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Diamine modified polymeric membranes for hydrogen/carbon dioxide separation
Get PDFThe separation of H2/CO2 is technologically crucial to produce clean and renewable H2-based energy. There are several established methods used to separate H2 from CO2, but membrane based separation is becoming more prominent due to high energy efficiency and cost effectiveness. However, separation efficiency of existing polymeric membranes is limited due to unfavourable diffusivity and selectivity between H2 and CO2. As such, research objective for this work is to investigate the effectiveness of diamine modification towards two different polymeric membrane materials, PSf and P-84, on their performance in H2/CO2 separation. The effects of different operating pressures and modification time on the permeance and selectivity are also studied. Comparison of pure and modified membranes will be further interpreted. The fabrication of membranes is done by using controlled evaporation method. Then, the prepared membranes will undergo diamine modification using BuDA for 10 and 30 minutes reaction times. All samples were analyzed by gas permeation test for separation performance and SEM
and FTIR for membranes characterization. From SEM analysis, the images show that both polymers have defectfree
surfaces and porous cross-section structures. FTIR spectra validate the cross-linking reaction by observing
the existence of adsorption peak at 1529 cm-1. This specific characteristic peak implies the occurrence of C-N
stretch within the membranes. The gas permeation test shows the respective modification towards P-84 and PSf
for 10 and 30 minutes reaction times causes H2 permeability to increase drastically. Based on the experimental
result, P-84 membrane with 10 minutes BuDA-modification reaction time and 5 bar operating pressure gives the
best H2 permeability performance. By increasing the time to 30 minutes, the H2/CO2 selectivity of both polymers
were increased to 4.97 and 6.09, respectively compared to its neat membranes
Sustainable design on semi-ducted reversible smoke extraction system in basement parking facilities
Get PDFBasement enclosed parking facilities require mechanical ventilation for emergency and normal operation. These two ventilation requirements are commonly combined into one hybrid system by many designers. This paper compares the smoke extraction system between the conventional ducted uni-directional ventilation system and the semi-ducted reversible ventilation system in a rectangular enclosed basement parking facility. In this reversible scheme, fans installed in fire zone are operated as extraction, whereas fans positioned in adjacent zones are running as make-up air to facilitate the extraction. The CFD simulation results show that both system performances are equivalent in maintaining the fire safety requirement. The installed ductwork for semi-ducted reversible system is significantly reduced. As such, the fans static can be reduced, resulting in lower power consumption during normal ventilation. It is estimated that energy savings of 41.4% can be achieved via semiducted reversible system
Effects of various hydrogenated temperatures on photocatalytic activity of mesoporous titanium dioxide
No full textHydrogenated titanium dioxide (H-TiO2) has drawn much research attention in the photocatalysis society since it has significantly improved solar absorption and enhanced photocatalytic activity. Nevertheless, the key factor that leads to the enhanced photocatalytic performance of H-TiO2 is still debatable. To clarify this issue, the structural properties of H-TiO2 and its effects on photogenerated charges are investigated. Mesoporous H-TiO2 was subjected to different hydrogenation temperatures rate under the flow of purified H2 gas and its photocatalytic activities are evaluated by reactive black 5 photodegradation. The H-TiO2 pretreated at different temperatures seems to have a detrimental effect on photocatalytic activity as compared with that of untreated H-TiO2. Further investigations reveal that H-TiO2 treated at high temperature can cause the formation of less photoactive rutile phase and agglomeration that leads to the inhibition of their photocatalytic activity
Electrochemical detection of hydrogen peroxide on a new microporous Ni–metal organic framework material-carbon paste electrode
No full textIn this paper a new Ni2+ metal organic framework (based on adipic acid as the linker & piperazine as the ligand) (AP-Ni-MOF) was synthesized and has been used as an electrode material (AP-Ni-MOF/CPE) for the detection of H2O2. The morphology and formation of AP-Ni-MOF was confirmed by field emission scanning electron microscopy, FT-IR spectroscopy, energy-dispersive spectroscopy, X-ray diffraction, and TGA. AP-Ni-MOF showed high electrochemical activity for the detection of H2O2 due to high conductivity i.e 1.28 × 10−3 S/cm. Electrochemical studies were carried out for AP-Ni-MOF/CPE by cyclic voltammetry and chrono-amperometry methods. Under optimized condition AP-Ni-MOF/CPE show a dynamic range (0.004 mM to 60 mM) with the limit of detection of 0.0009 mM. The effect of interfering species on the reduction peak current response show a minor change of signals (>5%). The modified electrode has good repeatability due to lifetime stability. AP-Ni-MOF/CPE electrode was also used in real samples (lens cleaner solution) for the detection of H2O2 with the recoveries of 94.7–107%
