Measurement of the Raman line widths of neat benzenethiol and a self-assembled monolayer (SAM) of benzenethiol on a silver-coated surface-enhanced Raman scattering (SERS) substrate

Raman line widths of neat benzenethiol and a self-assembled monolayer (SAM) of benzenethiol on a surface-enhanced Raman scattering (SERS) substrate have been measured using a mini spectrometer with a resolution (full width at half-maximum) of 3.3 ± 0.2 cm(-1). Values of 7.3 ± 0.7, 4.6 ± 0.6, 2.4 ± 0.6, 3.2 ± 0.5, 8.8 ± 0.9, and 11.0 ± 1.1 cm(-1) have been determined for the Raman line widths of the 414, 700, 1001, 1026, 1093, and 1584 cm(-1) modes of neat benzenethiol. Values of 13.3 ± 0.7, 9.1 ± 0.7, 5.1 ± 0.6, 5.9 ± 0.6, 13.3 ± 0.5, and 8.7 ± 0.5 cm(-1) have been determined for the SERS line widths of a benzenethiol SAM on a silver-coated SERS substrate for the corresponding frequency-shifted modes at 420, 691, 1000, 1023, 1072, and 1574 cm(-1). The line widths for the SERS modes at 420, 691, 1000, 1023, and 1072 cm(-1) are about a factor of two larger than those of the corresponding Raman modes. However, the line width of the SERS mode at 1574 cm(-1) is slightly smaller than the corresponding Raman mode at 1584 cm(-1).     

Recent evolution of modern datasets for human activity recognition: a deep survey

Multimedia Systems - Human activity recognition has been a significant goal of computer vision since its inception and has developed considerably in the last years. Recent approaches to this...     

Combining CNN streams of dynamic image and depth data for action recognition

RGB-D sensors have been in great demand due to its capability of producing large amount of multimodal data like RGB images and depth maps, useful for bette     

Swelling of cotton as a tool to enhance the response of cellulase enzymes

Enzymes are now widely used in various textile processes, such as pretreatment and finishing. In the present investigation, undyed as well as vat‐dyed cotton fabrics were pretreated with intracrystalline swelling agents, such as sodium hydroxide and ethylene diamine, and an intercrystalline swelling agent, morpholine. Acid hydrolysis was also carried out on cotton. All the samples were further treated with acid and neutral cellulase enzymes. The effect of pretreatment and enzyme action on the vat dyeing was then studied. In all cases, it was found that intra‐ as well as intercrystalline swelling resulted in enhancing the response of the enzymes.     

Applications of genetic algorithms in process planning: tool sequence selection for 2.5-axis pocket machining

Tool sequence selection is an important activity in process-planning for milling and has great bearing on the cost of machining. Currently, it is accomplished manually without consideration of cost factors a priori. Typically, a large tool is selected to quickly generate the rough shape and a smaller clearing tool is used to generate the net-shape. In this paper, we present a new systematic method to select the optimal sequence of tool(s), to machine a 2.5-axis pocket given pocket geometry, a database of cutting tools, cutting parameters, and tool holder geometry. Algorithms have been developed to calculate the geometric constructs such as accessible areas, and pocket decomposition, while considering tool holders. A Genetic Algorithm (GA) formulation is used to find the optimal tool sequence. Two types of selection mechanisms namely “Elitist selection” and “Roulette method” are tested. It is found that the Elitist method converges much faster than the Roulette method. The proposed method is compared to a shortest-path graph formulation that was developed previously by the authors. It is found that the GA formulation generates near optimal solutions while reducing computation by up to 30% as compared to the graph formulation.     

An approach for extracting non-manifold mid-surfaces of thin-wall solids using chordal axis transform

This paper proposes an approach for extracting non-manifold mid-surfaces of thin-wall solids using the chordal axis transform (CAT) (Prasad in CNLS Newsletter—Center for Nonlinear Studies, Los Alamos National Laboratory, vol 139, 1997). There is great demand for extracting mid-surfaces as it is used in dimension reduction. Quadros and Shimada previously used CAT in extracting 2-manifold mid-surfaces of a particular type of thin-wall solids. The proposed approach is an extension of the previous approach (Quadros and Shimada in 11th international meshing roundtable, 2002) in order to extract non-manifold mid-surfaces of general thin-wall solids. The three steps involved in extracting the mid-surface of a thin-wall solid are: (1) generating a tet mesh of a thin-wall solid without inserting interior nodes; (2) generating a raw mid-surface by smart cutting of tets; and (3) remeshing the raw mid-surface via smart clean-up. In the proposed approach, a discrete model (i.e., a tet mesh without any interior nodes) is used instead of working directly on a CAD model. The smart cutting of tets using CAT yields correct topology at the non-manifold region in the raw mid-surface. As the raw mid-surface is not directly suitable for engineering purposes, it is trimmed using a smart clean-up procedure and then remeshed. The proposed approach has been implemented using C++ in commercial ALGOR finite element analysis software. The proposed approach is computationally efficient and has shown effective results on industrial models.     

Effects of Ion Advection and Thermal Convection on Pore Pressure Changes in High Permeable Chemically Active Shale Formations

Wellbore instability problems are often encountered while drilling in water active shales due to changes in pore pressure. The change in pore pressure is caused by hydraulic, thermal, chemical, and electrical potential gradients. In all previous studies it has been found that the effects of ion advection and thermal convection have a negligible effect on changes in pore pressure for a range of very low permeable shale formations (>10^?5 md). This is an appropriate assumption for very low permeable shale formations. For high permeable shale formations (e.g., shale with a disseminated microfissure network), however, thermal convection and ion advection can play a significant role. The authors present a hydro-chemo-thermo-electrical model based on finite element method to investigate the effect of advection on ion transfer and thermal convection on temperature and their combined effect on pore pressure in shale formations. All equations are based on the thermodynamics of irreversible processes in a discontinuous system. The characteristic Galerkin discretization method is used to stabilize the solution of advection and convection equations in the finite element approach. Results of this study revealed that ion and heat transfer are controlled primarily by permeability of the shale formations. Movement of fluid into or out of the formation is due to a combination of hydraulic, chemical, electrical, and thermal osmotic flow. Results have also shown that in high permeable shale formations the chemical potential gradient between the pore fluid and drilling fluid reaches equilibrium faster than in low permeable shale formations. This is mainly due to the advection of ion from drilling fluid to the shale formation.     

Deflection-based method for seismic response analysis of concrete walls: Benchmarking of CAMUS experiment

A number of shake table tests had been conducted on the scaled down model of a concrete wall as part of CAMUS experiment. The experiments were conducted between 1996 and 1998 in the CEA facilities in Saclay, France. Benchmarking of CAMUS experiments was undertaken as a part of the coordinated research program on ‘Safety Significance of Near-Field Earthquakes’ organised by International Atomic Energy Agency (IAEA). Technique of deflection-based method was adopted for benchmarking exercise. Non-linear static procedure of deflection-based method has two basic steps: pushover analysis, and determination of target displacement or performance point. Pushover analysis is an analytical procedure to assess the capacity to withstand seismic loading effect that a structural system can offer considering the redundancies and inelastic deformation. Outcome of a pushover analysis is the plot of force–displacement (base shear–top/roof displacement) curve of the structure. This is obtained by step-by-step non-linear static analysis of the structure with increasing value of load. The second step is to determine target displacement, which is also known as performance point. The target displacement is the likely maximum displacement of the structure due to a specified seismic input motion. Established procedures, FEMA-273 and ATC-40, are available to determine this maximum deflection. The responses of CAMUS test specimen are determined by deflection-based method and analytically calculated values compare well with the test results.