Ultimate Power Research Articles

Smart Resistor: Stabilization of DC Microgrids Containing Constant Power Loads Using High-Bandwidth Power Converters and Energy Storage

Power electronic converters and electric motor drives have found increased application in dc microgrids, electric automobiles, and ships. Such converters when driving loads in a regulated fashion act as constant power loads (CPLs). These CPLs can cause destabilizing effects on the grid because of their negative incremental impedance. This paper proposes a method to dynamically stabilize CPLs at the point of load by making them behave as adaptive Smart Resistors by using high-bandwidth power converters and energy storage units. These Smart Resistors can work with smart sources to realize ultimate intelligent power networks. The control strategies needed to achieve the concept, including voltage and current trajectory control principles, are analyzed and validated with a hardware test setup.

Power Management for Multicore Processors via Heterogeneous Voltage Regulation and Machine Learning Enabled Adaptation

This work is based on the vision that the ultimate power integrity and efficiency may be best achieved via a heterogeneous chain of voltage processing starting from onboard switching voltage regulators (VRs), to on-chip switching VRs, and finally to networks of distributed on-chip linear VRs. As such, we propose a heterogeneous voltage regulation (HVR) architecture encompassing regulators with complimentary characteristics in response time, size, and efficiency. By exploring the rich heterogeneity and tunability in HVR, we develop systematic workload-aware power management policies to adapt heterogeneous VRs with respect to workload change at multiple temporal scales to significantly improve system power efficiency while providing a guarantee for power integrity. The proposed techniques are further supported by hardware-accelerated machine learning (ML) prediction of nonuniform spatial workload distributions for more accurate HVR adaptation at fine time granularity. Our evaluations based on the PARSEC benchmark suite show that the proposed adaptive three-stage HVR reduces the total system energy dissipation by up to 23.9% and 15.7% on average compared with the conventional static two-stage voltage regulation using off-chip and on-chip switching VRs. Compared with the three-stage static HVR, our runtime control reduces system energy by up to 17.9% and 12.2% on average. Furthermore, the proposed ML prediction offers up to 4.1% reduction of system energy.

Maximum power and corresponding efficiency for two-level heat engines and refrigerators: optimality of fast cycles

We study how to achieve the ultimate power in the simplest, yet non-trivial, model of a thermal machine, namely a two-level quantum system coupled to two thermal baths. Without making any prior assumption on the protocol, via optimal control we show that, regardless of the microscopic details and of the operating mode of the thermal machine, the maximum power is universally achieved by a fast Otto-cycle like structure in which the controls are rapidly switched between two extremal values. A closed formula for the maximum power is derived, and finite-speed effects are discussed. We also analyze the associated efficiency at maximum power showing that, contrary to universal results derived in the slow-driving regime, it can approach Carnot’s efficiency, no other universal bounds being allowed.

LiBH4 for hydrogen storage - New perspectives

Abstract Hydrogen energy has been recognized as “Ultimate Power Source” in the 21st century. It is a boon in these days of energy crunches and concerns about climate change because of the characterized advantages, such as high energy density, large calorific value, abundant resource, zero pollution, zero carbon emission, storable and renewable. State-of-the-art perspectives on tuning the stable thermodynamics and sluggish kinetics of dehydrogenation and re-hydrogenation of LiBH4, which has been regarded as a promising hydrogen storage alternative for onboard energy carrier applications have been discussed. Five major technological approaches are involved, including nanoengineering, catalyst modification, ions substitution, reactant destabilization and a novel process termed as high-energy ball milling with in-situ aerosol spraying (BMAS). It is worth noting that BMAS has the potential to help overcome the kinetic barriers for thermodynamically favorable systems like LiBH4 ​+ ​MgH2 mixture and provide thermodynamic driving force to enhance hydrogen release at a lower temperature.

Fine Multi-Phase Alignments in 2D Perovskite Solar Cells with Efficiency over 17% via Slow Post-Annealing.

