13474 research outputs found
Sort by
Terpolymer based gel electrolytes: Augmented redox couple diffusion via iodide salts and copper(II) oxide nanofiller for dye-sensitized solar cells / Nur Khuzaimah Farhana Abd Aziz
No full textDye-sensitized solar cell (DSSC) has received widespread attention for its low-cost, environmental benignity and potential high conversion efficiency as compared to conventional silicon solar cells. The utilization of liquid electrolyte in DSSCs is often associated with several practical issues such as electrolyte leakage and evaporation, and precipitation of salts in polymer at low temperature which make gel polymer electrolyte (GPE) is preferable. Gel polymer electrolytes (GPEs) consisting of terpolymer, poly(vinyl butyral-co-vinyl alcohol-co-vinyl acetate) (P(VB-co-VA-co-VAc)) and different compositions of iodide salts (sodium iodide, NaI and tetrapropylammonium iodide, TPAI) have been prepared and investigated. Host polymer-salt complex suffers from low ionic conductivity and poor mechanical strength due to slow ion mobility within the polymer system. Incorporating metal oxide nanofiller into GPE is one of the approaches that can be used to obtain improvement in ionic conductivity and efficiency due to their large surface area which provides cross linking centers for the polymer segment. Copper oxide (CuO) nanofillers were synthesized through sonochemical method and subsequently calcination at different temperatures (200 ℃, 350 ℃ and 500 ℃). These nanofillers were incorporated into the GPE to form polymer composite gel electrolyte (PCGE). Then, different amounts of CuO-350 nanofiller (CuO nanofiller calcined at 350 ℃) were added to the best polymer-salt system sample. The results of X-ray diffraction (XRD) were utilised to explain the trend in ionic conductivity obtained when increasing the amounts of NaI salt, TPAI salt, and CuO nanofillers. Fourier transform infrared spectroscopy (FTIR) measurements have confirmed the complexation of chemicals inside the electrolyte. The electrochemical performance of GPE was investigated using electrochemical impedance spectrometry (EIS) and linear sweep voltammetry (LSV). It was found that NaI-3 and TPAI-4 exhibited the highest ionic conductivity of ((3.22 ±0.01) × 10−3 S cm-1 and ((1.93 ±0.01) × 10−3 S cm-1) and apparent triiodide diffusion coefficient (3.25 × 10−6 cm2 s −1 and 5.96 × 10-6 cm2 s-1) in polymer-salt system, respectively. The addition of CuO-350 nanofillers has enhanced the ionic conductivity and apparent triiodide diffusion coefficient of the TCuO350-3 sample to (3.49 ±0.01) × 10−3 S cm-1 and 1.48 × 10-5 cm2 s-1, respectively. On the other hand, the developed GPEs and PCGEs were used to fabricate DSSC. For the salt-based GPE, the highest efficiency of 4.62 % was achieved by TPAI-4 system compared to NaI-3 system with the efficiency of 4.01 % due to the higher diffusion coefficient of the redox couple. By adding CuO-350 into the polymer-salt system, the efficiency increased to 7.05 %. The longer rod structures of CuO-350 provide a continuous path for redox couple diffusion than other calcination temperature nanofiller. The best sample among PCGE is TCuO350-3. It has 5 wt. % of CuO-350 and an efficiency of 7.69 % with JSC of 23.47 mA cm-2, VOC of 0.62 V, and fill factor of 52.9 %
Synthesis and characterization of polypropylene fumarate and poly[(R)-3 hydroxybutyrate]-based polyurethane scaffolds for tissue engineering / Bushra Naureen
No full textDegeneration of living cells/tissues, and organs is a global concern. Biodegradable tissue engineering scaffolds (TES) synthesized from natural or synthetic polymeric biomaterials aid tissue repair. Polyurethanes (PU) are prominent synthetic polymers for TES synthesis. However, PU TES based on polycaprolactone (PCL) and polylactic acid (PLA) polyols have slow degradation, limited biocompatibility (cell adhesion), and hindrance towards growth factors (GF) immobilization due to single functional group (COOR) per monomer unit. Hence, there is a need to explore alternative polyols and chain extenders (CE) to incorporate multiple functional groups per monomer unit of PU TES. This study aimed to synthesize new 3D PU foam scaffolds (PUFS) with more hydrolysis susceptible and crosslinkable functional groups, designed for enhanced/variable in-vitro degradation rate, biocompatibility, and GF immobilization/release (IR) potential. Four 3D PUFS (PU1,PU2,PU3, and PU4) with tunable in-vitro degradation rates were synthesized through addition polymerization reaction between polypropylene fumarate (PPF) the polyol, 1,6-hexamethylene diisocyanate (HDI) and variable concentrations of CE poly[(R)-3-hydroxybutyrate] (P3HB). To enhance PUFS biocompatibility and GF IR potential, PU4 was modified with four concentrations of κ-carrageenan (CMPU: PU4C1,PU4C2,PU4C3, and PU4C4). Different characterization techniques were employed for the analysis of PPF (GPC,FTIR,1H and 13C NMR) and PUFS (FTIR,1H and 13C NMR,FESEM,TGA/DTA and 70 days in-vitro degradation analysis (n=8)). Moreover, PU4 and CMPU were examined via FTIR and EDX. The biocompatibility of PU4 and CMPU scaffolds (n=4) were investigated by in-vitro cell culture (C2C12 myoblast) through (%) resazurin reduction assay (till day-21), live/dead, and SEM images (both up to 14 days). The GF(IGF-1) IR potential of PU4 and CMPU (n=3) was determined by ELISA kits and microplate reader for 14 days. GPC provided the molecular weight (Mn = 455.67 g mol-1, Mw = 587.15 g mol-1) and PDI (1.29) of the PPF. The results of FTIR or 1H and 13C NMR spectra confirmed the synthesis of PPF (C=C,COOR), PUFS (C=C,COOR,NHCOO) and CMPU (C=C,COOR,NHCOO,O=S=O,C-O-C,O-SO3-) with multiple functional groups. The EDX spectra presented an increase of sulfur (%) composition from 0.24% to 4.0% with the increase of incorporated κ-carrageenan in PU4. The PUFS FESEM images revealed pores (242-340μm) and void spaces (735-860μm) beneficial for TE. The PUFS (PU1,PU2,PU3,PU4) TGA/DTA curves showed an onset thermal decomposition temperature of 267.17ºC, 267.28ºC, 256.0ºC, and 240.72ºC, respectively. The results of day-70 PUFS in-vitro degradation analysis revealed a significant difference between the weight loss (%) (PU1=4.09±0.18%, PU2=8.03±0.17%, PU3=13.14±0.12%, and PU4=20.21±0.19%). Thus, confirmed the formation of PUFS with variable degradation rates (PU4>PU3>PU2>PU1) based on incorporated P3HB concentration (hydrolyzable COOR). The results of biocompatibility assessment day-21 (%) resazurin reduction (PU4=67.54±7.68%, PU4C1=71.40±5.07%, PU4C2=75.79±6.10%, PU4C3=82.42±6.82% and PU4C4=83.37±7.68%), live/dead and SEM images (day 1,7,14) proposed that C2C12 myoblasts adhesion, proliferation, metabolic activity, and viability on PUFS followed a trend (PU4C4>PU4C3>PU4C2>PU4C1>PU4). A similar trend was depicted from the results of IGF-1(ng ml-1) release from PU4 and CMPU scaffolds at all timepoints (day 1,3,7,10,14), suggesting successful synthesis of PUFS with enhanced biocompatibility and IGF-1 release potential, i.e., directly related to the incorporated κ-carrageenan concentration
Gold nanosphere-thioctic acid-Zn(Salophen) conjugate: Synthesis, characterisation, toxicity and protein interaction / Ng Yin Zhuang
No full textA novel inorganic metal complex gold nanoparticle conjugate was synthesised and characterised in this study. It was achieved by conjugating a Schiff base zinc complex, [N,N-bis(salicylidene)-1,2-phenylenediamine]zinc(II) or commonly known as Zn(salophen) (ZnS) to gold nanosphere with thioctic acid functioning as the linker. The conjugate (AuNS-TA-ZnS) was characterised with FTIR, UV-visible spectroscopy, fluorescence spectroscopy, dynamic light scattering (DLS) analysis, zeta potential analysis, inductively coupled plasma mass spectrometry (ICP-MS) analysis and transmission electron microscope (TEM). Both AuNS-TA-ZnS and ZnS were confirmed to be the proposed structures. The diameter of AuNS-TA-ZnS was determined to be 17.73 nm with 1785 ZnS conjugated to each gold nanosphere. The interactions of AuNS-TA-ZnS with proteins were studied. It was found that the conjugate has strong affinity to Bovine Serum Albumin (BSA). AuNS-TA-ZnS is able to alter the secondary structure of BSA without causing conformational change to the tertiary structure of BSA. Apart from demonstrating the ability to generate reactive oxygen species (ROS), AuNS-TA-ZnS also inhibits proteasome activities specifically at the Trypsin-like site of mouse 20S proteasome. Cytotoxicity study with breast cancer cells shows that AuNS-Ta-ZnS is more cytotoxic than unconjugated ZnS. Transepithelial electrical resistance (TEER) measurement across Caco-2 cell monolayer found AuNS-TA-ZnS has higher efficiency than ZnS in permeating thru the cells
Shell model calculations within SDPF-U Hamiltonian around N=20 region in "Island of inversion" / Firas Abed Ahmed Al-Ezzi
No full textThe N=20 island of inversion is a fascinating region of experimental and theoretical studies that consists of three nuclei chains; neon (Ne), sodium (Na), and magnesium (Mg). A feature of this region is the deformation of nuclei in the ground state which is evident during inversion between intruder and normal configurations. The spin-flip interaction, tensor interaction and correlation energy (Ecorr) play a central role in shape deformation and in the vanishing of the N=20 shell gap; thereby leading to an inversion in energy levels. SDPF-U; based on the sd-pf model space with two main shells and seven subshells; was one of the Hamiltonians used to describe and understand the N=20. Restriction was used to