Radon Concentration in the Work Atmosphere of Cement Plants in the Sulaymaniyah Area, Iraq.

Author(s)

Adil M Hussain, Kamal O. Abdullah, Kharman A.Faraj and Dara F. Hamamin

Journal

ARO-The Scientific Journal of Koya University, 6(1), 2018,

Webpage

Vol. 6, No.1 (2018)

Abstract

DOI: 10.14500/aro.10329

Title 

Effects of chronic exposure of X-ray on hematological parameters in human blood

Author(s)

Kharman Faraj and Sirwan Mohammed

Journal

Comparative Clinical Pathology

Webpage

27(1)2018 pp 31-36 (Springer)

Abstract

DOI 10.1007/s00580-017-2547-7

Title

Effects of occupational exposure of X-Ray on hematological parameters of diagnostic technicians

Author(s)

Ali H. Taqi, Kharman Faraj, Sarah A. Zaynal and Abd-Alkader A. Mahmood

Journal

Radiation Physics and Chemistry

Webpage

147,2018., pp 45-52 (Elsevier)

Abstract

Title

A Study of Fluctuations in Sun’s Radiation by Measuring Earth’s Angular Velocity

Author(s)

Hossien H, Jabar M.A.F, Burhan M., Abdulqadr I.H., Zhiar M.J.

Journal

Climatology & Weather Forecasting

Volume 4, Issue 1

ISSN: 2332-2594 JCWF

Webpage

http://dx.doi.org/10.4172/2332-2594.1000151

Abstract

During a normal day, the intensity of sunlight, as a vector, is measured. By calculating variation of angle between sun’s ray and surface of the earth, angular velocity of the Earth’s rotation at different time intervals is determined. This angular velocity is not unchanging and traces back to the variations in intensity of light emanating from the Sun.

Title

From Hyperion to Photon, a brief survey in the timeline of photon

Author(s)

Hossien Hossieni, J. M. A. Fatah, Sarwar Mohammad, Mohammad Naby

Journal

Vietnam Journal of Science (VJS)

Date

Publicaton Date (Web): May 25, 2016

Webpage

DOI: dx.doi.org/10.20328/vjsonline.2016.rr2

Abstract

We present in this paper a chronological study on the main line of the electromagnetic radiation throughout the history of mankind. This history is divided into three distinct eras: pre-classical, classical, and modern era. In pre-classical era, myths are studied starting with Hyperion (god of lightning), extramission theory and Euclid principles. While in classical era, the main focus is on classical theories of physics through introducing the Maxwell equations and Huygens and Newton’s theories on light. In addition, aspects of light via particle and wave theory are reviewed. Special relativity, photoelectric effect and radiation in quantum mechanics are the studied topics in the modern era. We present the advancement in photonic science from last century till present time and show its influences on fields such as laser, quantum field theory, holographs, LED and entanglement.

Title

Dynamic coefficients calculations for high energetic positrons  implanted into a semi-crystalline polymer target film

Author(s)

Jamal Abda , Mazin Elias , Laith Al-Ani and Loay George 

Journal

Diyala Journal for Pure Science

Vol. No. Year

Date of receipt 28\3\2015, Date of acceptance 6\12\2015 

Abstract

In this work , Absorbed , backscattering and transmitted probability coefficients has been calculated via Monte Carlo simulation technique PsMCS ( positronium Monte – Carlo Computer Simulation ) for a high energetic positrons implanted normally into a semi finite Polytetrafluoroethylene target ( PTFE ) with its two components. Comparison with available references yields good quantitative agreement for dynamics factors.

Title

Monte Carlo Dynamic Transmission Calculations For High Energetic Positrons Implanted Into A Semi-Crystalline Polymer Target Film (Polytetrafluoroethylene)

Author(s)

J.M.R.Abda

Journal

IJSR - INTERNATIONAL JOURNAL OF SCIENTIFIC RESEARCH

Vol. No. Year

Volume: 5,Issue: 1, January 2016, ISSN No. 2277-8179

Abstract

In this work, backscattering and transmitted probability coefficients with mean penetrating depth has been calculated via Monte Carlo simulation technique PsMCS ( positronium Monte – Carlo Computer Simulation ) for positrons with different energies starting by high energies and finishing with very slow energy ( from 0.15MeV to 70 eV) ,implanted normally and with different angles , into a semi finite Polytetrafluoroethylene target ( PTFE ) . Comparison with available references yields good quantitative agreement for dynamics factors.

