bluuebunny/crossref_metadata_2025 huggingface dataset:
Le juge administratif et l’expertise dans la conduite des politiques publiques
Authors: Touboul Charles
Published: September 2020

L’expertise des politiques publiques n’a pas encore véritablement fait son entrée dans les prétoires de la juridiction administrative. Il n’y a généralement pas de voie de droit pour contester l’insuffisance d’une évaluation préalable. Les rares voies ouvertes, et plus rarement encore empruntées, se sont jusqu’à aujourd’hui révélées sans issue pour ceux qui s’y sont aventurés. Et lorsque l’évaluation n’est pas elle-même l’objet du litige, son contenu influence peu son issue.
Le recours aux données empiriques, condition de la proportionnalité de l’action publique pour la Cour de justice de l’Union européenne ?
Authors: Rondu Julie
Published: September 2020

Le contrôle de proportionnalité exercé par la Cour de justice de l’Union européenne semble naturellement pouvoir constituer un terreau fertile pour la prise en considération des données empiriques. La Cour tend à s’assurer que le législateur de l’Union produise une analyse d’impact au soutien des actes qu’il adopte, et démontre qu’il a pris en considération l’ensemble des éléments pertinents. Néanmoins, ce contrôle demeure limité. Par ailleurs, lorsqu’elle examine les actes nationaux, la Cour se montre réticente envers les données empiriques invoquées par les États membres, ce qui s’explique par l’approche in concreto inhérente au raisonnement en termes de proportionnalité. La Cour peut toutefois mobiliser de telles données au service de l’effectivité du droit de l’Union.
La coproduction de la publicité foncière en ligne par l’État et le notariat
Authors: Dauchez Corine Delphine
Published: September 2020

La publicité foncière en ligne est le fruit d’un partenariat noué par l’État avec le notariat. Les notaires, représentés par le Conseil supérieur du notariat, se sont investis dès l’origine dans la construction technique de la publicité foncière en ligne aux côtés de l’État dont ils servent, aujourd’hui comme hier, les objectifs stratégiques. Ils participent au mouvement de transformation de l’État, dont le numérique est un moteur, que l’on considère la période où l’État s’est mué en stratège ou sa phase actuelle d’évolution en plateforme. Ce constat conduit à appeler à davantage de cohérence des politiques publiques à l’égard de la profession notariale, « malmenée » depuis la loi du 6 août 2015 pour la croissance, l’activité et l’égalité des chances économiques, dite « loi croissance ».
Mobilisées contre les discriminations salariales de genre. Les documentalistes de l’INA en grève (novembre 1981)
Authors: Tible Anna
Published: September 2020

En novembre 1981, les documentalistes de l’Institut national de l’audiovisuel (INA) mènent une grève de trois semaines, qui marque profondément l’histoire de leur profession. En s’arrêtant de travailler, elles, car ce sont quasiment uniquement des femmes, bloquent l’accès aux images et sons d’archives, qui illustrent en grande partie les programmes audiovisuels. La grève des documentalistes de l’INA repose sur des revendications explicitement féministes. À la lumière d’entretiens et d’archives inédites, cet article a pour ambition de retracer les enjeux de cette mobilisation, qui s’inscrit dans le contexte particulier de l’après-élection de François Mitterrand, et d’une plus grande visibilité des luttes de femmes dans les médias.
La médiatisation contrastée des luttes contre les délocalisations intra-européennes dans l’industrie française (1990-2000)
Authors: Lefébure Pierre , Noûs Camille
Published: September 2020

Comme toute mobilisation contestataire, la lutte des salariés contre la fermeture de leur usine peut être étudiée en termes de cadrage journalistique, c’est-à-dire la façon dont une interprétation des faits plutôt qu’une autre est suggérée par la mise en récit et par le vocabulaire. Nous étudions deux cas aux caractéristiques de départ assez proches (Renault-Vilvorde en 1997 et Continental-Clairoix en 2009) mais donnant lieu à la production de cadrages journalistiques substantiellement différents dont nous cherchons à expliquer la genèse. L’identité sociale des contestataires apparaît comme un facteur crucial pour expliquer la différence de traitement médiatique entre les deux cas en complément des processus de politisation qui soutiennent un niveau élevé de médiatisation.
Le street artivisme égyptien, de la mythologie au sanctuaire d’écritures
Authors: Abdel Hamid Mohammad
Published: September 2020

L’article traite de l’écriture street artiviste en Égypte et de ses implications théoriques sur l’espace public. Il s’agira d’effectuer une lecture originale des événements politiques en Égypte à l’aune de leur inscription dans la mémoire collective et des procédés de mémorialisation. Articulant les notions de lieux de mémoire et de sanctuaires d’écritures, l’étude propose d’apporter un nouvel éclairage au sujet des notions de mythologies et de mythographies qui permettent à des artivistes d’ériger des lieux sanctifiés, aussi bien urbain et socionumérique, dédiés à leur pratique.
Un concept sur la toile : le « je » et le « nous » des mobilisations afroféministes sur YouTube
Authors: Da Silva Jaércio
Published: September 2020

Cet article porte sur la manière dont l’intersectionnalité quitte la sphère académique et prend forme dans les espaces numériques. Il s’agit plus particulièrement de comprendre comment les différents formats d’expression personnelle peuvent créer d’autres formes de mobilisation autour de ce concept. Pour aborder le sujet, nous présentons une analyse à partir de six afroféministes qui sont sur YouTube. Nous commençons par situer historiquement la prise de parole des femmes noires et leurs revendications en France, pour ensuite mettre en évidence trois caractéristiques du corpus étudié : une mobilisation militante qui part d’une motivation personnelle, un « nous » formé par le partage d’expériences communes et la communauté d’action qui se mobilise en opposition à un « ils » supposé réel.
Enhancement of Electrical Conductivity of Electrospun Polyacrylonitrile Fibres Using Carbon Nanomaterials Synthesised from Polypropylene Waste
Authors: Koo Yong Siong , Soh Zhun Yuan , Norzilah A.H. , Bakar Sharifah Shahnaz Syed , Mohd Salleh Mohd Arif Anuar , Edzatty A.N. , Izzati Roslan Nur
Published: September 2020

