Process simulation of modelled reverse osmosis for desalination of seawater

Model equations for prediction of process parameters of reverse osmosis for desalination of seawater were developed via mathematical derivation from basic equations for reverse osmosis process. A model equation relating the interfacial solute concentration () with the process pressure difference () was developed. Taking the of a reverse osmosis as the basic independent variable, further model equations relating other process parameters such as the solute concentration polarity , water flux , osmotic pressure , water output rate (q), power density (Pd) and specific energy consumption (SEC) were developed. Simulation of a hypothetical reverse osmosis data using Microsoft Excel Worksheet and a Microsoft Windows 10 on a 64-bit operating system was carried out. Simulation results showed that the optimum fluid bulk concentration was = 0.0004 mole/cm3. The optimum rate of increase in the solute rejection factor per unit rise in ΔP was 0.45%. The optimum solute rejection factor was 97.6%. The optimum water output rate, specific energy consumption and power density were 103.2 L/h, 3.65 kWh/m3 and 6.09 W/m2, respectively.

The Phenomenon of National Security within Postmodern Cultures: Interests, Values, Mentality

The article is devoted to defining the essence of security, particularly national security, its interpretation, main features, structure, and factors. The research focuses on the main concepts of the modern understanding of national security and defines national security according to recent research. The authors have performed a structural and functional analysis of the system of national security of Ukraine, which would be an adequate counteraction to threats to vital national interests. The article examines the multi-vector interpretation and representation of the security phenomenon with an increased focus on the axiological paradigm of postmodern society analysis. The cardinal role of postmodernism is considered as a manifestation of postmodern culture in the value dimension of social-political existence. Postmodernism, on the one hand, enabled new vectors of analytical understanding and perception of the security phenomenon. On the other hand, it introduced an imbalance and determined the crisis factor in the space of classical perception of security guarantors due to violating the established foundations and traditions (especially in the perception of the state institution). The rejection factor is seen as a core feature of postmodern social-political reality. The emphasis is given to the problem of the security standard in the security studies and the idea of the mutual determination of both national interests and national values. The article states the importance and priority of historical memory and the phenomenon of mentality in the context of future analytical discourses in the scope of Ukrainian security studies.

Boosting background suppression in the NEXT experiment through Richardson-Lucy deconvolution

Next-generation neutrinoless double beta decay experiments aim for half-life sensitivities of ∼ 1027 yr, requiring suppressing backgrounds to < 1 count/tonne/yr. For this, any extra background rejection handle, beyond excellent energy resolution and the use of extremely radiopure materials, is of utmost importance. The NEXT experiment exploits differences in the spatial ionization patterns of double beta decay and single-electron events to discriminate signal from background. While the former display two Bragg peak dense ionization regions at the opposite ends of the track, the latter typically have only one such feature. Thus, comparing the energies at the track extremes provides an additional rejection tool. The unique combination of the topology-based background discrimination and excellent energy resolution (1% FWHM at the Q-value of the decay) is the distinguishing feature of NEXT. Previous studies demonstrated a topological background rejection factor of ∼ 5 when reconstructing electron-positron pairs in the 208Tl 1.6 MeV double escape peak (with Compton events as background), recorded in the NEXT-White demonstrator at the Laboratorio Subterráneo de Canfranc, with 72% signal efficiency. This was recently improved through the use of a deep convolutional neural network to yield a background rejection factor of ∼ 10 with 65% signal efficiency. Here, we present a new reconstruction method, based on the Richardson-Lucy deconvolution algorithm, which allows reversing the blurring induced by electron diffusion and electroluminescence light production in the NEXT TPC. The new method yields highly refined 3D images of reconstructed events, and, as a result, significantly improves the topological background discrimination. When applied to real-data 1.6 MeV e−e+ pairs, it leads to a background rejection factor of 27 at 57% signal efficiency.

Electrospun Nanostructured Membrane Engineering Using Reverse Osmosis Recycled Modules: Membrane Distillation Application

As a consequence of the increase in reverse osmosis (RO) desalination plants, the number of discarded RO modules for 2020 was estimated to be 14.8 million annually. Currently, these discarded modules are disposed of in nearby landfills generating high volumes of waste. In order to extend their useful life, in this research study, we propose recycling and reusing the internal components of the discarded RO modules, membranes and spacers, in membrane engineering for membrane distillation (MD) technology. After passive cleaning with a sodium hypochlorite aqueous solution, these recycled components were reused as support for polyvinylidene fluoride nanofibrous membranes prepared by electrospinning technique. The prepared membranes were characterized by different techniques and, finally, tested in desalination of high saline solutions (brines) by direct contact membrane distillation (DCMD). The effect of the electrospinning time, which is the same as the thickness of the nanofibrous layer, was studied in order to optimize the permeate flux together with the salt rejection factor and to obtain robust membranes with stable DCMD desalination performance. When the recycled RO membrane or the permeate spacer were used as supports with 60 min electrospinning time, good permeate fluxes were achieved, 43.2 and 18.1 kg m−2 h−1, respectively; with very high salt rejection factors, greater than 99.99%. These results are reasonably competitive compared to other supported and unsupported MD nanofibrous membranes. In contrast, when using the feed spacer as support, inhomogeneous structures were observed on the electrospun nanofibrous layer due to the special characteristics of this spacer resulting in low salt rejection factors and mechanical properties of the electrospun nanofibrous membrane.