Title

Neutronic and Thermal – Hydraulic Calculations for The Conversion of BN-350

Author(s)

Jamal Mohammed Rashid Abda

Journal

1st International Conference of Natural Science (ICNS 2016) College of Basic Education, Charmo University, 46023 Chamchamal, Sulaimani, Kurdistan-Iraq

Abstract

This paper represents the neutronic and thermal-hydraulic calculations for the conversion of BN-350 from 27% to 7% enriched Uranium fuel elements. Mixed enrichment cores has been studied where low enrichment uranium (LEU) cores fresh fuel elements substitute gradually the high enrichment uranium (HEU) depleted fuel elements in the equilibrium core. Thermal hydraulic calculations have been carried out to determine changes in the characteristics of the converted reactor during steady state conditions and transient response to a coolant flow loss (LOCA).

Title

Determination of 222Rn and 238U Concentrations in Some Selected Samples of Rock for Sulaimani Area (Kurdistan Region-Iraq)

Author

Kamal O. Abdullah

Journal

JZS ( Journal of Zankoy Sulaimani) 

Part A – Vol. 17  -  No. 4 ( Dec. 2015)

Abstract

Different rock samples collected from the Mountains located to the west and north of Sulaimani district. Solid state nuclear track detector technique, CR-39 passive detectors included, is used for analyzing concentrations Radon. The uranium concentrations determined from the secular equilibrium between uranium and radon activity. The concentrations of Radon and Uranium have been calculated. The maximum and the minimum concentrations determined (19632.904 ± 74.605 and 153789.072 ± 584.398)  Bq/m3  for Radon and (1.289±0.619 ppm, 10.094±4.854 ppm) for uranium, respectively. The higher concentration values of both Byara (Mountain of Balkha) and Penjween is due to sample rocks formation compared to the values appeared from Ranya and Chaqchaq regions. The highest annual effective dose was 0.8µSv/hr, which is higher than the value 1mSv ~ 0.114 µSv/hr recommended by the International Commission on Radiological Protection  ICRP.

Title

Indoor Radon Concentration Measurement in Cement Factories in Sulaimani City (Kurdistan region-Iraq)

Authors

Kamal O. Abdullah, Kharman A. Faraj and Adil M. Hussein

Journal

European Journal of Scientific Research

ISSN 1450-216X / 1450-202X 

Vol. 135 No 1 October, 2015, pp.41-46

Abstract

Measurement of radon level in cement factories (Tasluja, Mass and Bazyan) in Sulaimani governorate was done by using Solid State Nuclear Track Detector technique. In this study, CR-39 plastic detectors inside a dosimeter chamber have been put in some selected places in the three factories like Crusher, Correction stores, Raw Mill (Grinding Mill), Preheater (Tower), Clinker,….. .The average value of radon concentration in the factoriesTasluja, Mass and Bazyan were (98.320±9.910,102.816±10.137, 116.714±10.796) Bq/m3, respectively, and the minimum value of radon concentration was (47.982±4.438) Bq/m3 and the maximum value was (222.138±20.547) Bq/m3, comparing the values with the standard world values from Environmental Protection Agency (EPA) the maximum value is some higher which was appeared in the correctionstore of Bazyanfactory due to adding in this section some type of materials as Sand, Iron, Clay, Gypsum, Limestone,… may causes to high value of uranium and radon in this section.

Title

Cavity-Photon Controlled Thermoelectric Transport through a Quantum Wire

Author(s)

Nzar Rauf Abdullah, Chi-Shung Tang, Andrei Manolescu, and Vidar Gudmundsson

Journal

ACS Photonics 

Vol. No. Year

3, 249 (2016)

Webpage

http://pubs.acs.org/doi/abs/10.1021/acsphotonics.5b00532

Abstract

We investigate the influence of a quantized photon field on thermoelectric transport of electrons through a quantum wire embedded in a photon cavity. The quantum wire is connected to two electron reservoirs at different temperatures leading to a generation of a thermoelectric current. The transient thermoelectric current strongly depends on the photon energy and the number of photons initially in the cavity. Two different regimes are studied, off-resonant and resonant polarized fields, with photon energy smaller than, or equal to the energy spacing between some of the lowest states in the quantum wire. We observe that the current is inverted for the off-resonant photon field due to participation of photon replica states in the transport. A reduction in the current is recorded for the resonant photon field, a direct consequence of the Rabi-splitting.

