SCREENING OF SURFACTANTS FOR MICELLAR FLOODING AND FOAM FLOODING

A great deal of information has been published on the use of surfactants in chemical Enhanced Oil Recovery methods as it hold particular attraction for recovering the residual oil left in the reservoir after water flooding. The application of surfactants leads to the mobility control mechanism in foam flooding whereas interfacial tension reduction is the important mechanism micellar flooding. When foam flooding is conducted, some portion of the surfactant tends to adhere on the surface of the rocks due to the adsorption characteristic of the surfactants themselves. This will consequent to less amount of surfactant to be injected for the micellar flooding as remaining surfactant down hole will react with the injected solution to form microemulsion

SCREENING OF SURFACTANTS FOR MICELLAR FLOODING AND FOAM FLOODING

A great deal of information has been published on the use of surfactants in chemical Enhanced Oil Recovery methods as it hold particular attraction for recovering the residual oil left in the reservoir after water flooding. The application of surfactants leads to the mobility control mechanism in foam flooding whereas interfacial tension reduction is the important mechanism micellar flooding. When foam flooding is conducted, some portion of the surfactant tends to adhere on the surface of the rocks due to the adsorption characteristic of the surfactants themselves. This will consequent to less amount of surfactant to be injected for the micellar flooding as remaining surfactant down hole will react with the injected solution to form microemulsion

Preliminary assessment of Polytrichum commune extract as an antimicrobial soap ingredient

Mosses have long been used in traditional Chinese medicine due to the presence of secondary metabolites which have shown high biological activities. In particular, these secondary metabolites have demonstrated effective antibacterial activity against pathogenic microorganisms. In this study, the influence of different extraction solvents on the antibacterial activities of the Polytrichum commune was carried out using the disc diffusion method. Results showed that both 12.5 mg/mL of methanol moss extract and 6.25 mg/mL of ethanol moss extract were the most effective concentrations against Bacillus cereus and Pseudomonas aeruginosa. Additionally, the P. commune extracts were included as an added ingredient in soap bases to produce antibacterial soap prototypes where the effectiveness of the soaps containing the extracts in removing microorganisms from actual test individuals was carried out. Results of the thumb impression test of test individuals showed that the growth of microbial reduced after washing hands with the usage of both liquid and solid soap with the addition of P. commune extracts. Moreover, the antibacterial soaps performed better in eliminating microorganisms in comparison to control soaps without P. commune extracts. Taken together, P. commune extract could be a good candidate as a value-added ingredient utilized to produce antibacterial soaps due to its antibacterial properties

Impaction-fracture of the capitate and lunate: a case report

We report a 15-year-old girl who underwent a midcarpal fusion for undiagnosed impaction-fractures of the capitate, lunate, and triquetrum after a fall on her outstretched left hand in a dorsiflexed and radially deviated position. The joint was dis-impacted, and the height of the lunate was restored using a cortical bone graft. The damaged proximal capitate articular surface was decorticated to facilitate fusion, as was the lunotriquetral articulation. Kirschner wires were inserted along the coronal plane. At the one-year follow-up, the patient had achieved a satisfactory range of motion and fusion of the capitate-lunatetriquetral articulations

Impaction-fracture of the capitate and lunate: a case report

We report a 15-year-old girl who underwent a midcarpal fusion for undiagnosed impaction-fractures of the capitate, lunate, and triquetrum after a fall on her outstretched left hand in a dorsiflexed and radially deviated position. The joint was dis-impacted, and the height of the lunate was restored using a cortical bone graft. The damaged proximal capitate articular surface was decorticated to facilitate fusion, as was the lunotriquetral articulation. Kirschner wires were inserted along the coronal plane. At the one-year follow-up, the patient had achieved a satisfactory range of motion and fusion of the capitate-lunatetriquetral articulations

