Alloy selections in high-temperature metal hydride heat pump systems for industrial waste heat recovery

In an energy intensive industrial site such as a steel plant, there are plenty of medium and low temperature waste heat which could be recovered for heating purposes with advanced and feasible technologies for example metal hydride (MH) heat pumps. Compared to other heat pump systems such as those with compression and absorption cycles, the MH heat pump has some distinctive advantages including low carbon system in terms of less electricity input and environmentally friendly working mediums, compactness, and most importantly achievable heat output with relatively high temperature. However, the applicable alloys for the high-temperature MH heat pump systems are critical and need to be purposely selected. Accordingly, in this paper, a comprehensive procedure to select alloys for the high-temperature MH heat pump systems is explained based on the operating temperatures, system efficiencies and thermodynamic equilibriums. From the database of literatures, totally 82 alloys are potentially used for this special application of which 1560 alloy pairs are formed and each pair consists of one high-temperature alloy and another low-temperature alloy. Subsequently, a number of applicable alloys are selected for each designed temperature of heat pump output and one pair is ultimately finalised. The alloy can be further examined considering of its thermophysical properties, heat transfer behaviours, costs and safety issues

Performance analysis of a metal hydride refrigeration system

The varying applications of metal hydride refrigeration systems, such as cold storage and space air conditioning, grant them important advantages over conventional ones. These advantages include being a low-grade heat driven, more environmentally friendly and renewable working fluid with greater compactness and fewer moving parts. However, a metal hydride refrigeration system always operates under unsteady conditions due to the cyclic hydriding and dehydriding processes involved. To analyse and optimise the metal hydride refrigeration system’s design and performance, in this paper, a comprehensive transient system model has been developed with a new and revised intrinsic kinetic correlation inclusive of the essential operating controls and applicable process conditions of regeneration, cooling and transitions in between. In addition, the correlative model on the characterisation process of pressure, concentration and temperature (PCT) profiles for the metal hydride alloys employed in the system has been developed and is introduced briefly in this paper. It is integrated in the system model and ensures the accurate prediction of maximum capacities for the metal hydride isothermal desorption and absorption processes. The developed transient system model has been validated through comparison with experimental results from literature on the medium-temperature cooling process of a metal hydride refrigeration system. The model simulation is conducted for a specially designed low-temperature metal hydride refrigeration system at different operating conditions and controls. In quantity, when the high-grade heat source temperature increases from 90 ◦C to 120 ◦C, the low-grade heat source temperature increases from − 20 ◦C to 10 ◦C, the medium-grade heat sink temperature decreases from 30 ◦C to 15 ◦C, and the time period for regeneration or cooling process decreases from 10 min to 4 min, the cooling COP increases by 112.0%, 136.6%, 19.3% and 31.8% respectively. The optimisation strategies for the system operating conditions and controls are therefore recommended based on the detailed performance analyses of the system simulation results

A 40-GHz Load Modulated Balanced Power Amplifier using Unequal Power Splitter and Phase Compensation Network in 45-nm SOI CMOS

© 2023 IEEE - All rights reserved. This is the accepted manuscript version of an article which has been published in final form at https://doi.org/10.1109/TCSI.2023.3282731 ​​​​​​​In this work, a ten-way power-combined poweramplifier is designed using a load modulated balanced amplifier(LMBA)-based architecture. To provide the required magnitudeand phase controls between the main and control-signal paths ofthe LMBA, an unequal power splitter and a phase compensationnetwork are proposed. As proof of concept, the designed poweramplifier is implemented in a 45-nm SOI CMOS process. At 40GHz, it delivers a 25.1 dBm Psat with a peak power-addedefficiency (PAE) of 27.9%. At 6-dB power back-off level, itachieves 1.39 times drain efficiency enhancement over an idealClass-B power amplifier. Using a 200-MHz single-carrier 64-QAMsignal, the designed amplifier delivers an average output power of16.5 dBm with a PAE of 13.1% at an EVMrms of -23.9 dB andACPR of -25.3 dBc. The die size, including all testing pads, is only1.92 mm2. To the best of the authors’ knowledge, compared withthe other recently published silicon-based LMBAs, this designachieves the highest Psat.Peer reviewe

A W-Band SPDT Switch with 15 dBm P1dB in 55-nm Bulk CMOS

© 2022 IEEE -This is the accepted manuscript version of an article which has been published in final form at https://doi.org/10.1109/LMWC.2022.3159529Power-handling capability of bulk CMOS-based single-pole double-throw switch operating in millimetre-wave and sub-THz region is significantly limited by the reduced threshold voltage of deeply scaled transistors. A unique design technique based on impedance transformation network is presented in this work, which improves 1-dB compression point, namely P1dB, without deteriorating other performance. To prove the presented solution is valid, a 70-100 GHz switch is designed and implemented in a 55-nm bulk CMOS technology. At 90 GHz, it achieves a measured P1dB of 15 dBm, an insertion loss of 3.5 dB and an isolation of 18 dB. The total area of the chip is only 0.14 mm2.Peer reviewe

A 90-GHz Asymmetrical Single-Pole Double-Throw Switch with >19.5-dBm 1-dB Compression Point in Transmission Mode Using 55-nm Bulk CMOS Technology