Incorporation of carbon nanomaterials (CNMs) into polymer such as Polyacrylonitrile (PAN) fibres allow electric current to pass through easily. Therefore in this study, bulk quantities of CNMs are synthesised using Chemical Vapor Deposition (CVD) method by manipulating the reaction time and catalyst ratio. Polypropylene wastes are used as the carbon precursor and ferrocene as metal catalyst in the CVD experiment. Addition of 1 wt% synthesised-CNMs into electrospun PAN fibres successfully increased the electrical conductivity by 50%. Addition of CNMs improved the crystallinity of electrospun-PAN/CNMs fibres as proven by XRD analysis. Electrospun PAN/CNMs-A fibres show larger diameter than the diameter of electrospun PAN/CNMs-B. Large bead formations contained densely-packed CNMs-A within the structure of electrospun PAN/CNMs-A fibres hindered their effectiveness to conduct the electricity. On the contrary, PAN/CNMs-B shows remarkable improvement in electrical conductivity when loosely-packed CNMs-B are added to the PAN fibres.
Effect of Plasma Flow in Plasma MIG Welding Process to the Microstructure Refinement at Heat Affected Zone of As-Welded Carbon Steel
Authors: Mamat Sarizam , Afandi Aina Aqilah Mohd. , Abu Bakar Mohamad Bashree , Masri Mohamad Najmi , Mohamed Mazlan , Razab Mohammad Khairul Azhar Abdul , Yuji Toshifumi , Tashiro Shinichi , Tanaka Manabu
Published: September 2020

The use of plasma MIG welding which consists of plasma flow in surrounding of the MIG wire causes the divergence of MIG current from MIG wire to outside. The divergence then disperses the heat and force to the upper side of MIG wire, thus reduces the droplet temperature and affects the droplet size as well as metal transfer frequency. In this study, the effects of plasma flow in plasma MIG welding to the refinement of microstructure at heat affected zone is investigated. The microstructure evaluation is carried out by means of electron backscattered diffraction (EBSD). As a result, we found that the microstructure refined at HAZ area especially at coarse grain HAZ. The difference in grain size at coarse grain HAZ area and fine grain HAZ area was almost eliminated. This result was compared with the one with conventional MIG welding, which shows the clear difference in grain size at coarse grain HAZ and fine grain HAZ area. It is suggested that, the presence of plasma flow in plasma MIG welding process refines the microstructure at HAZ area.
Effect of Sintering Temperature on Properties of Setiu Clay Sediments
Authors: Muhamad Nor Mohd Al Amin , Ismail Adnen Noor Asliza , Noh Mohamad Zaky , Rashid Mohd Warikh Abdul , Mohamed Julie Juliewatty
Published: September 2020

The effect of sintering temperature on physical properties of Setiu clay sediment was studied. The ceramic samples were prepared via slip casting method, and sintered at different temperatures ranging from 900 to 1100°C, with 2 hours soaking time. Morphologies of ceramic samples were characterized using Tabletop Microscope. Shrinkage was determined from measurement of samples before and after sintering process. A good ceramic sample without warping or cracks obtained after casting process and after sintered at different temperatures. The results show that sintering temperatures greatly influence morphology of samples. As sintering temperature increased the grain boundaries between particles become smoother and compacted while pores shrunk due to the densification behavior. A considerable increased in shrinkage from 5 to 20% were observed with increasing temperature from 900 to 1100°C. As conclusion, Setiu clay sediment are suitable for production ceramic products and 1000°C can be consider the best sintering temperature in terms of quality of products and production costs.
Effect of Sintering Temperature on the Preparation and Characterization of Green Glass Ceramic from Rice Husk Ash as a Matrix
Authors: Saad Shahrizam , Chik Abdullah , Ahmad Khairel Rafezi , Bakar Sharifah Shahnaz Syed
Published: September 2020

Powder metallurgy technique were proved successful net-shape technology which suitable for the production of green glass ceramic (GGC) from rice husk ash (RHA) and characterized by good physical and mechanical properties of glass ceramic. In this research, the glass sample was formed by mixing varying percentage of weight of silica, flux and additives. The aim of this work is to study the effect of the sintering temperature to the physical and mechanical properties of GGC. The samples were mixed in different volume fraction of additives which is 5%, 10% and 15% in constant composition of RHA and flux. The mixture was consolidated into rigid die compaction at 300MPa, then sintered at 450, 550 and 750°C. Vickers hardness test were investigated. The glass composite were then characterize by scanning electron microscopy (SEM). The GGC with 10% additives at sintering temperature 550°C shows highest hardness strength which is about 213.0 HV.
Structural Characteristic and Dielectric Properties of Zirconia Toughened Alumina
Authors: Rejab Nik Akmar , Su Nurul Khairunnisa , Wan Ali Wan Fahmin Faiz , Ain Mohd Fadzil , Ahmad Zainal Arifin , Abdullah Norazharuddin Shah
Published: September 2020