reduce the dimensionality of the calculations and to create intruder states. Unmixed intruder configurations (1p-1h), (2p-2h) and (3p-3h) were studied for the N=20 region within the SDPF-U Hamiltonian. Restricted configurations were applied to calculate the low-lying states and the transition probabilities ( ) with effective charges ep=1.32 and en=0.421 for the 32-36Mg chains and ep=1.3 and en=0.537 for the 31,33,35Na chains. The best proton distributions in this work were found to be: (1) (d5/2) -2, (s1/2) +2 in sd-shell for positive-parity in the 32,34,36Mg isotopes, (2) (d5/2) -2, (d3/2) +2 in sd-shell for negative-parity in the 32Mg isotope, (3) (d5/2) -2, (d3/2) +2 in sd-shell for positive-parity in the 33,35Mg isotopes, (4) (d5/2) -2, (s1/2) +2 in sd-shell for negative-parity in the 33,35Mg isotopes, and (5) (d5/2)-1, (d3/2) +1 in sd-shell for positive-parity in the 31,33,35Na isotopes. Energy levels and transition probabilities were then calculated using the OXBASH code and compared with recent experimental data and previous theoretical calculations of different methods and models. The goodness of fit between the theoretical and experimental values confirmed the existence of intruder configurations in these nuclei. The theoretical results validated that an SDPF-U Hamiltonian, with restricted configurations, was able to describe the structure of 32-36Mg and 31,33,35Na nuclei within the N=20 region. Moreover, the SDPF-U Hamiltonian results confirmed the existence of many energy states and suggested other states as well
CRISPR-CAS9 HSF4-targeted for clear cell renal cell carcinoma proliferation capacity, colony and tumorspheres formation / Mei Juan Wong
No full textClear cell renal cell carcinoma (ccRCC) is the most prevalent form of kidney cancer, accounts for about 75% of all kidney cancer cases. Although anti-angiogenic drugs targeting the receptor tyrosine kinases and mTOR inhibitors were clinically approved for ccRCC, but the current available drugs are still having low efficacy and most of the patients can rapidly develop therapeutic resistance. Prior analysis of TCGA RNA-Seq data on the downstream analysis of KLF6-driven transcriptional programs in ccRCC revealed that HSF4 is among the genes those are significantly upregulated in ccRCC as compared to normal kidney tissues and high expression of HSF4 in ccRCC patients is associated with poor prognosis. To interrogate the HSF4 functional relevance in supporting kidney cancer cells growth and cellular fitness, we targeted HSF4 gene in ccRCC cell line (786-M1A) by using CRISPR-Cas9 (CRISPRko) system and carried out in-vitro functional assays to determine the phenotypic effects of targeting HSF4 in ccRCC cells. A point mutation of insertion was introduced into the HSF4-targeted 786-M1A cells and cause frameshift mutation and reduction of HSF4 protein synthesis. The in-vitro functional assays showed to decrease cell activities in terms of proliferation rate, colony formation, and ability to form tumorspheres in HSF4-targeted 786-M1A cells as compared with the non-targeted 786-M1A cells. The results indicated the HSF4 gene displayed functional role in maintain 786-M1A cells growth and cellular fitness. The further analysis will be focused on the analysis of the downstream pathways that are regulated by HSF4 gene. These findings are believed to be able to contribute to the foundation of the understanding on the molecular drivers in ccRCC pathogenesis and the development of effective therapeutic strategy for ccRCC patients
Developing an ecological visualization system for biodiversity and water quality data / Cham Hui
No full textInformation visualization is an essential tool for effective communication and interpretation. When opposed to numerical quantities, comprehending information through graphics is easier. Google Earth can be used to create a useful monitoring site visualization system. However, research in web-based visualization systems is still lacking, and it deserves to be addressed. The research aims to create a web-based system that depicts the Water Quality Index (WQI) and the biodiversity index on Google Earth. For easy interpretation of water quality conditions, as well as species richness and biodiversity indexes, the system utilized graphical representation through various forms and colors. pH, dissolved oxygen, chemical oxygen demand, biochemical oxygen demand, total suspended solids, and ammonia nitrogen are all used in the stand and manage WQI for water quality visualization. For the biodiversity element, the program includes common biodiversity indexes such as Species Richness, Shannon Index, Simpson Index, and Hill Numbers. Citizen science has contributed to the collection of biodiversity data that is useful for biodiversity site conservation and preservation. By