bluuebunny/crossref_metadata_2025 huggingface dataset:
Coordination over a unique medium of exchange under information scarcity
Authors: Nioche Aurélien , Garcia Basile , Lefebvre Germain , Boraud Thomas , Rougier Nicolas P. , Bourgeois-Gironde Sacha
Published: December 2019

Several micro-founded macroeconomic models with rational expectations address the issue of money emergence, by characterizing it as a coordination game. These models have in common the use of agents who dispose of perfect or near-perfect information on the global state of the economy and who display full-fledged computational abilities. Several experimental studies have shown that a simple trial-and-error learning process could constitute an explanation for how agents coordinate on a single mean of exchange. However, these studies provide subjects with full information regarding the state of the economy while restricting the number of goods in circulation to three. In this study, by the mean of multi-agent simulations and human experiments, we test the hypothesis according to which coordination over a unique medium of exchange is possible in the context of information scarcity. In our experimental design, subjects and artificial agents are only aware of the outcome of their own decisions. We provide results for economies with 3 and 4 goods to evaluate to which extent it is possible to generalize results obtained with 3 goods to $$n$$n goods. Our findings show that in an economy à la Iwai, commodity money can emerge under drastic information restrictions with three goods in circulation, but generalization to four or more goods is not guaranteed.
Sharing the same languages helps us work better together
Authors: Yow W. Quin , Lim Tony Zhao Ming
Published: December 2019

Collaborative problem-solving, the mutual engagement of people in a coordinated effort to solve a problem together, plays a critical role in the increasingly complex, linguistically diverse, and interconnected world. In particular, being able to communicate in the same languages provides a critical platform for facilitating problem solving among members of a multilingual team. Little research has explored whether sharing the same spoken languages would boost collaborative problem-solving over and beyond the effects of possible confounding variables such as language proficiency, personality, ethnicity, nationality, and non-verbal intelligence. This study manipulated the sharing of same languages by pairing 118 English-speaking bilingual participants either with someone who shares the same two spoken languages as themselves (English-same pair) or with someone who differs in one language (English-different pair). We explored whether such sharing of the same languages enhances collaborative problem-solving in multilingual pairs. Participants completed the Raven’s Matrices individually, as well as an insight problem-solving task (Triangle of Coins task) and a divergent thinking task (Mind-mapping) in pairs. English-same pairs performed better than English-different pairs in the insight problem-solving task but not in the divergent thinking task. English-different pairs collaborated (mean number of turns per minute) and communicated (mean number of utterances) more than English-same pairs in the divergent thinking task, although the effect of pair type on communication was fully mediated by a difference in ethnicity within pairs. More collaboration could have been needed between English-different pairs in the divergent thinking task to achieve comparable performance as English-same pairs, possibly due to the different communication processes experienced by English-different pairs. This study provides insights to the role of sharing spoken languages in enhancing collaborative problem-solving in small multilingual groups.
The second type of sharp-front wave mechanism of strong magnetic field diffusion in solid metal
Authors: Yan Chunhui , Xiao Bo , Wang Ganghua , Kan Mingxian , Duan Shuchao , Li Ping , Sun Dejun
Published: December 2019

When a strong magnetic field diffuses into a metal, the metal is ablated by Joule heating accompanying the magnetic diffusion process, and the metal’s resistance changes violently with the fast-growing temperature. This results in the formation of a so-called “nonlinear diffusion wave” characterized by a sharp “wave-front” where the magnetic field abruptly decays. A metal has its own threshold magnetic field value, which is determined by the critical temperature of the metal. If the constant vacuum magnetic field B0 is above the threshold value Bc, the magnetic diffusion process can be approximately described by sharp-front diffusion wave theory [B. Xiao et al., Physics of Plasmas 23, 082104 (2016)], which gives a simple formula to describe the velocity of the diffusion process. However, if B0 is below Bc, the sharp-front diffusion wave theory is no longer applicable. In this situation, one would need another type of sharp-front diffusion wave theory (type II theory) to describe the magnetic diffusion behaviors. In type II theory, the sharp-front diffusion wave velocity depends on three parameters, i.e., the magnetic boundary condition B0, the critical temperature Tc, and the cold metal resistance ηs. The dependence of the velocity on these three parameters is analyzed in detail in this paper.
Photoionization studies of benzene-argon complexes with synchrotron VUV radiation
Authors: Cheng Bing-Ming , Walters Edward A. , Grover J. Robb
Published: December 2019

Penning ionization of benzene-argon complexes of states corresponding to the two states of (3p)5(4s)1 of argon for which j = 1, at 11.8282 and 11.6237 eV, was studied using synchrotron radiation. Photoion yield curves for complex ions, (C6H6)nArm+, where n = 1, 2 and m = 1–3, for species less than m/e 200 were determined. For n = 1, the peaks are narrow (0.03 eV) and red-shifted (0.06 eV) by essentially the same amounts for all values of m. For n = 2, the peaks are wider (0.22 eV) and blue-shifted (0.07 eV) also for all values of m. In addition, the dissociation energies of C6H6Ar and C6H6Ar+ were measured to be 0.89 ± 0.07 and 1.37 ± 0.08 kcal mol−1 (i.e., 0.039 ± 0.003 and 0.059 ± 0.0035 eV).
3 GHz RF measurements of AlGaN/GaN transistors transferred from silicon substrates onto single crystalline diamond
Authors: Gerrer Thomas , Czap Heiko , Maier Thomas , Benkhelifa Fouad , Müller Stefan , Nebel Christoph E. , Waltereit Patrick , Quay Rüdiger , Cimalla Volker
Published: December 2019