Layered Ruddlesden-Popper (RP) phase (2D) halide perovskites have attracted tremendous attention due to the wide tunability on their optoelectronic properties and excellent robustness in photovoltaic devices. However, charge extraction/transport and ultimate power conversion efficiency (PCE) in 2D perovskite solar cells (PSCs) are still limited by the non-eliminable quantum well effect. Here, a slow post-annealing (SPA) process is proposed for BA2 MA3 Pb4 I13 (n = 4) 2D PSCs by which a champion PCE of 17.26% is achieved with simultaneously enhanced open-circuit voltage, short-circuit current, and fill factor. Investigation with optical spectroscopy coupled with structural analyses indicates that enhanced crystal orientation and favorable alignment on the multiple perovskite phases (from the 2D phase near bottom to quasi-3D phase near top regions) is obtained with SPA treatment, which promotes carrier transport/extraction and suppresses Shockley-Read-Hall charge recombination in the solar cell. As far as it is known, the reported PCE is so far the highest efficiency in RP phase 2D PSCs based on butylamine (BA) spacers (n = 4). The SPA-processed devices exhibit a satisfactory stability with <4.5% degradation after 2000 h under N2 environment without encapsulation. The demonstrated process strategy offers a promising route to push forward the performance in 2D PSCs toward realistic photovoltaic applications.

Removal of chemical oxygen demand (COD) and heavy metals by catalytic ozonation-microbial fuel cell and Acidithiobacillus ferrooxidans leaching in flotation wastewater (FW).

A catalytic ozonation-microbial fuel cell and Acidithiobacillus ferrooxidans leaching process was used in treating flotation wastewater to remove chemical oxygen demand (COD) and heavy metals in this study. The results indicated that when adding 1 g/L of manganese/modified activated carbon catalyst and 1.5 g/min ozone flow, the COD could be degraded from 2,043.67 mg/L to 711.4 mg/L. After that, the COD could continue decreasing down to 72.56 mg/L through an air-cathode single chamber microbial fuel cell (SCMFCs), coated with 0.4 mg/cm2 platinum catalyst, after 15 days. Meanwhile, the maximum voltages and the ultimate power density of the SCMFCs reached 378.96 mV and 7,608.35 mW/m2, respectively. For filter residue, when 1.2 g/L Fe3+, 10% (m/v) filter residue, and 10% Acidithiobacillus ferrooxidans were added, the copper leaching rate could reach 92.69% after 7 days if the pH values were adjusted to 1.9. Furthermore, the other heavy metals were also decreased to a level lower than the pollution control standard (Chinese standard GB3838-2002). The leaching parameters in terms of pH, redox potential, and cyclic voltammetry showed that the addition of an appropriate concentration of Fe3+ to the leaching systems was beneficial to copper dissolution.

The antecedent and performance of environmental managers’ proactive pollution reduction behavior in Chinese manufacturing firms: Insight from the proactive behavior theory

This paper contributes to our understanding of how to improve manufacturing firms' green operations underpinned by the proactive behavior theory. Chinese manufacturing firms are focused on because of their significant impact on global climate change and distinctive governance structure. Specifically, we survey 155 highest-level environmental managers (EMs) in these firms who have an ultimate decision-making power on environmental issues, and investigate the antecedents and consequence of their proactive pollution reduction behavior (PPRB). Through identifying the psychological motivation implied in EMs' environmental management behavior, we find that both EMs' role breadth self-efficacy (including in-role self-efficacy and extra-role self-efficacy) and felt responsibility (including felt responsibility establishment and felt responsibility coordination) can improve their PPRB. Further, available resources in firms only positively moderate the impact of extra-role self-efficacy on PPRB, and incentives from external stakeholders only moderate the impact of felt responsibility establishment on PPRB. Our empirical results also confirm that PPRB can improve corporate operational performance, strategic competitiveness, and environmental performance, but a higher level of PPRB's performance comes more from the driving force of PPRB's antecedents rather than PPRB itself.

Low-Pass Filtering SC-DAC for Reduced Jitter and Slewing Requirements on CTSDMs

In this paper, a technique is introduced that improves the performance of one-bit continuous-time sigma delta modulators (CTSDMs) using a low-pass filtering switched capacitor digital to analog converter (LPSC-DAC). This DAC effectively combines an infinite impulse response filter with a switched capacitor resistor DAC (SCR-DAC). The resulting DAC is inherently immune toward inter-symbol interference. Moreover, by filtering the feedback signal in the discrete-time domain, the jitter robustness of the modulator is greatly improved and most importantly the slewing requirements on the OpAmps in the modulator’s loop filter are greatly relaxed up to a level that the OpAmps can be scaled down toward their ultimate noise limited power level. Furthermore, this LPSC-DAC does not suffer from the SCR-DAC’s disadvantageous trade-off between the modulator’s jitter, slewing, and anti-aliasing performance. We also show how to compensate for the extra pole of the LPSC-DAC, such that the CTSDM’s loop filter, noise- and signal-transfer function remains unchanged. As a result, this technique is completely transparent to the system level designer and established system-level design techniques for sigma delta modulators remain applicable.