Zirconia toughened alumina (ZTA) has shown a great effect in the cutting tool application due to its high hardness and comparable fracture toughness. However, the capability of the materials to be applied in as the dielectric resonator antenna (DRA) is not being discussed in detail. In this study, an attempt is made to further explore the potential of ZTA to be applied in DRA. Various related characterization techniques were applied that is subjected to DRA properties. The addition of CeO2 (0 wt.% to 15 wt.%) on ZTA has been pressed into pellets shape and sintered at 1600 °C for 2 hours under pressureless conditions. Based on the XRD analysis, only corundum and yttria doped zirconia phases were present. Shift in position of the zirconia peaks was observed due to an existence of Ce2Zr3O10 phase. For the DRA measurement, ZTA with 10 wt.% CeO2 addition have resonated at 6.76 GHz which is suitable for X-band applications. Meanwhile the radiation pattern indicated the omnidirectional characteristic, which suggested that the signal could be received by this dielectric antenna in various positions. Therefore, ZTA- 10 wt.% CeO2 have high potential to be used as DRA that operates X-band frequency range applications.
Thermal Analysis of Ca1+xCu3Ti4O12+x Precursor in Nitrogen and Oxygen Environment at 1000 °C
Authors: Mohamed Julie Juliewatty , Daud Noruzaman , bin Abu Mohamad Johari , Ab Rahman Mohd Fariz , binti Hassan Siti Roshayu , Mohamad Hasmaliza , Ahmad Zainal Arifin
Published: September 2020

The thermal kinetic analyses are prepared on Ca1+xCu3Ti4O12+x powders using simultaneous thermogravimetry analysis (TGA) and differential scanning calorimetry (DSC) measurement in a dual atmospheric gases environment. Initially, the nitrogen gas flowed from room temperature to 1000 °C, and then the environment was shifted and hold for 1 hour with oxygen. The result shows that the TGA patterns of the temperature and mass loss are disorderly with x values. The mass loss % patterns slightly decreased with increased additional Ca-based element. The decreased of oxygen absorption as the values of x increased also can be explained by the reduction of single-phase CCTO structure when excess Ca ions. The DSC pattern shows two prominent endothermic peaks and two exothermic peaks that relate to the melting point of the reactant and crystalline phase changes of samples, while the significant endothermic peak at 1000 °C is corresponding to the formation of CCTO compounds as identified by XRD analysis.
The Effect of Sn Doping on the Thermoelectric Properties of SiGe Using First Principle Technique
Authors: Chik Abdullah , Kheng Haw Wei , Zaki Ruhiyuddin Mohd , Pa Faizul Che , Adewale Akeem Adekunle , Yeoh Cheow Keat
Published: September 2020

The thermoelectric properties of hexagonal SiGe doped with Sn with doping percentage of 12.5% and 25% were investigated using linearised augmented plane wave method using the WIEN2k package and semiclassical Boltztmann Transport equation using the BoltzTraP software for the purpose of understanding the role of Sn as a dopant in the SiGe. For temperature range of 300 to 1000 K, it can be seen that by doping with Sn, there is an improvement in overall thermal conductivity of the samples with the highest improvement is in the 25% doped sample. The conductivity vs temperature for 25% Sn doped SiGe also shows higher value through temperature range from 300 K to 1000 K, however the Seebeck coefficient decreases with Sn doping percentage for the same temperature range. Due to lower Seebeck coefficient and higher thermal conductivity values, the overall thermoelectric coefficient, ZT, of the doped compound is lower than the SiGe values with highest ZT equal to 0.29 and 0.17 at 650 K for 12.5% and 25% respectively while the ZT of simulated SiGe at 650 K is 0.35. Thus 25% Sn doping actually reduce the ZT but enhanced the thermal and electrical conductivity of SiGe for temperature range of 300 to 1000 K.
XRD Studies on Transformation of Dolomite under CO2 and N2 Atmosphere
Authors: Sulhadi Siti Sarahah , Abu Tahari Maratun Najiha , Samidin Salma , Wan Isahak Wan Nor Roslam , Yusop Muhammad Rahimi , Yarmo Mohd Ambar
Published: September 2020

In this study, dolomite was heated under CO2 and N2 gases using fluidized bed reactor from 85 °C to 835 °C. Dolomite under N2 atmosphere did not show any significant changes on its crystallite size, suggesting there is no significant chemical reaction. On the other hand, dolomite under CO2 atmosphere shows no significant changes on its crystallite size until it reaches high temperature (> 800 °C) where MgO started to be observed in X- ray diffraction. This shows that few chemical reactions started to happen in this reaction condition.
Particleboard Based on Glutardialdehyde Treated Oil Palm Trunk Particles Made at Different Pressing Temperatures
Authors: Amini Mohd Hazim Mohamad , Sulaiman Nurul Syuhada , Bakri Muhammad Afiq , Abu Bakar Mohamad Bashree , Mohamed Mazlan , Masri Mohamad Najmi , Nik Yusuf Nik Alnur Auli
Published: September 2020

This study was conducted to evaluate the effect of pressing temperature on chemical modification of oil palm particles as raw material for particleboard manufacturing. This study aims to evaluate the properties of particleboard made from chemically modified oil palm biomass and to determine the effect of pressing temperature on the properties of the particleboard. Oil palm was used in this study due to the problem arose where an abundance of oil palm was left at the site to be rotten when undergoing the replanting process. Therefore, this research was conducted to utilise the abundant oil palm trunk to fulfill the need of wood-based panel in Malaysia. Samples of oil palm trunk were collected and ground into smaller particle before treated with glutardialdehyde solution. The treated oil palm particle then inserted into the mould with a dimension of 21 cm x 21 cm x 0.5 cm to get the uniform size of particleboard before undergoing the process of hot pressing. The temperature was set at 130 °C, 140 °C and 150 °C for 10 minutes under pressure of 500kgcm-2 by using the hot pressing machine. Physical (density, moisture content, water absorption, and thickness swelling test) and mechanical (bending test) strength of the manufactured particleboard were tested afterward. The result showed that best particleboard was manufactured using 140 °C which yield the highest MOR of 3.09 N/mm2 and 340.51 N/mm2 for MOE.
Potential of Agricultural Waste Material (Ananas cosmos) as Biosorbent for Heavy Metal Removal in Polluted Water
Authors: Yusoff Abdul Hafidz , Mohammad Rosmawani , Mohamad Mardawani , Sulaiman Ahmad Ziad , Che Zaudin Nurul Akmar , Rosmadi Nursyahida , Aqsa Fakihin , Yusoff Mahani , Teo Pao Ter
Published: September 2020

