The Quantum Dynamics of Heterotic Vortex Strings

We study the quantum dynamics of vortex strings in N=1 SQCD with U(N_c) gauge group and N_f=N_c quarks. The classical worldsheet of the string has N=(0,2) supersymmetry, but this is broken by quantum effects. We show how the pattern of supersymmetry breaking and restoration on the worldsheet captures the quantum dynamics of the underlying 4d theory. We also find qualitative matching of the meson spectrum in 4d and the spectrum on the worldsheet.Comment: 13 page

The happiness of students and staff at two public universities respectively in Hong Kong and London: A comparative analysis from the Confucian perspective

Happiness is one of the important components in life and culture is considered having impact on happiness. Different cultures may define and perceive happiness dissimilarly. In particular, the collectivistic Confucian happiness is notably distinct from the individualist conceptions of happiness often seen as a feature of contemporary Western cultures. The virtuous considerations of Confucian happiness, according to Luo (2021), differentiate it from the individualist conceptions, where there are two levels in the Confucian happiness: (a) satisfaction of personal basic needs and (b) contribution to the social society at large (Zeng and Guo 2012), and group interests are accorded higher priority over individual interests. Notwithstanding cultural differences, happiness studies have been biased to a great extent towards the Western conceptions. Happiness research in the Chinese context is not common, let alone studies from the perspective of Confucianism. The current doctoral study adopted a comparative approach from the perspective of Confucianism to explore the perceptions of happiness of students as well as a few staff at the University DEF (pseudonym; “DEF” hereafter) in London and at the University NOP (pseudonym; “NOP” hereafter) in Hong Kong. There were four research questions: How would students and staff at DEF and NOP respectively perceive happiness? In what ways would responses at DEF be different from those at NOP? Would culture be a significant factor determining their perceived happiness? How could the findings be analysed and interpreted from the Confucian perspective? A bilingual questionnaire was prepared, incorporating the 48-item Chinese Happiness Inventory (CHI) as the measurement tool. The CHI combines 28 out of 29 dimensions from the Oxford Happiness Inventory (Argyle, Martin and Crossland 1989) with 20 Chinese culture dimensions (Lu and Shih 1997a), involving not only Western elements of individuality but also Chinese components of community. It is considered a culturally-balanced tool to measure happiness in the present study. Approval for the use of the CHI was granted by the first author of Lu and Shih (1997a) at the National Taiwan University. Questionnaires in both online and paper formats were sent out and there was a return of 213 completed questionnaires. Software employed was SPSS (version 28.0.1.1 (14)) and SmartPLS (version 3.3.7) for data analyses. The findings revealed statistically significant differences in happiness between students’ responses from the two universities. In general, respondents at DEF had higher happiness values than those at NOP. In particular, there were significant differences, to various degrees, in students’ levels, modes and years of study. Significant differences were also identified in demographic variables including gender, age, marital status, number of children, nationality, ethnicity and religion. There was no significant difference between staff groups and student groups. There was no difference in the attribute of “highest educational level attained”, either. The results of the present study pointed out that culture was a significant factor determining the respondents’ perceived happiness, but the anticipated Confucian values of respondents at NOP in Hong Kong may have been influenced by Western cultures. In addition to statistical interpretation, attempts were made to interpret the results from the Confucian perspective. The impact and limitations of the present study were discussed. Future studies were also suggested

Spectral flow invariants and twisted cyclic theory from the Haar state on SU_q(2)

In [CPR2], we presented a K-theoretic approach to finding invariants of algebras with no non-trivial traces. This paper presents a new example that is more typical of the generic situation. This is the case of an algebra that admits only non-faithful traces, namely SU_q(2), and also KMS states. Our main results are index theorems (which calculate spectral flow), one using ordinary cyclic cohomology and the other using twisted cyclic cohomology, where the twisting comes from the generator of the modular group of the Haar state. In contrast to the Cuntz algebras studied in [CPR2], the computations are considerably more complex and interesting, because there are nontrivial `eta' contributions to this index.Comment: 25 pages, 1 figur

Triclosan Adsorption Using Wastewater Biosolids-derived Biochar

Organic micropollutants are ubiquitous in the environment and stem from municipal wastewater treatment plant discharges. Adsorption can be used as a tertiary treatment to complement the conventional activated sludge process to remove micropollutants prior to discharge. This research evaluated the performance of wastewater biosolids-derived biochar as an adsorbent to remove triclosan from water. Pre-conditioning of the biochar using hydrochloric acid (HCl) was an essential step for triclosan adsorption. Using acid-conditioned biochar, maximum adsorption of 872 μg triclosan per g biochar was achieved with biochar produced at 800 °C. Biochar produced at higher pyrolysis temperatures tended to have higher triclosan sorption capacity using initial triclosan concentrations of 200 μg L−1 levels. However, pyrolysis temperature had less impact on triclosan sorption at lower, environmentally relevant concentrations. Low solution pH (3) enhanced adsorption and high pH (11) inhibited adsorption. Effective triclosan sorption was observed between pH 5 and 9, with little variation, which is positive for practical applications operated at near-neutral solution pH. In wastewater, acid-treated biochar also effectively sorbed triclosan, albeit at a decreased adsorption capacity and removal rate due to competition from other organic constituents. This study indicated that adsorption may occur mainly due to high surface area, hydrophobicity, and potential interaction between biochar and triclosan functional groups including hydrogen bonding and π-stacking. This work demonstrated that acid-conditioned biosolids-derived biochar could be a suitable sorbent to remove triclosan from wastewater as a final polishing treatment step

