Flexural behaviour of reinforced slab panel system with embedded cold-formed steel frames as reinforcement

This paper presents the experimental investigation on flexural characteristic of slab panels with embedded cold-formed steel frame as reinforcement. Perforated cold-formed steel channel sections are formed into steel frames as replacement to the conventional reinforcement bars inside precast concrete slab panels. A series of six experimental specimens for precast slab panels were tested. The specimens with 3 configurations namely control sample (CS) with conventional reinforcement bars, single horizontal C-channel section (SH) and double horizontal C-channel sections (DH) formed into rectangular hollow section. Results show that the tested slab specimens failed at the flexural crack at mid-span, under loading point and shear at the support. Tearing of shear connector in the cold-formed steel section was found to be the main factor for the structural failure. SH specimens achieved the highest ultimate load capacity, with average value of 138.5 kN, followed by DH specimens, 116.5 kN, and the control samples, 59.0 kN. The results showed that the proposed reinforced slab panel with embedded cold-formed steel frame was more effective compared to conventional reinforced sla

Compressive strength of lightweight foamed concrete with charcoal as a sand replacement

Foamed concrete, a high performance concrete with lightweight properties and strength-enhancing additive have drawn the attention of researchers towards a sustainable life style. This paper presents a study of the compressive strength of various charcoal-filled lightweight foamed concrete (LFC), where waste materials, water-reducing agent and strength enhancement additives are introduced to the mix design in order to obtain further lightweight concrete. Five series of experimental tests were carried out, where Series 1 tested optimum ratio of silica fume and superplasticizer, Series 2 depicted the design mix of sand replacement with charcoal, Series 3 described the mix for additives, Series 4 illustrated effect of aggregate size for charcoal and different densities, as well as Series 5 was the conventional design mix ratio. The fresh and harden densities have been recorded while the shrinkage of LFC had also been observed during the casting and curing period. From the results, the mixture with silica fume replacing the cement was found to have a lower compressive strength as compared to mixtures with a full portion of cement. The strength reductions ranged between 62 to 80% for the mix with no superplasticizer and 29 to 82% for the mix with superplasticizer, which was obtained from the 20 to 50% of cement replacement with silica fume. Foamed concrete with superplasticizer achieved 66% of higher compressive strength. However, concrete expansion and spalling were discovered at the later concrete age of Series 5 which degraded the concrete strength. From this study, it was found that charcoal with low specific gravity is a suitable for full sand replacement in foamed concrete prior to the treatment that can lower its alkalinity

Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely

Wander Women: Exploring the Gendered Experiences of Singapore’s Solo Travellers

Bachelor'sBachelor of Social Sciences (Honours

Finite analysis of steel frame multi-storey building by using ANSYS

In this research, a multi-storey building has been analysed by using ANSYS software. This research is to determine the strain, stress, maximum deflection, deformation and also checking the structure according to Eurocode 3. Major of the buildings constructed in Malaysia are reinforced concrete buildings compared to steel frame buildings. Steel structure design software is very important to help civil engineers in finite element analysis. The type of material and the geometry for the structure was satisfied in in cases it passed all the designing for tensile, buckling and compression. The values for the input variables are generated randomly by using Monte Carlo Simulation with given mean values and standard deviation or as prescribed samples using Response Surface Method. From the result of simulation, we can know the behaviour of the steel frame structure under the input parameter that applied. Then, from the probabilistic analysis, we collect the result of cumulative distribution function, the histogram plot for input and output parameter, sensitivity plot and simple history plot for all parameter

Development of a pico-satellite : sun sensors for attitude determination

Following the completion of the micro-satellite XSAT program, and currently waiting for the launch, NTU has started another program to develop a pico- and nano-satellite pair VELOX-I. This program includes many FYP projects working on the various sub-systems of a satellite. For a satellite to determine and control its location and orientation in space, the Attitude Determination and Control System (ADCS) is an essential sub-system for the task. This project focuses on the sun sensor in the ADCS which determines the sun direction with respect to the vertical axis of the satellite. The sun direction will allow the satellite to orientate itself perpendicular to the sun direction for maximum solar power collection and also to shelter sensitive equipments away from the strong solar radiation. In this project, hardware prototype has been designed and implemented on PCB. It has been tested using a sun simulator to simulate real parallel sunrays and a 2-axis turn motor to rotate the sensor. The hardware will provide four voltage analog outputs dependent on the sun spot position. The voltage outputs is first processed by the microcontroller. Subsequently, the digital data is transferred to PC for noise removal using Kalman filter, computation of sunray angle and error calibration based on the analysis of errors caused by mechanical and electrical design. The accuracy for the sensor is -1.3º to 0.7º for a field-of-view of -30º to 30º, and ±0.7º for a field of view of -25º to 25º. This performance is comparable to commercial products that have accuracies less than 1º. The prototype has also been tested in outdoors under the real sun and proven to function satisfactorily.Bachelor of Engineerin