The integration of AlGaN/GaN thin film transistors onto diamond substrates enables the efficient dissipation of device heat, thus providing a boost in performance and reliability of current high-frequency GaN power amplifiers. In this paper, we show 3 GHz load-pull measurements of GaN transistors on silicon (Si) and single crystalline diamond (SCD) as fabricated by our recently presented direct low-temperature bond process. After the transfer onto SCD, the efficiency and output power are increased by 15%, which is explained by a calculated temperature difference of ∼100 K. In addition, the temperature between individual gate fingers is reduced such that the output power density (Pout) is independent of the amount of fingers. A drawback of our GaN epilayer is identified in the huge thermal resistance of the buffer layer so that the heat spreading performance of our technology is significantly impaired. Nevertheless, we demonstrate a large GaN-on-diamond output power of 14.4 W at a Pout of 8.0 W/mm.
Influence of shade on panting score and behavioural responses of Bos taurus and Bos indicus feedlot cattle to heat load
Authors: Lees A. M. , Lees J. C. , Sejian V. , Sullivan M. L. , Gaughan J. B.
Published: December 2019

Context
Feedlot cattle can be negatively impacted by hot conditions, such that they have reduced performance and wellbeing. This study was conducted at the research feedlot located at The University of Queensland during a southern hemisphere summer (October to April).

Aims
The objective of this study was to evaluate the influence of shade on the behaviour and panting score of Bos taurus and Bos indicus feedlot cattle during summer.

Methods
Thirty-six steers (12 Angus, 12 Charolais and 12 Brahman) with an initial non-fasted liveweight of 318.5 ± 6.7 kg were used in a 154-day feedlot study consisting of two treatments: unshaded and shaded (3 m2/animal). Observational data were obtained for each steer at 2 h intervals between 0600 and 1800 hours daily from Day 1 to Day 154. Additional night time observational data were collected at 2-h intervals between 2000 and 0400 hours on 12 occasions. Data collected included activity (feeding, drinking, or ruminating), posture (standing or lying) and panting score. Panting scores were used to calculate a mean panting score for each breed × treatment group. Observational data were converted to a count for each breed × treatment group for each observation time point and were analysed using a binomial generalised linear model.

Key results
Maximum shade utilisation was the greatest at 1200 hours for Angus (85.5%), Charolais (32.7%) and Brahman (33.3%) steers. All breed × treatment groups exhibited a notable increase in mean panting score as heat load increased. Average increase in mean panting score was 0.36, where shaded Brahman exhibited the smallest increase (0.13) and unshaded Angus had the greatest increase (0.71). When heat load conditions were very hot (heat load index (HLI) ≥ 86) the mean panting score of all breed × treatment groups differed (P < 0.05).

Conclusions
Overall these results emphasise the importance of providing shade to feedlot cattle, irrespective of genotype.

Implications
These results further highlight the importance of providing shade to feedlot cattle. These results challenge the general perception that Bos indicus feedlot cattle do not require access to heat load alleviation strategies.
NZOA-ON: the New Zealand Ocean Acidification Observing Network
Authors: Vance J. M. , Currie K. I. , Law C. S. , Murdoch J. , Zeldis J.
Published: December 2019

A national observing network has been operating over the past 4 years to inform the scientific and economic challenges of ocean acidification (OA) facing New Zealand. The New Zealand Ocean Acidification Observing Network (NZOA-ON) consists of 12 sites across varied coastal ecosystems. These ecosystems range from oligotrophic ocean-dominated systems to eutrophic river-dominated systems, with sites that are pristine or affected by agriculture and urbanisation. Fortnightly measurements of total alkalinity and dissolved inorganic carbon provide the baseline of carbonate chemistry in these varied ecosystems and will facilitate detection of future changes, as well as providing a present-day baseline. The National Institute of Water and Atmospheric Research and the University of Otago have developed a ‘grass-roots’ sampling program, providing training and equipment that enable sampling partners to collect field samples for analyses at a central laboratory. NZOA-ON leverages existing infrastructure and partnerships to maximise data captured for understanding the drivers of chemical changes associated with OA and ecological responses. NZOA-ON coordinates with and contributes to global initiatives to understand and mitigate the broader impacts of OA. A description of NZOA-ON is presented with preliminary analyses and comparison of data from different sites after the first 4 years of the network.
The importance of grassland patches and their associated rainforest ecotones to insectivorous bats in a fire-managed tropical landscape
Authors: Broken-Brow Julie , Armstrong Kyle N. , Leung Luke K.-P.
Published: December 2019

