Load-line diagrams applied to reactive compensated loads in AC systems

1981 ◽  
Vol 128 (3) ◽  
pp. 172
Author(s):  
R. Yacamini
Keyword(s):  
Load Line ◽  
Ac Systems

MICROSTRUCTURE AND TEMPERATURE STABILITY OF SINTERED Nd-Dy-Fe-Co-Mo-Al-B MAGNETS

1993 ◽  
Vol 07 (01n03) ◽  
pp. 721-724
Author(s):  
W. RODEWALD ◽  
P. SCHREY ◽  
B. WALL
Keyword(s):  
Solid Solution ◽  
Surface Treatment ◽  
Corrosion Behaviour ◽  
Temperature Stability ◽  
Partial Replacement ◽  
Compound A ◽  
Corrosion Tests ◽  
Sintered Magnets ◽  
Load Line ◽  
Intrinsic Coercivity

Simultaneous additions of Co and Mo or V, respectively, to Nd-Dy-Fe-Al-B alloys improve the temperature stability of sintered magnets. The intrinsic coercivity at 150 ºC amounts to 9 kA/cm for magnets with a Dy-content of 3 at.%. Hence magnets with a load line, B/μoH=−2, may be operated at temperatures up to 200 ºC. The additions of Mo or of V result in the precipitation of a tetragonal Mo2FeB2 compound, a=0.58 nm, c=0.32 nm, or of a tetragonal V3–xFexB2 compound, x=0.2...1.2, within the (Nd, Dy)2(Fe, Co, A1)14B grains. The dimensions of the precipitates range from 10 to 600 nm. Besides Mo2FeB2- or V3–xFex+B2-grains, respectively, with dimensions up to 10 μm were observed within the Nd-rich constituents. The intrinsic coercivity, however, is determined by nucleation of reversed domains. The addition of Co results in a partial replacement of the Nd-Fe solid solution by the Nd3Co compound. Corrosion tests revealed, that the corrosion behaviour is not improved significantly and depends much more on the surface treatment.

Numerical Simulation of Pile-Bucket Foundation under Horizontal Load

2012 ◽  
Vol 460 ◽  
pp. 169-174
Author(s):  
Wen Bai Liu ◽  
Liang Yang ◽  
Chen Xia Zhu
Keyword(s):  
Failure Surface ◽  
Horizontal Load ◽  
Soil Pressure ◽  
Passive Region ◽  
Deep Soil ◽  
Maximum Displacement ◽  
Bucket Foundation ◽  
Load Line ◽  
Soil Stress ◽  
Pressure Changes

The pile-bucket foundation is a new kind of foundation. In this paper, the ABAQUS software was used to analyze the soil displacement field and the soil stress field surrounding of the pile-bucket foundation under the multi-cycle horizontal loading. Under the horizontal load, the active area of soil separated from the basics; the passive region takes the shape of a parabolic ring of soil wedge rotate failure surface. The maximum displacement was in the direction of horizontal load line on the surface of soil near the bucket. Horizontal and vertical soil pressure changes are concentrated under the surface of the soil near the bucket, and the maximum horizontal soil stress was in the deep soil around the bucket. There is a point of inflection between 1/3 and 1/2 of the pile into soil , and the soil pressure that upper and lower the point increased in the opposite direction. The horizontal forced resistance of the foundation mainly distributed under the bucket and 1/2 of the pile into soil .The conclusion could provide a reference basis for the analysis of bearing mechanism and destruction characters of pile-bucket foundation

Performance Improvement of Membrane Energy Exchanger using Ultrasound for HVAC Application

2021 ◽  
pp. 1-29
Author(s):  
Gurubalan Annadurai ◽  
Maiya M.P. ◽  
Patrick Geoghegan ◽  
Carey Simonson
Keyword(s):  
Air Conditioning ◽  
Energy Recovery ◽  
Mass Transfer Process ◽  
Porous Membrane ◽  
Air Conditioning System ◽  
Energy Saving Potential ◽  
Recovery Processes ◽  
Additional Resistance ◽  
Membrane Energy ◽  
Ac Systems

