bluuebunny/crossref_metadata_2025 huggingface dataset:
Stability of thyroid function in older adults: the Birmingham Elderly Thyroid Study
Authors: Roberts Lesley , McCahon Deborah , Johnson Oliver , Haque M Sayeed , Parle James , Hobbs FD Richard
Published: August 2018

Background

Thyroid function tests (TFTs) are among the most requested tests internationally. However, testing practice is inconsistent, and potentially suboptimal and overly costly. The natural history of thyroid function remains poorly understood.

Aim

To establish the stability of thyroid function over time, and identify predictors of development of overt thyroid dysfunction.

Design and setting

Longitudinal follow-up in 19 general practices in the UK.

Method

A total of 2936 participants from the Birmingham Elderly Thyroid Study (BETS 1) with a baseline TFT result indicating euthyroid or subclinical state were re-tested after approximately 5 years. Change in thyroid-stimulating hormone (TSH), free thyroxine (FT4), and thyroid status between baseline and follow-up was determined. Predictors of progression to overt dysfunction were modelled.

Results

Participants contributed 12 919 person-years; 17 cases of overt thyroid dysfunction were identified, 13 having been classified at baseline as euthyroid and four as having subclinical thyroid dysfunction. Individuals with subclinical results at baseline were 10- and 16-fold more likely to develop overt hypothyroidism and hyperthyroidism, respectively, compared with euthyroid individuals. TSH and FT4 demonstrated significant stability over time, with 61% of participants having a repeat TSH concentration within 0.5 mIU/L of their original result. Predictors of overt hypothyroidism included new treatment with amiodarone (odds ratio [OR] 92.1), a new diagnosis of atrial fibrillation (OR 7.4), or renal disease (OR 4.8).

Conclusion

High stability of thyroid function demonstrated over the 5-year interval period should discourage repeat testing, especially when a euthyroid result is in the recent clinical record. Reduced repeat TFTs in older individuals is possible without conferring risk, and could result in significant cost savings.
Les réfugiés espagnols en France et la formation d'une identité européenne, 1939-1981
Authors: Angoustures Aline
Published: August 2018

En s' interrogeant sur la participation des réfugiés espagnols en France à l'éventuelle formation d'une identité européenne dans l'après-guerre, on peut relever qu'ils sont une figure-type du statut de réfugié — construction juridique européenne — et que leur «deuxième» génération, en s'intégrant à la société française, a pris part à l'homogénéisation des modes de vie européens. Cette évolution, parallèle à celle de la société espagnole, a-t-elle contribué au rapprochement entre les descendants des vaincus et des vainqueurs de la guerre civile ?
Asesoramiento y represión : los agregados laborales del Franquismo y la emigración española en Europa
Authors: Baeza sanjuán Ramón
Published: August 2018

Las primeras agregadurías laborales españolas se constituyeron bajo el franquismo. Los agregados fueron el principal instrumento de la Organización Sindical Española - sindicato del Régimen - para ensayar un conato de diplomacia paralela a la desarrollada para el conjunto del Estado. Así, efectuaron labores político-institucionales, económicas y, en menor medida, culturales. Pero fue hacia la emigración española en el exterior donde, posiblemente, desplegarán una mayor actividad. Los agregados laborales contribuyeron a crear un marco jurídico que favoreciera la emigración, participando activamente en las negociaciones entre España y otros países tendentes a concluir acuerdos sobre esta materia. Prestaron asistencia y asesoramiento a los trabajadores españoles - en su mayoría con un escaso bagaje cultural-que debían enfrentarse a sociedades que les eran ajenas. Pero también se preocuparon de intentar reprimir toda actividad antifranquista de los emigrantes y de evitar la influencia sobre ellos de toda influencia política ajena al Régimen.
Ideas, políticas y prácticas migratorias argentinas en una perspectiva de largo plazo (1852-1950)
Authors: Devoto Fernando
Published: August 2018

El artículo estudia la relación entre necesidades de corto plazo e imágenes y estereotipos de largo plazo en la formulación de las políticas migratorias argentinas, y la contraposición entre los móviles económicos y los ideológicos en la construcción de las mismas y la tensión que existe entre dichas políticas y las prácticas administrativas que las instrumentan. En la perspectiva de un siglo (1852-1950) la política migratoria argentina aparece condicionada por factores inerciales de largo plazo (mitos civilizatorios, normativas constitucionales perdurables y características estructurales de su mercado de trabajo) progresivamente erosionados por enmarañadas disposiciones administrativas, inefíciencia y corrupción crecientes de la maquinaria estatal y transformaciones en las características del flujo migratorio y en las estrategias de los mismos migrantes.
Migrantes, refugiados y fugitivos : las ambiguas políticas migratorias del primer peronismo (1946-1955)
Authors: Biernat Carolina
Published: August 2018

The study is intended to advance in the comprehension of the migratory policies of the first Peronism, taking into account its ambiguities, which are manifested mainly in the tension between the political enunciations and the administrative practices. Those migratory policies are analyzed in this article though three dimensions that cross each other : the dimension of the ideas, the dimension of the legislative norms and the dimension of the actual institutional practices.
Un miroir des relations franco-espagnoles : les maquisards FFI-FTP détenus par le régime franquiste 1944-1955
Authors: Dulphy Anne
Published: August 2018