Conventional methods to remove heavy metals from polluted water are expensive and not environmentally friendly. Therefore, this study was carried out to investigate the potential of agricultural waste such as pineapple peel (Ananas Cosmos) as low-cost absorbent to remove heavy metals from synthetic polluted water. The results showed that Cd, Cr and Pb were effectively removed by the biosorbent at 12g of pineapple peels in 100 mL solution. The optimum contact time for maximum adsorption was found to be 90 minutes, while the optimum pH for the heavy metal’s adsorption was 9. It was demonstrated that with the increase of adsorbent dosage, the percent of heavy metals removal was also increased due to the increasing adsorption capacity of the adsorbent. In addition, Langmuir model show maximum adsorption capacity of Cd is 1.91 mg/g. As conclusions, our findings show that pineapple peel has potential to remove heavy metal from polluted water.
Swelling, Tensile and Thermal Behaviors of Citric Acid Crosslinked Tapioca Starch/Cellulose Biocomposite Films
Authors: Noor Zulaika Salleh Morgan , Ong Hui Lin , Zainuddin Firuz
Published: September 2020

The biocomposite films were prepared using a solution casting method and allowed to dry in the oven of 50°C. The cellulose used in this research was extracted from the rice straw. The biocomposite films firstly were prepared without crosslinker with various cellulose content; 0.2g, 0.4g, 0.6g, 0.8g, and 1.0g wt%. Based on the tensile strength result, 0.6g of cellulose is an optimum amount to prepare the biocomposite films with various amounts of crosslinker; 1g, 2g, 3g, 4g, and 5g. The tapioca starch/cellulose biocomposite films crosslinked with lemon juices have higher tensile strength (16MPa) and lower in swelling percentage (3.32%) compared to the biocomposite films crosslinked with key lime juice (5.44%). The thermal behavior was studied based on the Differential Scanning Calorimetry test shows the biocomposite film that highly crosslinked needs higher energy during their phase change. The energy liberated in the tapioca starch/cellulose biocomposite film with key lime juice as crosslinker is 201.6 J/g while that of biocomposite film with lemon juice as crosslinker is 383.0 J/g.
Effect of Acid Leaching on Different State of Rice Husk
Authors: Muzni Nur Haslinda Mohamed , Jamil Noorina Hidayu , Pa Faizul Che , Arif Wan Mohd
Published: September 2020

Rice husks (RH) are agricultural wastes available abundantly in rice producing country. A by-product obtained from combustion of rice husk is rice husk ash (RHA) which is rich in silica (SiO2) contents. This paper focused on the effect of acid leaching treatment on rice husk to produce high-purity silica. There are 4 different states of conditions involved; raw rice husk (RRH), treated rice husk (TRH), rice husk ash (RHA), and treated rice husk ash (TRHA). Citric acid; C6H8O7 was used as a leaching agent. TRH and TRHA was leached to see whether treated rice husk before combustion (TRH) or treated rice husk after combustion (TRHA) will produce more high-purity silica. Chemical composition analysis shows high amorphous silica content which is 98.47% with low metallic impurities at 1.0M C6H8O7, 70 oC for treated rice husk (TRH). X-ray diffraction (XRD) pattern shows the presence of amorphous silica in treated rice husk (TRH) and crystalline silica in treated rice husk ash (TRHA). Fragmentation of TRH into small pieces after acid leaching is seen where there is significant increase in the exposed surface areas. High-purity amorphous silica with more than 98% was prepared via citric acid leaching treatment and combustion process.
A Study on Chitosan Coated Polycaprolactone (Ch-PCL) Microspheres Prepared via Double Emulsion Solvent Evaporation Method
Authors: Te Zi Yang , Yeoh Wei Heng , Shahidan Muhammad Ashraf , Shahidan Nur Nabilah
Published: September 2020

