Effect Of Cationic Charging Agent On The Bonding Strength Of Coarse Titanium Particles Deposited By Electrophoretic Deposition

Electrophoretic deposition (EPD) is a potential coating technique for surface hardening of steel when combined with a subsequent rapid sintering process. This process requires synergy between suspension particles and charging agent, particularly when the particles involved are noncolloidal in nature. The present work will investigate the effect of three commercially-available cationic charging agents; aluminium (III) chloride (AlCl3), polyethyleneimine (PEI) and poly(diallyldimethylammonium chloride) (PDADMAC) on the EPD of coarse Ti particles onto steel. The obtained Ti coatings were characterized by their surface microstructure, deposit yield, electrophoretic mobility and electrical conductivity. The key finding of the present study is the bonding strength of charging agent-adsorbed coarse Ti particles deposits predominantly controlled their deposit yield. Electrophoretic mobility of the Ti particles only played a lesser role in the deposit yield because of strong hindrance of gravity on the moving coarse particles. Charging agent, which gave the strongest to the weakest bonding strength is as follow: AlCl3, PDADMAC (Mw = 100,000 -200,000 amu), PDADMAC (Mw = 400,000 -500,000 amu), PEI

Non-degenerate-pump four-wave mixing kinetic inductance travelling-wave parametric amplifiers

Kinetic inductance travelling-wave parametric amplifiers (KITWPAs) have been demonstrated to achieve high gain over broad bandwidths whilst achieving near quantum-limited noise performance, properties which are extremely important for many ultra-sensitive experiments. In early KITWPA designs, the requirement for phase-matching lead to the creation of a large zero-gain gap in the centre of the gain profile where the peak gain is, which also slightly narrows down the operational bandwidth of the device. This has been mitigated in more recent designs by introducing a DC bias to the KITWPA device, which allows the gap to be tuned away from the amplification band. However, the added DC biasing requires a more complicated experimental setup and potentially leads to unwanted heat leak in the cryogenic environment. Additionally, operation with a DC bias also become challenging at higher frequencies beyond the microwave regime. In this paper, we present the concept of a KITWPA operating in a non-degenerate-pump four-wave mixing (NP-4WM) regime, whereby the injection of two pump tones along with a weak signal results in a broad, flat gain profile that removes the zero-gain gap as well as eliminates the need for a DC bias and the complexities associated with it. We demonstrate how a NP-4WM KITWPA is feasible to achieve broadband amplification at a range of frequencies, first in the microwave range where most KITWPAs reported to-date have been successfully experimentally characterised. We then extend the designs to several millimetre (mm) bands to illustrate how we can use this technique to design a broadband front-end pre-amplifier that covers several Atacama Large Millimetre/sub-millimetre Array (ALMA) Bands

Electrophoretic Mobilities Of Dissolved Polyelectrolyte Charging Agent And Suspended Non-Colloidal Titanium During Electrophoretic Deposition

Coarse (<= 20 microns) titanium particles were deposited on low-carbon steel substrates by cathodic electrophoretic deposition (EPD) with ethanol as suspension medium and poly (diallyldimethylammonium chloride) (PDADMAC) as polymeric charging agent. Preliminary data on the electrophoretic mobilities and electrical conductivities on the suspensions of these soft particles as well as the solutions themselves as a function of PDADMAC level were used as the basis for the investigation of the EPD parameters in terms of the deposition yield as a function of five experimental parameters: (a) PDADMAC addition level, (b) solids loading, (c) deposition time, (d) applied voltage, and (e) electrode separation. These data were supported by particle sizing by laser diffraction and deposit surface morphology by scanning electron microscopy (SEM). The preceding data demonstrated that Ti particles of 1-20 microns size, electrosterically modified by the PDADMAC charging agent, acted effectively as colloidal particles during EPD. Owing to the non-colloidal nature of the particles and the stabilization of the Ti particles by electrosteric forces, the relevance of the zeta potential is questionable, so the more fundamental parameter of electrophoretic mobility was used. A key finding from the present work is the importance of assessing the electrophoretic mobilities of both the suspensions and solutions since the latter, which normally is overlooked, plays a critical role in the ability to interpret the results meaningfully. Further, algebraic uncoupling of these data plus determination of the deposit yield as a function of charging agent addition allow discrimination between the three main mechanistic stages of the electrokinetics of the process, which are: (1) surface saturation; (2) compression of the diffuse layer, growth of polymer-rich layer, and/or competition between the mobility of Ti and PDADMAC; and (3) little or no decrease in electrophoretic mobility of Ti, establishment of polymer-rich layer, and/or dominance of the mobility of the PDADMAC over that of Ti

