Towards Spinfoam Cosmology

We compute the transition amplitude between coherent quantum-states of geometry peaked on homogeneous isotropic metrics. We use the holomorphic representations of loop quantum gravity and the Kaminski-Kisielowski-Lewandowski generalization of the new vertex, and work at first order in the vertex expansion, second order in the graph (multipole) expansion, and first order in 1/volume. We show that the resulting amplitude is in the kernel of a differential operator whose classical limit is the canonical hamiltonian of a Friedmann-Robertson-Walker cosmology. This result is an indication that the dynamics of loop quantum gravity defined by the new vertex yields the Friedmann equation in the appropriate limit.Comment: 8 page

Multiband monopole antenna for mobile applications

— In this paper, a multiband monopole antenna has been proposed for mobile applications. The monopole antenna has simple structure with a physical size of 15 cm × 7 cm. The antenna consists of monopole shape loaded by a set of folded arms with a varying length which lead to a better impedance matching result and multiband performance. The simulated results show that the proposed antenna provide multiband frequency operation of 0.8 GHz, 1.8 GHz 2.1 GHz, 2.6 GHz and 3.5 GHz which covers the range from 0 to 4 GHz. The antenna is designed to operate at sub-6 GHz which proposed as lower frequency band to deliver 5G in early stage. The designed antenna has been fabricated and measured to validate the simulated results. RF Coaxial U.FL Connector was used as the port connector. The measurement results agrees well with the simulated ones for all frequency bands

Embroidery Leaf Shape Dipole Antenna Performances and Characterisation

In this paper, leaf shape textile antenna in ISM band has been chosen to study. The operating frequency of the dipole antenna is 2.45GHz. The effect of conductive threads with three different types of sewing has been analysed. The first type of sewing leaf shape dipole antenna is to stitch around itself and embroidered into a fleece fabric with circular follow by vertical and horizontal stitch respectively. From measured return loss, the antenna with circular stitch shows better performances with optimum resonances compared with the two types of stitching. The measured results confirm that the circular stitch is more suitable for leaf shape dipole antenna design. Thus it can be concluded that different stitch gives different results for leaf shape dipole antenna

Integrable mixing of A_{n-1} type vertex models

Given a family of monodromy matrices {T_u; u=0,1,...,K-1} corresponding to integrable anisotropic vertex models of A_{(n_u)-1}-type, we build up a related mixed vertex model by means of glueing the lattices on which they are defined, in such a way that integrability property is preserved. Algebraically, the glueing process is implemented through one dimensional representations of rectangular matrix algebras A(R_p,R_q), namely, the `glueing matrices' zeta_u. Here R_n indicates the Yang-Baxter operator associated to the standard Hopf algebra deformation of the simple Lie algebra A_{n-1}. We show there exists a pseudovacuum subspace with respect to which algebraic Bethe ansatz can be applied. For each pseudovacuum vector we have a set of nested Bethe ansatz equations identical to the ones corresponding to an A_{m-1} quasi-periodic model, with m equal to the minimal range of involved glueing matrices.Comment: REVTeX 28 pages. Here we complete the proof of integrability for mixed vertex models as defined in the first versio

Meander bowtie Antenna for Wearable Application

This paper proposes a flexible compact bowtie antenna for medical application that operates at 2.45 GHz. The proposed antennas are miniaturized using meander technique. Both substrates and conducting material of the antenna are made of flexible material semi-transparent film as the substrate and shieldit fabric as the conducting material which suitable for wearable and on body application. The results show that the total length of the antenna is significantly reduced by up to 38%. However, the gain of the antenna is slightly decreased when the size of the antenna become smaller. The results of this research could provide guidance and has significant implication for future development of wearable electronics especially in medical monitoring application

Frequency Reconfigurable Epsilon Negative Metamaterial Antenna

This paper proposes metamaterial (MTM) inspired frequency reconfigurable antenna based on thecircular electric field coupled (ELC) resonator. It is composed of circular shape ELC resonator with the radius size of 7 mm. By inserting two switches between the gaps at both side of the circular ELC resonator, it is possible to switch ON or OFF the unit cell. The antenna has been simulated using CST Microwave Studio software tool. The simulation result shows that the proposed antenna is capable of reconfiguring between two different frequencies which are2.18 GHz and 2.64 GHz. The simulated bandwidth at -10 dB is 4.12 % at resonance frequency of 2.18 GHz and 8.7% at 2.64 GH

