Photon Neutrino Scattering in Non-Commutative Space

We extend the non-commutative standard model based on the minimal $SU(3)\times SU(2)\times U(1)$ gauge group to include the interaction of photon with neutrino. We show that, in the gauge invariant manner, only the right handed neutrino can directly couple to the photon. Consequently, we obtain the Feynman rule for the $\gamma\nu\bar\nu$-vertex which does not exist in the minimal extension of non-commutative standard model (mNCSM). We calculate the amplitude for $\gamma\nu\to\gamma\nu$ in both the nonminimal non-commutative standard model (nmNCSM) and the extended version of mNCSM. The obtained cross section grows in the center of mass frame, respectively, as $(\theta_{NC})^2{M}_Z^{-4}E^6$ and $(\theta_{NC})^4E^6$ which can exceed the cross section for $\gamma\nu\to\gamma\gamma\nu$ and $\gamma\nu\to\gamma\nu$ in the high energy limit in the commutative space.Comment: 12 pages, 3 figures, to appear in Phys. Rev.

Equalization-Based Digital Background Calibration Technique for Pipelined ADCs

In this paper, we present a digital background calibration technique for pipelined analog-to-digital converters (ADCs). In this scheme, the capacitor mismatch, residue gain error, and amplifier nonlinearity are measured and then corrected in digital domain. It is based on the error estimation with nonprecision calibration signals in foreground mode, and an adaptive linear prediction structure is used to convert the foreground scheme to the background one. The proposed foreground technique utilizes the LMS algorithm to estimate the error coefficients without needing high-accuracy calibration signals. Several simulation results in the context of a 12-b 100-MS/s pipelined ADC are provided to verify the usefulness of the proposed calibration technique. Circuit-level simulation results show that the ADC achieves 28-dB signal-to-noise and distortion ratio and 41-dB spurious-free dynamic range improvement, respectively, compared with the noncalibrated ADC

Infrastructure Choices in Education: Location, Build or Repair

The purpose of this study is to develop a model to arrive at a joint optimizing strategy for the use of a given capital budget for the construction of new school buildings and for the repair of the already existing schools. This is to be done in a way that will have the maximum positive impact on the enhancement of the education system. Cost effectiveness analysis is used as the main analytical tool in the analysis. A key factor of the model is that it gives one the optimal mix of repair versus new construction that should be undertaken under a fixed budget constraint. The model is simulated using a sample data set from the information available for the education sector of Limpopo Province, South Africa. It utilizes a very basic set of information that is available in all school districts across the province. Application of this model for the selection of infrastructure investments (either building or repair) in the education sector would increase the efficiency of capital expenditure in this sector. This is particularly the case for the countries that are faced with a large excess demand for school buildings.education, cost effectiveness, school location, school construction, school repair, South Africa

Modeling of on-chip (bio)-particle separation and counting using 3D electrode structures

This paper was presented at the 4th Micro and Nano Flows Conference (MNF2014), which was held at University College, London, UK. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute, ASME Press, LCN London Centre for Nanotechnology, UCL University College London, UCL Engineering, the International NanoScience Community, www.nanopaprika.eu.In lab-on-a-chip applications, manipulation and quantification of (bio)particles is required in a variety of biomedical applications such as drug screening, disease detection and treatment. For manipulation of particles, electrical techniques such as dielectrophoresis (DEP) is very suitable. For the quantification or counting of the bioparticles, flow cytometer, fluorescence-activated cell sorting (FACS) and magneticactivated cell sorting (MACS) are common techniques. In this study, modeling of microfluidic (bio)-particle separation based on dielectrophoresis and counting based on capacitance measurement using COMSOL Multiphysics have been presented. The device performance with planar and 3D electrode structures have been compared. Microfluidic devices with an asymmetric pair (for separation) and a symmetric pair (for counting) of electrodes are considered. The effects of the geometrical parameters, material properties, flow rate, particle size and applied voltage on the device performance have been discussed. The fabrication procedure of 3D electrode structures is also addressed

