Rheological evaluation of the fabrication parameters of cellulose acetate butyrate membrane on CO2/N2 separation performance

The rise in emission of greenhouse gases (GHGs) mainly carbon dioxide (CO2) in recent years due to rapid development of modern civilisation, has been listed as the primary contributor to global warming. To address this global issue, membrane technology was applied and developed intensively because of its superior performance in terms of efficiency and economic advantages. In this study, the cellulose acetate butyrate (CAB) polymer was selected as the polymer matrix material since it exhibited excellent film-forming properties. In addition, the wet-phase inversion technique was adopted to synthesise the membrane based on different casting conditions. The optimum outcomes of the fabrication conditions were then characterised with the scanning electron micrograph (SEM) to determine the best CAB membrane for CO2/N2 separation. The results showed that CAB-70000 fabricated with 4 wt% of CAB polymer concentration, casting thickness of 250 µm, solvent evaporation time of 5 minutes, and 30 minutes of solvent exchange for isopropyl alcohol and n-hexane, exhibited the best gas separation performance. Further, CAB-70000 showed an average selectivity of 6.12 ± 0.09 and permeance up to 227.95 ± 0.39 GPU for CO2 and 37.28 ± 0.54 GPU for N2, respectively. In summary, this study is expected to show a detailed outline of the future direction and perspective of the novel CAB polymeric membrane that is suitable to be applied in the industry, and serves as an insight for researchers and manufacturers working in the related field of gas separation

PERILAKU MEMILIH DALAM MASYARAKAT MULTIKULTUR: STUDI KASUS PEMILIHAN WALIKOTA MEDAN 2020

Artikel ini menjelaskan tentang bagaimana perilaku memilih masyarakat dalam Pemilihan Wali Kota Medan Tahun 2020. Studi ini mengunakan metode kualitatif dengan pendekatan studi kasus, sumber data utama dari hasil survei perilaku memilih dan wawancara mendalam. Artikel ini menunjukkan bahwa perilaku memilih yang paling dominan pada masyarakat Medan ialah model sosiologis, yakni perilaku pemilih yang didasarkan pada preferensi sosiologis masyarakat. Faktor utamanya ialah disumbang oleh preferensi agama, etnis, maupun gender. Pemilih sosiologis tercatat dalam angka survey adalah sebesar 43,1%. Sedangkan pemilih rasional juga muncul, namun tidak sebesar pemilih sosiologis, yaitu pada persentase sebesar 36,8%. Demikian juga dengan pemilih psikologis yang jumlahnya hanya sekitar 10,8%. Kuatnya perilaku memilih sosiologis ini, kami menilai dipengaruhi salah satunya oleh narasi politik identitas yang sudah muncul dalam momen pemilihan sebelumnya, yakni Pemilihan Gubernur DKI Jakarta 2017, Pemilihan Gubernur Sumatera Utara 2018, dan Pemilihan Presiden 2019. Narasi politik identias ini ikut menyumbang terhadap menguatnya pertimbangan agama dalam perilaku pemilih di Kota Medan

Non-thermal Leptogenesis from the Heavier Majorana Neutrinos

We investigate a scheme for making leptogenesis by means of the CP violating decays of the seesaw Majorana neutrinos proposed by Fukugita and Yanagida. However, in order to avoid the wash-out of the produced lepton number we propose the production of the Majorana neutrinos to occur non-thermally and sufficiently late. After this time, in consequence, the B-L (baryon minus lepton) quantum number becomes a good ``accidental symmetry'' protecting the asymmetry produced. This non-thermal leptogenesis at late time is realized by a boson decaying into the Majorana neutrinos with a long lifetime. Suggestively this boson could correspond to a scalar field which causes the cosmic inflation, the inflaton, and thus its decay means really the reheating of the Universe. We find that this mechanism works well even if the lightest Majorana neutrinos are not produced sufficiently or not present, and the decays of the heavier seesaw Majorana neutrinos can be responsible to the baryon asymmetry in the present Universe, as we illustrate by the example of the family replicated gauge group model.Comment: 25 pages, 1 figure, Latex2e; section 5 modified, refs. adde

Radiative Corrections to Neutrino Mixing and CP Violation in the Minimal Seesaw Model with Leptogenesis