Abstract ContextEcotones are recognised globally as areas of high biodiversity, yet relatively little is known about how fauna use different types of ecotone. Tropical rainforest–grassland ecotones are shaped through particular fire regimes, creating both gradual and abrupt ecotones. Insectivorous bats contribute considerably to mammalian diversity, and their capacity for flight allows them to use ecotones in a three-dimensional way, making them an informative faunal group for evaluating ecotone use. AimsTo critically evaluate how insectivorous bats use gradual and abrupt ecotones between rainforest and grassland habitats. MethodsBat detectors were placed every 50m, along 200-m transects, through five gradual and five abrupt rainforest–grassland ecotones. The activity of all insectivorous bats, as well as open, edge–open and closed foraging guilds (defined by echolocation call type), was compared among grassland and rainforest habitats, gradual and abrupt ecotones and positions across the ecotones. Key resultsMean total bat activity, mean open and edge–open foraging guild activity were significantly higher in grassland positions, followed by the edge, and were lowest in the rainforest. Closed foraging guild bats showed no preference for either habitats, but had significantly higher activity in gradual compared with abrupt ecotones. Mean activity of edge–open foraging guild bats was affected strongly by the interaction between ecotone type and position along the ecotone. Gradual ecotones had a more even proportion of all three bat foraging guilds along the ecotone compared with abrupt ecotones. Most of these findings were likely driven by the structural complexity of gradual ecotones that fulfilled microhabitat requirements for all three foraging guilds, but may also have been influenced by insect prey abundance. ConclusionsThe present study demonstrated the importance of grassland patches in a tropical, rainforest landscape, and of gradual rainforest–grassland ecotones for insectivorous bats. Gradual ecotones promote complex habitat mosaics to allow closed foraging guild species to take advantage of food resources provided by grasslands, and provide all bats proximity to potential roosting and foraging sites. ImplicationsThe data clearly suggest that a suitable fire regime should be used to maintain current grassland patches within a rainforest landscape, and to promote gradual ecotones for use by insectivorous bats.
Smad7 in intestinal CD4+T cells determines autoimmunity in a spontaneous model of multiple sclerosis
Authors: Haupeltshofer Steffen , Leichsenring Teresa , Berg Sarah , Pedreiturria Xiomara , Joachim Stephanie C. , Tischoff Iris , Otte Jan-Michel , Bopp Tobias , Fantini Massimo C. , Esser Charlotte , Willbold Dieter , Gold Ralf , Faissner Simon , Kleiter Ingo
Published: December 2019

Significance

Mechanisms leading to initiation of the autoimmune disorder multiple sclerosis (MS) are still elusive. Environmental triggers acting at barrier organs such as the intestine could contribute to local activation of autoreactive lymphocytes and consecutive migration to the CNS. Here, we demonstrate that overexpression of the TGF-beta inhibitor Smad7 in intestinal CD4+T cells of mice lowered the threshold for autoimmunity and favored expansion and migration of inflammatory T cells. In contrast, specific deletion of Smad7 in CD4+T cells mediated protection toward development of autoimmunity via regulatory CD4+T cell differentiation and anergy. A dysregulation of TGF-beta/Smad7 signaling was also found in intestinal biopsies from MS patients, indicating a contribution of the intestinal barrier in the immunopathology of MS.
A candidate hypothesis about ecogenic science applied to fish and fisheries within the Great Laurentian Basin during the 19th and 20th Centuries
Authors: Regier Henry A.
Published: December 2019

Late in the 20th Century, participants in a trans-jurisdictional fisheries research network in the Great Laurentian Basin collaborated with participants of other research networks (waterfowl, piscivorous birds, benthic insects, plankton, bacteria, meteorology, hydrology, etc.) in a mega-scale happening during the years 1967 to 1992 that I call ‘The Great Laurentian Spring’. With a basin-wide version of adaptive management, the scientific researchers collaborated with citizen activists, private entrepreneurs, commission facilitators and governmental administrators in remediating harm done to the natural living features of the Great Laurentian Basin, particularly in the preceding 150 years. Like the degradation process that preceded it, the remediation process had features of a self-organizing movement that became complex beyond the ability of participants and observers to fully describe and explain it. Here I offer as an hypothesis, a rough sketch of how fisheries networkers in the Great Laurentian Basin came to play a role of helping to conserve valued fisheries and preserve vulnerable species during the degrading pre-Great Laurentian Spring period and then to help remediate harmful stresses, rehabilitate fisheries and prevent further degradation during the Great Laurentian Spring period and since then. In general fisheries researchers performed empirical science in responsible ways, with emphasis on the fish and on their habitats, and thus on the health of the aquatic ecosystems. Occasionally, the strongly modified natural system could be managed to produce major fisheries benefits, at least temporarily. The Scot T. Reid’s Common Sense science contributed to the American C.S. Peirce’s Pragmatism and together they informed the German A. Thienemann’s Limnology and the Canadians W.E. Ricker’s and F.E.J. Fry’s Fisheries Science. All along, mathematics of increasing sophistication played a role. Reputable criticisms of scientific inferences as well as untested and disreputable rhetoric of science deniers were taken seriously by the researchers.
A high-performance refractive index sensor based on a triangular-lattice photonic crystal with defect and surface modes
Authors: Cui Ting , Liu Xing , Zhou Lin , Feng Shuai , Chen Xiao , Guo Honglian , Li Chuanbo , Wang Yiquan
Published: December 2019

