Towards a thermally regenerative all-copper redox flow battery

An all-copper redox flow battery based on strong complexation of Cu+ with acetonitrile is demonstrated, exhibiting reasonable battery performance. More interestingly, the battery can be charged by heat sources of 100 degrees C, by distilling off the acetonitrile. This destabilizes the Cu+ complex, leading to recovery of the starting materials

Over-the-Air Performance Testing of 5G New Radio User Equipment:Standardization and Challenges

Abstract The Third Generation Partnership Project (3GPP) is accelerating 5G new radio (NR) global standards aimed at significant enhancement of wireless system performance for higher date rate, better energy efficiency, and higher reliability than the current 4G cellular systems. The operators, manufacturers, and test equipment vendors have worked together to develop standardized over-the-air (OTA) test methodologies for the overall performance evaluation of 5G NR devices. 3GPP is taking the lead in standardizing the OTA testing of 5G NR under fading channel conditions. In 3GPP specifications, test methods have been studied to verify the multiple-input multiple-output (MIMO) performance of 5G NR user equipments (UEs) in OTA mode. This article follows the 3GPP standardization work and discusses the MIMO OTA test methodologies for 5G NR UEs working at frequency range 1 (FR1) and FR2, with a focus on its new challenges and solutions compared to 4G MIMO OTA testing methods. Then the OTA throughput testing results of real 5G NRUEs are demonstrated under the standard channel models. Finally, the challenges and limitations of standard 5G MIMO OTA test solutions are also highlighted

Biomimetic Oxygen Reduction by Cofacial Porphyrins at a Liquid-Liquid Interface

Oxygen reduction catalyzed by cofacial metalloporphyrins at the 1,2-dichlorobenzene-water interface was studied with two lipophilic electron donors of similar driving force, 1,1'-dimethylferrocene (DMFc) and tetrathiafulvalene (TTF). The reaction produces mainly water and some hydrogen peroxide, but the mediator has a significant effect on the selectivity, as DMFc and the porphyrins themselves catalyze the decomposition and the further reduction of hydrogen peroxide. Density functional theory calculations indicate that the biscobaltporphyrin, 4,5-bis[5-(2,8,13,17-tetraethyl-3,7,12,18-tetramethylporphyrinyl)]-9,9-dimethylxanthene, Co-2(DPX), actually catalyzes oxygen reduction to hydrogen peroxide when oxygen is bound on the "exo" side ("dock-on") of the catalyst, while four-electron reduction takes place with oxygen bound on the "endo" side ("dock-in") of the molecule. These results can be explained by a "dock-on/dock-in" mechanism. The next step for improving bioinspired oxygen reduction catalysts would be blocking the "dock-on" path to achieve selective four-electron reduction of molecular oxygen

Hydrogen evolution across nano-Schottky junctions at carbon supported MoS2 catalysts in biphasic liquid systems

The activities of a series of MoS2-based hydrogen evolution catalysts were studied by biphasic reactions monitored by UV/Vis spectroscopy. Carbon supported MoS2 catalysts performed best due to an abundance of catalytic edge sites and strong electronic coupling of catalyst to support

Towards versatile access networks (Chapter 3)

Compared to its previous generations, the 5th generation (5G) cellular network features an additional type of densification, i.e., a large number of active antennas per access point (AP) can be deployed. This technique is known as massive multipleinput multiple-output (mMIMO) [1]. Meanwhile, multiple-input multiple-output (MIMO) evolution, e.g., in channel state information (CSI) enhancement, and also on the study of a larger number of orthogonal demodulation reference signal (DMRS) ports for MU-MIMO, was one of the Release 18 of 3rd generation partnership project (3GPP Rel-18) work item. This release (3GPP Rel-18) package approval, in the fourth quarter of 2021, marked the start of the 5G Advanced evolution in 3GPP. The other items in 3GPP Rel-18 are to study and add functionality in the areas of network energy savings, coverage, mobility support, multicast broadcast services, and positionin

On the Feasibility of Out-of-Band Spatial Channel Information for Millimeter-Wave Beam Search

| openaire: EC/H2020/101015956/EU//Hexa-XProlonged beam alignment is the main source of overhead in mobile wireless communications at millimeter-wave (mm-wave) frequencies due to narrow beams following the requirement of high antenna gains. Out-of-band spatial information may be used in initial beam search when lower-frequency-band radios are operating in conjunction with mm-wave radios. The feasibility of using low-band channel information for coarse estimation of high-band beam directions strongly depends on the spatial congruence between the two frequency bands. In this work, we try to answer two related questions. First, how similar is the power angular spectrum (PAS) of propagation channels between two widely separated frequency bands? Then, what is the impact of practical antenna configurations on spatial channel similarity? We propose a beam directions-based metric to assess the power loss and the number of false directions if out-of-band spatial information is used instead of in- band information. This metric is more practical and useful than comparing the PASs directly. Point cloud ray-tracing and propagation measurement results across multiple frequency bands and environments are used to show that the degree of spatial similarity of beamformed channels is related to antenna beam widths, frequency gap, and radio link conditions.Peer reviewe