Soon after the French Liberation, 46 former members of the FFI-FTP Resistance were arrested in Spain and were gravely condemned by Franco's military tribunals ; the last eleven of them were released only on October 1, 1955. During that period, French authorities defended them in the name of a common national allegiance, even hiding the fact that several of them were Spanish. They attempted to obtain sentence cuts and release decisions, relying on the emotion expressed by the opinion and on the Vatican mediation process. Unfortunately they could not prevent Franco government from using this paniful humanitarian issue as a blackmail argument to facilitate the settlement of the bilateal disagreement.
A discussion on the genus Fomitiporella (Hymenochaetaceae, Hymenochaetales) and first record of F. americana from southern South America
Authors: Pildain María Belén , Reinoso Cendoya Rodrigo , Ortiz-Santana Beatriz , Becerra José , Rajchenberg Mario
Published: August 2018

Fomitiporella has traditionally been delimited based on the gross morphology of the basidiomes, hyphal structure and basdiospores. Recently, phylogenetic studies supported the incorporation of an extensive number of species within the genus. Although most of its species are nested in the ‘Phellinotus clade’ (Hymenochaetaceae, Basidiomycota), genera such as Arambarria, Inocutis and Phellinotus were not included in previous analysis. To further our understanding of the genus, new sequences from 28S and ITS nuc rDNA genes were jointly analysed with a large selection of taxa in the ‘Phellinotus clade’, also with re-examination of morphological and ecological data. Results showed several lineages in what has hitherto been considered to represent Fomitiporella, indicating that the genus is paraphyletic as presently circumscribed. There is a well-supported Fomitiporella core group that includes the type species and nine other monophyletic lineages with high support, of which those representing Arambarria, Inocutis and Phellinotus are distinct from the Fomitiporella core group by macro and micromorphological traits and/or biogeographic distribution. Fomitiporellaamericana, a species described from SE USA, was found in the Patagonian forests of southern Argentina and Chile; it is the taxon responsible for the white heart-rot found on standing Austrocedruschilensis and one of the taxa decaying wooden tiles of historic churches in Chiloé Is., Chile.
Multilocus phylogeny reveals taxonomic misidentification of the Schizopora paradoxa (KUC8140) representative genome
Authors: Fernández-López Javier , Martín María P. , Dueñas Margarita , Telleria M. Teresa
Published: August 2018

Schizoporaparadoxa, current name Xylodonparadoxus, is a white-rot fungus with certain useful biotechnological properties. The representative genome of Schizoporaparadoxa strain KUC8140 was published in 2015 as part of the 1000 Fungal Genomes Project. Multilocus phylogenetic analyses, based on three nuclear regions (ITS, LSU and rpb2), confirmed a misidentification of S.paradoxa strain KUC8140 which should be identified as Xylodonovisporus. This wrong identification explains the unexpected geographical distribution of S.paradoxa, since this species has a European distribution, whereas the strain KUC8140 was recorded from Korea, Eastern Asia.
Tipificación de dos nombres en el género Asperula (Rubiaceae)
Authors: Ferrer-Gallego P. P. , Laguna E.
Published: August 2018

Se discute la tipificación de dos nombres en el género Asperula, A. cynanchica subsp. pyrenaica y A. paui subsp. dianensis (Rubiaceae) aplicables a especies endémicas de la Península Ibérica y Francia. Especímenes de UPS (Herbario Burser, Universidad de Uppsala) y BC (Institut Botànic de Barcelona) son indicados y designados como lectotipos de A. pyrenaica and A. paui var. dianensis, respectivamente.
Una síntesis de las localidades ibéricas conocidas para Craspedacusta sowerbii Lankester, 1880 (Cnidaria: Hydrozoa): nuevo registro para España procedente de la vega del Guadalquivir
Authors: Medina-Gavilán J. L. , González-Duarte M. M.
Published: August 2018

Las especies exóticas invasoras son una de las mayores amenazas para la biodiversidad. Particularmente, las especies de cnidarios son frecuentemente dispersadas lejos de sus áreas de origen por mediación de actividades humanas. Así, muchos hidrozoos han sido exitosamente transportados en las aguas de lastre, fijadas en los cascos de los barcos y como fauna asociada al tráfico comercial de otras especies acuáticas. Craspedacusta sowerbii Lankester, 1880 (Hydrozoa: Olindiidae) es la medusa de agua dulce más ampliamente distribuida en el planeta. Esta especie de hidrozoo es considerada probablemente nativa del valle del Yangtze (China) e invasora en ambientes epicontinentales de prácticamente todo el mundo. En esta nota, señalamos la presencia de una población de C. sowerbii establecida en el bajo Guadalquivir (Andalucía Occidental, Suroeste de España) y proporcionamos los datos ambientales asociados con su ocurrencia. La distribución espacial de C. sowerbii en la Península Ibérica está aún poco estudiada y la mayoría de la información proviene de publicaciones académicas regionales, informes técnicos de limitado acceso, observaciones puntuales de naturalistas o noticias de prensa sobre cuestiones ambientales. Por tanto, se han revisado estas fuentes para presentar reunidos todos los registros conocidos sobre esta especie en la Península Ibérica. Esta nota contribuye al conocimiento de su distribución en la Península Ibérica, un importante paso previo para evaluar posteriormente el impacto de esta especie invasora en los ecosistemas ibéricos.
Patterns of prominence, phrasing and tonal events in Spanish news reading: An illustrative case study
Authors: Aguilar Lourdes , Gutiérrez-González Yurena M.
Published: August 2018