The refractive index sensing capabilities of a 2D triangular-lattice photonic crystal (PhC) with defective and surface modes are studied. These are composed of silicon columns arranged in a liquid environment. Through changing the rods’ shape on the PhC’s surface from a circle to an ellipse and optimizing the sizes of two adjacent ellipses, the surface localized mode can be generated. Combining the central defective mode with surface modes, an ultra-small three-working-wavelength PhC refractive index sensor is proposed. The shift of the resonant wavelengths influenced by the slight alteration of the protein’s thickness attached by the special rods is studied, and it is found that a minimum alteration of the protein’s thickness of about 4 nm can be distinguished, and a maximum refractive index sensitivity of 0.516 is obtained. Three kinds of analytes can be detected in real-time and at the same time, which are bounded around the input/output surfaces and the central rods through biological specific binding.
A study of flat stick bamboo microwave absorber performance
Authors: Mohd Kasim L , Abdullah@Idris H , Ahmad Suffian A S , Mohamad Noor N , Mohamat Kasim N , Ahmad A , Ismail N A , Razali A R , Taib M N
Published: December 2019

Microwave absorber able to inhibit the reflection of electromagnetic radiation. Microwave absorbers are used in an anechoic chamber along with its wall, ceiling and floor for the electromagnetic compatibility (EMC) and electromagnetic interference (EMI) evaluation. This research is to develop a flat shape of biomass absorbers using an agricultural material. The main material used in constructing the flat absorber is a natural bamboo. The flat shaped absorber is chosen because it could reach the standard set in the specified industry and suitable to be used in the microwave frequency range. Cylindrical bamboo with different radius have been used for this study. Radius 0.2 cm for Design 1 and 1 cm for Design 2. The range of frequencies are set in the range from 1 GHz to 12 GHz. The result of microwave absorber is analyzed for its absorption performance. The generated result from the technique shows that the flat stick bamboo microwave absorber operates the best in Design 2 with 34.9% of absorption performance compared with Design 1. The overall results in different angles for both designs are analyze and compared.
Interaction of mineralogical content with engineering properties of selected weathered Semanggol formation mudrocks
Authors: Albar A , Osman M H , Kamaruddin M H , Hasan D , Dollah Z
Published: December 2019

A comprehensive study of rock properties is crucial to investigate and characterize the behavior of rock when it undergoes multiple loading and stresses. The properties of rocks are heavily influenced by weathering grade and the composition of minerals which indicates the hardness, swelling potential and abrasiveness, therefore give an effect on the strength and the durability of rocks. The interaction between mineralogy and engineering properties are significantly important for the engineer to fully understand the behavior of mudrock for further application especially in Malaysia. Selected weathered mudrocks from Bukit Kukus Kedah, a part of Semanggol formation were characterized for physical, mechanical and mineral properties. The result shows the degree of weathering influenced the physical and mechanical properties of mudrock. The sample with low porosity and high density possessed highest slake durability index of 91.43%. X-Ray diffraction revealed two of the sample tested were consists of goethite and quartz. The sample presence with goethite is higher in durability compare to sample consists of quartz only due to the cementation effect and denser minerals.
Rice husk ash (RHA) based geopolymer mortar incorporating sewage sludge ash (SSA)
Authors: Zaidahtulakmal M Z , Kartini K , Hamidah M S
Published: December 2019

Geopolymer based cementitious materials were produced to reduce or completely eliminate the use of cement in concrete in which could be incorporated with waste materials. In this study, rice husk ash (RHA) which is a waste having rich in silica content after burnt was intended to be used as based geopolymer. Besides, sewage sludge ash (SSA) was incorporated with RHA producing geopolymer mortar in which also having pozzolanic element of Si and Al. Geopolymerisation requires Si and Al elements to react with highly alkaline solution to produce geopolymeric material. Therefore, combination of RHA and SSA will be possible solution as base geopolymer mortar in order to provide Si and Al. The effect of SSA inclusion was investigated under different sodium hydroxide (NaOH) molarity and curing conditions to the strength development. NaOH and sodium silicate were used as activator with ratio of 1:1 and the solution to ashes ratio of 1:1 was used. Compressive strength was tested at 7, 14 and 28 days. The results showed that the geopolymer mortar made of SSA replacement exhibited higher compressive strength with reference to those made of RHA (control sample). In addition, the results showed that geopolymer mortar specimen containing 15% of SSA replacement activated with 8M NaOH solution gave the highest strength recorded 15.0MPa in oven curing condition (60°C for 24 hours). As conclusion, SSA up to 20% replacement has potential to be used in producing geopolymer as replacement alternative to RHA.
Eco-efficiency index analysis of single story structure of reinforced concrete house using economical and environmental score approach
Authors: Hamid M S A , Jasni O O , Shafiq N
Published: December 2019

Reinforced concrete structure is widely used in Malaysia as a common structural system of a building. As a common understanding, reinforced concrete is also known as a composite structure that combined two type of materials which is concrete and steel. Due to rapid development of residential houses, this situation was creating to higher energy consumption by producing high content embodied carbon emission Therefore, three main criteria should be considered in sustainable development that is economic, environment and social in order to produce better environment. This study was developed to produce eco-efficiency design of single story residential house for different optimization of concrete characteristic strength by using economical score and environmental score analysis method. Finding was recorded blast furnace slag reinforced concrete produce an eco-efficiency design than fly ash reinforced concrete due to positive impact to the economical and environmental criteria. Therefore, it can be concluding that waste materials need to be analyzed as an alternative material in concrete because it may produce high content of embodied carbon that give negative impact to the environment.
A Simulation Study Of Tubercles Effect Of Aerodynamics Performance On Car Rear Spoiler
Authors: Ghaffar H. , Yusoff H. , Ibrahim D. , Budin S. , Razak M.R.A.
Published: December 2019