Radiative corrections to neutrino mixing and CP violation are analyzed in the minimal seesaw model with two heavy right-handed neutrinos. We find that textures of the effective Majorana neutrino mass matrix are essentially stable against renormalization effects. Taking account of the Frampton-Glashow-Yanagida ansatz for the Dirac neutrino Yukawa coupling matrix, we calculate the running effects of light neutrino masses, lepton flavor mixing angles and CP-violating phases for both $m_1 =0$ (normal mass hierarchy) and $m_3 =0$ (inverted mass hierarchy) cases in the standard model and in its minimal supersymmetric extension. Very instructive predictions for the cosmological baryon number asymmetry via thermal leptogenesis are also given with the help of low-energy neutrino mixing quantities.Comment: 21 pages, 6 figures; more references adde

The role of Majorana CP phases in the bi-maximal mixing scheme -hierarchical Dirac mass case-

We discuss the energy scale profile of the bi-maximal mixing which is given at the GUT energy scale in the minimal SUSY model, associated with an assumption that Y_nu^dagger Y_nu is diagonal, where Y_nu is the neutrino-Yukawa coupling matrix. In this model, the Dirac mass matrix which appears in the seesaw neutrino mass matrix is determined by three neutrino masses, two relative Majorana phases and three heavy Majorana masses. All CP phases are related by two Majorana phases. We show that the requirement that the solar mixing angle moves from the maximal mixing at GUT to the observed one as the energy scale decreases by the renormalization effect. We discuss the leptogenesis, and the lepton flavor violation process by assuming the universal soft breaking terms.Comment: 19 pages, 2 figure

Interacting Modified Variable Chaplygin Gas in Non-flat Universe

A unified model of dark energy and matter is presented using the modified variable Chaplygin gas for interacting dark energy in a non-flat universe. The two entities interact with each other non-gravitationally which involves a coupling constant. Due to dynamic interaction, the variation in this constant arises that henceforth changes the equations of state of these quantities. We have derived the effective equations of state corresponding to matter and dark energy in this interacting model. Moreover, the case of phantom energy is deduced by putting constraints on the parameters involved.Comment: 9 pages; Accepted for publication in European Physical Journal

A texture of neutrino mass matrix in view of recent neutrino experimental results

In view of recent neutrino experimental results such as SNO, Super-Kamiokande (SK), CHOOZ and neutrinoless double beta decay $(\beta\beta_{0\nu})$, we consider a texture of neutrino mass matrix which contains three parameters in order to explain those neutrino experimental results. We have first fitted parameters in a model independent way with solar and atmospheric neutrino mass squared differences and solar neutrino mixing angle which satisfy LMA solution. The maximal value of atmospheric neutrino mixing angle comes out naturally in the present texture. Most interestingly, fitted parameters of the neutrino mass matrix considered here also marginally satisfy recent limit on effective Majorana neutrino mass obtained from neutrinoless double beta decay experiment. We further demonstrate an explicit model which gives rise to the texture investigated by considering an $SU(2)_L\times U(1)_Y$ gauge group with two extra real scalar singlets and discrete $Z_2\times Z_3$ symmetry. Majorana neutrino masses are generated through higher dimensional operators at the scale $M$. We have estimated the scales at which singlets get VEV's and M by comparing with the best fitted results obtained in the present work.Comment: Journal Ref.: Phys. Rev. D66, 053004 (2002

Baryogenesis via Lepton Number Violation and Family Replicated Gauge Group

We developed a previous model fitting all quark and lepton -- including neutrino quantities in the region of the Large Mixing Angle-MSW solar solution -- order of magnitudewise by only six adjustable parameters (Higgs vacuum expectation values) to also give an agreeing prediction for the amount of baryogenesis produced in the early time of cosmology. We use Fukugita-Yanagida scheme and take into account now also the effect of the remormalisation equation for the Dirac neutrino sector from Planck scale to the see-saw scale. The present version of our model with many approximately conserved (gauge) charges distinguishing various left- and right-Weyl particles has the largest matrix element of the mass matrix for the three flavour see-saw neutrinos being the off-diagonal elements associated with the second- and third-proto-flavour and gives the ratio of baryon number density to the entropy density to 2.59{+17.0\atop-2.25}\times 10^{-11} which agrees perfectly well as do also all the fermion masses and their mixing angles order of magnitudewise.Comment: 36 pages, 2 feynmf figures, Latex2e; one ref. added, refree responce slightly modifie

Constraints on coupling constant between dark energy and dark matter

We have investigated constraints on the coupling between dark matter and the interacting Chaplygin gas. Our results indicate that the coupling constant $c$ between these two entities can take arbitrary values, which can be either positive or negative, thus giving arbitrary freedom to the inter-conversion between Chaplygin gas and dark matter. Thus our results indicate that the restriction $0<c<1$ on the coupling constant occurs as a very special case. Our analysis also supports the existence of phantom energy under certain conditions on the coupling constant.Comment: 16 Pages, 3 figure