Modelling non-alcoholic fatty liver disease using patient derived liver stem cells and hepatic organoids

Non-alcoholic fatty liver disease (NAFLD) is described as a global epidemic. With no approved drugs in the market, the disease imposes huge economic and healthcare burden to the society. In-vitro models are deemed as a potential method to test and screen drugs. Hepatic organoids (HOs) differentiated from adult stem cells derived from the liver are attractive in-vitro models due to its ability to recapitulate functions of the liver. In-vitro models were established using tissues from Non-alcoholic steatohepatitis (NASH) patients and healthy donors. A transcriptomics approach was taken to determine if HOs from NASH donors can better recapitulate the disease in-vitro. It was discovered that NASH HOs have increased expression of genes associated to NASH. Inducing steatosis resulted in distinct upregulation of genes in NASH HOs which are associated to worse outcome in NAFLD patients. Together, the analysis suggests that HOs from NASH donors are better in-vitro models to recapitulate NAFLD.Doctor of Philosoph

Mismatched filter for transmit waveform with frequency notches

In order to reduce radar interference on communication systems within shared bands, the radar transmit waveform forms frequency notches in the shared bands. However, because of the notches, the auto-correlation of the transmit waveform with frequency notches leads to high-range sidelobes. In order to achieve low-range sidelobes, the authors propose a mismatched filter. The mismatched filter for the transmit waveform with frequency notches has the same range sidelobes as the auto-correlation of the transmit waveform without frequency notches at the expense of a signal-to-noise ratio (SNR) loss. Simulation and analysis results demonstrate that the proposed mismatched filter always has low sidelobes at the cost of a SNR loss. In addition, simulation results show that the SNR loss is acceptable even for the deep notches (i.e. 20 dB), when the ratio of the waveform energy in the shared bands to the total waveform energy is moderate (i.e. <;8%). However, the SNR loss increases rapidly with the depth of notches, when the ratio is large.Published versio

Strength Performance on Different Mix of Cement-Sand Ratio and Sand Condition for Lightweight Foamed Concrete

Proper cement-sand ratio and water content can provide excellent consistency and stability for lightweight foamed concrete. The aims of this study are to investigate the comprehensive optimisation design mix of lightweight foamed concrete with different cement-sand ratio and the effect of sand size and admixture towards the consistency and stability of the design mix. Silica fume as admixture was used to verify the improvements in the strength of the foamed concrete. Two types of foamed concrete were prepared, namely SC with sieved sand and UC with unsieved sand used in foamed concrete. Three different cement-sand ratios with different water content were tested for the above two types of foamed concrete for their compressive strength, consistency and stability. The results indicate that foamed concrete using sieved sand gained better consistency and stability. In addition, using silica fume in foamed concrete significantly improved the compressive strength with the highest strength at 27.12 MPa with 1700 kg/m3 density

Strength Performance on Different Mix of Cement-Sand Ratio and Sand Condition for Lightweight Foamed Concrete

Proper cement-sand ratio and water content can provide excellent consistency and stability for lightweight foamed concrete. The aims of this study are to investigate the comprehensive optimisation design mix of lightweight foamed concrete with different cement-sand ratio and the effect of sand size and admixture towards the consistency and stability of the design mix. Silica fume as admixture was used to verify the improvements in the strength of the foamed concrete. Two types of foamed concrete were prepared, namely SC with sieved sand and UC with unsieved sand used in foamed concrete. Three different cement-sand ratios with different water content were tested for the above two types of foamed concrete for their compressive strength, consistency and stability. The results indicate that foamed concrete using sieved sand gained better consistency and stability. In addition, using silica fume in foamed concrete significantly improved the compressive strength with the highest strength at 27.12 MPa with 1700 kg/m3 density