Beef acceptance index proposition

Summary: Beliefs, social rules, and food taboos influence the emotions we feel about food, determining our attitudes and consumption behaviors. The more a product represents values considered important to individuals, the greater the chance of being chosen for consumption. This article aimed to investigate levels of zoophagy and sarcophagy to propose an index to understand consumers' attitudes towards beef. Three hundred and eighty-five people answered a structured questionnaire that allowed them to assess personality traits and attitudes that can explain beef consumption, as well as its rejection. Factor analysis was the analytical model chosen to construct the attitude determination index. For the construction of the General Degradation Index (GDI), an attitude determination index associated with the degree of zoophagy was built first. The results indicate that extroversion, individualism, festivity, and immediacy were the traits that best characterized positive attitudes towards beef. On the other hand, negative attitudes of introspection, reflection, emotional character, and concern for the future marked the responses of those who answered.

Hybrid Modeling for Simultaneous Prediction of Flux, Rejection Factor and Concentration in Two-Component Crossflow Ultrafiltration

Ultrafiltration is a powerful method used in virtually every pharmaceutical bioprocess. Depending on the process stage, the product-to-impurity ratio differs. The impact of impurities on the process depends on various factors. Solely mechanistic models are currently not sufficient to entirely describe these complex interactions. We have established two hybrid models for predicting the flux evolution, the protein rejection factor and two components’ concentration during crossflow ultrafiltration. The hybrid models were compared to the standard mechanistic modeling approach based on the stagnant film theory. The hybrid models accurately predicted the flux and concentration over a wide range of process parameters and product-to-impurity ratios based on a minimum set of training experiments. Incorporating both components into the modeling approach was essential to yielding precise results. The stagnant film model exhibited larger errors and no predictions regarding the impurity could be made, since it is based on the main product only. Further, the developed hybrid models exhibit excellent interpolation properties and enable both multi-step ahead flux predictions as well as time-resolved impurity forecasts, which is considered to be a critical quality attribute in many bioprocesses. Therefore, the developed hybrid models present the basis for next generation bioprocessing when implemented as soft sensors for real-time monitoring of processes.

The CMS Trigger Upgrade for the HL-LHC

The CMS experiment has been designed with a two-level trigger system: the Level-1 Trigger, implemented on custom-designed electronics, and the High Level Trigger, a streamlined version of the CMS offline reconstruction software running on a computer farm. During its second phase the LHC will reach a luminosity of 7.5 1034 cm−2 s−1 with a pileup of 200 collisions, producing integrated luminosity greater than 3000 fb−1 over the full experimental run. To fully exploit the higher luminosity, the CMS experiment will introduce a more advanced Level-1 Trigger and increase the full readout rate from 100 kHz to 750 kHz. CMS is designing an efficient data-processing hardware trigger that will include tracking information and high-granularity calorimeter information. The current Level-1 conceptual design is expected to take full advantage of advances in FPGA and link technologies over the coming years, providing a high-performance, low-latency system for large throughput and sophisticated data correlation across diverse sources. The higher luminosity, event complexity and input rate present an unprecedented challenge to the High Level Trigger that aims to achieve a similar efficiency and rejection factor as today despite the higher pileup and more pure preselection. In this presentation we will discuss the ongoing studies and prospects for the online reconstruction and selection algorithms for the high-luminosity era.

Membrane Fabrications

The advancement in membrane technologies is driven by the development of membrane fabrication techniques and material studies. Nowadays, there are many fabrication techniques and materials available to produce membranes with characteristics that are ideal for specific applications. In this chapter, some fabrication methods are discussed for the three most widely used membrane types, i.e. the polymeric, ceramic, and metallic membranes. Each type of membrane possesses certain advantages and disadvantages attributed to the membrane structural properties as a result of the fabrication method. The choice of method and material are the two important aspects that determine membrane performance and efficiency. The membrane performance indicator is generally measured from the flux, rejection factor, and ability to withstand extreme chemical and physical conditions. Furthermore, the fabricated membranes are further assembled into a complete unit of membrane system called the membrane modules, namely tubular, plate-and-frame, spiral-wound, capillary, and hollow fibre.

Desalination of Highly Saline Water Using Direct Contact Membrane Distillation (DCMD)

In this work, laboratory experiments were carried out to verify direct contact membrane distillation system’s performance in highly saline water desalination. The study included the investigation of various operating conditions, like feed flow rate, temperature and concentration of NaCl solution and their impact on the permeation flux were discussed. 16 cm2 of a flat sheet membrane module with commercial poly-tetra-fluoroethylene (PTFE) membrane, which has 0.22 μm pore size, 96 µm thickness and 78% average porosity, was used. A high salt rejection factor was obtained greater than 99.9%, and the permeation flux up to 17.27 kg/m2.h was achieved at 65°C for hot feed side and 20°C for cold side stream.