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The stamps used in the nanoelectrode lithography (NEL) process require conductive layer deposition, which makes them a bit expensive. This paper reports the feasibility of using brass materials as the conductive stamps for NEL to shorten the process step and reduce the production cost. In this paper, the fabrication of nanostructures on the brass stamp was performed on a single point diamond turning (SPDT) machine. Some burrs were formed during the machining process, that prohibit the stamps from achieving a homogeneous contact with the substrates. Introduction of a thin layer of polymer (PS-OH) on the silicon substrate showed an improvement in contact uniformity so as the oxidation. However, some areas of the substrate remained unoxidized as few of the burrs were quite large. The brass stamps could be advantageous as they show no degradation after many uses. Nevertheless, the issues of the burr formation and non-uniformity should be alleviated first to make these stamps appropriate to the NEL process.

Background The present study covered an assessment of methanolic acetate fractions of Pistia stratiotes, commonly known as water lettuce, for analgesic, anti‐inflammatory, and CNS depressant activities. Methods The methanol acetate fractions were extracted from Pistia stratiotes and administered to the experimental animals as 200 and 400 mg/kg doses to determine the effect on acetic acid‐induced writhing and formalin‐induced licking and biting, for the assessment of analgesic activity. The anti‐inflammatory assay was done using the carrageenan‐induced hind paw edema method, while assessment of CNS depressant activity was done using the open field and hole cross tests. The effects were compared to standard reference drugs. Results At both doses (200 and 400 mg/kg body weight), the methanolic acetate extract of P. stratiotes showed significant analgesic action (P

Objectives: This study investigates analgesic, CNS depressant and anti-inflammatory activities of crude methanolic extract of Peel of Citrus maxima fruits. Materials and Methods: Methanolic extracts of Citrus maxima peel with different concentration were tested for analgesic activity in mouse model of acetic acid induced writhing and formalin induced licking and biting. Anti-inflammatory effect was tested by carrageenan induced paw edema model and the CNS depressant activity was evaluated by observing the reduction of locomotors activity by hole cross and open field test. Results: The extract, at 500 mg/kg, showed higher analgesic activity (73.34%) against acetic acid induced pain in mice while the standard reference drug Diclofenac sodium exhibited 87.13% activity at 10 mg/kg dose. The test dose at 500 mg/kg produced 48.23% protection in formalin induced hind paw licking and biting compared to 54.11% protection by the reference drug (10 mg/kg Diclofenac sodium). The antiinflammatory effect of the extract was comparable to reference drug Ibuprofen and the effect was sustained for 2-4 hr. However, the extract also showed significant dose dependent CNS depressant activity. Conclusion: Methanolic extract of peel of Citrus maxima fruits has CNS depressant effect with moderate analgesic and anti-inflammatory properties.

Continuous rapid shrinking of feature size made the authorities to seek alternative patterning methods as the conventional photolithography comes with its intrinsic resolution limit. In this regard, some promising techniques have been proposed as next-generation lithography (NGL) that has the potentials to achieve both high-volume production and very high resolution. This article reviews the promising NGL techniques and introduces the challenges and a perspective on future directions of the NGL techniques. Extreme ultraviolet lithography (EUVL) is considered as the main candidate for sub-10-nm manufacturing, and it could potentially meet the current requirements of the industry. Remarkable progress in EUVL has been made and the tools will be available for commercial operation soon. Maskless lithography techniques are used for patterning in R&D, mask/mold fabrication and low-volume chip design. Directed self-assembly has already been realized in laboratory and further effort will be needed to make it as NGL solution. Nanoimprint lithography has emerged attractively due to its simple process steps, high throughput, high resolution and low cost and become one of the commercial platforms for nanofabrication. However, a number of challenging issues are waiting ahead, and further technological progresses are required to make the techniques significant and reliable to meet the current demand. Finally, a comparative study is presented among these techniques.