Polycaprolactone coated with chitosan microspheres have the potential to be used as delivery systems and biosensors. Polycaprolactone (PCL) is, however hydrophobic, to improve the biofunctional and potential immobilization of PCL polymer, chitosan-coated PCL microspheres (MSs) were prepared using a double emulsion solvent evaporation method. Different particle sizes were prepared by altering five parameters. When the MSs were prepared using oil to water phase ratio or oil fraction (ϕo) of ϕo = 0.95 to ϕo = 0.38, the MSs average diameter (Dv) reduced from 3.86 to 3.53 µm along with its coefficient of variation (CV), reduced from 18.1 to 12.3 respectively. The MSs prepared with higher polymer concentration of 6wt.% shows higher Dv (4.51 µm) and CV (25.2) compared to 1.2wt.% of PCL, which Dv = 3.86 µm with CV of 18.1. The first homogenizer speed (H1) was increased in order to prepare smaller MSs. When H1 increased from 6 000 to 10 000 rpm, MSs Dv reduced from 3.86 to 3.45 µm along with its CV reduce from 18.1 to 16.6 for ϕo = 0.95. It is also the same case for ϕo = 0.52, where the Dv reduced from 3.70 to 3.19 µm and its CV reduce from 25.8 to 25.2. The effect of NaCl concentration on MSs preparation shows, higher NaCl concentration (1.8wt.%) produced smaller Dv(Dv = 3.86 µm) compared to lower concentration of 0.9wt.%, produced Dv = 4.51 µm for ϕo = 0.95. The trend also follows when the MSs were prepared for ϕo = 0.52. The delay in adding the NaCl shows distinct effect on Dv. For both 0.9 and 1.8 wt.% of NaCl, the Dv increase from 4.51 to 6.40 µm and 4.31 to 6.17 µm respectively. Therefore, the targeted Dv for certain application could be achieved by altering the parameters above. Finally, to study the Ch-PCL potential as enzyme immobilizer, horseradish peroxidase (HRP) was used to be immobilized on to the Ch-PCL MSs. After 7 days, the HRP enzyme still show 51% activity under robust storage condition.
Extraction of Biological Hydroxyapatite from Bovine Bone for Biomedical Applications
Authors: Mohd Pu'ad Nor Atiqah Syafinaz , Latif Amirul Faiz Abdul , Ramli Nurfarah Diyana , Muhamad Mimi Suliza , Abdullah Hasan Zuhudi , Idris Maizlinda Izwana , Lee Tee Chuan
Published: September 2020

Current biomedical field demands intensive research on cost-effective and high availability materials to fulfil its various applications. Owing to its similar characteristic to human bone, biological hydroxyapatite (HAp) has been used as an alternative in bone replacement and implantation. In this study, biological HAp was extracted from bovine bones via calcination. Powders calcined at 700 °C and 900 °C showed the presence of HAp. The FESEM analysis shows that the irregular morphology emerged and the size was increasing as the calcination temperature increased. By increasing the temperature of 1100 °C, β-TCP started to develop and influenced the ratio of Ca/P. At 900 °C, the Ca/P ratio obtained was 1.70, and closest to the theoretical ratio of Ca/P. The presences of trace elements like Ca, Mg, Sr Na, K and Zn in all samples are proved via EDS analysis, and these elements help to enhance the bioactivity hence make it a good alternative in biomedical applications.
Extraction of Biological Hydroxyapatite from Tuna Fish Bone for Biomedical Applications
Authors: Latif Amirul Faiz Abdul , Mohd Pu'ad Nor Atiqah Syafinaz , Ramli Nor Aziatul Akmar , Muhamad Mimi Suliza , Abdullah Hasan Zuhudi , Idris Maizlinda Izwana , Lee Tee Chuan
Published: September 2020

Natural hydroxyapatite (HAp) is known for its common use in biomedical applications including in orthopaedic and implantation. HAp can be extracted from natural resources such as eggshells, fish bones and coral. Annually, it is found that huge amount of tuna fish bones were thrown away and being wasted as results from great consumption of tuna fish. In this study, tuna fish bones were extracted and characterised to be used in biomedical applications. Specifically, tuna fish bones were cleaned, and calcined at high temperature of 700 °C, 900 °C and 1100 °C. Powders calcined at 700 °C showed pure HAp compared to powders calcined at 900 °C and 1100 °C which showed the presence of β-TCP. As temperature rising, the morphology of the powders also changes from spherical-shaped to irregular-shaped indicated the substitution of phosphate and calcium from the β-TCP which also influenced the ratio of Ca/P obtained. In this study, powders calcined at 700 °C obtained optimum Ca/P ratio of 1.60. Moreover, EDS analysis showed the presence of tracer elements such as Ca, Mg, Sr Na, K and Zn in all calcined samples. These elements can help improve the biocompatibility of the HAp and beneficial for biomedical applications.
Efficiency of Impressed Current Cathodic Protection in Repaired Reinforced Concrete
Authors: Malek Rohaya Abdul , Hattori Atsushi , Hirotaka Kawano , Kamaruddin Nadia
Published: September 2020

—Corrosion attack in reinforced concrete and thus contribute to degradation of concrete influenced by aggressive environment, represent a great concern in relation to the durability of reinforced concrete structures. In this respect, an interesting need is required that is patch repair with additional protection known as ICCP method to prolong the serviceability of the concrete structures. However, details inspection is crucial to understand the effect of different repairing materials and chloride content towards application of ICCP. To clarify this issue, non-protected and protected test specimens were prepared, and analyzed up to 175 days of protection. The result reveals that, reference specimen was found as most corroded specimen unable to obtain 100 mV depolarization at 56 days installation compared to repaired ones. However, all specimens show only greater depolarization values beyond 129 days of installation. To clarity further effectiveness of ICCP system to the studied specimens, time-dependence within 24 hours disconnecting CP current has been carried out and depolarization values was recorded every 4 hours interval. In the final analysis, all specimens are satisfying the CP criteria by obtaining depolarization potential ranging 100 to 250 mV at 4 and 24 hours monitoring period. Index Terms— corrosion attacks, reinforced concrete, repaired concrete, repairing materials, impressed current
Study of Heat Treatment Effect in MnCoGe Compound on Stucture and Electric Properties
Authors: Md Din Muhamad Faiz , Jusoh Mohamed Shafie Mohd , Rahman Abdul Rashid Abdul , Wang Jian Li , Idris Nurul Hayati , Ismail Mohammad , Wan Zambri Wan Fathul Hakim
Published: September 2020