Title

Cavity-photon contribution to the effective interaction of electrons in parallel quantum dots

Author(s)

Vidar Gudmundsson, Anna Sitek, Nzar Rauf Abdullah, Chi-Shung Tang and Andrei Manolescu

Journal

Annalen der Physik

Vol. No. Year

528, 394 (2016)

Webpage

http://onlinelibrary.wiley.com/doi/10.1002/andp.201500298/abstract;jsessionid=F4D84FE4565E34E7F1172B28C584A057.f01t01

Abstract

A single cavity photon mode is expected to modify the Coulomb interaction of an electron system in the cavity. Here we investigate this phenomena in a parallel double quantum dot system. We explore properties of the closed system and the system after it has been opened up for electron transport. We show how results for both cases support the idea that the effective electron-electron interaction becomes more repulsive in the presence of a cavity photon field. This can be understood in terms of the cavity photons dressing the polarization terms in the effective mutual electron interaction leading to nontrivial delocalization or polarization of the charge in the double parallel dot potential. In addition, we find that the effective repulsion of the electrons can be reduced by quadrupolar collective oscillations excited by an external classical dipole electric field.

Title

Analytical derivations of single-particle matrix elements in nuclear shell model

Author(s)

Aziz H. Fatah, R. A. Radhi, and Nzar Rauf Abdullah

Journal

Communication in Theoretical Physics

Vol. No. Year

Accepted for publication, In press (2016)

Webpage

Abstract

We propose a new analytical method to calculate single particle matrix elements used in atomic and nuclear physics. We show seven different formulas of matrix elements of the operator $f(r)d_r^{m}$ where $f(r)=r^{\mu},r^{\mu}j_J(qr), V(r)$ corresponding to the Gaussian and the Yukawa potentials used in nuclear shell models and nuclear structure. In addition, we take into account a general integral formula of the matrix element $\left\langle n'\, l'\left|f(r)\, d_{r}^{(m)} \right|n\, l\right\rangle$ that covers all seven matrix elements obtained analytically.

Title

Optical and structural investigation of synthesized PVA/PbS nanocomposites

Author(s)

Omed Gh. Abdullah, Dana A. Tahir, K. Kadir

Name of Journals

Journal of Materials Science: Materials in Electronics

Vol. No. Year

Vol. 26, Issue 9, pp. 6939-6944, (2015)

ISSN

0957-4522 (Print)  1573-482X (Online)

Publisher Springer

Springer

IF

1.569 (Thomson Routers)

DOI

DOI: 10.1007/s10854-015-3312-9

Webpage

http://www.springer.com/materials/optical+%26+electronic+materials/journal/10854

Abstract

Polymer nanocomposite based on polyvinyl alcohol (PVA) and lead sulfide (PbS) in the average radius of (1.88-2.23) nm, have been synthesized using the chemical reduction rote and solution casting technique for different concentrations of PbS. The characterization of the polymer nanocomposite films were carried out using UV-Visible Spectroscopy, SEM, and XRD. The effect of various concentration of PbS NP on the optical properties of the composite has been studied to understand the optimum conditions for the synthesis process. The nanocomposite film shows high UV and visible light absorptions in the wavelength range of (200-500) nm, which correspond to the characteristics of the PbS NPs. The significant decreasing trend of the direct allowed band gap of the nanocomposite was observed upon increasing the Pb source concentration, from (6.27 eV) for pure PVA to (2.34 eV) for 0.04M PbS concentration, which is much higher than the energy gap of bulk PbS value (0.41 eV). The calculated values of the static refractive index of Cauchy dispersion model were in the range of (1.09-1.20). X-ray diffraction analysis confirmed the cubic nanocrystalline PbS phase formation.