The present study examines the patterns in stress, phrasing and intonation found in a Spanish corpus of news read by broadcasters to describe the prosodic strategies that can be considered as genre-distinguishing features.
Results indicate that, firstly, the main stress modifications concern the upgrading of unstressed syllables to accented ones, the stress shift to mark word-initial boundaries and the maintenance of adjacent stresses. Secondly, the special features related to phrasing are unexpected pauses, which enhance the prosodic units that offer new information, and the prosodic marking of initial edges of groups with the aim of capturing the listener’s attention. Finally, the most relevant tonal events that identify the typical chanting of broadcasters are a recurrent use of rises whose f0 peak coincides with the stressed syllable, a variety of non-falling pitch movements signalling intermediate phrasing, and the use of rising-falling pitch movements to signal ends.
All the described prosodic and tonal strategies contribute to obtaining an emphatic style in news reading and are representative of a prosodically marked genre.
Gait Analysis of Pedestrians with the Aim of Detecting Disabled People
Authors: Mukhtar Amir , Cree Michael J. , Scott Jonathan B. , Streeter Lee
Published: August 2018

Gait classification is an effective and non-intrusive method for human identification and it has received significant attention in the recent years due to its applications in visual surveillance and monitoring systems. We analyse gait signatures using spatio-temporal motion characteristics of a person to answer the question ``is there a discriminating feature in the gait signal that can help to categorise a disabled person from healthy''. The procedure has three steps: detection of a pedestrian using YOLO followed by the silhouette extraction using the Gaussian Mixture Model (GMM). Finally, skeletonization from the silhouette image to estimate head and torso locations and their angles with the vertical axis. Furthermore, velocity and acceleration signals were recorded to look for accelerating behaviour of person walking with a limp. Manual segmentations shows that the gait signal has information about unusual walking patterns but existing pedestrian detectors lack accuracy in extracting an accurate gait signal due to localization errors.
Jitter Extraction in a Noisy Signal by Fast Fourier Transform and Time Lag Correlation
Authors: Anthonys Gehan , Cree Michael J. , Streeter Lee
Published: August 2018

Jitter in an electronic signal is any deviation in, or displacement of, the signal in time. This paper investigates on decomposition of two types of jitter, namely, periodic and random jitter in noisy signals. Generally, an oscilloscope generates an eye diagram by overlaying sweeps of different segments of a long data stream driven by the reference clock signal. We use the fast Fourier transform with time lag correlation of the signal since we do not have a clock reference signal and apply this technique to simulated noisy signals. We separately injected a random jitter (of known amount), periodic jitter (with known frequency and amount), and both together to various modulation frequencies of sinusoidal signals. The approach is validated by several experiments with numerous values in jitter parameters. When we separately inject random jitter (5 ps) and periodic jitter (5 ps at 4.37 MHz) to the signal, we obtained the results (4.52±0.25 ps) and (4.93±0.04 ps at 4.40±0.04 MHz), respectively.
Fibre Orientation Distribution Assessment of Dynamically Sheet Formed Hemp Fibre Mats by Image Analysis
Authors: Sunny Tom , Pickering Kim L. , Lim Shen Hin
Published: August 2018

Orientation of fibre preforms is an important factor that affects the properties of short natural plant fibre composites. In this paper, oriented short hemp fibre mats were produced using dynamic sheet forming and the fibre orientation distribution in the mats was analysed using ImageJ software as well as by a simple program developed on a MATLAB software package. The OrientationJ plug-in of ImageJ gave an orientation distribution curve with a peak at a predominant direction of 0° supporting alignment during dynamic sheet forming and from MATLAB software, a mean ratio of 0.64 was obtained for the oriented mats compared to 0.74 for an aligned bundles.
Model Building and Simulation of the Suspension System for a Robotic Asparagus Harvester
Authors: Min Ming Bin , Peebles Matthew , Lim Shen Hin , Duke Mike , Au Chi Kit
Published: August 2018

The demand for high accuracy on automated harvesters is getting higher. While system accuracy is lowered by vibration resulted when a robot with sensors and arms is running on the field. Applying suspension system onto these automated harvesters is a solution to reduce the vibration effects and assure required accuracy. This paper presents a model of the suspension system for a robotic asparagus harvester. The simulation results showed that the peak value of vibration was reduced to an acceptable level. Most importantly, the peak deflection of a vibrated platform was decreased to a required range as well. At the end of this paper, a conclusion is drawn. A suspension system is suggested to reduce vibration effects and improve the accuracy of both sensors and picking arms for mobile manipulators. In the future, this suspension system will be fabricated and installed onto a robotic asparagus harvester to validate this proposed model.
Investigation of Vial Position Controls for the Development of a Cave Auto-Sampler
Authors: Jangali Raul , Lim Shen Hin , Hartland Adam
Published: August 2018

Researchers at the University of Waikato visit caves on a periodic basis to collect samples of drip water, which over geological timeframes form stalagmites and other formations. However, most caves are remotely located, which makes it an arduous task to reach the study site and is economically unfeasible for frequent visits. This paper presents the position control aspect of the cave auto-sampler, which is a crucial operation to store water samples in an airtight container. The primary challenge was to position airtight sample vials under the needles for sample collection, within 3.5mm from the centre of the silicone septa. Various methods and makes of stepper motors were tested to find the balance between precision and power saving. A high gear ratio stepper motor was chosen as the primary drives due to its high precision and its ability to hold position when power is turned off between operations. Testing in lab conditions showed satisfactory consistency regarding position control and is integrated into the auto-sampler.
Destabilization of Natural and Commercial Bentonite Interlayers by Ultrasonication, pH Control and Salt Addition
Authors: Ahmad Fauzi A.A. , Osman Azlin Fazlina , Abdullah M.A.A , Mandal S.
Published: August 2018