Kin Endogamy and the Blood Taint in Ancient Egypt and Nigeria

Kin Endogamy, marriage between siblings, has been a practice among several cultures of the world. This is a deviation from positions of sociologists, anthropologists and psychologists on a universal incest taboo even as they premised it on four theories; the demographic, indifference, repression and evolution theories. Several scholars have discussed kin endogamy in the pre-Christian and Christian eras of the Greco-Roman societies citing evidences; explaining that indication of close-kin marriage could have been adoption rather than incest; and noting that royal incest may have been occasioned by the quest for ultimate power, even in the Ptolemaic dynasty. This paper took an in-depth study of sibling marriage in Ptolemaic Egypt and in some communities in Nigeria, with a view to understanding the rationale behind this socio-cultural practice and its effects on inbred children. The paper argues that it is highly probable that this consanguineous marriage even among the Ptolemies of Egypt may have resulted in genetic/biological and psychological setbacks among inbred descendants such that assassinations among siblings for power became the order of the day. The study further argued that kin endogamy was practiced due to, among others, the ideology of the blood taint or pure blood. Further studies that may examine exogamous culture in the Greco-Roman world and Nigeria were recommended.Key words: Endogamy, Blood taint, Inbreeding depression, Ptolemaic Egypt, Nigeria.

High-power x-ray tube for micro computed tomography

The present paper has suggested the idea to increase power of the microfocus x-ray tube of the transmission type due to application of the heat pipe as an anode. Ultimate heat power dissipating on such anode under various diameters of the electron beam has been evaluated. Possibility of significant overpowering of the suggested device has been shown in comparison with power of standard ones. Electron-optical scheme of the microfocus tube with electrostatic focusing has been developed.

Power performance assessment of H-rotor vertical axis wind turbines with different aspect ratios in turbulent flows via experiments

Vertical axis wind turbines (VAWTs) are suitable for applications in urban areas. Their ultimate power production relies on both the structural parameters and wind conditions. In this study, the power performance of H-rotor VAWTs immersed in turbulence of various length scales was assessed via wind tunnel testing. The influence of turbine aspect ratio on the power performance was investigated in the turbulent flows. A range of length scales were produced by wooden grids of different mesh sizes. The power coefficients, CP, of the VAWTs were measured by connecting an external resistance in the rotor circuit. Uncertainty analysis of the experimental data was conducted thereafter. Encouragingly, the rated CP was raised by approximately 100% in the turbulent flows compared to that in the smooth flow. The results evidently proved that turbulence was favorable for the operation of VAWTs. Moreover, the rated CP was inversely proportional to length scale, whereas it increased with aspect ratio, irrespective of flow regimes, the underline reasons for which were addressed. Further, the power-law equations were proposed to mathematically express the length scale and aspect ratio effects. This study contributes to the design and application of VAWTs in built environments.

A Contribuição do Constitucionalismo Popular para o Fortalecimento da Accountability Social sobre o Judiciário

A expansão do Poder Judiciário em democracias contemporâneas o afirma como o detentor da "última palavra" sobre o significado da constituição. Teóricos do constitucionalismo popular refutam a posição assumida pelo Judiciário, afirmando que o poder último de atribuição de tal significado pertence ao Povo, titular do poder constituinte originário e fiscal da aplicação desse documento. Uma revisão bibliográfica do constitucionalismo popular e da accountability judicial permite estabelecer os limites desta em assegurar o protagonismo do Povo preconizado por aquela, e explicitar a tensão existente entre a independência judicial operada pelo judiciário empoderado e a insuficiência da accountability judicial perante a sociedade. A accountability social, expressa majoritariamente por mecanismos que favoreçam a mobilização social e o uso democrático e responsável da mídia, pode contribuir para dissipar essa tensão, mas seus mecanismos ainda são insuficientes e escassos. O incremento de ferramentas efetivas de accountability social é necessário para ampliar a legitimidade do judiciário perante a sociedade, tornando-o mais responsivo a ela e mais receptivo a respeitar o protagonismo político do Povo na atribuição do significado da Constituição.

