Design Criteria for a Rotating Biological Contactor System for Treatment of Urinal Wastewater

Various design criteria have been set for Rotating Biological Contactor (RBC) for treating urinal wastewater. The aim of treating urinal wastewater is to remove odour and color from it so that it can be recycled for flushing. In the present paper, significance of RBC system for treating urinal wastewater has also been elaborated. The setting up of design criteria is based on the assumption that the rate of nitrification is zero-order with respect to total Kjeldhal nitrogen concentration. Principles of bioprocess involved in wastewater treatment have also been described in relation to the composition of human urine.     

Transfer film evolution and its role in promoting ultra-low wear of a PTFE nanocomposite

Polytetrafluoroethylene (PTFE) is an important solid lubricant with an unusually high wear rate. For a half-century, fillers have been used to reduce PTFE wear by >100× with >10% loading through hypothesized mechanisms involving mechanical load support, crack arresting, and transfer film adhesion. More recently it was discovered that specific nanoparticles provide a unique nanoscale reinforcement mechanism enabling unprecedented wear reductions of 10,000× with as little as 0.1% nano-fillers. Although the mechanisms responsible for this dramatic improvement remain unclear, there is substantial evidence that the transfer film plays a critical role. This paper uses interrupted microscopy measurements to investigate the evolution of transfer film development for an ultra-low wear PTFE nanocomposite. The run-in wear rates were similar to those of more traditional PTFE composites and transfer films consisted of large plate-like debris. Although the run-in wear rate and debris size decreased monotonically with distance, the run-in transfer films were removed each cycle. Detectible debris vanished and wear rates approached zero at an abrupt transition. During this ultra-low wear transition period, nanoscale and oxidized fragments of PTFE were transferred to the counterface. Most of these fragments persisted for the duration of the test and initiated the transfer film by progressively scavenging trace material from the bulk, growing into small islands, and merging with neighboring islands. The results of this study reflect a complex interplay involving elements of transfer film adhesion, chemistry, debris morphology, and mechanics.     

The MEK5/ERK5 Pathway in Health and Disease

The MEK5/ERK5 mitogen-activated protein kinases (MAPK) cascade is a unique signaling module activated by both mitogens and stress stimuli, including cytokines, fluid shear stress, high osmolarity, and oxidative stress. Physiologically, it is mainly known as a mechanoreceptive pathway in the endothelium, where it transduces the various vasoprotective effects of laminar blood flow. However, it also maintains integrity in other tissues exposed to mechanical stress, including bone, cartilage, and muscle, where it exerts a key function as a survival and differentiation pathway. Beyond its diverse physiological roles, the MEK5/ERK5 pathway has also been implicated in various diseases, including cancer, where it has recently emerged as a major escape route, sustaining tumor cell survival and proliferation under drug stress. In addition, MEK5/ERK5 dysfunction may foster cardiovascular diseases such as atherosclerosis. Here, we highlight the importance of the MEK5/ERK5 pathway in health and disease, focusing on its role as a protective cascade in mechanical stress-exposed healthy tissues and its function as a therapy resistance pathway in cancers. We discuss the perspective of targeting this cascade for cancer treatment and weigh its chances and potential risks when considering its emerging role as a protective stress response pathway.     

Two-dimensional single-crystalline Zn hexagonal nanoplates: size-controllable synthesis and X-ray diffraction study

We synthesized two-dimensional (2D) Zn hexagonal nanoplates using the thermal metal-vapor deposition technique. An increase and decrease in the surface area and thickness of the 2D Zn hexagonal nanoplates were shown with elevated annealing temperatures, indicating their sizes to be controlled using the annealing treatment. X-Ray diffractometry (XRD) studies revealed the crystalline nature of the 2D Zn hexagonal nanoplates and the diffraction intensity of the (002) lattice plane, which increased parabolically with elevated annealing temperatures.     