Natural and commercial bentonites can act as efficient fillers to reinforce a polymer matrix if their strong interlayer binding forces are weakened to reduce tactoid formation. In this research, interlayers destabilization process was applied to gain a loosely packed, swelled and disorganized clay layered structure for better polymer intercalation and filler dispersion during the polymer/clay composite fabrication. Three different destabilization methods were applied to the natural and commercial bentonites and their effects on swelling and platelets ordering/stacking of the clays were observed. The pristine and destabilized natural and commercial bentonites were characterized and compared based on their chemical component (XRF), chemical structure (XRD) and morphology (FESEM). Chemical analysis revealed that alumina content in the natural bentonite is less than in the commercial bentonite while silica content in natural bentonite is more than in the commercial bentonite. XRD results suggest that basal spacing (d001) of both natural and commercial bentonites reduced when single destabilization process (by salt addition) was applied but increased when destabilization was done by the combination of pH control and salt addition processes. These show that the destabilization process through combination of pH control and salt addition is more efficient in swelling both natural and commercial bentonite clays. This is supported by FESEM analysis where smaller, more loosely packed and uniform platelets were observed due to swelling and weakening of the interlayer binding forces of both natural and commercial bentonite clays.
Structure and Electrical Characteristics of BaTiO3 and Ba0.99Er0.01TiO3 Ceramics
Authors: Ismail F. A. , Osman Rozana Aina Maulat , Idris Mohd Sobri , Ahmad Hambali N.A.M.
Published: August 2018

Conventional solid state reaction method was used to prepare BaTiO3 and Ba0.99Er0.01TiO3 ceramics. Influence of Er3+ ion incorporation on their structural, microstructural and electrical properties was studied. The phase pure samples were obtained when heated at 1400 °C for overnight. The tetragonal perovskite phase of BaTiO3 and Ba0.99Er0.01TiO3 was confirmed by using X-ray Diffraction (XRD) analysis which is in agreement with results obtained from Rietveld refinement analysis. The lattice parameters and unit cell volume of BaTiO3 increased when doped with Erbium. Microstructural analysis of BaTiO3 and Ba0.99Er0.01TiO3 ceramics showed that the grain sizes of BaTiO3 and Ba0.99Er0.01TiO3 significantly decreased. The dielectric properties of BaTiO3 and Ba0.99Er0.01TiO3 were investigated as a function of temperature and frequency. It revealed that the Curie temperature (TC) increased by doping Er content from 110 °C to 120 °C. Ba0.99Er0.01TiO3 exhibited the high value of dielectric constant (ε=5929) at TC of 120 °C. The capacitance-voltage characteristic revealed that the voltage breakdown for both BaTiO3 and Ba0.99Er0.01TiO3 exceeded 30 V.
Growth Kinetic of Sn-0.7Cu-0.05Ni Solder Paste Subjected to Isothermal Aging
Authors: Said Rita Mohd , Mohd Salleh Mohd Arif Anuar , Ramli Mohd Izrul Izwan , Saud Norainiza
Published: August 2018

This paper studied the thermal stability of Sn-0.7Cu (SC) and Sn-0.7Cu-0.05Ni (SCN) solder paste after soldering and during subsequent aging. Isothermal aging was conducted for 24, 240 and 480 hours at a temperature of 75, 125, and 150 °C respectively. Characterization focuses on the morphology of intermetallic compound (IMC) and the thickness of IMC after soldering and aging. In addition, growth kinetics of SC and SCN solder paste was determined by using the power law and Arrhenius relationship. Findings revealed that additions of Ni has formed a new (Cu,Ni)6Sn5 interfacial IMC. Additionally, it was found that scallop-type Cu6Sn5 and uniform scallop-type (Cu,Ni)6Sn5 of IMC for as-reflowed IMC phase has changed into layer-type IMC after aged. Besides that, IMC thickness for both solders has increased with prolong aging time and temperature. The interfacial IMC grew faster at high temperature aging. The activation energy of SCN solder was calculated as 39.8 kJmol-1 better than 27.29 kJmol-1 possess by SC solder. The high activation energy of SCN solder may attribute to the inherently slower reaction of Ni with SCN solder compared to the faster reaction between SC Solder and Cu for the IMC growth. Besides that, Ni addition act as obstacle for the diffusion of Cu atom from the substrate and Sn atom from the solder to react each another.
Sn Whiskers Nucleation and Growth - Short Review
Authors: Mokhtar N. Mohd , Mohd Salleh Mohd Arif Anuar
Published: August 2018

Sn whisker growth on Cu substrate Pb-free solder is a serious problem in electric and electronic devices and as well as in aerospace applications. Due to the concern on the toxicity of lead by Restriction of Hazardous Substances Directive (RoHS), new lead free materials have been developed, and this resulted in the resurfacing of Sn whisker. The compressive stress, corrosionand surface oxide have been identified as the driving force for Sn whisker formation induced by mechanical alloying and oxidation. In this paper, we report the study to understand the mechanism of Sn whisker growth that control whisker formation on Sn finished.Based on the review, a preliminary conclusion has been made, where the analysis of the topography and microstructural characterization can be determined by evaluating under various environmental influences.Furthermore, the whisker growth happening on lead-free soldered can be considerably reduced by controlling the compressive stress in the solder which initiates the growth of intermetallic compounds (IMCs).
The Effect of Temperature on Tin Whisker Growth under Mechanical Stress
Authors: Mahim Z. , Ismail N.A. , Mohd Salleh Mohd Arif Anuar , Khor Chu Yee
Published: August 2018