The tubercle effect is a recently discovered phenomenon where the sinusoidal pattem ‘bumps’ on the leading edge of an airfoil can improve the aerodynamic performance. This effect was inspired by looking at the humpback whale pectoral flippers that give an exceptional acrobatic manoeuvrability in the water such as somersaults, also allowing for easier capture of prey. The objective of this research is to study the effect of implementing the tubercles concept on the car spoiler in order to see whether it bring advantage or disadvantage in the aerodynamic performance of a car. The design and simulation process are done by using Solidworks. The design of airfoil spoiler based on Selig S2091 (low Reynolds number airfoil) with sinusoidal pattern leading edge were computationally used. The Airfoil spoiler with 270 mm of the chord length (C), 1200 mm wingspan (L) and angles of attack of -5°, 0°, 5°, 10°, 15°, 20°, 25°, 30° were improvised with tubercles at 40 mm amplitude of bumps (h) and the distance of the wavelength between peaks (λ) of 1200 mm, 240 mm and 133.33 mm. The simulation was tested at 40 m/s. The investigation shown that the tubercles can improve the aerodynamic performance of car rear spoiler where the tubercles are able to increase the lift coefficient but has a significant decrease in drag only at 20° and above angle of attack.
Correlation between california bearing ratio (CBR) with plasticity index of marine stabilizes soil with cockle shell powder
Authors: Nujid M M , Idrus J , Azam N A , Tholibon D A , Jamaluddin D
Published: December 2019

Subgrade soil is important for design purpose of both flexible and rigid pavement structures; flexible and rigid. The quality of flexible and rigid pavement structures is correlated on the strength and stabilization of subgrade layers. The main function of subgrade is to act as a foundation for pavement layers and supporting the load which is transmitted from the overlying layers. The marine soil is a problematic soil which low in strength and do not suitable for road embankment for highway construction. Therefore, the soil strength can be improved by adding stabilizer or admixture to increase its strength. Soil stabilization change its physical and mechanical properties from its original soil. Thus, the physical properties of marine stabilized with cockle shell powder were determined and the potential of Cockle Shell Powder (CSP) as soil stabilizer based on percentage added in CBR test was investigated. Based on previous research, the performance of soil mixed with CSP in the proportion of constant 2.5%, 5%, 7.5% and 10% was examined with CSP properties and California Bearing Ratio (CBR) tests. The results obtained indicates an increment in specific gravity and decreasing in the plastic index (PI) with the addition of 2.5% of CSP. The CBR and PI show a good correlation and thus inclusion of CSP in marine soil could be used as alternative material for subgrade layer in increasing soil strength.
The waste heat recovery for power generation from automotive exhaust using thermoelectric cell (TEC)
Authors: Yaakob Y , Fahmi A , Ghafar H , Ibrahim D , Moria H
Published: December 2019

The internal combustion process to move the vehicles had indirectly releasing waste heat into the environment which contributed to global warming. Thermal-electric Cell (TEC) is a device that able to convert thermal energy to electrical energy cleanly. The TECs system work when it is sandwiched between the hot and cold side. The objective of this study is to investigate the possibility of tapping a waste heat using thermoelectric cell (TEC) from car exhaust. The experiment had been carried out in stagnation condition in the laboratory using 1500 cc petrol engine DOHC (4G91). Four TECs (SP1848-27145) were connected in series on the top of exhaust muffler. The experiments were run in two type of cooling methods using air flow from standing fan and the flowing cold water. The maximum voltage of 2.42V was produced when temperature difference, DT reached 83°C. The LED bulbs were connected to TEC and light up when the voltage of 1.60V is obtained. The results have proved that the temperature difference between two sides is the dominant effect to determine the TEC performance. The generated power could be utilized to power an auxiliary application in the vehicle itself.
An experimental study on the influence of tubercles on aerodynamics performance of car rear spoiler
Authors: Halidi S N A M , Yusoff H , Rosmidi M R Z , Farhan A , Suhaimi S
Published: December 2019

In this study, the aerodynamic performance of a car spoiler with tubercles configurations that was inspired by Humpback whale flipper morphology was investigated. This was done by producing three (T0, T3, and T9) spoiler designs where, tubercles sinusoidal protrusions pattern was applied at the leading edge of the spoiler. T0, is a base line spoiler that has no tubercles, T3, that contains three tubercles protrusions, and T9, contains nine tubercle protrusions. The baseline spoiler design was based on the Selig s2091 spoiler and the spoiler has a chord length (C) 100mm and 290mm wingspan. The spoiler was tested angle of attack from - 20 to 30° and at Reynolds number 60000 in an open circuit subsonic wind tunnel. The aerodynamic performance of the spoiler was measured by the recorded time averaged lift and drag. From the recorded it was observed that at certain angles of attack, the presence of a tubercle pattern can bring a significant aerodynamic improvement.
An experimental study on thermal conductivity of T2 copper with different surface roughness
Authors: Abdullah N S , Yusoff H , Zaba H S , Ghafar H , Farhan A , Budin S , Suhaimi S
Published: December 2019