A comprehension about magnetic refrigeration which develops strong materials as the refrigerant will be explained and develop in this project. Magnetic refrigeration comes from magnetocaloric effect (MCE) which is magnetic material known as refrigerant that react with a magnetic and demagnetic field. Refrigerant plays the roll in control the performance of magnetic refrigerator. One of interesting refrigerant is MnCoGe compound which found very favourable in produce high value of MCE. From this point of view, the process of producing of MnCoGe using ball milling treatment and heat treatment had been studied. Variable of temperature in heat treatment process and following by cooling down to room temperature have been implemented in order to produce good structure of MnCoGe compound. Furthermore, from structure properties measurement found this compound produce three type of structures which are hexagonal, orthorhombic and mix structure (hexagonal and orthorhombic). Based on the different temperature of heat treatment, it indicate for 1500o C and 1200o C treatment are dominant to the hexagonal structure type, then for 1000o C dominant to the orthorhombic structure and lastly for 1100o C dominant to mix structure. Electric properties measurement found the frequency play the role in change the structure as well as in 1000o C compound was found below 5M Hz frequency show the hexagonal structure and when increasing above 5M Hz the pattern change to orthorhombic structure respectively. Moreover, for the permittivity measurement it gives the information about conductivity and tan delta value. Systematically at 1000o C compound found this material is more to conductor behavior compare others compound. Therefore, when the temperature is increased to 1100o C, 1200o C and 1500o C then the conductivity value decreasing and its resistivity value become increasing.
Effect of Heat Treatment on Isothermal Oxidation of Fe-33Ni-18Cr Alloy at 1000°C
Authors: Zulnuraini Zahraa , Parimin Noraziana
Published: September 2020

This research study was focused on the effect of heat treatment on the isothermal oxidation of Fe-33Ni-18Cr alloy at 1000 °C. The Fe-33Ni-18Cr alloy was undergone heat treatment at three different temperatures, namely 1000 °C, 1100 °C and 1200 °C for 3 hours soaking time followed by water quench to vary the grain size of the alloy. The heat-treated alloys was prepared for further isothermal oxidation test. The heat-treated alloys was ground by using several grit of silicon carbide papers as well as weighed by using analytical balance and measured by using Vernier caliper before the oxidation test. The heat-treated Fe-33Ni-18Cr alloys was isothermally oxidized at 1000 °C for 150 hours exposure time. The characterization of the oxidized samples was carried out using optical microscope and scanning electron microscope (SEM). The heat treatment result shows that, increasing the heat treatment temperature was increased the average grain size of the alloy. The kinetics of oxidation was followed the parabolic rate law which represent the diffusion-controlled oxide growth rate. Fine grain structure of 1000i-1000 sample shows minimum weight gain and lower oxidation rate compared to samples of 1000i-1100 and 1000i-1200. On the other hand, 1000i-1100 and 1000i-1200 samples indicate the formation of oxide spallation and crack propagation on the oxidized surface, respectively.
Utility of late pulmonary artery banding in single-ventricle physiology
Authors: Mukherji Aritra , Ghosh Sanjiban , Pathak Nihar , Das Jayita Nandi , Dutta Nilanjan , Das Debasis , Chattopadhyay Amitabha
Published: September 2020

Background:

The standard first stage palliation for univentricular heart with unrestricted pulmonary blood flow (PBF) is surgical pulmonary artery (PA) banding for which the ideal age is within the first 8 weeks of life. This study aimed to look for the utility of PA band done beyond 3 months of age for patients presenting beyond the stipulated period.

Materials and Methods:

This is a retrospective analysis of the outcome of twenty patients with single ventricle (SV) physiology with unrestricted PBF who presented late and were selected on the basis of clinical, radiological, and echocardiographic parameters for PA banding.

Results:

The median age of the patients was 5.5 months (3.5–96 months), and the median body weight was 4.7 kg (3.2–22.0 kg). The patients were divided into three groups as follows: ten patients between 3 and 6 months of age (Group A), seven patients between 6 months to 1 year of age (Group B), and three patients > 1 year of age with additional features of pulmonary venous hypertension (Group C). The mean reduction of PA pressures following PA band was 60.9%, 48.8%, and 58.3% and the mean fall in oxygen saturation was 10.4%, 8.0%, and 6.6% in the three groups, respectively. The postoperative mortality rate was 10%. The mean follow up duration was 13.5 months (7–23 months). There was a statistically significant improvement in weight for age Z scores following PA band (P = 0.0001). On follow up cardiac catheterization, the mean PA pressures were 16.6 (±3.6), 22.7 (±5.7), and 33.3 (±12.4) mmHg, respectively, in the three groups, and the mean pulmonary vascular resistance index was 1.86 (±0.5), 2.45 (±0.7), and 3.5 (±1.6) WU.m2, respectively. Subsequently, seven patients in Group A, three patients in Group B, and one patient from Group C underwent successful bidirectional Glenn (BDG) surgery.

Conclusions:

Late PA band in selected patients with SV physiology can have definite benefit in terms of correction of heart failure symptoms and subsequent conversion to BDG and can potentially change the natural history of disease both in terms of survival and quality of life.
The BFK-gluing formula and the curvature tensors on a 2-dimensional compact hypersurface
Authors: Kirsten Klaus , Lee Yoonweon
Published: September 2020

In the proof of the BFK-gluing formula for zeta-determinants of Laplacians there appears a real polynomial whose constant term is an important ingredient in the gluing formula. This polynomial is determined by geometric data on an arbitrarily small collar neighborhood of a cutting hypersurface. In this paper we express the coefficients of this polynomial in terms of the scalar and principal curvatures of the cutting hypersurface embedded in the manifold when this hypersurface is 2-dimensional. Similarly, we express some coefficients of the heat trace asymptotics of the Dirichlet-to-Neumann operator in terms of the scalar and principal curvatures of the cutting hypersurface.
Native Umbilical Defect for Laparoscopic Entry
Authors: Hegazy Tarek Osama , Ali Mohamed Hassan , Mohsen Ahmed Amr , Azhary Mahmoud , Dayem Ahmad Yahia Abdel
Published: September 2020

Background: The presence of defects in native umbilical in adults and its use as laparoscopic first entry site is poorly documented. It would likely be a safer method than the Veress needle and direct trocar insertion. This work aimed to report the prevalence and size of native umbilical defects, and their relationship with gender, age and body mass index.

