Reduced graphene oxide-multiwalled carbon nanotubes hybrid film with low Pt loading as counter electrode for improved photovoltaic performance of dye-sensitised solar cells

In this work, the role of reduced graphene oxide (rGO) with hyperbranched surfactant and its hybridisation with multiwalled carbon nanotubes (MWCNTs) and platinum (Pt) nanoparticles (NPs) as counter electrode (CE) were investigated to determine the photovoltaic performance of dye-sensitised solar cells (DSSCs). Sodium 1,4-is(neopentyloxy)-3-(neopentyloxycarbonyl)- 1,4-dioxobutane-2-sulphonate (TC14) surfactant was utilised as dispersing and stabilising agent in electrochemical exfoliation to synthesise graphene oxide (GO) as initial solution for rGO production prior to its further hybridisation and fabrication as thin film. A chemical reduction process utilising hydrazine hydrate was conducted to produce rGO due to the low temperature process and water-based GO solution. Subsequently, hybrid solution was prepared by mixing 1 wt% MWCNTs into the produced rGO solution. TC14-rGO and TC14-rGO_MWCNTs hybrid solution were transferred into fluorine-doped tin oxide substrate to fabricate thin film by spraying deposition method. Finally, the CE films were prepared by coating with thin Pt NPs. Photoanode film was prepared by a two-step process: hydrothermal growth method to synthesise titanium dioxide nanowires (TiO2 NWs) and subsequent squeegee method to apply TiO2 NPs. According to solar simulator measurement, the highest energy conversion efficiency (η) was achieved by using CE-based TC14-rGO_MWCNTs/Pt (1.553%), with the highest short current density of 4.424 mA/cm2. The highest η was due to the high conductivity of CE hybrid film and the morphology of fabricated TiO2 NWs/TiO2 NPs. Consequently, the dye adsorption was high, and the photovoltaic performance of DSSCs was increased. This result also showed that rGO and rGO_MWCNTs hybrid can be used as considerable potential candidate materials to replace Pt gradually

Effect of Manganese Content on the Fabrication of Porous Anodic Alumina

The influence of manganese content on the formation of well-ordered porous anodic alumina was studied. Porous anodic alumina has been produced on aluminium substrate of different manganese content by single-step anodizing at 50 V in 0.3 M oxalic acid at 15°C for 60 minutes. The well-ordered pore and cell structure was revealed by subjecting the porous anodic alumina to oxide dissolution treatment in a mixture of chromic acid and phosphoric acid. It was found that the manganese content above 1 wt% impaired the regularity of the cell and pore structure significantly, which can be attributed to the presence of secondary phases in the starting material with manganese content above 1 wt%. The pore diameter and interpore distance decreased with the addition of manganese into the substrates. The time variation of current density and the thickness of porous anodic alumina also decreased as a function of the manganese content in the substrates

Chemical constituents and lipoxygenase inhibitory activity of Piper stylosum Miq.

ABSTRACT. Chemical constituents and lipoxygenase inhibitory activity of the aerial part of Piper stylosum have been studied. Fractionation and purification of the extracts afforded five lignans, identified as yangambin (1), sesamin (2), syringaresinol (3), pinoresinol (4), and medioresinol (5), together with other constituents; 4-allyl resorcinol, β-sitosterol, β-sitostenone, taraxerol, vanilin, and vanilic acid. The structures of these compounds were established by analysis of their spectral data, as compared to that of reported compounds. The lipoxygenase inhibitory activity of the extracts and isolated lignans were also evaluated.               KEY WORDS: Piperaceae, Piper, Piper stylosum, Lignan, Lipoxygenase Bull. Chem. Soc. Ethiop. 2019, 33(3), 587-592.   DOI: https://dx.doi.org/10.4314/bcse.v33i3.1

Public attitude towards modern biotechnology

This article reviews the literature related to the main idea of the study, rooting from the definition of biotechnology, global status of commercialized biotechnology products, and global and local public attitudes towards modern biotechnology and past models for attitude towards modern biotechnology. The first section of the review will be the in-depth-discussion regarding the definition of modern biotechnology according to several established international organizations, followed by global status of commercialized biotechnology products which will emphasize on how modern biotechnology is classified and which area are being focused more by the stakeholders, and global and local public attitudes towards modern biotechnology based on previous studies. Last but not least, the final section is credited to past studies related to attitudes and past models of public attitudes towards biotechnology, both globally and locally. A developing country like Malaysia was chosen in this article as an example of the case study related to local situation of modern biotechnology.Key words: Modern biotechnology, genetically modified (GM), public attitude, Malaysi

Examining the fit of social media as a tool to share disaster-related knowledge: From the perspective of task-technology fit theory

ICT is emerging as a process of knowledge-sharing without any physical and geographical constraints.ICT has successfully been used to disseminate knowledge during a constrained situation (i.e. disaster).In other words, ICT can be used to connect the public during a time of crisis.In Malaysia, the National Security Council(NSC) is one of the agencies responsible for managing disasters.Having a reputation as being a "champion of agencies", the NSC is responsible for providing a social media by which to share disaster-related knowledge with the public.Nevertheless, to what extent this social media actually supports the knowledge-sharing process is unknown.Hence, the purpose of this study is to determine the extent to which a social media actually supports the knowledge-sharing process; a theory known as Task-Technology Fit (TTF) is adopted. The data will be collected by distributing questionnaires to the users who have experience in accessing the social media tools of the NSC to acquire disaster-related knowledge during the occurrence of a disaster (i.e. flood). Structural Equation Modelling (SEM) will be used to analyze the data.The development of a theoretical research model will assist the agencies involved in disaster management to predict user evaluation of the social media tool in order to gather knowledge/information related to disasters

Workplace assessment of naphtha exposure in a tire manufacturing industry.