Recent previous studies have shown that there is a correlation between heat conductivity and surface materials. In this project, the heat conductivity 3 different samples of T2 copper with different surface roughness was studied. This was done by measuring the temperature of the samples at 9 different point using SOLTEQ Heat Conduction Study Bench (Model HE106). The surface roughness of the different samples was achieved using sandpaper and measured using the (SURFTEST SJ-410) where the different surface roughness was A: Ra=0.379μm, B: Ra=0.71μm, C: Ra=0.053μm. The sample was heated using a heater with 10W of power. From the collected data, it was observed that the specimen with the smoothest surface roughness has the best performing heat transfer with the specimen C that have the highest decreasing percentage temperature followed by specimen B and specimen A.
Feasibility study on the application of alum sludge (AS) as alternative landfill liner material in sustainable landfill infrastructure model: XRD and SEM analysis
Authors: Muhamad Bashar N A , Syarhida Isa N H , Sofiyah Rahman N R , Alias S , Chay T C , Abdul Aziz N H , Jamalludin D
Published: December 2019

The increasing number of Alum Sludge (AS) in water treatment plant (WTP) from water treatment process has been directed to the reduction of storage capacity for keeping of AS waste itself in the landfill. Other than disposed in the landfill site, this accumulated AS can be commercialized into a useful product such as landfill barrier. Conventionally, clay is used as the protection layer in the engineered sanitary landfill to reduce the leachate intrusion into groundwater. However, due to higher usage and demand on the clay (C) material caused its depletion and higher in cost. Therefore, accumulated AS can be recycled and reused to reduce the disposal problem in landfill and financial burden facing by the landfill operator. In this study, AS was investigated and compared with the kaolin clay (KC) in terms of XRD and SEM characteristics. The index properties and hydraulic conductivity, k test were also conducted to classify the AS and KC composition. Based on the testing, AS can be classified as High Plasticity Clay and the value of k for AS is higher than KC. Based on the results from XRD, both of KC and AS samples was having a similar crystalline phase which is Quartz. Based on the summary of compounds elements, the chemical elements of Oxygen, Aluminium, Silicon and Iron presence in AS have a quite similar percentage of weight (%) with KC. From all of these results, it can be concluded that the AS is mostly having similar materials to KC and amorphous in nature.
Ultraviolet photodetectors based on doped ZnO films
Authors: Ng Z N , Chan K Y
Published: December 2019

In this paper, we report the realization of ultraviolet (UV) photodetector based on doped ZnO films. The ZnO p-n junction was fabricated on indium tin oxide (ITO) coated glass, which consists of n-type and p-type layers based on Ga-doped (2 at.%) and N-doped (20 at.%) ZnO films, respectively. The current-voltage (IV) characteristics, photosensitivity, photoresponsitivity, and photocurrent gain were derived to determine the performance of the device. At 5 V reverse bias, the ZnO-based UV photodetector exhibits photosensitivity of 10.9, photoresponsivity of 2.1 × 10−2 AW−1, and photoconductive gain of 7.2 × 10−2.
Outstanding performance of waste chicken eggshell derived CaO as a green catalyst in biodiesel production: Optimization of calcination conditions
Authors: Lani N S , Ngadi N , Jusoh M , Mohamad Z , Zakaria Z Y
Published: December 2019

The utilization of conventional catalyst such as sodium hydroxide in biodiesel production possesses several disadvantages as they are difficult to separate from biodiesel products, particularly prone to soap formation and require a multiple neutralization step. For this reason, CaO derived from waste chicken eggshell was explored as an alternative catalyst. Normally, CaO from natural source was synthesized through the calcination process. Thus, this paper aims to identify the optimum condition of calcination process for high biodiesel yield. On the basis of statistical analysis, a central composite design (CCD) was used to optimize the calcination conditions which are calcination temperature and time to achieve high yield of biodiesel. The calcination temperature and time were varied in the range of 600 to 1000 °C and 60 to 300 minutes, respectively. The optimum calcination conditions are 900 °C and 3.5 hours, whereby the most significant factor affecting biodiesel yield was identified as calcination temperature. The result also indicated that the second order model was adequate for both independent variables on the response with R2 of 0.9383. The maximum biodiesel yield of 92.81 and 94.72% were obtained by experimental and predicted values, respectively.
Optimization of supercritical fluid extraction of Mariposa Christia Vespertilionis leaves towards antioxidant using response surface methodology
Authors: Ariff MAM , Tukiman S , Razak NAA , Osman M S , Jaapar J
Published: December 2019

Mariposa Christia Vespertilionis (MCV) or also known as butterfly wing leaves, is popular in the traditional medicine practice. The objective of this study is to optimize the antioxidant components (based on antioxidant activity analysis) from the MCV leaves extract using Supercritical Fluid Extraction (SFE) based on different temperature, pressure, and particle size via Response Surface Methodology (RSM). Besides that, it is also to evaluate the optimal condition of different extracting antioxidant activity from MCV leaves using Design Expert 10 software. The condition range for both pressure and temperature were between 150-350 bar and 30-70 °C with constant extraction time. The size of particle samples were between 63 μm-1000 μm. The antioxidant was analyzed using UV–vis Spectrophotometer (UV-vis). The lowest antioxidant activity was 8.20 % and higher antioxidant activity was obtained at 49.76 %. Lower absorbance indicated highest free radical scavenging activities. Maximum percentage (%) indicated high scavenging activities, thus higher 1,1-diphenyl-2-picrylhydrazyl (DPPH) is a good indication for antioxidant. The predicted RSM optimal condition of antioxidant activity was at temperature 50 °C, pressure 282 bar, and particle size 500 μm, which the predicted antioxidant was 50.62 %. Upon verification through experiment, it was found out that the antioxidant activity value was close to the predicted value with an average error of less than 1%.
A hybrid electrocoagulation-adsorption process for fluoride removal from semiconductor wastewater
Authors: Jalil S N A , Amri N , Ajien A A , Ismail N F , Ballinger B
Published: December 2019