Balanced travelling-wave parametric amplifiers for practical applications

The development of superconducting travelling-wave parametric amplifiers (TWPAs) over the past decade has highlighted their potential as low-noise amplifiers for use in fundamental physics experiments and industrial applications. However, practical challenges, including signal-idler contamination, complex pump injection and cancellation, impedance mismatch, and the reciprocal nature of the device, have made it challenging to deploy TWPAs in real-world applications. In this paper, we introduce an innovative solution to these issues through phase-controlled balanced-TWPA architectures. These architectures involve placing two TWPAs in parallel between a pair of broadband couplers. By carefully controlling the phases of the tones propagating along the TWPAs, we can effectively separate the signal and idler tones, as well as the pump(s), using a straightforward injection and cancellation mechanism. The balanced-TWPA architecture offers versatility and flexibility, as it can be reconfigured either intrinsically or externally to suit different application needs. In this manuscript, we provide a comprehensive discussion of the working principles of the balanced-TWPA, including various configurations designed to meet diverse application requirements. We also present the expected gain-bandwidth products in comparison to traditional TWPAs and conduct tolerance analysis to demonstrate the feasibility and advantages of the balanced-TWPA architecture. By addressing the practical challenges associated with TWPAs, the balanced-TWPA architecture represents a promising advancement in the field, offering a more practical and adaptable solution for a wide range of applications

The impact of topical mupirocin on peritoneal dialysis infection rates in Singapore general hospital.

Background. Peritonitis and exit-site infections (ESI) are major causes of technique failure and morbidity in peritoneal dialysis (PD) patients. Topical mupirocin on the exit-site has been shown to reduce such complications and prolong life in PD. Since the year 2000, such an approach has been adopted for our new incident PD population. We now report the results of this new protocol. We also studied the effect of co-morbidity on peritonitis occurrence. Methods. A total of 740 incident PD patients were studied. Patients were divided into two groups based on year of entry into PD (Group 1 from January 1998–December 1999 without topical mupirocin and Group 2 from January 2000–March 2004 with topical mupirocin). Variables studied included gender, age, diabetic status, ischaemic heart disease, peripheral vascular disease, cerebrovascular disease and serum albumin. Results. Topical mupirocin at the exit-site has led to a significant reduction in peritonitis rate (0.443 vs 0.339 episodes/patient-year; P<0.0005) and ESI (0.168 vs 0.156 episodes/patient-year; P<0.005) attributed primarily to the significant reduction in Staphylococcus aureus infections. There was an unexpected finding of lower Pseudomonas aeruginosa peritonitis in the mupirocin group (P<0.005). Stepwise multiple logistic regression analysis revealed that only mupirocin application and serum albumin were significant predictors of peritonitis. Conclusions. Our study, although limited by its retrospective nature, demonstrated that topical mupirocin was associated with a significant reduction in ESI and peritonitis with unexpected findings of lower Pseudomonas peritonitis. Serum albumin prior to the initiation of PD was a strong predictor of subsequent peritonitis. Mupirocin, with its low toxicity, ease of application and demonstrable beneficial effect in reducing ESI and peritonitis is now used on all incident PD patients

Decision support framework for supply chain planning with flexible demand

The most challenging issue of today’s production management is certainly to manage networked organisations under an uncertain demand so that to provide a good service to the customer at low cost. In this article, a model of the decision making parameters involved in this management process is suggested, on the base of case studies. A mixed integer linear planning model embedded in a framework simulating a rolling horizon planning process is described on the base of this analysis. The model takes into account the capabilities of reaction of the planned system and of its environment (suppliers, subcontractors and customers), as well as the corresponding costs. The suggested simulation framework may assist the decision maker for coping with an uncertain or flexible demand, using various planning strategies. Some possible applications of this simulation framework are given in order to illustrate how it can help to solve various types of practical planning problems