Electron barrier height change and its influence on EEPROM cells

The effect of floating polysilicon doping on electron injection barrier height and therefore the PROGRAM/ERASE window of an electrically erasable programmable ROM (EEPROM) cell has been studied. The introduction of dopant and the concentration of electrically active sites at the floating-gate polysilicon/tunnel oxide interface influence the electron injection barrier height during cell ERASE operation. The electron injection barrier increases up to 250 meV upon degenerate doping of the floating-gate polysilicon electrode as measured by dark current-voltage characteristics. The application of these observations in this study is in the design and scaling of EEPROM cells     

A Technology‐Enhanced Learning Environment for an Optical Fiber Communications Course*

This paper describes a technology‐enhanced learning environment for an undergraduate course on Optical Fiber Communications ( http:ctle.colorado.edunsf2000 ).     

Design and performance analysis of a CNFET-based TCAM cell with dual-chirality selection

The carbon nanotube field-effect transistor (CNFET) is emerging as one of the most promising alternatives to complementary metal–oxide–semiconductor (CMOS) transistors due to its one-dimensional (1-D) band structure, low off-current capability, near-ballistic transport operation, high stability, and low power consumption. This paper presents the design of a CNFET-based ternary content-addressable memory (TCAM) cell and rigorously analyzes its performance in terms of power–delay product (PDP) and static noise margin (SNM). The effect of variations of the chiral vector on the performance of the TCAM cell is also comprehensively investigated. While selecting the chirality, SNM, PDP, and search time are considered as figures of merit. In this TCAM cell design, we apply the same chirality for all CNFETs of the same type. Extensive HSPICE simulations have been performed for computation of performance parameters using the Stanford University CNFET model. Comparison of CNFET- and CMOS-based TCAM cells has been carried out at the 16-nm technology node. The results show that the CNFET-based TCAM cell exhibits significant improvements of PDP, i.e., by 38 % during write operation and 98 % during search operation, and 53 % in SNM, compared with its CMOS counterpart. It is also observed that the best chirality for the TCAM cell design is (22, 19, 0) or (10, 19, 0) from the point of view of SNM and PDP, respectively.     

Synthesis and evaluation of ciprofloxacin-loaded carboxymethyl tamarind kernel polysaccharide nanoparticles

Nanotechnology is currently employed as a tool to fight more efficiently against human pathogens. Nanoparticles can be prepared from a variety of materials such as protein, biodegradable polymers and synthetic polymers. Tamarindus indica Linn. or tamarind is one of the most important biodegradable polymer. In the present study, chemically modified polymer of tamarind ‘carboxymethyl tamarind kernel polysaccharide’ (CMTKP) is used for the synthesis of nanoparticulate formulation. Antibacterial activity of CMTKP was analysed which was then enhanced by incorporating a flouroquinolone antibiotic, ciprofloxacin to it. Ciprofloxacin-loaded CMTKP nanoparticles were synthesised via ionotropic gelation technique. Nanosuspension so formed was lyophilised by addition of a cryoprotectant. Nanoparticles obtained were characterised for its particle size, morphology and stability. Interaction studies were confirmed by Fourier transform infrared spectroscopy (FT-IR). Antibacterial activities of ciprofloxacin, CMTKP and ciprofloxacin-loaded CMTKP nanoparticles were tested against two Gram negative and positive bacteria. The antibacterial assay results revealed greatest zone of inhibition by ciprofloxacin-loaded CMTKP nanoparticles in Micrococcus luteus. Toxicity analysis of the prepared formulation was carried out on vero cell lines via resazurin assay which revealed its minimum toxicity.     

Survey of cooling technologies for worldwide agricultural greenhouse applications

This paper reviews the available worldwide cooling technologies for agricultural greenhouses and discusses the representative applications of each technology. Relevant information about the system characteristics, application and performance of the existing greenhouse cooling technologies such as ventilation (natural and forced), shading/reflection, evaporative cooling (fan-pad, mist/fog and roof cooling) and composite systems (earth-to-air heat exchanger system and aquifer coupled cavity flow heat exchanger system) is collected and presented in detail. As per the collected information, the pros and cons of each technology are also discussed. Finally, some important conclusions are drawn (based on the collected information) regarding the performance of each discussed system.     