combining graphical components, the applicability of site biodiversity indexes can be improved. Previous research that attempted to integrate the calculation of biodiversity indices into biodiversity monitoring systems lacked the visual element. This unique study aims to create an online module that integrates citizen science biodiversity data with a visualization component. A graphical depiction of the system output is shown. It uses a variety of forms and colors to make water quality and diversity status easier to understand. It promotes environmental protection and improved interpretation of data, aiding biologists and environmentalists to better und the environment. The web-based system prototype can be accessed at the following website: http://www.umlivinglabsystem.com/
The cost implication of green building materials in the sustainable government green building constructions / Maizali Halil Ghazali
No full textThe procurement of work in the public sector that consider environmental criteria to reduce the detrimental consequences of human activity and to protect the environment and natural resources, are referred to government green building construction projects. It entails boosting the efficiency of government building construction projects while also utilizing the public market's potential to change the Malaysian economy into a green economy. As Malaysia's largest technical department, the Public Works Department (JKR) currently lacks cost data that includes green products utilized in JKR projects with green project status. The study's objective was to look into green building issues, assess the cost implications of green products utilized in government green building construction, and determine the percentage cost of green product components involved. Its aim is to make it easy for the designer to plan an appropriate design based on the project provisions. The Bill of Quantities from a single case study of a pioneer project classified as a green building construction project was used to assess cost data. A detailed cost analysis was conducted to determine the percentage cost of green product components based on the contract price as a means of comparison the percentage cost of green product components generated using the Green Product Scoring System (GPSS). The 48 green product categories identified represented 62 percent of the value above the overall cost of the building, according to the findings. Additional study is required to determine the cost of incorporating green building systems into green building construction projects, as well as other elements that can improve the accuracy of cost estimates in sustainable building construction
The role of R&D and universities in patenting and scientific publications, and economic growth: A study of Malaysia / Than Lee Lee
No full textUsing patents, industrial designs, and scientific publications, this study examines the
R&D performance of Malaysia over the period from 1996 to 2017. In doing so, the thesis
also examines the state of research and patenting participation of Malaysian researchers,
universities, and firms. Although not all patents eventually attract commercial value,
given the complexities associated with R&D spillover, it is still widely used as an
innovation output to support economic growth. In this regard, this thesis uses patent-to-
GDP ratio alongside Catch-up Index estimate R&D expenditure and R&D performance
gaps. The use of GERD-to-GDP is a weak indicator of innovative progress among
particularly developing countries because a significant share of it do not go to supporting
economic growth. Hence, studying this gap will allow us to understand the extent of
commercialization that takes place from R&D investment in Malaysia. Using a variety of
sources of national and international data on patent and growth, and the Error Correction
Model, and Autoregressive Distributed Lag (ECM-ARDL) approach, we construct an
analytical model using the theoretical concepts of Romer’s endogenous growth on
innovation and Griliches’s knowledge production framework to advance this study,
though we eventually criticize the Romer and Grichiches’ models for not including
innovation inputs (e.g., R&D investment) and output (e.g., patents, especially domestic
patents). The model consists of patent, industrial design, GERD, fixed capital formation,
employed scientific human capital and GDP growth to measure the process of innovation,
and their association with economic development. The results show that both patents and industrial designs are significantly correlated with economic growth in the overall sample
but is negatively correlated in the short run in the Malaysian data, though the long run
relationship between Malaysian patents and the trade structure is positively correlated.
