Non-Archimedean meromorphic solutions of functional equations

In this paper, we discuss meromorphic solutions of functional equations over non-Archimedean fields, and prove analogues of the Clunie lemma, Malmquist-type theorem and Mokhon'ko theorem

Ultrafast wavelength jumping and wavelength adjustment with low current using monolithically integrated FML for long-reach UDWDM-PON

Ultrafast wavelength jumping at optical network units (ONUs) for an access network with frequency modulated lasers (FMLs) is demonstrated. This FML consists of an intracavity tunable phase section and filtering gain section. It provides a total of 4.2 nm tuning range with fast wavelength jumping (2.2 nm in 1 µs) and fast adjustment (1.3 nm in 1.8 ns), providing a candidate for the fast tuning ONU for coherent ultradense wavelength-division multiplexing passive optical networks (WDM-PONs).Peer ReviewedPostprint (author's final draft

The optimal use of tris-2-ethylhexylamine to recover hydrochloric acid and metals from leach solutions and comparison with other extractants

This document is the Accepted Manuscript version of the following article: Uchenna Kesieme, Andreas Chrysanthou, Maurizio Catulli, and Chu Yong Cheng, ‘The optimal use of tris-2-ethylhexylamine to recover hydrochloric acid and metals from leach solutions and comparison with other extractants’, Journal of Environmental Chemical Engineering, Vol. 6 (2): 3177-3184, April 2018. Under embargo until 1 May 2019. The final, definitive version is available online via: https://doi.org/10.1016/j.jece.2018.05.001This paper describes the use of TEHA for HCl recovery from a leach solution generated by a hydrometallurgical plant. Four organic extractants were tested including TEHA, Alamine 336, Cyanex 923 and TBP. TEHA organic system performed best in terms of acid extraction, stripping and scrubbing efficiency. The successive extraction shows that more than 99% HCl was extracted after three stages of extraction. Scrubbing tests with different A/O ratios at different temperatures were conducted to identify the optimal conditions to separate HCl, Mn and Fe. After scrubbing the loaded organic solution at an A/O ratio of 1:4 and 22 °C, 94–100% of entrained metals were removed in a single contact with only 5.2% acid lost in the loaded scrub liquor. It was found that the phase disengagement time was in the range of 2– 4 min for both extraction and stripping, indicating reasonable fast phase separation. Based on these results from batch tests, it can be expected that after optimisation in a counter current circuit consisting of extraction, scrubbing, selective and bulk stripping, nearly all metals and HCl would be recovered and recycled.Peer reviewe

A review of acid recovery from acidic mining waste solutions using solvent extraction

This is the peer reviewed version of the following article: Uchenna Kesieme, Andreas Chrysanthou, Maurizio Catulli, and Chu Yong Cheng, ‘A review of acid recovery from acidic mining waste solutions using solvent extraction’, Journal of Chemical Technology and Biotechnology, (2018), which has been published in final form at https://doi.org/10.1002/jctb.5728. Under embargo until 1 July 2019. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.The minerals industry is increasingly being forced by regulatory and cost pressures to reduce the amount of liquid acidic waste they produce. This requires a strong focus on waste reduction by recycling, regeneration and reuse. Four mineral acids were examined for recovery from waste acidic solutions including H 2SO 4, HNO 3, HCl, and H 3PO 4. The selection of the optimal extractant for acid recovery was based on extraction, stripping and scrubbing efficiencies. The extractants suitable for the recovery of H 2SO 4 and HCl are in the order of TEHA > Cyanex 923 > TBP > Alamine 336. TEHA has the highest degree of acid extraction and stripping compared with Cyanex 923 and almost 99% of the acid can be stripped. Alamine 336 can extract higher acid (for H 2SO 4 and HCl systems) than Cyanex 923 and TBP. However loaded acid for Alamine 336 system cannot be stripped using water at 60°C. For the recovery of nitric and phosphoric acids from acidic waste effluents, TBP was the best option. This work clearly demonstrates that extractant suitable for acid extraction may not be suitable for its recovery. However such extractant may be applied for the removal of acid from any waste acidic solution sacrificing the back extraction of the loaded acid. The effective implementation of options for acid recovery was examined to improve sustainability in the mineral industry.Peer reviewe