Analyses of Beamspace MIMO Channels at 142GHz

| openaire: EC/H2020/101015956/EU//Hexa-X | openaire: EC/H2020/101095759/EU//Hexa-X-IIThis paper presents the analyses of a single-user beamspace MIMO on measured indoor and outdoor channels at 142 GHz. The rank is evaluated under different antenna sizes, number of beams, and thresholds. We assume a total power constraint at the transmitter which results in a decrease in signal-to-noise ratio as the link distance increases. When using spatial multiplexing, the indoor and outdoor sites demonstrate an average capacity gain of 2x and 1.5x at link distances below 60 m. Also, the rank for our measured 142 GHz channels is comparable to that at 60 GHz channels but significantly lower than the rank at 5 GHz channels reported in the literature. We also found that at 142 GHz, the indoor and outdoor sites have median ranks of 3.0 and 1.7 for the small antenna case, and 4.9 and 2.4 for the large antenna case assuming a rank threshold of 20 dB. The indoor site has a rank higher by 1.8 than the outdoor site, regardless of antenna size. The rank decreases by only 20% and 15% for indoor and outdoor scenarios when beam density is halved, allowing a significant reduction in implementation complexity of the beamspace MIMO without remarkably reducing the rank.Peer reviewe

Codes of conduct : A case study of four Swedish textile companies' work with codes of conduct

Idag använder sig många textilföretag av långa leverantörskedjor över stora avstånd samtidigtsom företagens omgivning ställer allt högre krav på dem i samband med sociala frågor. Dethar resulterat i ett allt större behov av att kunna kontrollera företagens produktion. På grundav det har uppförandekoder blivit allt vanligare. Uppförandekoder är ett sätt för företagen attförsäkra sig om att deras produkter tillverkas på ett socialt ansvarstagande sätt. Dock finns detflera frågetecken i samband med om uppförandekoder verkligen fyller sitt syfte.Syftet med uppsatsen är att utvärdera hur fyra svenska textilföretag arbetar meduppförandekoder för att minimera de sociala problem som finns i deras leverantörskedjor. Viville undersöka företagens arbete med uppförandekoderna samt deras innehåll, uppbyggnad,struktur och språk och på så vis ta reda på vilka problem företagen anser vara kopplade tilldetta arbete för att skapa förutsättningar för vidare forskning samt ge en djupare förståelse förhur man borde arbeta med uppförandekoder inom textilföretag.Undersökningen bygger på primär data vilket består av företagens uppförandekoder ochinsamlat material från intervjuer med de personer som ansvarar för uppförandekoden påföretagen. De företag som studerats och intervjuats är Nudie Jeans Co, Tailor Store, Hemtexoch Blåkläder.Vår studie visar att företagen själva anser att kontrollen av att uppförandekoderna efterföljssamt brister i arbetsförhållanden utgör de största problemen i deras arbete meduppförandekoderna. Vi anser dock att det största problem för samtliga undersökta företag harmed trovärdighet att göra då så mycket av deras arbete med sin uppförandekod präglas avsekretess.Today, many textile companies use long supply chains over large distances while thecompanies’ environment is putting more pressure on them in connection with social issues.This has resulted in an increasing need to control the companies’ production and because ofthis, codes of conduct have become increasingly used. Codes of conduct are a way forcompanies to ensure that their products are produced in a socially responsible way. However,there are several question marks if the code of conduct actually constitutes its purpose.The purpose of this paper is to evaluate four Swedish textile companies’ work to minimize thesocial problems that exist in their supply chains. An additional purpose is to examine thecodes of conduct content, constituents, structure and language and thus find out whatproblems companies believe to be connected to this work to create conditions for furtherresearch and provide a deeper understanding of how to work with codes of conduct in thetextile business.The study is based on primary data consisting of corporate codes of conduct and materialcollected from interviews with the persons responsible for each of the companies’ code ofconduct. The companies studied and interviewed are Nudie Jeans Co, Tailor Store, Hemtexand Blåkläder.Our study shows that companies themselves believe that the enforcement of codes of conductare followed and inadequate working conditions are the biggest problems in their work withtheir codes of conduct. However, we believe that the biggest problem for all the investigatedcompanies is credibility because much of their work with their codes of conduct ischaracterized by secrecy.Program: Textilekonomutbildninge