Tuning the Structural and Optical Properties of SILAR-Deposited Cu_2O Films Through Zn Doping

Undoped and Zn-doped Cu2O films were deposited onto glass substrates using successive ionic layer adsorption and reaction(SILAR) technique with different Zn doping levels(0, 1, 2, 3, 5 and 10 wt%). The structural,optical, and surface morphological studies were carried out and reported. The structural study revealed that the crystalline quality is gradually enhanced up to 5 wt% of Zn doping level, and then quality begins to degrade for further increase in doping level. Moreover, the preferential orientation changes from(111) to(110) for the highest doping level were examined. Optical study shows that the transmittance(65%) and optical band gap values are maximum(2.41 e V) when the Zn doping level is at 5 wt%. The photoluminescence study confirms the presence of various defects in the Cu2O matrix and also the variation obtained in the optical band gap from the transmittance data. SEM images revealed the annealinginduced changes in the surface morphology of the films.     

Hardware design implementation issues of the estimator-based controller using FPGA

Hardware implementation issues play a vital role to realize the system accurately. Realization of hardware in digital domain has more advantages than analog domain. Field programming gate array (FPGA) based architectures are suitable for fast and reconfigurable systems. In this paper, implementation issues of an estimator based controller using FPGA are discussed. Verilog coding is developed to defeat these issues and efficient hardware mapping is derived. Input signal processing is proposed to overcome the analog to digital converter (ADC) interfacing issues such as quantization, sampling rate, resolution, non-linearity error and offset error. Optimum bit sizing of digital control modules are derived, considering system requirements and specifications. Controller operations are analyzed in binary form to choose the bit size of various operands and control modules, to derive accurate results. In this application, a 16-bit control architecture is proposed to estimate states of the converter and to generate control signals. Estimator based controller is designed for a dc-dc converter. Atlys Spartan-6 XC6SLX45 FPGA is used to implement the controller. Implementation issues such as ADC errors, settling time, the bit size of variables, quantization effects of the estimator and controller are mainly focused. It enables verilog coding quite easier to implement non-linear controllers using FPGA.     

Effect of heat-treatment on the structural and optical properties of Cu2S thin films deposited by CBD method

Semiconducting Cu₂S thin films were successfully deposited on glass substrate under three different conditions such as as-deposited, post heat-treated and pre heated precursor solution by chemical bath deposition technique. Structural and optical properties of the films were characterized by X-ray diffraction (XRD), scanning electron microscope, energy dispersive X-ray (EDX) analysis and UV–Visible spectrophotometer. The XRD spectra showed the amorphous nature of thin films with hexagonal structure. The d value and micro strain increased and the average crystallite size decreased from 1.9 to 1.4 and 1.3 nm respectively when the as-deposited film was subjected to post heat-treatment and the precursor solution temperature was elevated. The presence of more nucleation centers and fast reaction rate decreased the average crystallite size in films grown with pre heated precursor solution. The noticed blue shift in energy gap and the shift of XRD peak position towards the lower 2θ side by heat-treatment could be considered as a sign of the quantum confined effect due to the formation of the nano-sized Cu₂S crystals on the surface. The transmittance of heat-treated Cu₂S films in the visible region matched the phototropic vision of human eye (~600 nm) which makes them suitable for solar control coatings on architectural windows and automobiles in the regions with warm climates. Low transmittance behaviour of pre heated Cu₂S films could be used for anti dazzling coatings for car windscreens and driving mirrors to reduce the dazzling effects of light at night. EDX spectra showed the chemical purity of the films. The observed broad absorption and blue shift in band gap of the heat-treated films were due to quantum confinement effect. Fourier transform infrared studies were also carried out and the results are presented.     

Application of Ozonated Dry Ice (ALIGAL™ Blue Ice) For Packaging and Transport in the Food Industry

Abstract: Dry ice is used by meat and poultry processors for temperature reduction during processing and for temperature maintenance during transportation. ALIGAL? Blue Ice (ABI), which combines the antimicrobial effect of ozone (O₃) along with the high cooling capacity of dry ice, was investigated for its effect on bacterial reduction in air, in liquid, and on food and glass surfaces. Through proprietary means, O₃ was introduced to produce dry ice pellets to a concentration of 20 parts per million (ppm) by total weight. The ABI sublimation rate was similar to that of dry ice pellets under identical conditions, and ABI was able to hold the O₃ concentration throughout the normal shelf life of the product. Challenge studies were performed using different microorganisms, including E. coli, Campylobacter jejuni, Salmonella, and Listeria, that are critical to food safety. ABI showed significant (P < 0.05) microbial reduction during bioaerosol contamination (up to 5‐log reduction of E. coli and Listeria), on chicken breast (approximately 1.3‐log reduction of C. jejuni), on contact surfaces (approximately 3.9 log reduction of C. jejuni), and in liquid (2‐log reduction of C. jejuni). Considering the stability of O₃, ease of use, and antimicrobial efficacy against foodborne pathogens, our results suggest that ABI is a better alternative, especially for meat and poultry processors, as compared to dry ice. Further, ABI can potentially serve as an additional processing hurdle to guard against pathogens during processing, transportation, distribution, and/or storage. Practical Application: A new product known as ALIGAL? Blue Ice (ABI) incorporates ozone in dry ice pellets, combining the high cooling capacity of dry ice pellets and the antimicrobial efficacy of ozone. This study evaluated the antimicrobial efficacy of ABI compared to dry ice under potential commercial processing conditions, specifically examining the impact on airborne, surface, moisture, and food contamination. Treatment with ABI resulted in higher reductions of bacteria with airborne contamination, on chicken breast, on surfaces, and in liquid compared to dry ice. Thus, ABI can serve as an additional processing hurdle to guard against pathogens during food processing and storage.     

Trajectory based abnormal event detection in video traffic surveillance using general potential data field with spectral clustering

Detection of abnormal trajectories in a traffic scene is an important problem in Video Traffic Surveillance (VTS). Recently, General Potential Data Field (GPDf)-based trajectory clustering scheme has been adopted for detecting abnormal events such as illegal U-turn, wrong side and unusual driving behaviors and it uses spatial and temporal attributes explicitly. The concept of data field is used to discover the relation between the spatial points in data-space and grouping them into clusters based on their mutual interaction. Existing methodologies related to potential data field-based clustering have certain limitations such as pre-defined cluster size, non-effective cluster center identification, and limitation in range estimation using isotropic impact factor (h) which leads to inaccurate results. In order to address the above-mentioned issues, this paper proposes an efficient anomaly detection scheme based on General Potential Data field with Spectral Clustering (GPDfSC). The proposed GPDfSC scheme utilizes potential data field technique along with spectral clustering for effective identification of abnormalities. The Limitation in impact factor(h) is overcome by using anisotropic impact parameter Bmat. Further, Bayesian Decision theory is used to classify the events as normal or abnormal. The proposed scheme is implemented in real time using GPU and from the results it is found that it gives 12% better accuracy in detecting abnormalities than the state of art technique.