A qualitative and quantitative workplace assessment was carried out to determine naphtha exposure in a tyre manufacturing industry. A qualitative chemical health risk assessment was conducted to identify naphtha hazard at the workplace. Quantitative assessment using Portable VOC Monitor, Automatic Sampling Pump and personal air sampling pump was used to determine VOC concentrations, organic solvents, and individual air naphtha respectively. The risk rating of naphtha was estimated to be 5. The mean VOC concentration was in the range of 2.43 to 92.93 ppm. Repair area had the highest VOC concentration while the lowest was in the moulding area. Each work station had significant differences for VOC concentrations (p < 0.001). Laboratory analysis found various solvents including 2-methyl pentane, hexane, methyl cyclopentane, heptane, cyclohexane and toluene which were present in the liquid naphtha. Only xylene has been detected in the making and moulding areas with a range of 2 to 5 ppm. Meanwhile, the air naphtha concentrations of the exposed workers were significantly higher than those unexposed. The risk of naphtha exposure was qualitatively significant and not adequately controlled. Naphtha was detected in all work stations since it is the main solvent used. The “Repair Area” was significantly more contaminated than the other area

Comparison of Double Unit Tunnel Form Building before and after Repair and Retrofit under in-Plane Cyclic Loading

This paper present the experimental work on the seismic performance of double unit tunnel form building (TFB) subjected to in-plane lateral cyclic loading. A one third scale of 3-storey double unit of TFB is tested at ±0.01%, ±0.1%, ±0.25%, ±0.5%, ±0.75% and ±1.0% drifts until the structure achieves its strength degradation. After that, the TFB is repaired and retrofitted using additional shear wall, steel angle and CFRP sheet. A similar testing approach is applied to the specimen after repair and retrofit. The crack patterns, lateral strength, stiffness, ductility and equivalent viscous damping (EVD) were analyzed and compared before and after repair and retrofit. The result indicates that the lateral strength increases by 22 in pushing direction and 27% in pulling direction. Moreover, the stiffness and ductility obtained before and after retrofit increase tremendously by 87.87% and 39.66%, respectively. Meanwhile, the energy absorption measured by equivalent viscous damping obtained after retrofit increase by 12.34% in pulling direction. It can be concluded that the proposed retrofit method is capable to increase the lateral strength capacity, stiffness and energy absorption of double unit TFB

Business intelligence readiness factors for higher education institution

Higher Education Institution (HEI) have embarked on the new style of decision-making with the aim to enhance the speed and reliability of decision-making capabilities. One of the hardest challenges in implementing Business Intelligence (BI) is the organization’s readiness towards adopting and implementing BI systems. Currently, few published studies have examined BI readiness in HEI environment. Seeing this challenge, this study aims to contribute in determining the BI readiness factors in HEI specifically in the deployment strategies. Through inductive attention to BI in HEI environment, three broad factors have been identified: a) Organizational – that concerning on business strategies, process and structure, b) Technology – involves the BI system and knowledge for managing including the sources and c) Social – the culture within organization that may influence decision-making and its processes. This paper also makes recommendations for future research

The effects of thickness on biomechanical behavior of articular cartilage: a finite element analysis

It is important to study joint contact mechanics in order to understand the human joint function and degeneration. In previous studies, the cartilage behavior was investigated using computational method assuming the cartilage to be flat and an ideal thickness. But, this assumption may not appropriate because the joint is naturally curved and the cartilage thickness varies across the articular cartilage. In this study, finite element (FE) analysis was performed to investigate the effect of cartilage thickness on contact pressure and pore pressure of cartilage in indentation test. An axisymmetric FE model of cartilage was developed according to the thickness and radius measured in the experiment. The cartilage was modeled as biphasic material to describe the properties of cartilage. Based on the result, the lowest cartilage thickness of 0.3 mm thickness generated 48% higher in contact pressure and 59% higher in pore pressure, compared to the highest thickness cartilage. This could indicate that the cartilage thickness does affect the contact pressure and pore pressure

3D Image Plane from Stereo Camera Calibration on Extrinsic Parameters in Stereo Vision Aplication

This paper presents a 3D image plane in a group of target or image during the process of stereo pair calibration. The extrinsic parameters of camera calibration can be viewed in 3D image or scene which contains the rotation and translation of vector. The error re-projection of a single image could determine the less error of distortion during the extraction of chessboard corner each image taken. The distortion model also generates an error coordinate system in pixel value. The 3D image will viewed the result and output of extrinsic parameters during the calibration process.