Semiconductor processing facilities regularly emit wastewater with fluoride concentrations exceeding 100 mg/L which can cause major health issues in the local population. This research aims to address this issue by optimising an electrocoagulation-adsorption (EC-AD) process using two aluminium electrodes and activated carbon. The applied voltage (5, 15, and 20V) and adsorbent dosage (0.20, 0.50, and 1.00g) parameters were varied to treat a synthetic wastewater solution containing 100 mg/L of fluorine. It was found that fluoride removal efficiencies are significantly affected by the adsorbent dosages and applied voltages used. Increasing the applied voltage from 5V to 20V increased the removal efficiency from 37.55% to 64.25% for 0.2g adsorbent dosage and from 33.85% to 67.25% for 0.5g dosage. After all the parameter combinations were tested, an applied voltage of 20V and an adsorbent dosage of 0.50g produced the maximum fluoride removal efficiency. These parameter values thus define the optimal conditions for the EC-AD process to reduce fluoride from highly concentrated wastewater. The AD, EC, and hybrid EC-AD process achieved fluoride removal efficiencies of 2.86%, 41.13%, and 67.25% respectively from synthetic wastewater. Therefore, it was showed that the combination EC-AD process performs better than adsorption (AD) or electrocoagulation (EC) processes used in isolation.
Characterisation of polysaccharide composite incorporated with turmeric oil for application on fresh-cut apples
Authors: Sharif Z I M , Jai J , Subuki I , Zaki N A M , Mustapha F A , Mohd Yusof N
Published: December 2019

Composite edible coatings were made up from two types of polysaccharide which are cassava starch and carboxymethyl cellulose (CMC) incorporated with turmeric oil (TO) as an antioxidation agent. Weight loss, firmness loss and moisture content were studied to determine the effect of composite edible coating incorporated with different TO concentration and dipping times towards the quality of fresh-cut Fuji apples. Findings showed that the coating with 17.5 μL/mL concentration of TO and 180 s dipping time had the lowest weight loss and percentage of firmness loss. While for percentage of moisture content, 17.5 μL/mL concentration of TO with 60 s dipping time had the lowest moisture content loss. Surface morphology was analysed to observe the uniformity of coating on fresh-cut Fuji apples surface. The oxidase enzyme activities of fresh-cut Fuji apples reduce when there is TO present in edible coating. It showed that the coating with 180 s dipping time had the best surface coating compared to 60 s and 300 s dipping time. The composite edible coating emulsion can be huge potential as fresh-cut fruits coating to preserve the quality of the fruits.
Characterization of type III and IV solar radio bursts from e-CALLISTO
Authors: Ansor N M , Hamidi Z S , Shariff N N M
Published: December 2019

This paper presents the characterization of solar radio burst type III and IV obtained from e-CALLISTO website. Solar radio burst (SRB) is one of the tools in space weather studies as each type of SRB indicates the production of solar activity at that moment which can also bring it towards the prediction of solar events. Generally, SRB has five different type of emissions which are named as type I, II, III, IV and V, this paper will only focus on type III and IV. Data of type III and IV bursts were selected on 15th Sept. 2015 and 27th Feb. 2018 respectively and discussions on each type of bursts include two stations to make a comparison. At the end of this work, type III bursts show a rapidly drift structure from high to low frequency, strongly associated to solar flares and the burst is due to Langmuir waves. Meanwhile, type IV bursts are recognized by its broadband continuum with rapidly fine structure and they act as a hint of geomagnetic storm commencement. More details on the formation of these burst are discussed.
Optimization of biodiesel production from Chlorella Vulgaris using CuO, NiO and MgO on zeolite 4A catalysts
Authors: Ariffin M I , Abdullah N , Bahruji H , Mohd Kasim N A , Abdul Halim N , Yun Hin T Y
Published: December 2019

The activities of metal oxide on zeolite as catalysts for production of fatty acid methyl ester from microalgae lipid oil were investigated by impregnation of MgO, CuO and NiO on zeolite 4A. The physical properties of the catalysts were characterized using TGA, XRD, Fe-SEM and Nitrogen Physisorption analysis. Evaluation on activity for biodiesel production from Chlorella vulgaris microalgae shows the trend of catalysts performance as CuO/Zeo>NiO/ZeO>MgO/Zeo. The amount of catalysts, the methanol to oil ratios and the length of reaction times affects the production of biodiesel with 69% of biodiesel produced using CuO/Zeolite catalysts at optimized conditions.
Rock water interaction on the effect of drying and wetting to the mechanical and dynamic properties of tropical weathered granite
Authors: Hasan A S Md , Osman N M , Ismail M K A , Albar A , Razali M
Published: December 2019