La finzione del "re" da Ciro il Grande (Erodoto) a Nerone (Svetonio, Tacito)

Greek and Roman sources depict an ancient children´s game, wherein one was chosen by drawing lots as king (basileus) and his playmates were appointed as servants or soldiers and were obliged to obey him. Herodotus already accounts a story about this game with reference to Cyrus the Elder and his discovery as royal heir. In ball-games, the winner was also appointed as king, while the defeated player was called donkey (onos). The roles of king and servant were also acted out in Roman times (ducatus et imperia ludere), as Tacitus and Suetonius confirm in connexion with the Emperor Nero. In fact, power was highly attractive for children, as Ancient basilinda game clearly shows. Neverthless, playmates should previously know ultimate power before acting a role game upon sovereignty.

Das Ende der Naivität gegenüber China? Die Reform des europäischen Investitionskontrollregimes

The European Union (EU) has introduced measures to better screen investments from third countries, in particular by enterprises and state actors of the People’s Republic of China. These measures highlight the profound change in bilateral relations which have turned from “strategic partnership” into “systemic rivalry”. Reacting to new Chinese policies of foreign trade and investment, the EU followed a revision of investment screening policies in the US. The EU has overcome deep splits among member states and established a new legal framework at the supranational level that leaves the ultimate screening and decision-making power to the national level. This paper identifies the changes in Chinese investment and investment policies and highlights key contents of the US legislation on investment control before discussing the new EU framework. It interprets the new measures as further examples of an increased reliance on state policies instead of market forces - by all partners involved.

Monetizing Hijab: Analysis on State’s National Interest on the Growing Hijab Fashion Trend in Indonesia

Hijab and its practices grow consistently as an iconic fashion of Muslim women in Indonesia. This phenomenon yields scholarly commentaries pertaining to the motivation of hijab’s massive production and Muslim women in veiling as well as the socioeconomic impact it carries with. However, the discussion on what sources of power underlie such a trend is still underrated. Therefore, this study aims at elucidating why now hijab receives greater support from the government under Joko Widodo’s administration that illuminates massive production and consumption on hijab domestically. The analyst came to argue that hijab consumption and production has become Indonesia’s national interest along with the mushrooming liberalization in its economy. Employing the qualitative research method to explain the source of power that makes hijab marketable in global and national market, the analyst also found that this trend is widely undermined by the implementation of neo-liberal economic policy that stresses the power of economic liberation of every individual while maintaining the state as the ultimate power of directing economic trajectory. Thus, the government of Indonesia seems to reconcile with the increasing domestic and global market demand on hijab. It is due to the state’s interest in establishing Indonesia as a global hijab centre by 2020.

Simultaneous Profiling of mRNA Transcriptome and DNA Methylome from a Single Cell.

Single-cell transcriptome and single-cell methylome analysis have successfully revealed the heterogeneity in transcriptome and DNA methylome between single cells, and have become powerful tools to understand the dynamics of transcriptome and DNA methylome during the complicated biological processes, such as differentiation and carcinogenesis.Inspired by the success of using these single-cell -omics methods to understand the regulation of a particular "-ome," more interests have been put on elucidating the regulatory relationship among multiple-omics at single-cell resolution. The simultaneous profiling of multiple-omics from the same single cell would provide us the ultimate power to understand the relationship among different "-omes," but this idea is not materialized for decades due to difficulties to assay extremely tiny amount of DNA or RNA in a single cell.To address this technical challenge, we have recently developed a novel method named scMT-seq that can simultaneously profile both DNA methylome and RNA transcriptome from the same cell. This method enabled us to measure, from a single cell, the DNA methylation status of the most informative 0.5-1million CpG sites and mRNA level of 10,000 genes, of which 3200 genes can be further analyzed with both promoter DNA methylation and RNA transcription. Using the scMT-seq data, we have successfully shown the regulatory relationship between DNA methylation and transcriptional level in a single dorsal root ganglion neuron (Hu et al., Genome Biol 17:88, 2016). We believe the scMT-seq would be a powerful technique to uncover the regulatory mechanism between transcription and DNA methylation, and would be of wide interest beyond the epigenetics community.

