A compound current limiter and circuit breaker

© 2019 by the authors. Licensee MDPI, Basel, Switzerland. The protection of sensitive loads against voltage drop is a concern for the power system. A fast fault current limiter and circuit breaker can be a solution for rapid voltage recovery of sensitive loads. This paper proposes a compound type of current limiter and circuit breaker (CLCB) which can limit fault current and fast break to adjust voltage sags at the protected buses. In addition, it can act as a circuit breaker to open the faulty line. The proposed CLCB is based on a series L-C resonance, which contains a resonant transformer and a series capacitor bank. Moreover, the CLCB includes two anti-parallel power electronic switches (a diode and an IGBT) connected in series with bus couplers. In order to perform an analysis of CLCB performance, the proposed structure was simulated using MATLAB. In addition, an experimental prototype was built, tested, and the experimental results were reported. Comparisons show that experimental results were in fair agreement with the simulation results and confirm CLCB’s ability to act as a fault current limiter and a circuit breaker

Structural Observation of the Primary Isomerization in Vision with Femtosecond-Stimulated Raman

the substrate surface (27) with DOS of polymers could occur, or there could be charge transfer (28) based on the interaction between the polymers and the I-Au(111). These electronic interactions between the polymers and the surface might reduce the HOMO-LUMO gaps compared with those in solution. Chem. Soc. 124, 11862 (2002). 11. H. Sakaguchi, H. Matsumura, H. Gong, Nat. Mater. 3, 551 (2004 Science 271, 1705Science 271, (1996. Adv. Mater. 4, 282 (1992 The primary event that initiates vision is the light-induced 11-cis to all-trans isomerization of retinal in the visual pigment rhodopsin. Despite decades of study with the traditional tools of chemical reaction dynamics, both the timing and nature of the atomic motions that lead to photoproduct production remain unknown. We used femtosecond-stimulated Raman spectroscopy to obtain time-resolved vibrational spectra of the molecular structures formed along the reaction coordinate. The spectral evolution of the vibrational features from 200 femtoseconds to 1 picosecond after photon absorption reveals the temporal sequencing of the geometric changes in the retinal backbone that activate this receptor. Understanding the mechanism of a chemical reaction requires measuring the structure of the reactant as it evolves into product. Many of the most intriguing and efficient photochemical and photobiological reactions take place on ultrafast time scales and their kinetics have been well characterized by femtosecond absorption and fluorescence spectroscopies (1-5). Although x-ray diffraction is being developed for timeresolved structural studies of reactions, this approach is challenging to apply in the condensed phase and currently limited to processes slower than È100 ps (6). Ultrafast vibrational spectroscopy is advantageous in this quest because it offers both excellent temporal and structural information (7). The traditional picosecond timeresolution limitation (8) is being transcended through the use of femtosecond pulses in the infrared (IR) in multidimensional as well as direct time-resolved experiments of ultrafast chemical and biological processes (9-11). The complementary Raman vibrational techniques have also advanced with the recent development of stimulated Raman in the femtosecond time domain (12, 13), which is valuable because of its ability to interrogate biological processes in aqueous media. Here, we demonstrate the capabilities of femtosecond-stimulated Raman spectroscopy (FSRS) in studies of reaction dynamics by elucidating the molecular mechanism of the primary photochemical events in vision. In FSRS, two laser pulses drive the Raman transition: a picosecond BRaman pulse[ and a femtosecond broadband continuum Bprobe pulse[ that stimulates the scattering of any vibrational modes with frequencies between 600 and 2000 cm j1 . The use of the additional probe pulse to induce the Raman scattering offers a number of notable improvements over traditional timeresolved spontaneous Raman spectroscopy (14), such as greatly enhanced cross sections and an order-of-magnitude improvement in time resolution (G100 fs) while maintaining excellent energy resolution (G15 cm j1 ) (15, 16). The impulsive creation of vibrational coherence by the Raman and probe pulses reveals highly time-resolved vibrational structural information that is not accessible by incoherent processes such as spontaneous Raman. The primary step in vision is the photochemical cis-trans isomerization of the 11-cis retinal chromophore in rhodopsin We address these questions by acquiring femtosecond time-resolved vibrational spectra of retinal in rhodopsin throughout the reaction. Modeling of the vibrational structural features after rapid internal conversion to the ground state reveals the highly distorted structure of photorhodopsin. Surprisingly, a large fraction of the atomic rearrangement leading to the formation of fully isomerized bathorhodopsin is shown to occur in the ground electronic state. Vivid details of thi

