An Empirical Pixel-Based Correction for Imperfect CTE. I. HST's Advanced Camera for Surveys

We use an empirical approach to characterize the effect of charge-transfer efficiency (CTE) losses in images taken with the Wide-Field Channel of the Advanced Camera for Surveys. The study is based on profiles of warm pixels in 168 dark exposures taken between September and October 2009. The dark exposures allow us to explore charge traps that affect electrons when the background is extremely low. We develop a model for the readout process that reproduces the observed trails out to 70 pixels. We then invert the model to convert the observed pixel values in an image into an estimate of the original pixel values. We find that when we apply the image-restoration process to science images with a variety of stars on a variety of background levels, it restores flux, position, and shape. This means that the observed trails contain essentially all of the flux lost to inefficient CTE. The Space Telescope Science Institute is currently evaluating this algorithm with the aim of optimizing it and eventually providing enhanced data products. The empirical procedure presented here should also work for other epochs (eg., pre-SM4), though the parameters may have to be recomputed for the time when ACS was operated at a higher temperature than the current -81 C. Finally, this empirical approach may also hold promise for other instruments, such as WFPC2, STIS, the ACS's HRC, and even WFC3/UVIS.Comment: 86 pages, 25 figures (6 in low resolution). PASP accepted on July 21, 201

Silicon compilation

Silicon compilation is a term used for many different purposes. In this paper we define silicon compilation as a mapping from some higher level description into layout. We define the basic issues in structural and behavioral silicon compilation and some possible solutions to those issues. Finally, we define the concept of an intelligent silicon compiler in which the compiler evaluates the quality of the generated design and attempts to improve it if it is not satisfactory

From FPGA to ASIC: A RISC-V processor experience

This work document a correct design flow using these tools in the Lagarto RISC- V Processor and the RTL design considerations that must be taken into account, to move from a design for FPGA to design for ASIC

A study on stryhcnos potatorum and pisum sativum as natural coagulants for meat food processing wastewater

Wastewater generated from meat food processing industry has significant effects on the environment. Many methods have been reported for removing turbidity, total suspended solids (TSS), chemical oxygen demand (COD), oil and grease (O&G) and colour from meat food processing wastewater (MFPW). The most common method among them is flocculation-coagulation process which is widely used. Although inorganic coagulants are prominent in wastewater treatments, its application may cause toxic residual. In this study, the attempt has been made to study the performance of S. Potatorum (nirmali) and P. Sativum (pea) seed as natural coagulants in the flocculation process. A further aim is to determine the optimum conditions for the treatment of MFPW effluents such as coagulant dosage, mixing rate and pH. An adsorption study was also carried out to study the adsorption potential of these coagulants to treat MFPW. A lab-scale treatment tank was developed to evaluate the effectiveness in MFPW treatment. Jar test results showed that optimum dosage, pH and mixing rate for S. Potatorum were pH 8 with dosage of 150 mg/L and 150 rpm mixing rate with the removal of turbidity, TSS, COD, O&G and colour are 91%, 97.6%, 58.4%, 79.9% and 84.3% respectively. Meanwhile, for P. Sativum, the optimum condition were observed at pH 8 with dosage of 150 mg/L and 150 rpm mixing rate with the removal of turbidity, TSS, COD, O&G and colour 87.8%, 97.3%, 65.5%, 77.9% and 76.5% respectively. The adsorption study was found that the analysis fitted well to the Langmuir isotherm for both natural coagulants. Results show that the percentage of turbidity, TSS, COD, O&G removal by chemical coagulants are quite similar than natural coagulants when lab-scale treatment tank was used to treat the MFPW. This indicated that these natural coagulants have a potential to use as alternative in wastewater treatment

Hybrid receiver conceptual design and test report

The Hybrid Receiver described uses an acquisition and demodulation scheme tailored to the Jovian environment. The large Doppler offsets expected during initial acquisition led to development of the Hilbert Acquisition Aid, which provides for rapid acquisition for low signal to noise densities