothelial cell inflammation by suppressing TXNIP/NLRP3 pathway

Purpose: To investigate the involvement of ruscogenin in palmitic acid (PA)-induced endothelial cell inflammation. Method: Cultured human umbilical vein endothelial cells (HUVECs) were divided into five groups: control (normal untreated cells), PA (cell treated with palmitic acid), and PA + ruscogenin (1, 10, or 30 μM). Cell viability and apoptosis rate were determined using MTT (3-(4,5)-dimethylthiahiazo(-z-y1)-3,5- di-phenytetrazolium bromide) and flow cytometry assays, respectively. The levels of cytokines, including interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), intercellular adhesion molecule-1 (ICAM-1), and monocyte chemo-attractant protein-1 (MCP-1) were determined by an enzyme-linked immunosorbent assay. Western blotting and real-time polymerase chain reaction (RT-PCR) were used to evaluate the underlying mechanisms of action. Results: PA treatment decreased the viability of HUVECs and induced apoptosis (p < 0.05). Ruscogenin attenuated PA-induced cell death in a dose-dependent manner (p < 0.05). On the other hand, PA induced an increase in IL-1β, TNF-α, ICAM-1, MCP-1, TXNIP (thioredoxin-interacting protein),as well as NLRP3 (nucleotide oligomerization domain-, leucine-rich repeat- and pyrin domain-containing protein 3), all of which were attenuated by ruscogenin (p < 0.05). Conclusion: Ruscogenin alleviates PA-induced endothelial cell inflammation via TXNIP/NLRP3 pathway, thereby providing an insight into new therapeutic strategies to treat cardiovascular diseases. Keywords: Ruscogenin, Palmitic acid, Endothelial cells, Inflammation, TXNIP, NLRP3, Cardiovascular disease

A feasibility study of a novel combined solar concentration/wind augmentation system

For deeper understanding of the formation of elite at enterprises, the article proposed to consider a hierarchy of an enterprise from the point of view of two main factors: social and organizational-occupational status.It was determined that the status of an individual in the structure of an enterprise is an integral characteristic, based on the synthesis of hierarchical aspects of organizational structure of an enterprise. It was noted that the current establishment at an enterprise is characterized by a position of an individual in the system of interpersonal relations, his/her rights, duties and privileges.As a social status, we suggested the amount of power, social perspective of the status and prestige of an individual. It was emphasized that the organizational-occupational status of the elite is characterized by different levels of management.It was noted that at enterprises each element serves to meet corresponding challenges to achieve a common goal. It was concluded that the structural-functional approach provides the possibility of further system analysis of the elite at enterprises.В статье рассмотрены проблемы становления элиты на современном предприятии с позиции социального и организационно-профессионального статуса. Определено, что статус индивида в структуре предприятия является интегральной характеристикой, основу которой составляет синтез иерархических аспектов организационной структуры предприятия. Отмечено, что современный истеблишмент на предприятии характеризуется позицией индивида в системе межличностных отношений, его прав, обязанностей и привилегий.У статті розглянуто проблеми становлення еліти на сучасному підприємстві з позиції соціального та організаційно-професійного статусу. Визначено, що статус індивіда в структурі підприємства є інтегральною характеристикою, основу якої складає синтез ієрархічних аспектів організаційної структури підприємства. Зазначено, що сучасний істеблішмент на підприємстві характеризується позицією індивіда у системі міжособистих відносин, його прав, обов’язків та привілеїв

Effect of different carrier gases on productivity enhancement of a novel multi-effect vertical concentric tubular solar brackish water desalination device

A novel multi-effect vertical concentric tubular solar brackish water desalination device is introduced in present study. The device consists of four closely spaced concentric pipes, in which the feed water gets preheated by hot brine water to guarantee the evaporation efficiency. An experimental investigation and analytical analysis were carried out to signify the effect of carrier gas-water vapor mixture on productivity enhancement of the device. Different carrier gases were used in the performance evaluation: carbon dioxide, helium, nitrogen, oxygen, air and argon. The water yield and the top/bottom temperature values of condensation surface of the device with different carrier gases were tested. In addition, the present investigation is presented an approach to predict the theory yield based on the internal heat and mass transfer mechanism. The experimental results indicate that, when the heating temperature is 80 °C and the carrier gas is helium, the water productivity rate can reach to 1.19 kg/h. It is increased by 30.76% than the carrier gas of air. The numerical results had been calculated and a consistent agreement with the experimental results had been obtained of different operation temperatures. The Dv under different heating temperature were obtained according to the experimental results

Performance of steel frames with new lightweight composite infill walls under curvature ground deformation

In this paper, the structural performance of steel frames with novel lightweight composite infill walls is experimentally and numerically investigated under curvature ground deformation, which is a common consequence of ground mining activities that can cause significant effects on structures and buildings in these areas. A new structural form that combines steel frames and lightweight composite infill walls has recently been used; its performance under curvature ground deformation is of great interest but still not entirely clear. This study compares the mechanical behavior of the open-frame, the closed-frame with mudsill, and the closed-frame with infill walls, through experimental testing under positive and negative curvature ground deformations. Structural responses such as basement counterforce, additional strains at different key locations, and effects of mudsill and infill walls are evaluated. In addition, 3D finite element models are established to simulate the performance of the tested samples and are validated by comparing the results against those from experiments. After validation, the numerical model is applied to a few complex structures incorporating the composite infill walls to investigate their structural performance under both positive and negative curvature ground deformation. It has been found that steel frames with the new composite infill walls can considerably increase the stiffness of structures in resisting ground deformation and re-distribute the loads amongst the beam and column members in the frame. Failure modes for the structures can also be changed by shifting the most dangerous ones from the upper part of the frame to the lower part. Moreover, it has been found that the vertical force of the infill walls is more sensitive to curvature ground deformation than the horizontal force. Further, the influence of the infill wall on the column is more significant, in comparison to that on the beam of the frame