The nanoelectrode lithography has been strengthened in recent years as one of the most promising methods due to its high reproducibility, low cost and ability to manufacture nano-sized structures. In this work, the mechanism and the parametric influence in nanoelectrode lithography have been studied qualitatively in atomic scale using ReaxFF MD simulation. This approach was originally developed by van Duin and co-workers to investigate hydrocarbon chemistry. We have investigated the water adsorption and dissociation processes on Si (100) surface as well as the characteristics (structure, chemical composition, morphology, charge distribution, etc.) of the oxide growth. The simulation results show two forms of adsorption of water molecules: molecular adsorption and dissociative adsorption. After breaking the adsorbed hydroxyls, the oxygen atoms insert into the substrate to form the Si–O–Si bonds so as to make the surface oxidized. The influence of the electric field intensity (1.5–7 V/nm) and the relative humidity (20–90%) on the oxidation process have also been discussed. Nevertheless, the results obtained from the simulations have been compared qualitatively with the experimental results and they show in good agreements. Variable charge molecular dynamics allowed us to characterize the nanoelectrode lithography process from an atomistic point of view.

In order to reveal the underlying mechanism of surface microstructure-determined wetting states, this paper adopted Volume of Fluid (VOF) method to investigate the dynamic behaviours of water droplets impacting on surfaces with different structures at low and high Weber numbers. The simulation results showed that the high and stable pressure of air pockets is critical for the formation of the superhydrophobicity. A superhydrophobic substrate will result in shorter recoiling time and longer rebound time for water droplet than the hydrophobic substrate. Furthermore, superhydrophobic surface resulted in higher kinetic energy for water droplet than hydrophobic surfaces, which is the underlying mechanism of microstructure-enabled self-cleaning function. High-speed camera tests of laser processed surface microstructures were conducted to validate the observation in dynamic impacting simulation. The results in both high-speed camera testing and VOF simulation proved that water droplet will have a lower adhesion force when impacting superhydrophobic surface than hydrophobic surface.

The crystallographic orientation of the substrate is an essential parameter in the kinetic mechanism for the oxidation process. Hence, the choice of substrate surface orientation is crucial in nanofabrication industries. In the present work, we have studied qualitatively the influence of substrate orientation in nanoelectrode lithography using ReaxFF reactive molecular dynamics simulation. We have investigated the oxidation processes on (100), (110) and (111) orientation surfaces of silicon at different electric field intensities. The simulation results show the thickness of the oxide film and the initial oxygen diffusion rate follow an order of (100) > (110) > (111) at lower electric field intensities. It also confirms that surfaces with higher surface energy are more reactive at lower electric field intensity. Crossovers occurred at a higher electric field intensity (7 V nm−1) under which the thickness of the oxide film yields an order of T(110) > T(100) > T(111). These types of anomalous characteristics have previously been observed for thermal oxidation of silicon surfaces. Experimental results show different orders for the (100) and (111) substrate, while (110) remains the largest for the oxide thickness. A good correlation has been found between the oxide growth and the orientation-dependent parameters where the oxide growth is proportional to the areal density of the surfaces. The oxide growth also follows the relative order of the activation energies, which could be another controlling factor for the oxide growth. Less activation energy of the surface allows more oxide growth and vice versa. However, the differences between simulation and experimental results probably relate to the empirical potential as well as different time and spatial scales of the process.

In this study an attempt is made to investigate the properties and CBR characteristics of fine sand and waste dust from construction debris. Attempts are also made to study the effect of soaking period on CBR value of waste dust from construction debris. Waste dusts passing through 600 µm sieve from construction debris and river sand are selected for investigation. Standard Test procedures specified by AASHTO are followed in this investigation. The testing includes the determination of specific gravity, sieve analysis, optimum moisture content, dry density and CBR value. Dense unit weight, specific gravity and fineness modulus of construction debris is 1273.44 Kg/m3, 2.43 and 1.36 respectively and for fine sand 1132.25 Kg/m3, 2.62 and 1.64 respectively. Un-soaked CBR value of construction debris and fine sand are 10.36% and 12.5% respectively. Soaked CBR values of construction debris and fine sand are 5.36% and 6.07% respectively. The study reveals that waste dust from construction debris is as good as fine sand for construction of sub-grade from the stand point of properties and CBR characteristics.