Hvdc breaker power loss reduction by bridge-type hybrid breakers

Several types of high voltage direct current (HVDC) breakers have been introduced and commercialized. Each of them has advantages and disadvantages. Among them, the hybrid HVDC breaker is highly successful. One of the most important concerns that the hybrid HVDC breaker has faced is high power loss throughout its fault current breaking process. The hybrid HVDC breaker comprises a high voltage bidirectional main HVDC breaker. A significant number of electronic switches need to be connected in a series where anti-parallel diodes are essentially embraced. During fault inception, a number of series solid-state switches and a number of series diodes dramatically increase the power loss of the main breaker. This study, firstly, studies the power loss of the hybrid HVDC breaker and later develops a structure of a full-bridge hybrid breaker (FBHB) to reduce the losses of the current structure both in the normal and fault protection states. In this paper simulations are done based on PSCAD. In addition to the analytical study and simulations, we show that the developed structure substantially decreases the amount of power lost during the normal operation and fault current breaking stage

Construction contingency determination : a review of processes and techniques

Abstract

Cultural engagement and the economic performance of the cultural and creative industries: an occupational critique

This article presents a new critical engagement with the concept of Cultural and Creative Industries (CCIs), focusing on the rationale for grouping occupations and industries under this label. We show how the definition of ‘creativity’ used to demonstrate CCIs’ economic performance remains contested and variable, particularly with regard to the inclusion of specific parts of the IT sector. In demonstrating the importance of IT to the economic narrative regarding CCIs, we then unfold a related critique, exploring patterns in cultural consumption within CCI occupations. We demonstrate how some CCI workers have distinctively high cultural consumption, others reflect their broader social class, and some, including IT workers, show lower than expected consumption. Overall, we question the coherence of the prevailing CCI category, particularly in government policy, and suggest a new mode of ‘cultural’ occupational analysis for the sociology of CCIs

Cross - national comparisons of attitudes towards suicide and suicidal persons in university students from 12 countries

This paper reports the results of a comparative investigation of attitudes to suicide and suicidal persons in 5,572 university students from 12 countries. Participants filled out two scales measuring attitudes towards suicide and suicidal persons, a measure of psychological distress together with the questions about suicidal behavior. Results showed that the highest suicide acceptance scores were observed in Austrian, UK, Japanese and Saudi Arabian samples and the lowest scores were noted in Tunisian, Turkish, Iranian and Palestinian samples. While the highest social acceptance scores for a suicidal friend were noted in Turkish, US, Italian and Tunisian samples, the lowest scores were seen in Japanese, Saudi Arabian, Palestinian and Jordanian samples. Compared to participants with a suicidal past, those who were never suicidal displayed more internal barriers against suicidal behavior. Men were more accepting of suicide than women but women were more willing to help an imagined suicidal peer. Participants with accepting attitudes towards suicide but rejecting attitudes towards suicidal persons reported more suicidal behavior and psychological distress, and were more often from high suicide rate countries and samples than their counterparts. They are considered to be caught in a fatal trap in which most predominant feelings of suicidality such as hopelessness or helplessness are likely to occur. We conclude that in some societies such as Japan and Saudi Arabia it might be difficult for suicidal individuals to activate and make use of social support systems

Is Individualism Suicidogenic? Findings From a Multinational Study of Young Adults From 12 Countries