Title

In-situ synthesis of PVA/HgS nanocomposite films and tuning optical properties

Author(s)

Omed Gh. Abdullah, Yahya A.K. Salman, Salwan A. Saleem

Name of Journals

Physics and Materials Chemistry

Vol. No. Year

Vol. 3, No. 2, pp. 18-24, (2015)

ISSN

 2372-7098 (Print) 2372-7101 (Online)

Publisher Springer

Science  & Education

DOI

DOI:10.12691/pmc-3-2-1

Webpage

http://www.sciepub.com/journal/PMC

Abstract

Polymer based nanocomposite films of polyvinyl alcohol (PVA) doped with mercury sulfide (HgS) were prepared via in-situ chemical reduction and the solution cast methods, with different HgS concentrations, in order to study the effect of HgS content on optical properties of PVA. The nanocomposites films were characterized using FTIR, XRD, and SEM. The UV-Visible absorption spectra in the wavelength range (190–1100) nm were analyzed in terms of absorption formula for non-crystalline materials. The band gap and the fundamental optical constants of the prepared samples have been investigated and showed a clear dependence on the HgS concentration. The observed value of band gap for pure polyvinyl alcohol is about 6.27 eV and decreases to a value 4.88 eV for the film of 0.04M HgS content. The refractive index and consequently the related dispersion parameters of PVA and PVA/HgS nanocomposite versus HgS content have been determined and explained using Wemple-DiDomenico single oscillator model.

Title

Electrical conductivity and dielectric characteristics of in-situ prepared PVA/HgS nanocomposite films

Author(s)

Omed Gh. Abdullah, Yahya A.K. Salman, Salwan A. Saleem

Name of Journals

Journal of Materials Science: Materials in Electronics

Vol. No. Year

Vol. 27, Issue 4, pp. 3591-3598, (2016).

ISSN

0957-4522 (Print)  1573-482X (Online)

Publisher Springer

Springer

IF

1.569 (Thomson Routers)

DOI

DOI: 10.1007/s10854-015-4196-4

Webpage

http://www.springer.com/materials/optical+%26+electronic+materials/journal/10854

Abstract

Polyvinyl alcohol (PVA) and mercury sulfide (HgS) polymer nanocomposite were prepared using the solution casting and the in-situ chemical reduction of mercury nitrate (Hg(NO3)2) and sodium sulfide (Na2S) in aqueous solutions of PVA as capping for different molar content of Hg(NO3)2 and Na2S. The nanocomposites films were characterized by Fourier Transform Infrared (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The XRD results for the nanoparticles revealed the hexagonal structure of the HgS, (α-phase). The influence of embedded HgS nanoparticles on the conductivity and dielectric properties of Polyvinyl Alcohol (PVA) films are investigated, over the frequency range 1 KHz to 1 MHz, and the temperature range (30 − 110) oC. The variation of ac-conductivity with a frequency of the films follows Jonscher's universal power law and found to be increased with increasing temperature, frequency and nanoparticle content. The variation of frequency exponent (s) indicated that the conduction mechanism was correlated barrier hopping (CBH) model. The dielectric constant (ε'), and dielectric loss (ε'') was found to decrease with increasing frequency, but increase with increasing temperature and HgS nanoparticles content. The dc-conductivity (σ_dc) increase with increase of HgS concentration, and follows Arrhenius behavior in the investigated temperature region.

Title

Synthesis, Structural and Optical Characterization of MgO Nanocrystalline Embedded in PVA Matrix

Author(s)

Shahbaa F. Bdewi, Omed Gh. Abdullah, Bakhtyar K. Aziz, Ayad A.R. Mutar

Name of Journals

Journal of Inorganic and Organometallic Polymers and Materials

Vol. No. Year

Vol. 26, Issue 2, pp. 326-334, (2016).

ISSN

1574-1443  (print) 1574-1451  (Online)

Publisher Springer

Springer

IF

1.160 (Thomson Routers)