Facile hydrothermal method for synthesizing nitrogen-doped graphene nanoplatelets using aqueous ammonia: dispersion, stability in solvents and thermophysical performances
No full textA simple and green approach has been developed to synthesize nitrogen-doped graphene nanoplatelets (N-doped GNPs) for mass production with a very high stability in different solvents e.g. water, ethylene glycol, methanol, ethanol, and 1-hexanol. The strategy is based on mild oxidation of GNPs using hydrogen peroxide and doping with nitrogen using hydrothermal process. The modification of N-doped GNPs was demonstrated by FTIR, TGA, XPS, Raman spectroscopy and high resolution-transmission electron microscope (HRTEM). Further study was carried out by using N-doped GNPs as an additive to prepare different colloidal dispersions. Water-based N-doped GNPs, methanol-based N-doped GNPs, ethanol-based N-doped GNPs, ethylene-glycol based N-doped GNPs and 1-hexanol-based N-doped GNPs dispersions at 0.01 wt.% shown great colloidal stabilities, indicating 17%, 29%, 33%, 18%, and 43% sedimentations after a 15-days period, respectively. The thermophysical properties e.g., viscosity and thermal conductivity of water-based N-doped GNP nanofluids were also evaluated for different weight concentrations of 0.100, 0.075, 0.050, and 0.025 wt.%. Through this, it is found that the obtained dispersions have great potential to be used as working fluids for industrial thermal systems
Investigation of the thermophysical properties and stability performance of non-covalently functionalized graphene nanoplatelets with Pluronic P-123 in different solvents
No full textThe employment of nanofluids involving the dispersion of nanomaterials in the base fluid has become a major interest of the researchers due to great potential in enhancing the thermophysical properties and heat transfer coefficients. The stability of nanoparticles in base fluids is a major concern with heat transfer applications. The main purpose of this research was to study the stability of graphene nanoplatelets (GNPs) in the presence of Pluronic P-123 surfactant (P-123) in aqueous media and to compare with other common surfactants such as sodium dodecyl sulfate (SDS), cetyltrimethylammonium bromide (CTAB) and Triton X-100 (TX). Each of the surfactants was mixed with GNPs at different ratios of 1:1, 1:2, 1:3 and 1:4. Then, the best ratio with the most stable sample was selected and compared with other samples. The stability of samples was evaluated by using UV-vis spectrometry, zeta potential and particle size distribution. The viscosity and thermal conductivity of the best sample were also measured at different temperatures. High resolution-transmission Electron Microscopy (HR-TEM) was used to characterize the morphology of GNPs. Interestingly, P-123 as a new surfactant showed the best colloidal stability between our samples. Furthermore, the presence of SDS, CTAB and TX surfactants in the nanofluids caused the formation of excessive foam, while P123-GNPs showed no foam-formation after shaking within the given time. It is worthy to highlight that the rises in thermal conductivity and stability in the presence of P-123 were higher than those of other surfactants. Also, the addition of rheological property (viscosity) was found to be insignificant once loading P-123
Exploring Underpinning of Outsourcing Success: A case of Multinational Automotive group in Malaysia
No full textThis study explored underpinning of outsourcing success by analyzing different theories of outsourcing. This study is unique in its nature as it used interpretive paradigm to explore, analyze outsourcing success theatrically by comparing different phases of outsourcing, then the case of Boeing analyzed in the context of outsourcing and after that come up with real time case study of one big automotive group operating in Malaysia through using semi structured interview by developing and comparing themes of this study. This study figured out that cost reduction and efficiency can be attained by creating economies of scale, using and managing vendors appropriately with the combination of efficient strategic alliance
Positive psychological interventions for people with epilepsy: An assessment on factors related to intervention participation
No full textBackground: Positive psychological interventions (PPI) are increasingly employed as a coping strategy with physical and mental conditions, including neurological diseases. Its effectiveness on improving wellbeing in people with epilepsy (PWE) has been shown in a few studies. This study aimed to explore factors related to participants' willingness to engage in psychological interventions from the perspective of patients with epilepsy. Methods: Participants answered a needs assessment questionnaire eliciting information about their illness perception (Brief Illness Perception Questionnaire (Brief-IPQ)), emotions (Hospital Anxiety and Depression Scale (HADS)), willingness to participate in psychological interventions, preferences in types of PPI and intervention designs, as well as barriers in seeking mental health services. Results: A total of 154 patients with epilepsy participated, with a mean age of 37.3 years (range 16–86 years). Most patients had focal epilepsy (68.2%), and drug-resistant (59.1%). Majority (71.4%) of them indicated a strong willingness to participate in PPI. Out of nine types of PPI, character strengths, mindfulness-based and expressive-based interventions were highly preferred. Those with negative illness perception (p = 0.001), anxiety (p = 0.004), and being unemployed (p = 0.048) were more willing to participate in PPI. Most participants preferred group rather than individual session, and a shorter duration (30 min) was favored by most. Conclusion: This study captured the self-report willingness to participate in psychological interventions. Findings suggested that psychological interventions delivered in short-group session were highly preferred. Future study is required to determine the feasibility of such design for patients with epilepsy