Extended Variational Cluster Approximation

The variational cluster approximation (VCA) proposed by M. Potthoff {\it et al.} [Phys. Rev. Lett. {\bf 91}, 206402 (2003)] is extended to electron or spin systems with nonlocal interactions. By introducing more than one source field in the action and employing the Legendre transformation, we derive a generalized self-energy functional with stationary properties. Applying this functional to a proper reference system, we construct the extended VCA (EVCA). In the limit of continuous degrees of freedom for the reference system, EVCA can recover the cluster extension of the extended dynamical mean-field theory (EDMFT). For a system with correlated hopping, the EVCA recovers the cluster extension of the dynamical mean-field theory for correlated hopping. Using a discrete reference system composed of decoupled three-site single impurities, we test the theory for the extended Hubbard model. Quantitatively good results as compared with EDMFT are obtained. We also propose VCA (EVCA) based on clusters with periodic boundary conditions. It has the (extended) dynamical cluster approximation as the continuous limit. A number of related issues are discussed.Comment: 23 pages, 5 figures, statements about DCA corrected; published versio

Biosolids-Derived Biochar for Triclosan Removal from Wastewater

Micropollutants, including antibiotics, hormones, pharmaceuticals, and personal care products, are discharged into the environment with liquid and solid effluent streams from water resource recovery facilities (WRRFs). The objective of this research was to determine whether biosolids-derived biochar (BS-biochar) could be used as a sorbent in continuous flow-through columns to remove micropollutants as a polishing step for wastewater treatment. Triclosan (TCS) was selected as a representative micropollutant due to frequent detection in liquid effluents, residual biosolids, and surface waters. Bench-scale column experiments were conducted to determine the effect of flow rate and competition due to the presence of other organic micropollutants and inorganic nutrients on TCS adsorption to BS-biochar. TCS removal efficiency was compared in Milli-Q water and secondary wastewater effluent by using two commercial adsorbents: a granular activated carbon and a wood-based biochar. Increased removal of TCS was observed at lower flow rates (2.6 gpm/ft2) compared with higher flow rates (10.3 gpm/ft2). Presence of inorganic nutrients (NH4+ and PO43−) and organic micropollutants 17β-estradiol and sulfamethoxazole decreased adsorption of TCS to BS-biochar. TCS was sorbed to BS-biochar in wastewater, but percent removal decreased in wastewater relative to Milli-Q water. This study demonstrated that BS-biochar can remove TCS from wastewater in continuous flow-through columns, although to a lesser extent than activated carbon. An additional benefit of using BS-biochar is that WRRFs could re-activate biochar on-site by using a pyrolysis reactor

Broadband double-layered coplanar patch antennas with adjustable CPW feeding structure

In this paper, we have presented the double-layered coplanar patch antennas of enhanced impedance bandwidth and adjustable conductor-backed coplanar waveguide feed lines. The proposed structure retains the advantage of laying the coplanar patch and coplanar waveguide (CPW) feed line on the same surface, which makes direct integration with other devices easier. In addition, the substrate thickness of the radiating patch can be adjusted to achieve a wider impedance bandwidth while the dimensions of the CPW feed line are kept unchanged. Simulation has been done by using commercial electromagnetic (EM) simulation software. Four testing antennas, which have centre frequency at about 10 GHz, were designed. The four testing antennas had the same total thickness, but different thickness combinations. From the measured return loss, gain, and radiation patterns of the antennas, it was demonstrated that different thickness combinations do not affect the characteristics of the antennas seriously. Therefore, the dimensions of the CPW feed structure of the antennas can be adjusted individually and can be selected for different applications

Measurements of the instantaneous velocity difference and local velocity with a fiber-optic coupler

New optical arrangements with two single-mode input fibers and a fiber-optic coupler are devised to measure the instantaneous velocity difference and local velocity. The fibers and the coupler are polarization-preserving to guarantee a high signal-to-noise ratio. When the two input fibers are used to collect the scattered light with the same momentum transfer vector but from two spatially separated regions in a flow, the obtained signals interfere when combined via the fiber-optic coupler. The resultant light received by a photomultiplier tube contains a cross-beat frequency proportional to the velocity difference between the two measuring points. If the two input fibers are used to collect the scattered light from a common scattering region but with two different momentum transfer vectors, the resultant light then contains a self-beat frequency proportional to the local velocity at the measuring point. The experiment shows that both the cross-beat and self-beat signals are large and the standard laser Doppler signal processor can be used to measure the velocity difference and local velocity in real time. The new technique will have various applications in the general area of fluid dynamics.Comment: Patent number: 67437 for associated information on the hardware, see http://karman.phyast.pitt.edu/horvath