Thermo-mechanical correlations to erosion performance of short carbon fibre reinforced vinyl ester resin composites

Thermo-mechanical properties and erosion performance of short carbon fibre reinforced vinyl ester resin based isotropic polymer composites with four different fibre weight fractions have been investigated. The storage, loss and damping characteristics were analysed to assess the energy absorption/viscous recoverable energy dissipation and reinforcement efficiency of the composites as a function of fibre content in the temperature range of 0–140 °C. The composite with 30 wt.% of short carbon fibres has been observed to exhibit superior thermo-mechanical response with highest energy dissipation/damping ability accompanied with a constant storage modulus without any substantial decay till 60 °C. The erosion rates (Er) of these composites are evaluated at different impingement angles (30–90°), fibre loadings (20–50 wt.%), impact velocities (43–76 m/s), stand-off distances (55–85 mm) and erodent sizes (250–600 μm) following the erosion test schedule in an air jet type test rig. An optimal parameter combination is determined and subsequently validated for erosion rate minimization following Taguchi method and by conducting confirmation experiments. A correlation between the loss-modulus inverse and the erosion rate has been observed which conceptually establishes a possible mechanistic equivalence between erosion and dynamic mechanical loading modes. The morphologies of eroded surface are examined by the scanning electron microscopy to investigate the nature of wear-craters, material damage mode and other qualitative attributes responsible for promoting erosion.     

Rheological characterization of xanthan suspensions of nanoscale iron for injection in porous media

Nanoscale zerovalent iron (NZVI) represents one of the most interesting reagents for the remediation of contaminated aquifers, but its application is hindered by a lack of colloidal stability. Prior studies have shown that nanoscale iron slurries can be successfully stabilized against aggregation and sedimentation through dispersion in xanthan solutions; thus, further research was carried out by focusing on the flow behavior of xanthan-modified NVZI suspensions. This work aims at understanding the rheological properties of NZVI-xanthan suspensions, which have been extensively tested under two different flow conditions: simple shear flow and flow through a porous medium. According to both experimental approaches, the suspensions show a shear thinning behavior that is dependent on iron concentration. These rheological properties are explained by referring to the microstructure of the colloidal system. Flow equations have been formulated and solved in radial coordinates in order to demonstrate the feasibility of such suspensions in field scale applications.     

Incidence and genetic variability of Listeria species from three milk processing plants

The presence of Listeria in three milk processing environments as a potential source of milk contamination was assessed. Swab samples (n = 210) taken from milk processing plants were examined. Sample sites included the milk processing equipment, besides areas handling raw and pasteurized milk. The USDA Listeria-selective enrichment procedure was used to process the samples. Forty one (19.52%) Listeria isolates were recovered. The isolates were further subjected to biochemical and genotypic characterization. Out of 41 isolates, 16 (7.62%) were confirmed as Listeria monocytogenes, 2 (0.95%) as L. ivanovii, 19 (9.05%) as L. innocua. 1 (0.48%) as L. seeligeri and 3 (1.43%) as L. grayi. All the L. monocytogenes isolates were positive for the hlyA gene. PCR based serotyping revealed all L. monocytogenes to be of 1/2a, 1/2c, 3a and 3c serovar group. AscI and ApaI restriction analysis yielded four PFGE clusters for 16 L. monocytogenes isolates obtained from raw milk collector, milk silos, buttermilk mixer, cheese and other milk product processor. No predominant PFGE cluster was observed among these L. monocytogenes isolates. The main sources of L. monocytogenes were found to be raw milk collector and milk silos. In the present study L. monocytogenes was isolated from milk and milk products processing plants which could cross-contaminate the processed products and may possess a potential threat to public health.