Unbraiding the braided tensor product

We show that the braided tensor product algebra $A_1\underline{\otimes}A_2$ of two module algebras $A_1, A_2$ of a quasitriangular Hopf algebra $H$ is equal to the ordinary tensor product algebra of $A_1$ with a subalgebra of $A_1\underline{\otimes}A_2$ isomorphic to $A_2$, provided there exists a realization of $H$ within $A_1$. In other words, under this assumption we construct a transformation of generators which `decouples' $A_1, A_2$ (i.e. makes them commuting). We apply the theorem to the braided tensor product algebras of two or more quantum group covariant quantum spaces, deformed Heisenberg algebras and q-deformed fuzzy spheres.Comment: LaTex file, 29 page

Comparative study of herbal plants on the phenolic and flavonoid content, antioxidant activities and toxicity on cells and zebrafish embryo

Natural antioxidants derived from plants have shown a tremendous inhibitory effect on free radicals in actively metabolizing cells. Overproduction of free radicals increases the risk factor of chronic diseases associated with diabetes, cancer, arthritis and cardiovascular disease. Andrographis paniculata, Cinnamon zeylanicum, Curcuma xanthorrhiza, Eugenia polyantha and Orthosiphon stamineus are ethnomedicinal plants used in the Asian region to treat various illnesses from a common fever to metabolic disease. In this study, we have quantified the total phenolic (TPC) and flavonoid content (TFC) in these plants and its inhibitory effect on 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) free radicals as well as the cytotoxicity effect on cell lines proliferation and zebrafish embryogenesis. Results showed that Cinnamon zeylanicum and E. polyantha have the highest phenolic and flavonoid content. Furthermore, both herbs significantly inhibited the formation of DPPH and ABTS free radicals. Meanwhile, O. stamineus exhibited minimum cytotoxicity and embryotoxicity on tested models. Good correlation between IC50 of 3T3-L1 cells and LC50 embyrotoxicity was also found. This study revealed the potent activity of antioxidant against free radical and the toxicology levels of the tested herbal plants

Quantum Groups and Noncommutative Geometry

Quantum groups emerged in the latter quarter of the 20th century as, on the one hand, a deep and natural generalisation of symmetry groups for certain integrable systems, and on the other as part of a generalisation of geometry itself powerful enough to make sense in the quantum domain. Just as the last century saw the birth of classical geometry, so the present century sees at its end the birth of this quantum or noncommutative geometry, both as an elegant mathematical reality and in the form of the first theoretical predictions for Planck-scale physics via ongoing astronomical measurements. Noncommutativity of spacetime, in particular, amounts to a postulated new force or physical effect called cogravity.Comment: 72 pages, many figures; intended for wider theoretical physics community (special millenium volume of JMP

Short-Term Ability of Concrete Containing Palm Oil Fuel Ash Exposed to Sodium Sulphate

Uncontrolled palm oil waste disposal can lead to an environmental problem, and recycling the waste can assist in reducing the disposal problem. On another side, concrete exposed to sulphate normally will lose its strength after some time. Replacing cement with palm oil fuel ash (POFA) can lower the disposal issue and help reduce the concrete from strength losses. The main objective of this study is to investigate the short-term effects on the strength of concrete containing POFA exposed to sulphate solution. The POFA was prepared by drying in an oven for 24 hours at 105°C and sieved passing through a 300 μm sieve. Then, the POFA had been refined using ball mills for two hours. The percentage of POFA as cement replacement used in this study is 10%, 20% and 30% by volume of cement. Two types of specimens were prepared, i.e., cube specimen (100 mm × 100 mm × 100 mm) and prism specimen (500 mm × 100 mm × 100 mm) that fully immersed in water and 3.5% sulphate solutions. Density test, water absorption test, compression strength test and flexural strength test were conducted after 7 and 28 days of the exposure period. A total of 144 specimens was subjected to these tests. The experiments show that concrete with 10% replacement of POFA had a higher slump value, while the density test showed that the 10% POFA mixture had a lower density than the other specimens. Furthermore, the water absorption test showed that more POFA in concrete contributes to higher water absorption when exposed to sulphate solution compared to water. In conclusion, the compressive strength and flexural strength test recorded replacement of 10% POFA is the highest strength of concrete containing POFA exposed to sulphate solution and water