The whisker phenomenon has caused the reliability issues which induce short circuit in the electronic manufacturing industries. The research is conducted to study on the formation of pure tin whisker under the control of stress and temperature with the application of mechanical indentation and the formation of whisker can be classified into distinct shape accordingly. The specified ranges of stress and surrounding temperature are set up accordingly to promote the whisker mechanism of pure tin whisker. The pure tin whisker formed is examined in term of morphology characterization via Optical Microscope and Scanning Electron Microscope to analyze on the effect of stress and temperature on the growth morphology of pure tin whisker. This report outlines the research in progress on the development of the pure tin whisker formation.
Synthesis and Characterisation of Anodized Powder Metallurgy Mg-Ca Alloy
Authors: Zuraidawani C.D. , Norhadira F.W. , Derman Mohd Nazree B.
Published: August 2018

The Mg-1wt.%Ca alloy was fabricated using powder metallurgy method. The anodizing process were done by using different voltage (5V, 15V, 25V) and concentration of KOH (0.1M, 0.5M, 1.0M). The surface changes on PM Mg/1wt.%Ca resulted by anodizing was analyzed using SEM-EDX and XRD pattern. Meanwhile, surface hardness was measured by micro-Vickers hardness machine. The experiment found different XRD pattern between all non-anodized and anodized samples. The study found that increasing the voltage will increase the hardness while increasing KOH concentration reduced the hardness. The relation of the hardness and oxide film formation can be analyzed using SEM-EDX and XRD pattern. The optimum value for voltage, KOH concentration and hardness are 25V, 0.1M and 27.2 HV. The XRD detect the changes in PM Mg/1wt.% Ca indicates the oxide film formation.
Mechanical Properties and Morphology of Epoxy/Graphene Nanocomposite Using Bath Sonication and Tip Sonication
Authors: Wong Wee Chun , Teh Pei Leng , Osman Azlin Fazlina , Yeoh Cheow Keat
Published: August 2018

There are different graphene loadings (0, 0.2, 0.4, 0.6, 0.8, and 1.0 vol%) were used in order to study the effect graphene loading using different type of ultrasonication. Two types of ultrasonication: bath and tip sonication were applied in the preparation of epoxy/graphene nanocomposites. Effect of different ultrasonication applied on the mechanical properties and morphology of nanocomposites were investigated. By using tip sonication, epoxy/graphene shown better improvement in the mechanical properties due to direct ultrasonication that generates higher sound pressures and intensity compared to bath sonication which is indirect ultrasonication. Besides, epoxy/graphene nanocomposites prepared using tip sonication exhibits greater fracture toughness where lower intensity and non-uniform sonication effect failed to achieve optimum dispersion of graphene nanoplatelets and also its distribution using bath sonication. Rougher surface with increased deflected crack lines was observed on the samples that prepared using tip sonication further proven that more fracture energy was dissipated which inhibits the propagation of cracks and hence delayed the failure of nanocomposites.
Effect of Blend Ratio on the Mechanical and Thermal Properties of Polyurethane/Silicone Rubber Conductive Material
Authors: Wei Heng Chun , Teh Pei Leng , Yeoh Cheow Keat
Published: August 2018

This work reports on mechanical and thermal properties of a novel polymer blend. Blends were prepared by mixing silicone rubber with diphenyl – 4,4 – dissocyanate in different ratios. Graphene nanoplatelets was added as conductive filler to improve the electrical conductivity of the blends. The mechanical properties, including tensile and tear performances were measured by a material testing system. The thermal stability of the blends was measured by thermogravimetric analysis. Incorporation 20 vol.% of silicone rubber can help to improve the thermal stability of the blend, meanwhile optimum mechanical properties of the blends is achieved.
P84 Co-Polyimide Based-Tubular Carbon Membrane: Effect of Heating Rates on Helium Separations
Authors: Sazali N. , Salleh W.N.W. , Ismail A.F. , Kadirgama K. , Othman F.E.C.
Published: August 2018

Helium is one of the most valuable gases with unique features and properties as well as widely used in various applications. Generally, most of the helium sources was extracted from natural gas and it is very crucial to develop efficient technology for helium recovery from natural gas sources, in order to overcome the deficit of the helium supply. Up to now, there are various available traditional separation methods for helium recovery, however these methods possessed several disadvantages such as expensive in cost and energy intensive. Recently, gas separation by using membranes have been utilized and showed potential in recovering and purifying helium from natural gas. This method directly separating the helium from the methane through natural gas liquefaction process where in this process the helium is recovered from the nitrogen rejection unit (NRU) exit gas. Due to the potential benefits that can be obtained from this membrane-based separation method, this current study is aiming to provide more comprehensive scientific reports on the effects of preparation parameters on the performance of tubular carbon membranes (TCMs) for helium separation. In this study, the carbonization heating rate was varied from 1 to 7°C/min by controlling the final temperature at 800°C under Argon environment for all polymeric tubular membranes. The permeation performance of the resultant TCMs have been determined by using a single permeation apparatus. It is necessary to fine-tuning the carbonization conditions in order to obtain the desired permeation properties. From the results, it can be concluded that the most optimum heating rate was found to be at 3°C/min with 463.86±3.12 selectivity of He/N2 separation.
Effect of Microwave Heating Variables on Nitrogen-Enriched Palm Shell Activated Carbon toward Efficient Hydrogen Sulfide Removal
Authors: Nor N. Mohammad , Chung L. L. , Hameed Bassim H. , Sethupathi Sumathi , Mohamed Abdul Rahman
Published: August 2018