© Copyright 2021 IEEE. This is the accepted manuscript version of an article which has been published in final form at https://doi.org/10.1109/TCSI.2021.3106231The millimeter-wave (mm-wave) single-pole double-throw (SPDT) switch designed in bulk CMOS technology has limited power-handling capability in terms of 1-dB compression point (P1dB) inherently. This is mainly due to the low threshold voltage of the switching transistors used for shunt-connected configuration. To solve this issue, an innovative approach is presented in this work, which utilizes a unique passive ring structure. It allows a relatively strong RF signal passing through the TX branch, while the switching transistors are turned on. Thus, the fundamental limitation for P1dB due to reduced threshold voltage is overcome. To prove the presented approach is feasible in practice, a 90-GHz asymmetrical SPDT switch is designed in a standard 55-nm bulk CMOS technology. The design has achieved an insertion loss of 3.2 dB and 3.6 dB in TX and RX mode, respectively. Moreover, more than 20 dB isolation is obtained in both modes. Because of using the proposed passive ring structure, a remarkable P1dB is achieved. No gain compression is observed at all, while a 19.5 dBm input power is injected into the TX branch of the designed SPDT switch. The die area of this design is only 0.26 mm2.Peer reviewe

Inverse Approach to Evaluate the Tubular Material Parameters Using the Bulging Test

Tubular material parameters are required for both part manufactory process planning and finite element simulations. The bulging test is one of the most credible ways to detect the property parameters for tubular material. The inverse approach provides more effective access to the accurate material evaluation than with direct identifications. In this paper, a newly designed set of bulging test tools is introduced. An inverse procedure is adopted to determine the tubular material properties in Krupkowski-Swift constitutive model of material deformation using a hybrid algorithm that combines the differential evolution and Levenberg-Marquardt algorithms. The constitutive model’s parameters obtained from the conventional and inverse methods are compared, and this comparison shows that the inverse approach is able to offer more information with higher reliability and can simplify the test equipment

Antikaon production in nucleon-nucleon reactions near threshold

The antikaon production cross section from nucleon-nucleon reactions near threshold is studied in a meson exchange model. We include both pion and kaon exchange, but neglect the interference between the amplitudes. In case of pion exchange the antikaon production cross section can be expressed in terms of the antikaon production cross section from a pion-nucleon interaction, which we take from the experimental data if available. Otherwise, a $K^*$-resonance exchange model is introduced to relate the different reaction cross sections. In case of kaon exchange the antikaon production cross section is related to the elastic $KN$ and $\bar KN$ cross sections, which are again taken from experimental measurements. We find that the one-meson exchange model gives a satisfactory fit to the available data for the $NN\to NNK\bar K$ cross section at high energies. We compare our predictions for the cross section near threshold with an earlier empirical parameterization and that from phase space models.Comment: 16 pages, LaTeX, 5 postscript figures included, submitted to Z. Phys.

Bcl3 prevents acute inflammatory lung injury in mice by restraining emergency granulopoiesis

Granulocytes are pivotal regulators of tissue injury. However, the transcriptional mechanisms that regulate granulopoiesis under inflammatory conditions are poorly understood. Here we show that the transcriptional coregulator B cell leukemia/lymphoma 3 (Bcl3) limits granulopoiesis under emergency (i.e., inflammatory) conditions, but not homeostatic conditions. Treatment of mouse myeloid progenitors with G-CSF — serum concentrations of which rise under inflammatory conditions — rapidly increased Bcl3 transcript accumulation in a STAT3-dependent manner. Bcl3-deficient myeloid progenitors demonstrated an enhanced capacity to proliferate and differentiate into granulocytes following G-CSF stimulation, whereas the accumulation of Bcl3 protein attenuated granulopoiesis in an NF-κB p50–dependent manner. In a clinically relevant model of transplant-mediated lung ischemia reperfusion injury, expression of Bcl3 in recipients inhibited emergency granulopoiesis and limited acute graft damage. These data demonstrate a critical role for Bcl3 in regulating emergency granulopoiesis and suggest that targeting the differentiation of myeloid progenitors may be a therapeutic strategy for preventing inflammatory lung injury

Effects of affective picture viewing on postural control

<p>Abstract</p> <p>Background</p> <p>Emotion theory holds that unpleasant events prime withdrawal actions, whereas pleasant events prime approach actions. Recent studies have suggested that passive viewing of emotion eliciting images results in postural adjustments, which become manifest as changes in body center of pressure (COP) trajectories. From those studies it appears that posture is modulated most when viewing pictures with negative valence. The present experiment was conducted to test the hypothesis that pictures with negative valence have a greater impact on postural control than neutral or positive ones. Thirty-four healthy subjects passively viewed a series of emotion eliciting images, while standing either in a bipedal or unipedal stance on a force plate. The images were adopted from the International Affective Picture System (IAPS). We analysed mean and variability of the COP and the length of the associated sway path as a function of emotion.</p> <p>Results</p> <p>The mean position of the COP was unaffected by emotion, but unipedal stance resulted in overall greater body sway than bipedal stance. We found a modest effect of emotion on COP: viewing pictures of mutilation resulted in a smaller sway path, but only in unipedal stance. We obtained valence and arousal ratings of the images with an independent sample of viewers. These subjects rated the unpleasant images as significantly less pleasant than neutral images, and the pleasant images as significantly more pleasant than neutral images. However, the subjects rated the images as overall less pleasant and less arousing than viewers in a closely comparable American study, pointing to unknown differences in viewer characteristics.</p> <p>Conclusion</p> <p>Overall, viewing emotion eliciting images had little effect on body sway. Our finding of a reduction in sway path length when viewing pictures of mutilation was indicative of a freezing strategy, i.e. fear bradycardia. The results are consistent with current knowledge about the neuroanatomical organization of the emotion system and the neural control of behavior.</p