Photonic devices for next generation fiber-to-the-home access network

It would be unaffordable if the WDM-PON technologies were directly applied for massive deployment. Hence, the potential WDM-PON is to be integrated and improved in order to adapt it for NGPON and the future 5G. The UDWDM-PON can be considered as an ultimate solution for the next-generation access network capable of providing unlimited bandwidth for each user, thanks to the coherent detection. Plenty of scientists have believed that it is crucial to increase the operating speed and maximum reach of WDM-PON, while it has no sense if people achieve them without a ordable cost. In order to apply them cost-effciently, the system should require colorless ONUs and bidirectional systems. It is desired that the whole system use modulators on a low bias consumption, even limit the number of amplifiers. However, for bidirectional transmission the backscattering effects would limit the performance if we want to reuse the carrier from OLT. So, we should design a method to separate the wavelength between upstream and downstream. The traditional UDWDM-PON uses 2 laser at ONU, in this thesis, the single-DFB based ONUs are presented with integrated devices. What is the most plausible configuration? The photonic devices such as RSOA, DEML, FML with advanced configurations are presented in this thesis with different applications. The proposed thesis includes these parts: key devices for WDM-PON and the chirp parameters of these integrated photonic devices are measured, the polarization independent RSOA with different applications is also included, demonstration of dual output DEML with bidirectional coherent UDWDM-PON transmission, mitigating residual AM of DEML for phase modulation, and fast tuning for the UDWDM channel via FML are described.Por sus altos requerimientos técnicos, sería inasumible aplicar las tecnologías WDM-PON directamente para el despliegue masivo de Fiber-to-the-Home de nueva generación. Por lo tanto, el potencial se WDM-PON se debe integrar y mejorar con el fin de adaptarlo para NGPON y el futuro 5G. Hoy dia, operadores, usuarios y científicos, ven crucial augmentar la velocitat de funcionament y el alcance de las redes de acceso PON, si bien no tiene sentido conseguirlo con un coste inasequible. El UDWDM-PON puede considerarse como una solución definitiva para la red de acceso de próxima generación, capaz de proporcionar ancho de banda ilimitado para cada usuario, gracias a la detección coherente, por lo que en esta tesis se aborda su realización con un coste e integración prácticos. Con el fin de aplicarlos de manera rentable, el sistema debería exigir a las ONU que sean idénticas, si láseres preseleccionados o incoloros, y ser bidireccionales. Se desea que el conjunto de moduladores del sistema tengan en un bajo consumo, e incluso limitar el número de amplificadores. Sin embargo, para la transmisión bidireccional los efectos de retrodispersión limitarían el rendimiento si queremos volver a utilizar la portadora generada en la OLT. Por lo tanto, debemos diseñar un método para separar la longitud de onda en las transmisiones de bajada y de retorno del usuario a la central. El tradicional UDWDM-PON utiliza 2 láseres en la ONU; en esta tesis, las ONUs usan dispositivos integrados basados en un sólo DFB. ¿Cuál es la configuración más plausible? Los dispositivos fotónicos como RSOA, DEML, FML con configuraciones avanzadas se presentan en esta tesis con diferentes aplicaciones, que resuelven distintos problemas técnicos. La tesis incluye las siguientes partes: análisis y medida de dispositivos fotónicos clave para WDM-PON con modulación de fase, la independencia a la polarización de RSOA con diferentes aplicaciones, demostración de DEML con doble salida para transmisión bidireccional coherente UDWDM-PON, mitigación de AM residual de DEML para la modulación de fase, y la sintonía rápida de canal de UDWDM a través de FML.Postprint (published version

2-(Furan-2-yl)-5-(2-nitro­benz­yl)-2,3-dihydro-1,5-benzothia­zepin-4(5H)-one

The title compound, C20H16N2O4S, was prepared by introduction of a 2-nitro­benzyl group to 2-(furan-2-yl)-2,3-dihydro-1,5-benzothia­zepin-4(5H)-one via an alkaline-catalysed reaction. The thia­zepine ring adopts a twist-boat conformation. The furan ring is oriented at dihedral angles of 56.75 (14) and 10.82 (14)° with respect to the two benzene rings, while the two benzene rings make a dihedral angle of 62.96 (10)°. Weak inter­molecular C—H⋯O hydrogen bonds occur in the crystal structure

Coherent ONU based on 850 µm-long cavity-RSOA for next-generation ultra-dense access network

In this Letter, an efficient bidirectional differential phase-shift keying (DPSK)-DPSK transmission for a ultradense wavelength division-multiplexed passive optical network is proposed. A single distributed feedback laser at the optical network unit (ONU) is used both as the local laser for downlink coherent detection and the optical carrier for uplink. Phase-shift keying is generated using a low-cost reflective semiconductor optical amplifier (RSOA) at the ONU. The RSOA chip has the bandwidth of 4.7 GHz at the maximum input power and bias current. For uplink transmission, the sensitivity of the RSOA chip reaches -48.2 dBm at the level of bit error rate = 10(-3) for back-to-back, and the penalty for 50 km transmission is less than 1 dB when using polarization diversity.Peer ReviewedPostprint (published version