DOI

DOI: 10.1007/s10904-015-0321-3

Webpage

http://www.springer.com/chemistry/inorganic+chemistry/journal/10904

Abstract

Nano-magnesium oxide (MgO) was prepared by wet chemical method using magnesium chloride and sodium hydroxide as precursors and soluble gelatin as stabilizing agent in this paper. The synthesized nano MgO was characterized by XRD, SEM, and FTIR. The results showed that the size of nano-MgO was about 20.62 nm. Polyvinyl alcohol (PVA) polymer based nanocomposites, with different concentrations of MgO (1, 2, 3, 4 wt%), have been prepared using solvent casting technique. The results of SEM revealed that the MgO nanoparticles are uniformly distributed in PVA polymer matrix. FTIR analysis evidently saw the interaction between MgO with hydroxyl group of PVA through hydrogen bonding. The influences of MgO nanoparticle on the optical characterisation of PVA have been considered using UV-Vis-NIR spectroscopy. Energy band gap and tail of localized state of PVA/MgO nanocomposites have been calculated by using Tauc and Urbach relations, respectively. The band gap of the nanocomposites samples decreases as MgO Wt% increases. Wemple-DiDomenico single-oscillator model has been applied to analyze the dispersion of the refractive index of the films, and the dispersion parameters are calculated to obtain the information about disorder degree.

Title

Optical Properties of Polyvinyl Alcohol (PVA) / Silver Sulfide Polymer Composites

Author(s)

Dana A. Tahir, Soran M. Mamand, Sarkawt A. Hussein, Omed Gh. Abdullah, Shuja B. Aziz

Name of Journals

Journal of Zankoy Sulaimani, part A (JZS-A)

Vol. No. Year

Vol. 18, No. 3, pp., (2016).

ISSN

1812-4100

Publisher Springer

University of Sulaimani

IF

0.425 (Global Impact Factor)

DOI

doi.org/10.17656/jzs.10001

Webpage

http://univsul.edu.iq/JournalsAbout.aspx?Jimare=1&main=13

Abstract

In this work silver sulfide (Ag2S) has been synthesized inside the PVA polymer by in situ chemical reduction method. The UV-Visible spectrophotometer was used to study the optical properties of the prepared composite samples. The absorption spectra reveal the influence of Ag2S particles on optical behavior of PVA. There is an increase in refractive index of the samples contains Ag2S filler, and exhibits a dispersion behavior. The extinction coefficients of the composite samples are higher than that of pure PVA. The linear relationship between the refractive index at high wavelength region and Ag2S concentration was observed, indicating homogeneous dispersion of the filler in the PVA matrix. The absorption coefficient shifts to lower photon energy at higher Ag2S concentration, in which the optical band gap will reduce.

Title

Tuning the absorption of ultraviolet spectra and optical parameters of aluminum doped PVA based solid polymer composites

Author(s)

Shujahadeen B. Aziz, Hameed M. Ahmed, Ahang M. Hussein, Awder B. Fathulla, Rawaz M. Wsw, Rekawt T. Hussein 

Journal

Journal of Materials Science: Materials in Electronics

Vol. No. Year

October 2015, Volume 26, Issue 10, pp 8022-8028

Abstract

In this research work PVA:xAl (0.01 ≤ x ≤ 0.05) based solid polymer composites have been prepared by solution cast technique. The transmittances of the samples are decreased with increasing Al powder concentration. The absorption spectra of the samples are shifted to higher wavelengths which indicate their importance for shielding. The increase of absorption intensity in UV region was observed. The clear shift of absorption edge upon the addition of Al powder content indicated the decrease of energy band gap. The increase of extinction coefficient at high wavelengths for the samples containing Al powder revealed the loss of photon energy. The refractive indexes of the doped samples are increased compared to that of pure PVA. The linear relationship between the refractive index and volume fraction indicates a good dispersion of Al powder in PVA host polymer. The direct optical band gap measured from the plot of (αhυ)2 versus photon energy (hυ) showed a decreasing trend with increase of Al content. The Urbach energy was found to increase with increasing aluminum concentration. The complex optical dielectric functions were used to determine the type of electron transition.

Title

Modifying Poly(Vinyl Alcohol) (PVA) from Insulator to Small-Bandgap Polymer: A Novel Approach for Organic Solar Cells and Optoelectronic Devices

Author(s)