This research work is focuses on understanding the characteristics of modified nitrogen-enriched palm shell activated carbon (N-PSAC) that undergo different microwave (MW) operating parameters towards efficient H2S removal. The nitrogen functional groups were tailored onto PSAC micropore structures through impregnation of urea onto palm shell activated carbon (PSAC). The effect of MW heating variables (heating temperature, N2 flow rate, heating time and amount of adsorbent) on N-PSAC adsorbent was investigated and analyzed with respect to H2S adsorption capacity.One factor at a time (OFAT) approach was used to produce an efficient N-PSAC adsorbent, where theH2S breakthrough capacity (measured at 5% of H2S outlet concentration) attained was in the range of 98.71 – 211.35 mg/g.It was found that MW heating variables contribute a significant impactto the modification of N-PSAC adsorbent in catering the H2S emission.
The Novel Usage of Nitrocellulose as a Propellant of 5.56 mm Bullet
Authors: Yolhamid Mohd Najib Abdul Ghani , Ibrahim Farizha , Zarim Mohamad Abu Ubaidah Amir Abu , Ibrahim Rushdan , Adnan Sharmiza , Yahya Muhd Zu Azhan
Published: August 2018

Gun powder is predicted to be more expensive in relation to the world oil shortage crisis in the future. However, cellulose (generic chemical formula (C6H10O5) is the carbohydrate that makes up the main structure of plants. It is more economical especially for countries with a lot of natural resources and rain forests like Malaysia. The finding of the study reveals the capability of nitrocellulose as gunpowder. In this research, a comparison of the same mass of nitrocellulose and gunpowder is made to find out which propellant produce longer distance and greater impact. The main objectives of this study are to find out the performance and capability of nitrocellulose extracted from Rhizophora apiculata compared to gunpowder in terms of velocity, calorific value of bullets and kinetic energy produced. The result shows that the nitrocellulose has better performance than gun powder. The new application of smokeless gun powder ensures troops especially snipers hardly being detected by enemy and at the same time improves safety and security level.
Synthesis and Characterisation of Carbon Nanomaterials (CNMs) Using Polypropylene(PP) Waste as Carbon Precursor: Effect of Reactor Temperature
Authors: Sim X.H. , Norzilah A.H. , Edzatty A.N.
Published: August 2018

Fully utilisation of urban wastes such as polymer waste is considered as promising step to save the environment besides contributing to the production of Carbon Nanomaterials (CNMs) and their insight in mechanism involved. In this work, CNMs were successfully synthesised using polypropylene (PP) waste as carbon precursor via Chemical Vapour Deposition (CVD). Ferrocene was used as metal catalyst whereas argon was used as purging gas. The CVD were operated at various reactor temperatures to assess the possibility of CNMs growth at 600°C, 700°C, 800°C, 900°C, and 1000°C. The reaction time and argon flow rate were fixed at 90 minutes and 85 ml/min, respectively. The production of CNMs started at reactor temperature of 700°C and increased steadily from 0.0178 g to 0.2950 g with elevated temperature up to 1000°C. The diameter distribution of synthesised-CNMs reduced with the increased of reactor temperature. The XRD patterns revealed a sharp diffraction peak at around 26o (002) and broad diffraction peak at around 44o (111) which was proven to be Carbon Nanotubes (CNTs). Reactor temperature of 800°C considered as the best temperature to synthesis small diameter of CNMs in high quantity.
The Use of Coagulation-UV Irradiation/H2O2 and Electrocoagulation Methods on Pulp and Paper Mill Wastewater Treatment
Authors: Yuliani Galuh , Agustiningsih R. , Munawaroh H. S. Halimatul , Rahmi N. F.
Published: August 2018

Effluents from pulp and paper mill typically consist of high loading of inorganics compounds (e.g., Na2CO3, Na2S, NaOH and NaCl) and organics compounds (e.g., lignin and polysaccharides fragments, alcohols, carboxylic acids) Several methods, such as biological, physical and chemical treatment, have been reported to degrade these molecules. However, coagulation is by far the cheapest, simplest and most common method employed for secondary wastewater treatment to reduce colour and organics. In this research, two most widely used methods were employed to treat a model wastewater of pulp and paper industry, namely a combination of coagulation-flocculation-UV irradiation/H2O2 and electrocoagulation (EC). In the application of coagulation-flocculation-UV irradiation/H2O2 method, the decrease in colour (measured as absorbance at 500 nm) was 71%, and the COD removal was measured to be 38% under the optimum conditions of pH 8, coagulant dose of 700 ppm, flocculant dose of 60 ppm, 130 rpm of coagulant stirring rate, 1 day irradiation time, and 25 mM of H2O2. For the EC method, 91% reduction of color and 84% reduction of COD were achieved at 40 min of electrolysis time, pH of 8, 600 ppm of NaCl concentration, electrode distance of 1.5 cm and 2 V of voltage. The EC method may serve as an efficient method for color and organics removals from pulp and paper mill wastewater.
Effects of Palm Waste Filled Thermoplastic Composites on Dynamic Mechanical Analysis
Authors: Zakaria Muhammad Salihin , Ghazali Che Mohd Ruzaidi , Kamarudin Hussin , Wahab Mohd Kahar A. , Halim Khairul Anwar Abdul , Yevon L.
Published: August 2018