Methods: In 160 consecutive laparoscopic operations, a trans-umbilical incision was made and a defect at its base was looked for. When found, the defect was measured and used as the first port entry site. Relationships of presence of native defects and their sizes in relation to gender, age and BMI were analyzed.

Results: The prevalence of a native defect in this series was 90%. Its presence had no relation with gender, age or BMI. Its size, however, positively correlated with age and BMI. No complications were related to the defect’s use for first laparoscopic entry site.

Conclusion: A native umbilical defect is present in 90% of adults. Whenever present, it is recommended for use as the first port entry site by an open technique. This method is simple and safe and avoids unnecessarily inducing another defect.

Keywords: Laparoscopy, Open technique, Access, Native defect, Umbilical defect
Atraumatic Ruptured Giant Renal Tumor
Authors: Ayane Gezahen Negusse , Kadimo Khutsafalo
Published: September 2020

Massive hemoperitoneum due to spontaneous rupture of renal cell carcinoma is a rare presentation during emergency laparotomy. A 60-year-old female patient presented with severe abdominal pain, nausea, vomiting and abdominal distension. A massive hemoperitoneum secondary to ruptured left kidney tumor was found during laparotomy. Histology confirmed a papillary renal cell carcinoma. Ruptured renal cell carcinoma can be a cause of bleeding into the retroperitoneum space. Emergency sonography and laparotomy are advocated for its management.

Keywords: Renal cell carcinoma, Rupture, Complex mass, Nephrectomy, Papillary
Investigation of injection molding process parameters characteristics using RSM approach
Authors: Goyal Ashish , Pathak Vimal Kumar , Ogra Siddharth , Pandey Anand
Published: September 2020

The present study analyzes the important characteristics of plastic injection molding machining process. The polypropylene (PP) material has used as a specimen and effect of melt temperature, packing pressure and injection pressure has been investigated on the tensile modulus and elongation. Total 20 experiments have been performed to analyses the results. Response surface methodology (RSM) was adopted for optimization of injection molding process parameters. The experiments were conducted by using central composite design. The analysis of variance (ANOVA) techniques was used for selection of significant and non-significant parameters. The experimental results show that the RSM influence elongation by 87.04%, 11.52%, 1.43% and tensile modulus by 85.35%, 11.4%, 3.25%.

Keywords: Injection molding; polypropylene; tensile modulus; elongation
Design and implementation of multiple output forward converter with Mag-amp and LDO as post regulators for space application
Authors: Patil Soumya , Geetha R.S. , Santosh B.L. , Singh Bhoopendra Kumar , Chippalkatti Vinod
Published: September 2020

Linear power supplies are commonly used power supplies for many applications. They have some drawbacks such as low efficiency, difficulty in  thermal management and also in regulation of the output voltage. Some of these drawbacks can be overcome by Switch Mode Power Supplies (SMPS). One of the best-suited applications of SMPS is for space applications that require power supplies which are lighter, smaller, more efficient and highly reliable. Multiple-output DC-DC converters are an important topology of SMPS that can be used for space applications. But, in multiple output converters usually, only the master output is regulated and the other outputs are left unregulated and this can result in cross-regulation. In this paper, post regulators such as Magnetic amplifiers (Mag-amp) and Low DropOut regulator (LDO) are proposed to regulate each output and also to improve load regulation. In addition to this, the input voltage feed-forward control technique is proposed to control the duty cycle of the switch, which is dynamically faster and provides better line regulation when compared to the voltage feedback controller. Besides, over current protection circuit for the converter is discussed in detail.

Keywords: Cross regulation effect, Mag-amp and LDO, multiple output forward converter, output over current protection, voltage feed forward control.
Analysis and implementation of electricity generation of 1000VA using wind turbine
Authors: Okandeji A.A. , Olajide M.B. , Jagun Z.O. , Kuponiyi D.S. , Aderanti T.A.
Published: September 2020

The project involved the design and construction of a three-blade wind turbine, selection of generator by consideration of the available wind speed and the maximum generated voltage per revolution, and assembly of the pulse width modulated inverter with microontroller based status display and low battery shutdown system. On completion of the work, tests were conducted and the result shows that the design work was very good, the output of the generator was good enough to charge the batteries and the inverter performed an excellent task of converting the direct current (DC) voltage available in the battery to alternating current (AC) at 230V 50Hz 20”. Furthermore, results from the discharge characteristics of the battery shows that as the battery is being used up, the output voltage remains constant.

Keywords: wind, blade, turbine, magnetic field, battery, oscillator, inverter, controller
Investigations of the structural characteristics of concrete produced from recycled aggregates at varying water/cement ratios
Authors: Otunyo A.W. , Jephter B.G.
Published: September 2020

The paper tried to investigate the structural characteristics of concrete produced by partially replacing natural aggregates with recycled aggregates at varying water/cement ratios. The study is basically a laboratory experimental study. Water/cement ratio component of the concrete were varied at 0.40, 0.45, 0.50, 0.55, 0.60; while the natural aggregate was partially replaced with RCA of 0%, 15%, 30%, 45%, 60%, 75% and 90% for concrete productions for 7, 14 and 28 days structural characteristics. The densities, water absorption capacity and Compressive Strength of these concretes were determined. The results were presented in graphs and Tables. Results of the study indicate an increased compressive strength at low percentage of RCA and water /cement ratio values. There is a marginal difference between compressive strength of normal concrete and concrete produced by partial RCA of 15% replacement at 0.4 w/c ratio.