Efficient implementation of activation functions for LSTM accelerators

Activation functions such as hyperbolic tangent (tanh) and logistic sigmoid (sigmoid) are critical computing elements in a long short term memory (LSTM) cell and network. These activation functions are non-linear, leading to challenges in their hardware implementations. Area-efficient and high performance hardware implementation of these activation functions thus becomes crucial to allow high throughput in a LSTM accelerator. In this work, we propose an approximation scheme which is suitable for both tanh and sigmoid functions. The proposed hardware for sigmoid function is 8.3 times smaller than the state-of-the-art, while for tanh function, it is the second smallest design. When applying the approximated tanh and sigmoid of 2% error in a LSTM cell computation, its final hidden state and cell state record errors of 3.1% and 5.8% respectively. When the same approximated functions are applied to a single layer LSTM network of 64 hidden nodes, the accuracy drops by 2.8% only. This proposed small yet accurate activation function hardware is promising to be used in Internet of Things (IoT) applications where accuracy can be traded off for ultra-low power consumption.Accepted versionWe thank the Programmatic grant no. A1687b0033, Singapore RIE 2020, AME domain

An energy-efficient convolution unit for depthwise separable convolutional neural networks

High performance but computationally expensive Convolutional Neural Networks (CNNs) require both algorithmic and custom hardware improvement to reduce model size and to improve energy efficiency for edge computing applications. Recent CNN architectures employ depthwise separable convolution to reduce the total number of weights and MAC operations. However, depthwise separable convolution workload does not run efficiently in existing CNN accelerators. This paper proposes an energy-efficient CONV unit for pointwise and depthwise operation. The CONV unit utilizes weight stationary to enable high efficiency. The row partial sum reduction is engaged to increase parallelism in pointwise convolution thereby lightening the memory requirements on output partial sums. Our design achieves a maximum efficiency of 3.17 TOPS/W at 0.85V/40nm CMOS which is well-suited for energy constrained edge computing applications.Accepted versio

0.08mm² 128nW MFCC engine for ultra-low power, always-on smart sensing applications

Mel frequency cepstral coefficient (MFCC) features are widely used in applications such as keyword spotting, bearing fault detection and heart sound classification. This work proposes a low power MFCC engine that enables its use for battery-powered edge applications. Three hardware algorithm co-optimizations were adopted to achieve energy efficient MFCC hardware implementation. The approximated MFCC features due to the optimizations still allows good accuracy when deployed in several applications such as keyword spotting and bearing fault detection, reporting negligible accuracy drop of 1.5%. The proposed MFCC hardware consumes only 128nW at 0.3V supply and occupies only 0.08mm2 in 40nm CMOS technology, which are 5x and 2.75x power and area reduction respectively when compared to the prior arts.National Research Foundation (NRF)Submitted/Accepted versionWe thank the Programmatic grant no. A1687b0033, Singapore RIE 2020, AME domain

Analysis of anionic post-blast residues of low explosives from soil samples of forensic interest

The growing threats and terrorist activities in recent years have urged the need for rapid and accurate forensic investigation on post-blast samples. The analysis of explosives and their degradation products in soils are important to enable forensic scientist to identify the explosives used in the bombing and establish possible links to their likely origin. Anions of interest for post-blast identification of low explosives were detected and identified using ion chromatography (IC). IC separations of five anions (Cl - , NO2 - , NO3 - , SO4 2- , SCN- ) employed a Metrosep Anion Dual 2 column with carbonate eluent. The anions were separated within 17 minutes. Sampling of post blast residues was carried out in Rompin, Pahang. The post-blast explosive residues were extracted from soil samples collected at the seat of three simulated explosion points. The homemade explosives comprised of black powder of various amounts (100 g, 150 g and 200 g) packed in small plastic sauce bottles. In black powder standard, three anions (Cl- , NO3 - , SO4 2- ) were identified. However, low amounts of nitrite (NO2 - ) were found present in post-blast soil samples. The amounts of anions were generally found to be decreased with decreasing amount of black powder explosive used. The anions analysis was indicative that nitrates were being used as one of the black powder explosive ingredients