The effects of palm waste (palm slag and palm ash) filled thermoplastic (high density polyethylene (HDPE) and recycled HDPE (rHDPE)) composites on dynamic mechanical analysis were examined. Two different particle size (150 μm – 300 μm) as coarse size and (≤ 75 μm) as fine size were used in this study. The palm waste of HDPE and rHDPE with 8 different types of sample were prepared using a twin screw extruder. 10 % of filler loading was chosen to produce the composite. The DMA result indicated that the fine size palm ash and coarse size palm slag have highest storage modulus incorporated with rHDPE composite meanwhile the effect of palm slag incorporated with HDPE also shown the similar findings as palm ash incorporated with HDPE. The loss modulus indicated that the coarse size of palm slag shows the lowest value and virgin HDPE gained the highest value after 90 °C in HDPE composite meanwhile fine size of palm ash and coarse size of palm slag both indicates the highest value when incorporated with rHDPE composite. For tan δ there are no significant differences recorded between the palm waste filled HDPE composite where virgin HDPE show the highest value. Meanwhile coarse size palm slag composite recorded the nearly identical tan δ value of rHDPE as the highest filled rHDPE composite. Conclusively, fine size palm ash and coarse size palm slag show the better viscoelastic properties in rHDPE composite.
Ga-Sn Co-Doped ZnO Films via Sol-Gel Route
Authors: Ng Zi Neng , Chan Kah Yoong
Published: August 2018

Zinc oxide (ZnO) has gained worldwide attention due to its direct wide band gap and large exciton binding energy, which are important properties in the application of emerging optoelectronic devices. By doping ZnO with donor elements, a combination of good n-type conductivity and good transparency in the visible and near UV range can be achieved. Co-doping ZnO with several types of dopants is also beneficial in improving the electronic properties of ZnO films. To the best of our knowledge, the fundamental properties of gallium-tin (Ga-Sn) co-doped ZnO (GSZO) films were rarely explored. In this work, we attempt to coat GSZO films on glass substrates via sol-gel spin-coating method. The Ga-Sn co-doping ratio was fixed at 1:1 and the concentration of the dopants was varied at 0.5, 1.0, 1.5, and 2 at.% with respect to the precursor. The AFM image show granular features on the morphology of all GSZO films. All samples also exhibit a preferential c-axis orientation as detected by XRD. The XRD indicates higher crystal quality and larger crystallite size on GSZO thin films at 2.0 at.% and agrees well with the AFM results. However, the transparency and optical band-gap of the GSZO thin films degrade with higher co-doping concentration. The best electrical properties were achieved at co-doping concentration of 1 at.% with conductivity and carrier density of 7.50 × 10-2 S/cm and 1.37 × 1016 cm-3, respectively. At 1.0 at.% co-doping concentration, optimal optical transmittance and electrical properties were achieved, making it promising in the application of optoelectronics.
Investigate the Properties of Solid Waste Bottom Ash (SBA) and Lime Reinforced in Composite Bricks
Authors: Namboonruang Weerapol , Suphadon Nutthanun , Yong-Amnuai P.
Published: August 2018

This research studies on the possibility of producing a more sustainable lightweight brick. Solid waste bottom ash (SBA) and lime found in area of Ratchaburi province of Thailand were mixed into the composite brick for the replacement of fine aggregates and Portland cement contents, respectively. Effects of varied amount of SBA and local lime contents typically (10, 20, 30, 40 and 50% by weight) on mechanical and physical properties of bricks were studied. Results showed that with the replacement cement and fine aggregate of 20% by weight with SBA and local lime, respectively showed the maximum values. Similarly, the thermal conductivity and density and product weight showed the maximum values at the same replacement contents. By conclusion, this application may be an interesting solution in order to improve sustainability and energy efficiency of the low cost house in local area of Thailand.
Categories and Types of Raw Materials Using in Geopolymer Cement Production: An Overview
Authors: Suwan Teewara
Published: August 2018

Geopolymer cement is an aluminosilicate material which activated by the alkaline solution. With appropriate heat curing regimes, geopolymer cement could achieve an excellent performance as construction material. Apart from that, geopolymer cement is one of the alternative cementitious materials for green construction as its raw starting materials could be any pozzolanic industrial by-products. Global carbon-dioxide emission from Portland cement consumption could be reduced with the replacement of that geopolymer cement. Therefore, the development of geopolymer cement is receiving much more attention. However, various kinds of materials have been used as geopolymer precursors. The main aim of this paper is, thus, to summarize current information on the usage of raw materials in geopolymer production by categorize its types and sources. The summarised details of chemical composition and compressive strength could provide a guide line for readers to evaluate possible reactions or outputs of their selected local raw materials as well as the prediction of material’s combination for the improvement of targeted strength of each possible prime material.
Thermophysical Properties of Metakaolin Geopolymers Based on Na2SiO3/NaOH Ratio
Authors: Nur Ain Jaya , Liew Y.M. , Al Bakri A.M. Mustafa , Heah C.Y.
Published: August 2018

In the present work, the effect of different sodium silicate-to-sodium hydroxide ratio on the physical, mechanical and thermophysical properties of metakaolin geopolymers (MkGPs) was investigated. Geopolymers were prepared by activating the metakaolin with a mixture of NaOH and sodium silicate (Na2SiO3). The products obtained were characterized after 28 days of ageing. The density, porosity, compressive strength, thermal conductivity (TC), thermal diffusivity and specific heat capacity were determined. In general, the Na2SiO3/NaOH ratio has a significant effect on the compressive strength of the MkGPs. The thermal conductivity, thermal diffusivity and specific heat of MkGps measured in this work were in the range between 0.44 to 0.92 W/mK, 0.22 to 0.44 mm2/s and 1 to 3.7 MJ/m3K respectively. The highest compressive strength was 32 MPa achieved with Na2SiO3/NaOH ratio of 1.0. This mix has the best thermophysical performance due to low thermal conductivity, low thermal diffusivity and high specific heat compared to the other alkaline activator ratios. The results showed that the geopolymer is able to be used as the thermal insulating material.
Conductivity Characterizationof Iron Oxide Doped 8 mol% Yttria Stabilized Zirconia
Authors: Selvaraj Tinesha , Johar Banjuraizah , Khor S.F. , Mohd Zainol M.N.
Published: August 2018