Shujahadeen B. Aziz 

Journal

Journal of Electronic Materials

Vol. No. Year

January 2016, Volume 45, Issue 1, pp 736-745

Abstract

An innovative method has been used to reduce the bandgap of poly(vinyl alcohol) (PVA) polymer by addition of a nontoxic, inexpensive, and environmentally friendly material. The resulting materials are small-bandgap polymers, hence opening new frontiers in green chemistry. The doped PVA films showed a wide range of light absorption of the solar spectrum from 200 nm to above 800 nm. Nonsharp absorption behavior versus wavelength was observed for the samples. The refractive index exhibited a wide range of dispersion. Shift of the absorption edge from 6.2 eV to 1.5 eV was observed. The energy bandgap of PVA was diminished to 1.85 eV upon addition of black tea extract solution, lying in the range of small-bandgap polymers. Increase of the optical dielectric constant was observed with increasing tea solution addition. The results indicate that small-bandgap PVA with good film-forming ability could be useful in terms of cost–performance tradeoff, solving problems of short lifetime, cost, and flexibility associated with conjugated polymers. The decrease of the Urbach energy upon addition of black tea extract solution indicates modification of PVA from a disordered to ordered material. X-ray diffraction results confirm an increase of the crystalline fraction in the doped samples.

Title

Study of electrical percolation phenomenon from the dielectric and electric modulus analysis

Author(s)

Shujahadeen B. Aziz 

Journal

Bulletin of Materials Science

Vol. No. Year

October 2015, Volume 38, Issue 6, pp 1597-1602

Abstract

Chitosan : AgI solid polymer composite films have been prepared by the well-known solution cast technique. Electrical impedance spectroscopy was used to investigate the electrical percolation threshold phenomenon in this work. A wide dispersion can be seen in dielectric constant spectra at low frequencies. The dielectric constant at selected frequencies as a function of AgI concentration indicates the occurrence of electrical percolation threshold via the appearance of two distinguishable regions. The behaviour of dielectric constant and DC conductivity vs. AgI concentration are almost the same at low and high filler concentrations. The steep increase of dielectric constant and DC conductivity from 5 to 10 wt% of AgI was observed and a plateau was achieved from 10 to 20 wt% of AgI. The pattern of real part of electric modulus (M′) at selected frequencies is similar to dielectric constant. The existence of distinct peaks in M′′ spectra with no corresponding peaks in ε′′ spectra indicated that ionic and polymer segmental motions are strongly coupled. Argand plots of M′′ vs. M′ was used to detect the relaxation type process. The Argand plots at different temperatures exhibit incomplete semicircular arc with a diameter below the real axis.

Title

In Situ Synthesis of CuS Nanoparticle with a Distinguishable SPR Peak in NIR Region

Author(s)

Shujahadeen B. Aziz*,1, Rebar T. Abdulwahid2 , Hazhar A. Rsaul3, Hameed M. Ahmed4 

Journal

Journal of Materials Science: Materials in Electronics

Vol. No. Year

May 2016, Volume 27, Issue 5, pp 4163-4171

Abstract

In this article we report the synthesis of CuS nanoparticle with distinguishable surface plasmonic resonance (SPR) peaks in near infrared region. For this purpose in situ synthesis (one-step fabrication) has been used to prepare CuS nanoparticles in PMMA polymer matrix at room temperature. The X-ray diffraction spectrum confirms the formation of CuS nanoparticles. The transmittance spectra of nano-composite samples reveal that the samples have a good transparency. The absorption spectra show a broad absorption peak in the wavelength region from 570 to 980 nm which is a characteristic SPR peak for CuS nanoparticle. An increase of refractive index was observed for the samples containing CuS nanoparticles. The linear relationship between the refractive index and volume fraction was observed. The appearance of SPR peak in refractive index spectra was attributed to CuS nanoparticles. Shifting of absorption edge to lower photon energy has been observed for nano-composite samples. The direct energy bandgap of nano-composite samples are reduced compare to pure PMMA polymer. The plot between the direct energy band gap and refractive index reveals that the decrease in bandgap energy is associated with the increase in index of refraction. The increase of optical dielectric constant can be ascribed to the formation of CuS nanoparticles. The low band gap of CuS nanoparticles in the present work reveals their importance for applications in optoelectronic devices.