The associations of individualistic versus collectivistic value orientations with suicidal ideation and attempts, attitudes towards suicide and towards suicidal individuals, and psychological distress were investigated across 12 nations (N = 5572 university students). We expected differential associations of value orientations with suicidal behavior and moderating effects of the prevailing value orientations in the various countries. Findings showed that intermediate levels of individualism appeared protective against suicide attempts across all investigated nations, but that, otherwise, there seemingly are no universal associations of individualism and collectivism with suicidal behaviors. High collectivism was associated with less suicidal ideation only in individualistic countries. Low individualism appeared to be a risk factor for suicidal ideation specifically in Muslim collectivistic cultures, whereas high individualism in Asian collectivistic cultures. Collectivistic values are uniformly associated with less permissive attitudes to suicide, whereas individualistic values with a more stigmatized view of suicidal behavior. Both individualistic and collectivistic values were associated with socially accepting attitudes to a suicidal peer, helping a suicidal friend, and emotional involvement. The associations of individualistic and collectivistic values with disapproving attitudes to suicidal disclosure were complex. Beliefs in punishment after death for suicide, seeing suicide as mental illness, and emotional involvement with a suicidal friend were lower in high-suicide-rate countries. These evidence patterns are discussed in the light of related research evidence, along with directions for future research in this area

The Role of Religion on Suicidal Behavior, Attitudes and Psychological Distress in University Students: A Multinational Study

The purpose of this study was to determine the association of religion to suicidal behavior, attitudes and psychological distress in 5572 students from 12 countries by means of a self-report questionnaire. Our results showed that an affiliation with Islam was associated with reduced risk for suicide ideation, however affiliating with Orthodox Christianity and no religion was related to increased risk for suicide ideation. While affiliating with Buddhism, Catholic religion and no religion associated with lowered risk for attempting suicide, affiliation with Islam was related to heightened risk for attempting suicide. Affiliation with Hinduism, Orthodox Christianity, Protestantism, Catholicism, other religions and with no religion was associated with decreased risk for psychological distress but those reported affiliating with Islam evinced greater risk for psychological distress. The associations of the strength of religious belief to suicidal ideation and attempts were in the expected direction for most but it had a positive relation in respondents affiliating with Catholicism and other religions. Students reporting affiliation with Islam, Orthodox religion and Buddhism were the least accepting of suicide but they displayed a more confronting interpersonal style to an imagined peer with a suicidal decision. It was concluded that the protective function of religion in educated segments of populations (university students) and in university students residing in Muslim countries where freedom from religion is restricted or religion is normative and/or compulsory is likely to be limited. Our findings suggest that public policies supporting religious freedom may augment the protective function of religion against suicide and psychological distress

IKZF1 Deletions with COBL Breakpoints Are Not Driven by RAG-Mediated Recombination Events in Acute Lymphoblastic Leukemia

IKZF1 deletion (ΔIKZF1) is an important predictor of relapse in both childhood and adult B-cell precursor acute lymphoblastic leukemia (B-ALL). Previously, we revealed that COBL is a hotspot for breakpoints in leukemia and could promote IKZF1 deletions. Through an international collaboration, we provide a detailed genetic and clinical picture of B-ALL with COBL rearrangements (COBL-r). Patients with B-ALL and IKZF1 deletion (n = 133) were included. IKZF1 ∆1-8 were associated with large alterations within chromosome 7: monosomy 7 (18%), isochromosome 7q (10%), 7p loss (19%), and interstitial deletions (53%). The latter included COBL-r, which were found in 12% of the IKZF1 ∆1-8 cohort. Patients with COBL-r are mostly classified as intermediate cytogenetic risk and frequently harbor ETV6, PAX5, CDKN2A/B deletions. Overall, 56% of breakpoints were located within COBL intron 5. Cryptic recombination signal sequence motifs were broadly distributed within the sequence of COBL, and no enrichment for the breakpoint cluster region was found. In summary, a diverse spectrum of alterations characterizes ΔIKZF1 and they also include deletion breakpoints within COBL. We confirmed that COBL is a hotspot associated with ΔIKZF1, but these rearrangements are not driven by RAG-mediated recombination