A facile strategy was proposed to incorporate the dopant Fe into 8YSZ-based material, which can be potentially applied as solid electrode materials for Solid Oxide Fuel Cells (SOFC). In this study, 8YSZ powder was investigated in terms of densification, conductivity and thecrystal structure as a solid electrolytes. Therefore, varying mol% of Fe included 1, 2, and 3 were prepared for investigation. The crystalline structure of the pristine and Fe doped samples were characterized by X-ray diffraction (XRD) and the phase contents were evaluated by using the Rietveld method. Rietveld quantitative phase analysis demonstrates that the monoclinic-ZrO2phase increases (12.8 wt% to 39.7 wt%) as the concentration of Fe increases, while the amount of tetragonal-ZrO2 phase drop (40.4 wt% to 11.9 wt%) dramatically. Sintering activity was applied to improve incorporation of the 8YSZ powder and the dopant Fe where the relative density increases from 77% to 92%. Sample YSZ-2Fe has been fitted with CPE equivalent circuit and achieved 6.251 x 10-6S/cm at 300 °C in air. However, it was found that conductivity levels decreased as the mol% of Fe increased. In short, sample YSZ-2Fe ceramic demonstrated good results in terms of densification (92.09%), cubic ZrO2 phase (22 wt%) and conductivity 6.251 x 10-6 S/cm.
Photocatalytic Properties and Graphene Oxide Additional Effects in TiO2
Authors: Noor N.A. Mohd , Kamarudin S.K. , Darus M. , Yunos Nur Farhana Mohd , Idris Muhammad Asri
Published: August 2018

Photocatalytic activity in TiO2 attract great attention because it promising application in contaminations on degradation and energy conversation. However there is a need on TiO2 band gap modification to be equivalent with the visible light. Thus, inviting several method of addition certain elements including in this study, the additional of graphene oxide (GO) was investigated. GO were prepared by Hummer method before it was added into TiO2. The formation of GO from it graphite precursor had been confirmed by Raman spectroscopy. The existence of D-band at wavelength of 1328 cm-1 and G-band at 1573 cm-1 shows the formation of GO. The GO was then added in different concentration; 0.0 - 1.0 wt% into TiO2. The photocatalytic activity was determined using calculating the photodegradation efficiencies of methylene blue under UV light irradiation. The experimental results showed that the photodegradation of MB were increased with higher dopants concentration due to reduction of band gap energy of TiO2 from 3.2 eV to 3.0 eV for 1.0 wt% GO-with the photodegradation efficiency of GO doped TiO2 was 61.38%.
Investigation on the Thickness Effect of TiO2 Photo- Anode on Dye-Sensitized Solar Cell Performance
Authors: Yeoh Mian En , Chan Kah Yoong , Wong Hin Yong
Published: August 2018

Dye-sensitized solar cell (DSSC) has attracted immense interest over the past decade due to its low cost and simplicity as a renewable energy source. In DSSC, the photo-anode that governs the collection and transportation of photo-excited electrons plays a critical role in determining the cell performance. In particular, the thickness of the photo-anode is known to be one of the decisive factors in dictating cell efficiency. In this paper, the thickness effect of TiO2 film as photo-anode on the photovoltaic performance of DSSC is studied. The TiO2 films were characterized by UV-visible absorbance spectroscopy to correlate the film thickness with the light harvesting efficiency of DSSC. The effects of film thickness on the photocurrent density-voltage characteristics of DSSCs were also investigated. The optimized thickness (4m) of the TiO2 film was discovered to be the best compromise between the amount of dye loading and the electron transport resistance.
Preparation and Characterization of Macro Porous Glass-Ceramics as Bioactive Scaffold Material
Authors: Zainudin Siti Rohani , Syed Adam Syed Nuzul Fadzli , Che Halin Dewi Suriyani , Yusof Mohd Reusmaazran , Johar Banjuraizah , Zainuddin Firuz
Published: August 2018

Bioactive glass and glass-ceramics have a huge interest in biomedical application due to their high biocompatibility and bioactive property. In this study, macro porous glass-ceramic based on 51.26% SiO2 - 36.56% CaO - 11.83% P2O5 and 42.11% SiO2 - 18.42% CaO - 29.82% Na2O - 9.65% P2O5 (in mol%) were prepared via sol-gel synthesis and powder sintering method. Sodium nitrate was used as the precursor for sodium oxide (Na2O) composition in the sol-gel glass. Effect of sodium nitrate addition on the sintered glass (glass-ceramic) properties were studied. The stabilized gel-glasses obtained were compacted into pellets and sintered at 1000 °C for 3 hours. It was found that, Na-contained glass-ceramic (Na-GC) crystallized at 71.5% due to increase in sodium-related crystalline phases. Na-GC showed 72.98% of apparent porosity and densified at 27.02% with macro porous structure with pore sizes in the range of 22.4 μm to 302 μm. The macro porous structure of Na-GC was obtained due to the foaming effect occurred during sintering. Flux effect occurred during sintering also resulted in relatively high compressive strength of Na-GC at 21.53 MPa. The macro porous Na-GC also proved to be bioactive as apatite-like structures were deposited on its surface after immersed into SBF solution for 14 days. The prepared macro porous Na-GC has high potential to be used as a scaffold material in biomedical application due to combination of suitable macro-pore size range, bioactive and has sufficient mechanical strength.