This study deals with the effect of water on the tropical weathered granite and sandstone rock characteristics. Water act as an agent in the weathering process that lead to the weakness of the cementation and bonding condition. The process of wetting and drying are able to take place with the presence of water inside the rock microstructure, then further created the numbers of micro-pore which contributing to weakens the rock structure. Thus, this study is focusing to analyses the effect of the presence of water on the mechanical and dynamic properties of granitic rock depending on its weathering degree. The interaction between water and rock was observed through the water-rock interaction test by using saturation and caliper method, where all the rock samples, totalling 81 samples allowed to experience the wet and dry conditions for 21 days, 56 days and 90 days. Uniaxial compressive strength test, indirect (Brazilian) tensile strength and point load tests were conducted to determine the strength of the rock. Meanwhile, P-wave velocity test was conducted to measure the wave velocity that able to penetrate through the intact rock. In conclusion, the increasing of weathering degree, will allowed the rock to absorb the water as their particles has not more tightly bonding. Therefore, it found that the strength of tropical weathered granite was decrease as the interaction with water causes the interlocking of the rock particles is reduces from the process of weathering.
Cation-exchanged NaY Zeolite: Effect of temperature and ion concentration to membrane performance
Authors: Isa M A , Halim M H
Published: December 2019

Zeolite membranes possess well defined pore structures which able to separate gasses with high selectivity. The separation between adsorptive and non-adsortive gasses depends on the affinity of permeating gas molecules with the zeolites structures whereby different types of cations resides in the zeolitic framework will affect the permeselectivity of the membranes. Several efforts have been made to modify zeolite membranes in order to enhance their capability in gas separation by ion exchange process. Here, investigations were performed on the ion exchange process of zeolite NaY membrane with Ag+ cation at different concentrations (0.1M, 0.025M) and temperatures (ambient temperature and 80°C). The results revealed that temperature plays significant role in maintaining the morphologies of zeolite NaY membranes. Dealumination process was also observed to occur simultaneously with the ion exchange process. Overall, CO2/CH4 selectivity of the cation-exchanged NaY zeolite membranes increased by 100% with less CO2 flux reductions were recorded by samples which had been ion exchanged with less concentrated ion exchange solution i.e. 0.0125M at ambient temperature. Nevertheless, CO2/CH4 selectivity decreased for membrane samples which had been ion exchanged at higher temperature (80°C) due to dissolution of the zeolite membranes layer.
Characteristic of phenol and 2,4-dichlorophenol synthetic wastewater degradation in a DBD (dielectric barrier discharge) reactor
Authors: Permata Y E , Cahyani R A , Karamah E F , Bismo S
Published: December 2019

In this study the content of phenol and 2,4-DCP (2,4-dichlorophenol) in synthetic wastewater was decomposed using the excitation technique of a mixture of waste liquid and air in a cold plasma Dielectric Barrier Discharge (DBD) reactor. The purpose of this study was to study the degradation process of organic compounds of phenol and 2,4-DCP liquid waste into simpler compounds. Plasma technology applied to the liquid-air mixture in the DBD reactor has the ability to oxidize and degrade organic synthetic wastewater into simpler compounds with relatively faster processing times without forming new waste compounds. Plasma air (excited air) will degrade wastewater by breaking the atomic bonds of synthetic wastewater compounds at high voltages between 220 - 330 V. The performance of the degradation process of synthetic waste can be known through analysis of phenolic compounds, hydroxyl and dissolved ozone, COD, and the final product. The parameters studied in this study are air gas flow rate 2 - 2.5 L/min, waste water flow rate 52 - 100 mL/min, plasma voltage between 220 - 330 V, and volume of waste water. This study also compared the degradation process of phenol and 2,4-DCP in cold plasma DBD reactor with the degradation process in multi-injection bubble column reactor. The removal efficiency of the process achieved 57.5% for phenol and 89.55% for 2,4-DCP.
Agriculture waste from banana peel as low cost adsorbent in treating methylene blue from batik textile waste water effluents
Authors: Abu Bakar A A , Wan Mazlan W N R , Akbar N A , Badrealam S , Muhammad Ali K A
Published: December 2019

Batik industrial textile waste water effluent if improperly disposed to the catchment can cause the water pollution that will endanger human health and the environment. The contaminants discharge in the dye processing causes the water pollution. Banana peel is a potential agriculture waste that can be used to reduce the concentration of color from synthetic dye effluents. This study is aim to determine the potential of banana peel as agricultural waste adsorbent for Methylene Blue (MB) removal at different contact time (15minutes, 30 minutes, 45 minutes, 90 minutes, 120 minutes, 150 minutes, and 180 minutes) and different adsorbent dosage (0.05, 0.1, 0.15, 0.2, 0.25, 0.3, and 0.4 gram) and to develop kinetic model for Methylene Blue (MB) removal. The experiments were conducted at room temperature using batch study. As the banana peel dosage is added from 0.05 g to 0.4 g in 100 ml of Methylene Blue solution, the percentage of MB solution removal also increase from 34.69 % to 86.88 %, indeed due to the increase in phenolic compounds adsorption rates. The adsorption process reached the optimum contact time at 150 minutes with MB solution removal of 86.22 %. The kinetic data obtained specified that the data follow closely the pseudo-second-order. It is concluded that banana peel can act effectively as natural adsorbent in treating Methylene Blue (MB) from batik textile wastewater effluents.