Association of DSM-5 Betel-Quid Use Disorder With Oral Potentially Malignant Disorder in 6 Betel-Quid Endemic Asian Populations
No full textIMPORTANCE Betel-quid (BQ) is the fourth most popular psychoactive agent worldwide. An emerging trend across Asia is the addictive consumption of BQ, which is associated with oral cancer and other health consequences. OBJECTIVE To investigate the validity and pattern of DSM-5-defined BQ use disorder (BUD) and its association with oral potentially malignant disorder (OPMD) among Asian populations. DESIGN, SETTING, AND PARTICIPANTS In-person interviewswere conducted from January 1, 2009, to February 28, 2010, among a random sample of 8922 noninstitutionalized adults from the Asian Betel-quid Consortium study, an Asian representative survey of 6 BQ-endemic populations. Statistical analysis was performed from January 1, 2015, to December 31, 2016. MAIN OUTCOMES AND MEASURES Participantswere evaluated for BUD using DSM-5 criteria for substance use disorder and for OPMD using a clinical oral examination. Current users of BQ with 0 to 1 symptoms were classified as having no BUD, those with 2 to 3 symptoms as having mild BUD, those with 4 to 5 symptoms as having moderate BUD, and those with 6 or more symptoms as having severe BUD. RESULTS Among the 8922 participants (4564 women and 4358 men; mean [SD] age, 44.2 [0.2] years), DSM-5 symptoms showed sufficient unidimensionality to act as a valid measure for BUD. The 12-month prevalence of DSM-5-defined BUD in the 6 study populations was 18.0%(mild BUD, 3.2%; moderate BUD, 4.3%; and severe BUD, 10.5%). The 12-month proportion of DSM-5-defined BUD among current users of BQ was 86.0% (mild BUD, 15.5%; moderate BUD, 20.6%; and severe BUD, 50.0%). Sex, age, low educational level, smoking, and drinking were significantly associated with BUD. Among individuals who used BQ, family use, high frequency of use, and amount of BQ used were significantly linked to moderate to severe BUD. Compared with individuals who did not use BQ, those who used BQ and had no BUD showed a 22.0-fold (95%CI, 4.3-112.4) risk of OPMD (P < .001), whereas those with mild BUD showed a 9.6-fold (95%CI, 1.8-56.8) risk (P = .01), those with moderate BUD showed a 35.5-fold (95%CI, 4.3-292.3) risk (P = .001), and those with severe BUD showed a 27.5-fold (95%CI, 1.6-461.4) risk of OPMD (P = .02). Individuals with moderate to severe BUD who used BQ and had the symptom of tolerance had a 153.4-fold (95%CI, 33.4-703.6) higher risk of OPMD than those who did not use BQ, and those with moderate to severe BUD who used BQ and had a larger amount or longer history of BQ use had an 88.9-fold (95%CI, 16.6-476.5) higher risk of OPMD than those who did not use BQ. CONCLUSIONS AND RELEVANCE This international study gathered data about BQ users across 6 Asian populations, and it demonstrates that DSM-5 symptoms could fulfill a BUD construct. Most current Asian users of BQ already have BUD, which is correlated with risk of OPMD. Among individuals with moderate to severe BUD who used BQ, tolerance and a larger amount or longer history of BQ use are the key symptoms that correlated with enhanced risk of OPMD. These findings play an important role in providing a new indication of an additional psychiatric management plan for users of BQ who have BUD
Measurement of binding strength between prey proteins interacting with Toxoplasma gondii SAG1 and SAG2 using isothermal titration calorimetry (ITC)
No full textFollowing the outcome from a previously performed yeast two-hybrid experiment, the binding strength between T. gondii SAG1 and SAG2 and their respective prey proteins were further confirmed in this study. The sag1, sag2 and their prey genes were amplified and cloned into a pGEMT vector. To express the recombinant proteins, the fragments were then subcloned into a pRSETA vector and transformed into E. coli BL21 (DE3) cells. The recombinant proteins were expressed optimally at 37°C and 1mM of IPTG. The 6X His-tag fusion proteins were purified, dialyzed and concentrated. To confirm the expressed proteins, the recombinant proteins were analysed by SDS-PAGE and Western blot. As expected, the size of SAG1, SAG2, HLY and HZF protein were 32, 23, 28 and 37 kDa, respectively. The purified proteins were loaded onto a MicroCal Auto-iTC200 calorimeter from MicroCal™ to quantify binding strength. ITC results indicated there was a typical binding curve for interactions between SAG1 and HLY protein. However, there was an atypical binding curve obtained for interactions between SAG2 and HZF protein. By observing the data obtained from the ITC assay, both of the human proteins (HLY and HZF) were demonstrated to bind to their respective SAG1 and SAG2 proteins