Process intensification of synthesis of magnetite using spinning disc reactor

An instantaneous co‐precipitation reaction for the synthesis of magnetite particles has been investigated in conventional mechanically agitated reactor and novel spinning disc reactor (SDR) with an objective of process intensification. Characteristics of the particles have been analysed using Coulter Counter particle analyser. It has been observed that the particle size distribution is more uniform with overall lower power consumption in the SDR as compared to the conventional reactors. With a viewpoint of improving the synthesis process in terms of the obtained conversion levels in the SDR, effect of different operating parameters viz. rotational speed, diameter and type of the disc, flow rate of the reactants and the operating temperature on the synthesis process has also been investigated. It has been observed that the flow rate of the reactants as well as disc characteristics have a significant influence on the extent of conversion. Overall, it has been established that the SDR gives excellent particle size distribution characteristics as compared to the conventional approaches and hence results in process improvement/intensification for magnetite synthesis process at comparatively lower energy inputs.     

Vapor phase synthesis of hexagonal shaped single crystal yttria stabilized zirconia nanoparticles using CO2 laser

Growth of hexagonal shaped single crystal yttria stabilized zirconia nanoparticles has been observed in the vapors emanating from solid targets vaporized using CO₂ laser in CW and pulsed modes of operation. The mean size and yttrium concentration in these nanoparticles are found to be in the range of 5–40 nm and ～10.4–11.6 wt% respectively, which depend on the laser power density and the gaseous environment used during the growth process. Nanoparticles synthesized with pulsed mode of laser operation were found to be smaller in size compared to those generated in the CW mode. It was also found that formation of these nanoparticles was more pronounced in helium gas environment compared to those in nitrogen and argon. X-ray and electron diffraction studies showed that in all experimental conditions the generated nanoparticles were in cubic phase. From high resolution TEM it was observed that the nanoparticles with identical orientations coalesced with each other in line with the oriented attachment theory.     

Optimization of WEDM process of pure titanium with multiple performance characteristics using Taguchi’s DOE approach and utility concept

This paper describes the development of multi response optimization technique using utility method to predict and select the optimal setting of machining parameters in wire electro-discharge machining (WEDM) process. The experimental studies in WEDM process were conducted under varying experimental conditions of process parameters, such as pulse on time(T_on), pulse off time(T_off), peak current (IP), wire feed (WF), wire tension (WT) and servo voltage (SV) using pure titanium as work material. Experiments were planned using Taguchi’s L27 orthogonal array. Multi response optimization was performed for both cutting speed (CS) and surface roughness (SR) using utility concept to find out the optimal process parameter setting. The level of significance of the machining parameters for their effect on the CS and SR was determined by using analysis of variance (ANOVA). Finally, confirmation experiment was performed to validate the effectiveness of the proposed optimal condition.     

Stress dependent band gap shift and valence band studies in ZnO nanorods

ZnO nanorods are grown on seedless and ZnO seeded glass substrates using chemical solution method and their structural, morphological, optical and valence band studies have been carried out. On seedless substrate horizontal nanorods are observed whereas for the seeded substrates vertically aligned hollow and solid nanorods grows. X-ray diffraction analysis revealed the presence of tensile stress in the vertical nanorods. Blue shift has been observed in the band gap of the vertical nanorods as compared to the horizontal nanorods which is attributed to the presence of tensile stress in the vertically aligned nanorods. Photoluminescence spectra revealed the dominance of Zinc vacancies (V(Zn)) related defects in the nanorods and oxygen defects are found to be higher in the vertically aligned nanorods as compared to the horizontal nanorods. The difference between the Fermi level and valence band maxima for horizontal, hollow vertical and solid vertical nanorods are found to be approximately 0.56 eV, approximately 0.70 eV and approximately 0.92 eV respectively indicating the possibility of p-type of conduction in the nanorods which has been attributed to presence of V(Zn) defects in the ZnO nanorods.     

Study of transient currents in discharging mode in pure and iodine doped ethyl cellulose films

A study of transient currents in discharging mode in vacuum aluminized pure and iodine doped ethyl cellulose (EC) films, approximately 20 μm in thickness, measured at various temperatures (303–353K) and applied fields (2.0 × 10⁴?4.5 × 10⁴ V/cm) is described. The order of current has been found to increase considerably with increase in poling temperature, field and iodine mixing. The currents have been found to show I ∝? t^?n (i.e. Curie–Von Schweidler law) time dependence with different slopes in the short and long time regions. The conductivity of the films is increased on doping with iodine. The dopant molecules are considered to act as additional trapping centres and provide a link between the polymer molecules in the amorphous region, thus resulting in the formation of a charge transfer complex. The results of the experiments and the mechanisms involved are discussed on the basis of available theories.