Title

Role of Dielectric Constant on Ion Transport: Reformulated Arrhenius Equation

Author(s)

Shujahadeen B. Aziz 

Journal

Advances in Materials Science and Engineering

Vol. No. Year

Volume 2016 (2016), Article ID 2527013, 11 pages

Webpage

http://dx.doi.org/10.1155/2016/2527013

Abstract

In this research work solid and nanocomposte polymer electrolytes based on chitosan has been prepared by solution cast technique. The XRD results reveal the occurrence of complexation between chitosan (CS) and the LiTf salt. The deconvolution of the diffractogram of nanocomposite solid polymer electrolytes demonstrates the increase of amorphous domain with increasing alumina content up to 4 wt.%. Further incorporation of alumina nanoparticles (6 to 10 wt.% Al2O3) results in crystallinity increase (large crystallite size). The morphological (SEM and EDX) analysis well supported the XRD results. Similar trends of DC conductivity and dielectric constant with Al2O3 concentration was explained. The TEM images were used to explain the phenomena of space charge and blocking effects. The reformulated Arrhenius equation ( ) was proposed from the smooth exponential behavior of DC conductivity versus dielectric constant at different temperatures. The more linear behavior of DC conductivity versus 1000/(ɛ'×T) reveals the crucial role of dielectric constant in Arrhenius equation. The drawbacks of Arrhenius equation can be understood from the less linear behavior of DC conductivity versus 1000/T. The relaxation processes has been interpreted in terms of Argand plots.

Title

Electrical impedance and conduction mechanism analysis of biopolymer electrolytes based on methyl cellulose doped with ammonium iodide

Author(s)

N. S. Salleh, Shujahadeen B. Aziz, Z. Aspanut , M. F. Z. Kadir

Journal

Ionics

Vol. No. Year

DOI:10.1007/s11581-016-1731-0 (This all he wrote)

Abstract

In the present study, the potential of methyl cellulose (MC) as biopolymer electrolyte (BPE) will be studied extensively by means of conductivity and the conduction mechanism. BPE films based on MC doped with ammonium iodide (NH4I) salt were prepared by solution-casting method. X-ray diffraction (XRD) explains that the conductivity enhancement of the electrolytes is affected by the degree of crystallinity. Field emission scanning electron microscopy (FESEM) analysis shows the difference in the electrolyte’s surface with respect to NH4I. On addition of 40 wt.% of NH4I, the highest room temperature conductivity of (5.08 ± 0.04) × 10−4 S cm−1 was achieved. The temperature dependence relationship for the salted electrolyte was found to obey the Arrhenius rule where R2 ∼1 from which the activation energy (E a) was evaluated. The dielectric study analyzed using complex permittivity ε* for the sample with the highest conductivity at elevated temperature shows a non- Debye behavior. These salted electrolytes follow the correlated barrier hopping (CBH) model.

Title

 A sensing mechanism for the detection of carbon nanotubes using selective photoluminescent probes based on ionic complexes with organic dyes

Author(s)

Allsop, T., Arif, R., Neal, R., Kalli, K., Kundrát, V., Rozhin, A., Culverhouse , P. & Webb, D. J. 

Journal

Light: Science & Applications

Vol. No. Year

 vol. 5, no.2, February 2016

Webpage

http://dx.doi.org/10.1038/lsa.2016.36

Abstract

  The multifunctional properties of carbon nanotubes (CNTs) make them a powerful platform for unprecedented innovations in a variety of practical applications. As a result of the surging growth of nanotechnology, nanotubes present a potential problem as an environmental pollutant, and as such, an efficient method for their rapid detection must be established. Here, we propose a novel type of ionic sensor complex for detecting CNTs – an organic dye that responds sensitively and selectively to CNTs with a photoluminescent signal. The complexes are formed through Coulomb attractions between dye molecules with uncompensated charges and CNTs covered with an ionic surfactant in water. We demonstrate that the photoluminescent excitation of the dye can be transferred to the nanotubes, resulting in selective and strong amplification (up to a factor of 6) of the light emission from the excitonic levels of CNTs in the near-infrared spectral range, as experimentally observed via excitation-emission photoluminescence (PL) mapping. The chirality of the nanotubes and the type of ionic surfactant used to disperse the nanotubes both strongly affect the amplification; thus, the complexation provides sensing selectivity towards specific CNTs. Additionally, neither similar uncharged dyes nor CNTs covered with neutral surfactant form such complexes. As model organic molecules, we use a family of polymethine dyes with an easily tailorable molecular structure and, consequently, tunable absorbance and PL characteristics. This provides us with a versatile tool for the controllable photonic and electronic engineering of an efficient probe for CNT detection.            