Development of scaffolds by thermally-induced phase separation from biodegradable poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and poly(butylene succinate)

Aplicat embargament des de la data de defensa fins el 31 de juliol de 2022TIPS process followed by freeze-dtying was used to prepare blodegradable and biocompatible matrices from poly(3- hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) containing 5 and 12 wt% of 3-hydroxyvalerate (HV) and poly(butylene succinate) (PBS). 1,4 dioxane (DXN) and tetrahydofuran (THF) were used as solvents. The cloud points of the polymer solutions were determíned by turbidimetry method, to predict the locus of binodal curve in the binary phase diagrams. A multidirectional cooling from ~70ºC to 25ºC, and then to -5 ºC or -25 ºC was applied to PHBV solutions in the TIPS process. The effect of the applied thermal gradients and HV molar ratio of PHBV copolymer on phase separation mechanism, morphology and mechanical properties of the scaffolds was studied. Upon high HV contents and fast cooling, the solid-liquid phase separation through crystallization of DXN was the controlling mechanism and generated large pores with well-distinguished walls and great structural continuity. The morphologies ascribed to polymer crystallizatíon, mostly with low structural consistency were further discernible upon slow cooling. An improvement in scaffolds rigidity were observed in low HV and fast cooling conditions, due to the increased polymer crystallinity and the greater structural consistency, respectively. PHBV scaffolds showed a complete biocompatibility towards MDCK and NRK cell adhesion and proliferation. A multidirectional cooling from ~70 ºC to -20 or -74 ºC were applied to PBS-DXN and PBS-THF solutions and a uniaxial cooling from ~70ºC to -74 or -196 ºC to PBS-DXN. 5 and 100 wt% ofcurcumin (CUR) and piperine (PIP) natural drugs were loaded into PBS matrices via a one-step TIPS fabrication/drug loadlng protocot. Utílizing DXN and THF solvents, solid-liquid and liquid-liquid phase separation were respectívely detected as the main mechanisms responsible for creating the porous structures, while the subregions composed of crysta llized PBS were also obse rved . The applied uniaxial thermal gradient enabled DXN solvent to crystallize along the heat transfer direction and form an oriented pare structure. Although the low drug values did not significantly influence the morphology, the high-level drug loading gave rise to the decreased porosity and superficial roughness ofthe scaffolds . A uniform distribution ofprismatic PIP crystals and matrix-integrated CUR aggregation was observed all overthe structure. The integration of CUR which was confirmed by the physicochemical analyses attributed to a possible interaction with the PBS matrix, as it also showed a slower release profile compared to PIP. Oriented matrices showed greater biocompatibility and also retarded drug release from their·dense spherulitic pore walls. Biobased highly rigid polycarbonate and polyesters with terpene oxide units were blended with PBS at different ratios to increase the biocontents and modify the properties. Ali the terpene-derived polymers exhibi ted high Tg, thermal stability biocompatibility and mechanical strength. Their rigid nature and stiff chains led to insignificant hydrolytic and enzymatic biodegradation, while an accelerated degradation in oxidative media was observed. Their blends with PBS were also biocom patible and to sorne extent biodegradable . 