Keywords: recycled concrete aggregate, natural aggregate, compressive strength, water/ cement ratio and natural aggregate concrete.
Assessment of infrastructure maintenance practices of three airports in southern Nigeria
Authors: Okafor C.C. , Ezeoyili M.N.
Published: September 2020

This research examined the maintenance plans and strategies used by three airports in Nigeria to ascertain how they maintain existing infrastructure for full assets utilization and safer operational capacities. Interviews and questionnaires were employed to get concise data from all the areas and infrastructure available at Akanu Ibiam International Airport, Port Harcourt International Airport and Margaret Ekpo International Airport. Descriptive statistics and ordinal logistic regression were used in analysis and report. While Akanu Ibiam International Airport employs preventive maintenance practices on most of their facilities, Port Harcourt International Airport and Margaret Ekpo International Airport adopt corrective maintenance practices. All the airports investigated suffer poor operational efficiency, dilapidating infrastructure and facilities, and lack maintenance actions. The maintenance schedule available at Akanu Ibiam International airport can serve as a template at Port Harcourt International Airport and Margaret Ekpo International Airport. This maintenance plan must be implemented in order to achieve improvement in operational capacities.

Keywords: Infrastructure, maintenance practices; airports; challenges; Akanu Ibiam; Port Harcourt; Margaret Ekpo
Exhaust emission characteristics of a gardener compression ignition engine fuelled with rapeseed methyl ester and fossil diesel
Authors: Dandajeh H.A. , Sanusi Y.S. , Ahmadu T.O.
Published: September 2020

This paper presents an experimental investigation into the exhaust emissions characteristics of a gardener Compression Ignition (CI) Engine fuelled with rapeseed methyl Esther (RME) and fossil diesel under lean equivalence ratios (0.2≤ φ ≤0.8). The experiments were carried out at engine speeds of 750 and 1250 rpm under five different loads. The experimental results showed that NOx and CO2 emissions increased while emissions of HC, O2 and CO decreased with increasing equivalence ratio, exhaust temperature, brake mean effective pressure and specific fuel consumption. All exhaust emissions were found to decrease with increasing engine speed from 750 to 1250 rpm. There was reduction in exhaust emissions of RME over fossil diesel by 0.06% for O2, 84% for CO and 4.7% for CO2 at 750rpm. At higher speed of 1250rpm however, RME was observed having higher NOx and CO2 but relatively lower O2 and CO than the fossil diesel.

Keywords— Exhaust Emission, Compression ignition engine, rapeseed methyl Esther, engine speed, fossil diesel
A new test analysis procedure for pressure drawdown test of a horizontal well in an infinite-acting reservoir
Authors: Idudje E.H. , Adewole E.S.
Published: September 2020

This paper develops a new well test analysis procedure of a horizontal well in an infinite-acting reservoir. Hitherto, horizontal well pressure drawdown test analysis during infinite-acting flow was accomplished based on a straight line method obtained from a plot of flowing wellbore pressure versus log of flow time. In that procedure, only limited system characterization was possible. Furthermore, the rigorous type curve matching was resorted to when a straight line did not appear. In the method developed here, a plot of flowing wellbore pressures, pwf, against dimensionless wellbore pressures, pD, is made for analysis. Results show that a straight line relationship exists between the two plotted parameters on a linear paper. The straight line slope across the middle time region can be taken to perform test analysis. From the plot, reservoir pressure, near wellbore permeability, reservoir capacity, fluid mobility and transmissibility can be calculated. Mathematical procedure leading to this method of analysis is based on selection of relevant source and Green’s functions for a horizontal well during infinite-acting flow and purely as a line source. A case pressure test selected for analysis using the method developed here yielded very close reservoir character compared to the reservoir being characterized

Keywords: Dimensionless pressure, dimensionless derivatives, infinite-acting, horizontal well, early radial flow
Creep and morphological evaluation of polypropylene waste modified asphalt for pavement applications
Authors: Otuoze H.S. , Shuaibu A.A. , Ahmed H.A. , Suleiman I.T. , Bello I. , Yusuf K.O.
Published: September 2020

Synoptic findings by researchers have revealed tremendous physic-chemical improvements of polymer modified mixes over the conventional asphalt. Traditionally, laboratory mechanical properties were carried out for asphalt testing, but cannot calibrate simple performance test (SPTs) criteria for fatigue and field performance. Marshall test-sized specimens of polymer asphalt mixtures were engineered with arbitrary contents of 0 to 3.0% polypropylene waste admixed with 4.5 to 6.5% bitumen contents based on relevant literature. Creep deformation involves uniaxial static creep (USC) test using BS 598-111. Morphological examinations were test with Hitachi S-4700 field-emission scan-electron-microscope (FE-SEM). Thirdly, thermal degradation was determined using Shimadzu TGA-50 thermo-gravimetric analyzer. The results showed creep resistivity with fatigue recovery of 23.2% and 28.9% strain reduction at 10oC and 60oC respectively from the optimal 2.0% polypropylene and 6.0% bitumen compared to the control mix. Also, the same mix produced well dispersed and better enhanced pore packaging micro-structure capable of resisting ageing volatization under severe traffic and environmental loading conditions considered.

Keywords: Asphalt pavement, polypropylene, creep deformation, age volatization and microstructure