Title

Photonic gas sensors exploiting directly the optical properties of hybrid carbon nanotube localized surface plasmon structures

Author(s)

Allsop, T., Arif, R., Neal, R., Kalli, K., Kundrát, V., Rozhin, A., Culverhouse , P. & Webb, D. J. 

Journal

Light: Science & Applications

Vol. No. Year

 vol. 5, no.2, February 2016

Webpage

http://dx.doi.org/10.1038/lsa.2016.36

Abstract

We investigate the modification of the optical properties of carbon nanotubes (CNTs) resulting from a chemical reaction triggered by the presence of a specific compound (gaseous carbon dioxide (CO2)) and show this mechanism has important consequences for chemical sensing. CNTs have attracted significant research interest because they can be functionalized for a particular chemical, yielding a specific physical response which suggests many potential applications in the fields of nanotechnology and sensing. So far, however, utilizing their optical properties for this purpose has proven to be challenging. We demonstrate the use of localized surface plasmons generated on a nanostructured thin film, resembling a large array of nano-wires, to detect changes in the optical properties of the CNTs. Chemical selectivity is demonstrated using CO2 in gaseous form at room temperature. The demonstrated methodology results additionally in a new, electrically passive, optical sensing configuration that opens up the possibilities of using CNTs as sensors in hazardous/explosive environments.

Title

High Power Q-Switched Thulium Doped Fibre Laser using Carbon Nanotube Polymer Composite Saturable Absorber

Author(s)

Chernysheva, M., Mou, C., Arif, R., Al Araimi, M., Rummeli, M., Turitsyn, S. & Rozhin

Journal

Nature/ Scientific Reports

Vol. No. Year

vol. 6, April 2016

Webpage

http://dx.doi.org/10.1038/srep24220

Abstract

We have proposed and demonstrated a Q-switched Thulium doped fibre laser (TDFL) with a ‘Yin-Yang’ all-fibre cavity scheme based on a combination of nonlinear optical loop mirror (NOLM) and nonlinear amplified loop mirror (NALM). Unidirectional lasing operation has been achieved without any intracavity isolator. By using a carbon nanotube polymer composite based saturable absorber (SA), we demonstrated the laser output power of ~197 mW and pulse energy of 1.7 μJ. To the best of our knowledge, this is the highest output power from a nanotube polymer composite SA based Q-switched Thulium doped fibre laser.

Title

Carbon nanotubes for ultrafast fibre lasers

Author(s)

Chernysheva, M., Rozhin, A., Fedotov, Y., Mou, C., Arif, R., Kobtsev, S. M., Dianov, E. M. & Turitsyn, S. 

Journal

Nanophotonics

Vol. No. Year

 June 2016

Webpage

http://www.degruyter.com/view/j/nanoph.ahead-of-print/nanoph-2015-0156/nanoph-2015-0156.xml

Abstract

Carbon nanotubes (CNTs) possess both remarkable optical properties and high potential for integration in various photonic devices. We overview, here, recent progress in CNT applications in fibre optics putting particular emphasis on fibre lasers. We discuss fabrication and characterisation of different CNTs, development of CNT-based saturable absorbers (CNT-SA), their integration and operation in fibre laser cavities putting emphasis on state-of-the-art fibre lasers, mode locked using CNT-SA. We discuss new design concepts of high-performance ultrafast operation fibre lasers covering ytterbium (Yb), bismuth (Bi), erbium (Er), thulium (Tm) and holmium (Ho)-doped fibre lasers.

Title

High chaotic spiking rate in a closed loop semiconductor laser with optical feedback

Author(s)

Banaz O. Rasheed, Parekhan M. Aljaff , Kais A. Al Naimee , Mahdi H. Al Hasani, Riccardo Meucci

Journal

Elsevier.com/results-in-physics

Vol. No. Year

6 (2016) 401–406

Webpage

http://dx.doi.org/10.1016/j.rinp.2016.07.006

Abstract

We investigate experimentally and numerically the existence of fast chaotic spiking in the dynamics of a
semiconductor laser with ac-coupled optical feedback. The observed dynamics is chaotic in the explored
range of both bias current optical feedback strength. The effects of a modulation applied to the bias current
are also investigated. We eventually indicate that the observed chaotic dynamics is a good candidate
to hide information to satisfy secure communications.