An integrated model of dynamic cellular manufacturing and supply chain system design

In a global dynamic environment, there is a need to develop organizations and facilities significantly more flexible and responsive. This work proposes an integrated model of dynamic cellular manufacturing and supply chain design with consideration of various issues such as multi-plant locations, multiple markets, multi-time periods, reconfiguration, etc. The model objective was to minimize the sum of various costs such as facility/plant to market transportation cost, part holding cost at a facility/plant, part outsourcing cost, machine procurement cost, machine maintenance overhead cost, machine repair cost, production loss cost due to machine breakdown, machine operation cost, setup cost, tool consumption cost, inter-cell travel cost, intra-cell travel cost, and system reconfiguration cost for the entire planning time horizon. To study the model, three procedures—LINGO, artificial immune system, and hybrid artificial immune system—are used to perform computational experiment on some problems from existing literature. The best result generally is found by the hybrid artificial immune system algorithm.     

An in vitro release study of 5-fluoro-uracil (5-FU) from swellable poly-(2-hydroxyethyl methacrylate) (PHEMA) nanoparticles

Nanomaterials are at the leading edge of the rapidly developing field of nanotechnology. The use of nanoparticles as drug delivery vehicles for anticancer therapeutics has great potential to revolutionize the future of cancer therapy. The present paper concerns both the optimizations of anticancer drug loading and its release from polymeric nanoparticles. The major aim of this study was to design poly (HEMA) nanoparticles as swelling controlled drug release system for anticancer drug. The prepared nanoparticles were characterized by Infra-Red (IR) Spectra, Particle size Analysis, and Scanning Electron Microscopy (SEM). The nanoparticles were loaded with widely used anticancer drug, 5-Fluorouracil, and controlled release of drug was investigated to observe the effects of various parameters such as percent loading of the drug, chemical architecture of the nanocarriers, pH, temperature, and nature of release media on the release profiles. The chemical stability of 5-Fluorouracil (5-FU) was also tested in phosphate buffer saline (PBS) (pH = 7.4) and release was studied in various simulated biological fluids. The prepared nanoparticles could provide a possible pathway for controlled and targeted delivery of anticancer drug, thus causing lower side effects and higher efficacy.     

Evaluation of dissolution for radioactive waste repositories in salt deposits

Several evaporite basins containing bedded salt and dome salt deposits in the USA and Europe are currently being investigated as potential repositories for radioactive waste. While salt has good geomechanical properties for the long-term isolation of radioactive wastes, all such deposits have undergone various degrees of dissolution by circulating unsaturated groundwater. The extent and rate of such dissolution poses a challenge to the geologists evaluating an area for a repository. Detailed investigations at the Waste Isolation Pilot Plant (WIPP), a proposed repository for transuranic (TRU) radioactive wastes located in the Delaware Basin in Southeastern New Mexico, U.S.A., have outlined a broad dissolution front for the Salado formation. An approximate rate of advance of the dissolution front at 1 km per 100,000 years horizontally and 10 meters per 100,000 years vertically, has been calculated. Similar calculations have been performed for other basins with different degrees of uncertainty due to the limitations in surface mapping and core or well-log correlations. Unless such calculations can be performed satisfactorily, questions will remain about the future integrity of a repository located in such an area.     

PolyDADMAC and dimethylamine as precursors of N-nitrosodimethylamine during ozonation: reaction kinetics and mechanisms

Interactions of ozone with organic precursors during water treatment may generate carcinogenic N-nitrosodimethylamine (NDMA) byproduct. This study investigates the reaction mechanisms responsible for NDMA formation from ozonation of the commonly used poly(diallyldimethylammonium chloride) (polyDADMAC) coagulant. Upon ozonation, polyDADMAC yields the highest amount of NDMA among several water treatment polymers, including polyamines and cationic polyacrylamides. Ozonation transforms polyDADMAC to dimethylamine (DMA) and NDMA formation is correlated to polyDADMAC degradation and DMA release. Hydroxyl radicals generated from ozone play an important role in the degradation of polyDADMAC's quaternary ammonium ring groups and subsequent release of secondary amine. Although nitrite and formaldehyde are detected as ozonation products of DMA and polyDADMAC, contribution of formaldehyde-enhanced nitrosation pathway is determined to be insignificant in NDMA formation. In contrast, reaction of hydroxylamine, another ozonation product of DMA, with DMA in the presence of ozone is deemed critical in the formation of NDMA during ozonation. The study results show that that contact of polyDADMAC with ozone will lead to release of the more potent NDMA precursor DMA but may not generate a significant amount of NDMA under typical drinking water treatment conditions due to low yield. The mechanistic understanding from this study can help develop source control strategies for minimization of NDMA formation risk at water and wastewater utilities.     

A High Capacity Preamble Sequence for Random Access in 5G IoT Networks: Design and Analysis

International Journal of Wireless Information Networks - 5G NR aims to enable the high density of Internet of Things (IoT), around one million $$(10^{6})$$ connections per square kilometer, through...