Also, patent-to-GDP and industrial design-to-GDP ratios affect patenting activities in
Malaysia. Consequently, while it is fine to continue the focus on scientific publications,
the knowledge created should also be used to file patents and industrial designs. The
science, technology and innovation (STI) infrastructure in Malaysia requires a revision to
raise the focus on patenting and commercialization. Malaysia remains a strong candidate
among the Asian-8 economies to make the transition to high-tech developed country
status if the increasing trend of R&D investment is translated into patenting. That the
potential exists cannot be dismissed as the country has witnessed a sharp rise in scientific
publications since 2005. In addition, there is a need to improve university industry
linkages to overcome such a shortcoming. In doing so, efforts must be taken to
reinvigorate the science and number parks in Malaysia through requiring researchers
granted research incentives and grants to undertake prototyping and new product
development
Study of thermal performance and properties of 1-pyrene carboxylic-acid functionalized graphene nanofluids in a heat pipe / Alireza Esmaeilzadeh
No full textA new trend in the heat pipes and successful thermosyphons application is related to nanotechnologies. Nano liquids, nanocoating, and nanocomposites invention open a new niche in the heat pipe and thermosyphon design and use. This research is carried out experimentally and analytically to investigate the thermal performance of heat pipe when functionalized graphene nanoplatelets (GNP) with 1-pyrene carboxylic acid (PCA) is utilized as a working fluid.
In this study's first stage, three influential parameters on the viscosity and thermal conductivity, including concentration, temperature, and specific surface area of nanofluid, were investigated. In the second stage, an experimental investigation was accomplished to study a sintered wick heat pipe's thermal performance using stable aqueous dispersions of noncovalently functionalized graphene nanofluids. The experiments are conducted to characterize a low-cost nanofluid and evaluate its effect on the sintered-wick heat pipe efficiency. The various parameters being investigated include different fluids, tilt angles of the heat pipe, and input powers. The result shows the enhancement of thermal conductivity of PCA-functionalized graphene nanofluids in the range of 21% and 40%. It is found that the tilt angle of heat pipe has a substantial impact on the thermal properties, which could enhance the thermal performance by 79%. The experimental results indicated that the heat pipe thermal resistance is reduced using PCA-functionalized graphene nanofluids. The reduction in thermal resistance was the best at the high heat flux.
The last stage focused on the CFD modeling of nanofluid heat transfer in the heat pipe. Numerical modeling of a heat pipe included with a phase change heat transfer was developed to assess the effects of three parameters of nanofluid, heat pipe inclination angles, and input heating power. Distilled water (DW) and 1-pyrene carboxylic-acid (PCA)-functionalized graphene nanofluid (with concentrations of 0.06 wt%) were used as working fluids in the heat pipe. A computational fluid dynamic (CFD) model was developed to evaluate the heat transfer and two-phase flow through the heat pipe's steady-state process. It was found that inclination significantly affects the heat transfer of the heat pipe. The maximum increment of thermal performance in the heat pipe peaked at 49.4% by using the amount of 0.06 wt% of PCA-functionalized graphene as working fluids. The result associated with this comparison indicates that the highest deviation is less than 6%, consequently confirming that the CFD model was successful in reproducing the heat and mass transfer processes in the DW and nanofluids charged heat pipe. The results of the CFD simulation have good agreement between predicted temperature profiles and experimental data
Organizational readiness for Artificial Intelligence (AI) adoption in project risk management of Malaysian construction industry / You Jin Wei
No full textIn this era of technology advancement, IT technologies have been developed with a fast-moving pace and there is no exceptional case in Malaysian construction industry which associates with poor project risk management. Digital transformation has been a topic to be discussed among the construction practitioners to incorporate digital tools for organization project risk management and ultimately to move forward IR4.0. The arising Artificial Intelligence (AI) technologies has been prospected as the solution to answer the demand from the industry. However, numerous research found that level of awareness of Malaysian construction industry is at a low level and readiness of organization towards AI adoption remains unknown. This research study is aimed to investigate on the status of organizational readiness towards AI adoption in project risk management of Malaysian construction industry. Quantitative research methodology has been adopted to accomplish the intention and a questionnaire survey was conducted. Total of two hundred and fourteen (214) CIDB registered G7 construction organizations have participated in the questionnaire survey. A theoretical framework with the inclusive of fifteen (15) key factors that influence the organizational readiness has been developed and validated to be applicable to the study. The study has discovered that Malaysian construction industry is at the level of “quite ready” for AI adoption in project risk management with CRI value of 62%. Output of this study is likely to be referred for providing insightful information for Malaysian construction industry to move on AI adoption