Abstract Air conditioning (AC) systems consume the maximum proportion of the total electricity used in the building sector. The demand of AC systems is expected to increase exponentially in the coming years due to various reasons such as climate change, increasing affordability and increase in living floor space. Membrane-based liquid desiccant AC system along with energy recovery ventilating equipment is considered as a prospective alternative to the conventional air conditioning system (CACS) and has the potential to meet the increasing current and future AC demand in a sustainable manner. Its efficiency and energy saving potential with respect to CACS depends on the performance of the membrane-based dehumidifier, regenerator and energy recovery ventilating equipment which are commonly referred to as membrane energy exchangers (MEEs). MEE is an indirect exchanger type in which the working streams are separated by a porous membrane. This intermediate membrane creates an additional resistance for the heat and mass transfer process in the MEE. To reduce the resistance, this study experimentally and numerically investigates the influence of ultrasound on the performance of the MEE for dehumidification, humidification (applicable for membrane-based evaporative cooling and desiccant regeneration devices) and energy recovery processes. It is found that the vibration due to ultrasound has the potential to improve the effectiveness of the MEE by 55% in the dehumidification process and by 65% in the humidification and energy recovery processes.

Active control of surge in centrifugal compressors using a brain emotional learning-based intelligent controller

2015 ◽  
Vol 230 (16) ◽  
pp. 2828-2839 ◽  
Author(s):  
Ali Jokar ◽  
Roozbeh Zomorodian ◽  
Mohammad Bagher Ghofrani ◽  
Pooya Khodaparast
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
High Fidelity Simulation ◽  
Variable Speed ◽  
Load Line ◽  
Neuro Fuzzy ◽  
Performance Map ◽  
Compressor Performance ◽  
Artificial Neural ◽  
Brain Emotional Learning

Efforts have been targeted at providing a comprehensive simulation of a centrifugal compressor undergoing surge. In the simulation process, an artificial neural network was utilized to produce an all-inclusive performance map encompassing those speeds not available in the provided curves. Two positive scenarios for the shaft speed, constant, and variable, were undertaken, and effects of load line on the dynamic response of the compressor have been studied. In order to achieve high-fidelity simulation in the variable speed case, an artificial neural network was utilized to produce an all-inclusive performance map encompassing those speeds not available in the provided curves. Moreover, effects of dynamic characteristics of throttle valve were also investigated. A novel controlling scheme, based on neuro-fuzzy control philosophy, was implemented to stabilize the compressor performance in the unstable region. Results indicate that if applied, this scheme could produce practical and satisfactory outcomes, possessing certain virtues compared to available techniques.

scholarly journals Practical Diagnostic Approach of Systematic Fault of AC Systems

2015 ◽  
Vol 121 ◽  
pp. 2098-2105
Author(s):  
Weijie Zhang ◽  
Bingyao Wang ◽  
Mujie Li ◽  
Yipeng Qin
Keyword(s):  
Diagnostic Approach ◽  
Ac Systems

Determination of AlGaN/GaN HEMT Reliability Using Optical Pumping as a Characterization Method

2012 ◽  
Vol 1432 ◽  
Author(s):  
D. Cheney ◽  
R. Deist ◽  
B. Gila ◽  
F. Ren ◽  
P. Whiting ◽  
...  
Keyword(s):  
Band Gap ◽  
Optical Pumping ◽  
Drain Current ◽  
Stress Tests ◽  
Optically Pumped ◽  
Gan Hemt ◽  
Load Line ◽  
Gan Hemts ◽  
Dc Stress

ABSTRACTBy pumping AlGaN/GaN HEMTs with below band-gap light we observe changes in drain current that correspond to the trapping and detrapping of carriers within the band-gap. These changes in drain current are indicators of trap density, since the energy from a specific wavelength of light pumps traps whose activation energies are less than or equal to that of the light source.AlGaN/GaN HEMTs on SiC with dual submicron gates with widths of 125nm, 140nm, or 170nm, are DC-stressed under three different conditions along a load line: VGS=0, VDS=5 (on-state), VGS=-2, VDS=9.2 and, VGS=-6, VDS=25 (off-state). The stress tests are interrupted at 20% degradation and the optically pumped comparisons to the baseline are measured.This paper describes the optical pumping technique and results from experiments of AlGaN/GaN HEMTs under the three DC stress biases along a load line.

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