Faecal sludge generating from fixed-place defecation system has been an increasing concern in Bangladesh. In the city, this challenge is acute due to high population density, rapid and unplanned growth, and inadequate service provisions. Energy can be recovered from faecal sludge (FS) by converting the waste into usable heat, electricity, or fuel through pyrolization. Through Pyrolyzation biochar, biofuel, biogas can be obtained. Biochar can be produced by heating FS at high temperature. The burned portion of the sludge is the biochar, condensed steam is the biofuel and the uncondensed part is the biogas. This study shows that FS has volatile matter ranged between 39 to 50%, which qualify the FS as fuel. The ash residue of FS is between 34 to 45%. The rest of this is moisture. From Thermo Gravimetric Analysis (TGA) it was observed that major thermal events (mass loss rate) were found approximately between 150°C and 400°C which was considered as the ideal temperature range for pyrolysis process. Significant amount of biochar but negligible amount of biogas and biofuel were obtained from the samples by the pyrolysis process. 93.3% biochar, 2.8% biofuel and 3.8% biogas (at 200°C); 91.4% biochar, 3.5% biofuel and 5.1% biogas (at 300°C); 84.6% biochar, 9.3% biofuel and 6.1% biogas (at 400°C) were obtained. The result of pyrolysis analysis shows significant potential for energy recovery from FS.

In bituminous road construction aggregate is the principal material. Aggregates constitute about 90% or even more of the total construction materials. While selecting aggregate for road construction, search has to be intensified for easily accessible, low-cost natural aggregates and investigate the suitability of indigenous aggregates. Every effort must be taken to select the most economical aggregate which should also perform satisfactorily the design criteria for the road construction conditions. A laboratory investigation was carried out to investigate the design performance of bituminous pavement using different fine aggregates. While constructing bituminous pavement a mix of coarse aggregate, fine aggregate, mineral filler, and bitumen are used. The demand for natural fine aggregate can be reduced by recycling waste tiles chips. Waste tiles, chips aggregate refer to aggregate that has been previously used in the concrete structure as a floor finish. This study easy carried out to investigate the possibility of using waste tiles, chips as a fine aggregate. Therefore, two types of fine aggregate were used to study and compare the behavior of bituminous mixes using waste tiles with that of coarse sand. The Marshall Mix design procedure specified by AASHTO standard was followed in the determination of stability, flow, density, voids in the mixes and the optimum bitumen content. The test specimens were compacted with 50 blows from the consideration of medium traffic. The test results indicated that dense graded bituminous mixes with two types of different fine aggregates satisfy the Marshall Design criteria. From the economic consideration, mixes with waste tiles, chips are comparatively more suitable when available at the construction site. Dense bituminous mix using waste tiles, chips as fine aggregate for medium traffic, is a feasible option from the standpoint of stability, stiffness, deformations and void characteristics.

Embankments play a significant role in protecting cities from many natural disasters. Erosion and landslides of embankments and natural slopes are common phenomena occurring every year in Bangladesh. It has become a great concern of protecting embankments and natural slopes from failure. In many cases, traditional methods for protecting embankments and natural slopes are not effective during their designed lives. In such a condition, bio-engineering has been adopted in many countries as an effective and environment friendly measure for the protection of slopes. The role played by vegetation in improving slope stability is now well recognized. Many research works have been done in many countries on many species of trees that are locally available and suitable for the climatic and soil conditions of that country. In this study, an attempt has been made to evaluate the performance of lebbek tree and royal poincianain protecting the Rajshahi City Protection embankment. In-situ direct shear test was performed on block samples to determine the in-situ shear strength of rooted soil and soil without root. A numerical analysis has been performed to compute the factor of safety and shear strength of slope soil with root and without root. Also the effect of different types of vegetation on slope stability is observed by numerical analysis. It has been found that the values of factor of safety vary between 1.781 and 1.926 in case of slope without root whereas the values of factor of safety vary between 1.997 and 2.173 in case of slope with root. In numerical analysis, the shear strength of soil varies between 40.311 kPa to 41.782kPa in case of slope without root whereas in case of slope with root this value varies between 50.929 kPa to 52.13 kPa. The average percentage of increase in shear strength for lebbek tree root is 14.35% whereas this value for royal poinciana is 24.29%. It has been also found thatthe factor of safety of soil slopes without vegetation, with uniform vegetation, cylindrical vegetation and semi-spherical vegetation are 1.605, 1.653, 1.654 and 1.616 respectively. From the results, it is understood that plants with cylindrical root architecture increase the most significantly slope stability. It also appears that lebbek tree and royal poinciana may be low-cost and environment friendly alternative solution for the protection of embankment in Bangladesh.