Science and Dissent

Reading C.P. Snow’s 1959 lecture, ‘Two Cultures and the Scientific Revolution’ in 2017, I was struck by the ways in which the essay, written over half a century ago, addresses issues that I’ve been engaged with for most of my life. Snow defined a world of cultures split between: ‘Literary intellectuals at one pole, at the other scientists. Between the two a gulf of mutual incomprehension, sometimes hostility and dislike, but most of all lack of understanding.’ I’ve encountered this lack of understanding in my own profession and in public life. But it was Snow’s closing argument that really grabbed my attention: he proposed to his Cambridge audience that they had ‘better look at education with a fresh eye’ and that there was a ‘good deal to learn from the Russians’. Not really. If, as Snow proposed, ‘Scientists have the future in their bones’, we’d all do better to respond to the cool reason of dissidents such as Andrei Sakharov and Anatol Sharansky and to recognize the ultimate power of free speech, which only exists in a free society.

Harvesting the Ultimate Electrical Power From MEMS Piezoelectric Vibration Energy Harvesters: An Optimization Approach

Optimized MEMS piezoelectric vibration energy harvesters with maximum possible power generation have been proposed. The energy harvesters work based on the transduction of the applied vibration induced stress on the cantilever beams into the electrical power. Particle swarm optimization approach has been used to design the optimum unimorph and bimorph structures. The optimization has been done for different combinations of the top and bottom piezoelectric layers in bimorph energy harvesters. The geometries of the proposed structures and their harvested powers before and after the optimization have been calculated and compared. The optimization parameters have been chosen so that asymmetric structures with partial coverage of piezoelectric layers would be investigated. The results show that the proposed structures serve as the maximum power generators and provide the largest possible electrical power. In order to limit the beam free end displacement, a guided two beam design has been proposed and optimized. The proposed bimorph guided two beam energy harvester could achieve the minimum displacement which has a key effect on the lifetime of the energy harvesters.

Parliamentary Sovereignty and the Locus of Constituent Power in the United Kingdom

This paper argues that parliamentary sovereignty’s assimilation of constituent power — the ultimate power in a legal order to create and posit a constitution — has stultified the development of British constitutional law. The result is a deeply ideological, as distinct from oft-heralded pragmatic, constitutional structure that is incapable of confronting the systemic challenges the UK currently faces. By conceptualising a more antagonistic relation between the Crown in Parliament and ‘the People’ by questioning the democratic credentials of the former, this paper contends that the UK constitutional order can be re-invigorated. This re-appraisal, however, also requires the interrogation of the notion of ‘the People’ in the UK constitutional order itself. Part I argues that despite what appear to be substantial constitutional reforms in recent decades, parliamentary sovereignty’s inviolability is stultifying deeper constitutional reform. The result is a constitutional law in ‘crisis’ in search of a paradigmatic revolution. A descriptive — as distinct from normative — account of constituent power is then introduced paving the way for a distinction to be drawn between the possessor of constituent power in a constitutional order and ‘the people’. Constituent power in the context of the UK is then discussed, arguing that parliamentary sovereignty incorporates much what the idea of constituent power does. However, this does not mean that constituent power is vested in ‘the people’; rather, the locus of constituent power in the UK should be more forcefully critiqued from a democratic perspective. By acknowledging this distinction, the sacrosanctity of parliamentary sovereignty can be broached and more effective constitutional reform can follow by embracing this tension between Parliament and ‘the People’.

English

Since the enactment of the Charities and Societies Proclamation 621/2009 in Ethiopia, civil societies were not performing their proper role for the advancement of the country’s democracy. The proclamation places excessive restrictions on the work of civil society organizations in the country. This, in turn, makes the public passive to engage in the politics of the country, rather the law gives ultimate power for the government to control the activities of the civil society organizations (CSOs). Furthermore, the law has a devastating impact on the CSOs activities, both in practical sense, it creates restriction on their area of engagement, and exacerbating climate of fear in which they operate. In the nutshell, the proclamation risks the observance and protection of the democratic rights of every person in Ethiopia. Key words: Civil society, democracy, human right, proclamation.