Water‐soluble polypyrrole‐polybis (4‐oxy benzene sulfonic acid) phosphazene composites and investigation of their performance as cathode binder in Li‐ion batteries

Current electric storage systems eagerly focus on high‐power and energy‐dense Lithium‐ion batteries to cope with increasing energy storage demands. Since cathode materials are one of the bottlenecks of these batteries, there is much interest in layered lithium‐rich manganese oxide‐based (LLMO) cathodes which can develop this technology. However, Initial Coulombic Efficiency (ICE) loss, poor rate performance and cycling instability issues are still persistent as problems to be solved for these materials. Recent research shows that water‐soluble binders are effective in improving the performance of LLMO materials. Herein, we describe the synthesis, characterisation, and application of a series of water‐soluble composites as a binder for LLMO cathodes. The PPy is introduced as part of the binder to improve the electronic conductivity and two different oxidants and various PPy to PSAP ratios were used to optimise the final properties. The electrochemical performance and morphology of the cathodes before and after cycling were investigated and compared with the conventional PVDF binder. The LLMO−2c electrode showed excellent charge‐discharge performance, especially at 5 C and 10 C rates, and high cycling stability at 0.2 C whilst maintaining a final capacity of 184 mAh/g after 200 cycles, which is equal to 89.3 % capacity retention

Inappropriate antimicrobial use in Turkish pediatric hospitals: A multicenter point prevalence survey

Objectives: Although well-defined principles of rational antimicrobial use are available, inappropriate prescribing patterns are reported worldwide. Accurate information on the usage of antimicrobials, including factors associated with and influencing their use, is valuable for improving the quality of prescription practices. Methods: In this cross-sectional point prevalence survey, data on patients hospitalized in 12 different children's hospitals were collected on a single day. Appropriateness of prescription was compared between the types of antimicrobials prescribed, indications, wards, and presence of/consultation with an infectious disease physician (IDP). Results: A total 711 of 1302 (54.6%) patients evaluated were receiving one or more antimicrobial drugs. The antimicrobial prescription rate was highest in pediatric intensive care (75.7%) and lowest in the surgery wards (37.0%). Of the 711 patients receiving antimicrobials, 332 patients (46.7%) were found to be receiving at least one inappropriately prescribed drug. Inappropriate use was most frequent in surgery wards (80.2%), while it was less common in oncology wards (31.8%; p < 0.001). Respiratory tract infection was the most common indication for antimicrobial use (29.4%). Inappropriate use was more common in deep-seated infections (54.7%) and respiratory infections (56.5%). Fluoroquinolones were used inappropriately more than any other drugs (81.8%, p = 0.021). Consultation with an IDP appears to increase appropriate antimicrobial use (p = 0.008). Conclusions: Inappropriate antimicrobial use remains a common problem in Turkish pediatric hospitals. Consultation with an IDP and prescribing antimicrobial drugs according to microbiological test results could decrease the inappropriate use of antimicrobials

Preventing tacit collusion in deregulated electricity markets through trilevel optimization

Deregulation in electricity markets aims to promote the market competition in order to minimize the cost of electricity to the public. Among the many threats that may lead to inflated electricity prices, tacit collusion is challenging to deal with. Tacit collusion, which may not be detected by the system operators easily, is usually considered as an outcome of the strategic behaviour of the electricity generators in a repeated game under the existence of certain market conditions and settings of the transmission network. We present a trilevel optimization problem which intertwines the decisions of agents in the market; a solution to this problem aims to prevent potential collusion by modifying the transmission network. Due to intractibility of the resulting trilevel problem formulation, an iterative algorithm solving a restricted version of the original trilevel problem in each iteration is proposed. Computational results show that it is possible to attain a collusive-free environment in an oligopolistic market with an efficient algorithm. We also investigate the effect of an intuitive compound objective function and problem attributes that affect the computational difficulty and effectiveness of the proposed algorithm

Experimental and analytical investigation of third deformation zone in orthogonal cutting

In this study, an analytical investigation of cutting forces of third deformation zone is presented. An orthogonal cutting model including a thermo-mechanical model with dual zone friction behaviour is proposed in order to determine the effects of hone radius and flank contact on cutting forces. Furthermore different approaches for friction and material behavior are considered for precise modeling. Also full and elastic recovery of the material are considered for contact length calculations for the same reasons. Predictions of the proposed model are compared with the force and thermal measurements and it is shown that the model predictions are reasonably comparable with the experimental data

Reformulations of a bilevel model for detection of tacit collusion in deregulated electricity markets

In this study, we consider a collusion model for competitive pool based electricity markets operated by an independent system operator (ISO), where it aims to prevent tacit collusion among generators. In order to determine the existence of tacit collusion in the market, we have employed the the game-Theoretic bilevel optimization model proposed by [1]. This model represents the market clearing mechanism, where generators determine their bids in order to maximize their profit while the system operator allocates power and determine locational electricity prices. The resulting optimization problem is a bilevel multi-criteria problem with non-linear terms, which is already complex and difficult to solve. We provide reformulations and linearization methods to obtain equivalent problems, e.g., a mathematical problem with equilibrium constraints (MPEC), a mixed integer non-linear problem (MINLP) and a mixed integer problem (MIP). A simple 6-bus system is used to test the rate of detection for collusive states for the reformulations and the results are presented. We have found that MIP models and reformulations detect strong collusive states. This model can guide ISOs in identifying and preventing cases of generator collusion

Endonasal Dacryocystorhinostomy; The Learning Curve and Our Experience

Aim: It was aimed to give an insight on the learning curve adopted by an ophthalmic surgeon while performing endonasal dacryocystorhinostomy under the supervision of an otolaryngologist with the results experienced during this survey. Materials and Methods: In this retrospective study, consecutive cases with endonasal dacryocystorhinostomy (DCR) surgery were performed by a single ophthalmic surgeon while a second otolaryngologist was overlooking the procedures. A total of 29 surgeries were performed on 23 patients. Patients that were diagnosed with complete nasolacrimal duct obstruction were then evaluated and proceeded to the surgery. The intraoperative video was recorded in all surgical cases and recording time was noted for each case. All of the complications that occurred during or at the postoperative stages were noted. Results: The mean age of the 23 patients was 55.25±18.6 years (15 y-80 y), of which 20 cases (87%) were female. The left side was involved in 69% (20/29) of cases. At the final follow-up of the mean of 12,4 months, the anatomical and functional success was achieved in 89% (26/29) cases. The mean time spent in the operating theatre was 84±17.2 minutes (range, 40–110 min). It was found that the only 3 failed surgeries were in the first 5 surgeries performed with no surgical failure in the remaining 24 eyes. Conclusions: Endonasal dacryocystorhinostomy is a safe, effective and cosmetically pleasing surgery for the treatment of nasolacrimal duct obstruction. Although it has a somewhat longer learning curve than some surgeries, once handling of the endoscope has been mastered and familiarity with the surgical field is improved, the duration of the surgery will decrease significantly. We believe multidisciplinary coordination plays an important role in decreasing potential complication rates and also in perfecting the technique