30 wt% of poly (PA-LO) the copolyester derived from phthalic anhydride and limonene oxide, was blended with PBS and porous matrices were prepared by a one-step TIPS fabrication/blending protocol. Multidirectional cooling to -20 ºC or-74 ºC and uniaxial cooling to -74 ºC or-196 ºC was applied to PBS-Poly (PA-LO)-DX N system. Although the blending did not affect the morphology and pore structure of the random/oriented matrices, could somewhat restrict the crystallization of PBS from the solution during the TIPS process. Accordin gly, thinner polymer leaves upon multídirectional and lower thermal gradient, and smaller, less planar and less integrated spherulites were formed upon high uniaxial gradient.El proceso TIPS seguido de liofilización fue usado para preparar matrices porosas ("scaffolds") biodegradables y biocompatibles a partir del poliéster poli (3-hidroxibutirato-co-3-hidroxivalerato) (PHBV) que contiene 5 y 12 wto/o de 3- hidroxivalerato (HV) y del poliéster poli(butilensuccinato) (PBS). El 1.4 dioxano (DXN) yel tetrahidofurano (THF) fueron los disolventes. En el TIPS para las disoluciones de PHBV se aplicó un enfriamiento multidireccional de 70 a 25ºC y luego a -5 ó -25ºC. Se estudiaron los efectos del gradiente térmico y contenido de HV del copolímero sobre el mecanismo de separación de fases, la morfología y propiedades mecánicas de los scaffolds. La separación de fase sólido-líquido en la cristalización del DXN durante el enfriamiento rápido fue el mecanismo que controla la formación de los scaffolds del copolímero con alto contenido de HV. Los scaffolds mostraron grandes poros con paredes bien formadas y gran integridad estructural. Las morfologías atribuidas a la cristalización del polímero. en su mayoría con poca integridad estructural. fueron obtenidas con el enfriamiento lento. Se observó una mejora en la rigidez y mayor integridad estructural de los scaffolds con bajo HV y enfriamiento rápido. debido al aumento de la cristalinidad del polímero. Los scaffolds de PHBV mostraron gran biocompatibilidad determinada por la adhesión y proliferación de células MDCK y NRK. Las disoluciones de PBS-DXN y PBS-THF fueron enfriadas multidireccionalmente de 70ºC a -20 ó -74ºC. y de manera uniaxial para PBS-DXN de 70ºC a -74 ó -196ºC. Los scaffolds de PBS durante su preparación por TIPS fueron cargados con 5 y 100 wt% de curcumina (CUR) o piperina (PIP). La separación de fases sólido-líquido y líquido-líquido (con los disolventes DXN y THF respectivamente) fueron los principales mecanismos responsables para formar las estructuras porosas y subregiones compuestas por PBS cristalizada. El gradiente térmico uniaxial permitió la cristalización del DXN a lo largo de la dirección de transferencia de calor y la formación de poros orientados. La presencia de los fármacos no influyo significativamente en la morfología de los scaffolds. La gran cantidad del fármaco disminuye la porosidad y la rugosidad superficial en los scaffolds. En los scaffolds se observó una distribución uniforme de cristales de PIP y agregación de CUR. La integración de CUR indico una posible interacción con la matriz de PBS y mostró un perfil de liberación más lento en comparación con PIP. Los scaffolds orientados mostraron una mayor biocompatibilidad y una liberación lenta del fármaco debido a sus densas paredes formadas por esferulitas policarbonatos y poliésteres biobasados altamente rígidos y formados por unidades de óxido de terpeno fueron mezclados con PBS en diferentes proporciones para aumentar su biocontenido y modificar sus propiedades. La Tg. estabilidad térmica, biocompatibilidad y resistencia mecánica son elevadas en los polímeros derivados del terpeno. La biodegradación hidrolítica y enzimática de estos polímeros fue insignificante debido a la rigidez de sus cadenas. mientras una degradación acelerada fue lograda en medios oxidativos. Las mezclas con PBS fueron biocompatibles y algo biodegradables. La mezcla del copoliéster derivado de anhídrido phtalico y óxido de limoneno (poli(PA-LO)) con PBS (30:70 wo/o, respectivamente) fue usada para preparar scaffolds con la metodología TIPS. El enfriamiento multidireccional a -20ºC ó -74ºC y el enfriamiento uniaxial a -74ºC ó -196ºC fue aplicado al sistema PBS-Poly(PA-LO)-DXN. Esta mezcla no influye en la morfología y estructura de los poros de los scaffolds con porosidad orientada o al azar. Durante el proceso TIPS, la cristalización del PBS fue afectada. En consecuencia, el PBS en el menor gradiente térmico multidireccional forma estructuras en hojas más delgadas y con el mayor gradiente uniaxial se formaron esferolitas más pequeñas, menos planas y menos integradas.Postprint (published version