Theoretical Investigation of Iterative Phase Retrieval Algorithm for Quasi-Optical Millimeter-Wave RF Beams

In this paper, we present a detailed analysis of the iterative phase retrieval approach (TPRA) for determining the phase profile of the output microwave beam of a gyrotron from known intensity patterns emphasizing the field propagation techniques which are used to propagate the RF field of the microwave beam between known intensity planes. The propagation method, based on first Rayleigh-Sommerfeld diffraction integral (RSDI), is solved using fast Fourier transform (FFT) technique and zero padding. It is observed that the use of FFT and, therefore, the discretization of the RSDI propagation kernel introduce aberrations in the propagated field due to the superposition of the original field with its replicated versions. This problem is solved by approximations leading to the Huygens-Fresnel propagation method which further Imposes the restrictions on the distances of propagation depending on the size of the transverse plane used to discretize the intensity pattern. This constraint of the distance of propagation causes problem in the iterative phase retrieval approach (IPRA) when more than two intensity planes are used. A method based on interpolation is proposed to overcome this restriction. IPRA is then further discussed to optimize several parameters, such as plane separation, plane dimension, mesh size, and measurement accuracies, which become more of an issue during the measurements of infrared Intensity thermograms of the output microwave beam

Infrared Measurements of the RF Output of 170-GHz/2-MW Coaxial Cavity Gyrotron and Its Phase Retrieval Analysis

We report the experimental results of the infrared measurements of output RF beam of the European 2-MW 170-GHz coaxial cavity gyrotron for ITER. The output beam profile is measured by the infrared thermographic technique using an infrared camera and a target material which is being irradiated by the RF output. The beam intensity was measured at several locations along the propagation direction. The data were processed for noise reduction and perspective correction and then used with the phase retrieval algorithm to yield an accurate estimate of the phase profile. The moments of the measured intensity arrays are calculated to improve the reliability of the measured infrared image data and data processing. The beam profile is also measured at specific locations in order to compare the phase calculated with the HuygensFresnel propagation method for fixed distance and RayleighSommerfeld diffraction integral method used for field propagation in the phase retrieval algorithm

Mode Content Analysis of the RF output of a Gyrotron Based on the Astigmatic Gaussian Beams of High Order

We have performed this work again

Multi-item economic production quantity model for imperfect items with multiple production setups and rework under the effect of preservation technology and learning environment

This study aims to investigate the multi-item inventory model in a production/rework system with multiple production setups. Rework can be depicted as the transformation of production rejects, failed, or non-conforming items into re-usable products of the same or lower quality during or after inspection. Rework is very valuable and profitable, especially if materials are limited in availability and also pricey. Moreover, rework can be a good contribution to a ‘green image environment’. In this paper, we establish a multi-item inventory model to determine the optimal inventory replenishment policy for the economic production quantity (EPQ) model for imperfect, deteriorating items with multiple productions and rework under inflation and learning environment. In inventory modelling, Inflation plays a very important role. In one cycle, production system produces items in n production setups and one rework setup, i.e. system follows (n, 1) policy. To reduce the deterioration of products preservation technology investment is also considered in this model. Holding cost is taken as time dependent. We develop expressions for the average profit per time unit, including procurement of input materials, costs for production, rework, deterioration cost and storage of serviceable and reworkable lots. Using those expressions, the proposed model is demonstrated numerically and the sensitivity analysis is also performed to study the behaviour of the model

Factors Influencing Attitude Towards The Use of Mosquito Nets in Households in The Gambia

Malaria is caused by Plasmodium parasites, which are transmitted via the bite of infected female anopheles mosquitoes. There were 217 million cases of malaria worldwide, and about 435,000 malaria related deaths in 2017. WHO Africa region accounted for 92% and 93% of malaria cases and deaths worldwide. According to The Gambia National Malaria Strategic Plan 2013-2020, malaria is a leading cause of morbidity and mortality. The aim of this study was to identify factors influencing attitude towards the use of mosquito nets in households in The Gambia using Demographic and Health Survey (DHS) data. The current study is a secondary data analysis with a, cross-sectional study design. The source of the data for this study is the DHS, which was conducted by the United States Agency for International Development (USAID) together with the Gambia Bureau of Statistics (GBOS) in 2013. The study sample is representative of The Gambian population. The sample size for the study was 5276 subjects. Statistical Analysis System (SAS 9.3) was used for data analysis. Descriptive statistics were generated for the factors been tested. These included area of residence, presence of electricity, indoor residual spraying, highest level of education and wealth index. The outcome variable measured was household use of mosquito nets (Yes/No). Logistic regression analysis was done to determine whether area of residence, wealth index, education level, presence of electricity and indoor residual spraying influence attitude towards use of mosquito nets in households. Stepwise binary logistic regression was used to determine the final model with the most significant predictors. Odds ratios and corresponding confidence intervals were reported. Most of the study participants were poor (46%). Those with no education made up 45.5% of the study population and 58% of dwellings had no indoor residual spraying done in the past year. 76.6% and 59.1% of respondents lived in households that had at least one mosquito net and no electricity supply, respectively. 50.6% of the respondents resided in rural areas. Logistic regression analysis showed that wealth index, indoor residual spraying and area of residence were significant factors (p\u3c0.05) influencing attitude towards use of mosquito nets in households. Indoor residual spraying (OR=2.00; 95% C.I. 1.71-2.36), primary school education (OR=1.1; 95% C.I. 0.94-1.32), middle class wealth index (OR=1.32; 95% C.I. 1.05-1.67) and rural residence (OR=1.29; 95% C.I. 1.01-1.64) are all independent factors that increased likelihood of mosquito net usage in households. Identifying factors that influence the usage of mosquito nets in households, can be useful in developing target interventions to further reduce malaria morbidity and mortality in The Gambia. Knowledge from this study can be used to further strengthen the national malaria strategic plan. To further establish causality and increase strength of association between factors and outcome, a case control or cohort study design will be needed, since that is one of the limitations of a cross sectional study

Comparing the long-term impact on health care resources utilization and costs due to various single-piece acrylic monofocal intraocular lens implantation during cataract surgery: a cost-consequence analysis for the United Kingdom, Italy, and Denmark

Mukesh Dhariwal,1 Christine Bouchet,2 Shantanu Jawla3 1Global Health Economics & Outcomes Research, Alcon Laboratories, Inc., Fort Worth, TX, USA; 2Global Patient Access, Novartis Pharma AG, Basel, Switzerland; 3Patient Access Services, Novartis Healthcare Private Limited, Hyderabad, India Purpose: The objective of this study was to estimate the cost impact of neodymium-doped yttrium aluminum garnet (Nd:YAG) laser capsulotomy and its complications due to single-piece acrylic monofocal intraocular lenses (IOLs) in the healthcare setting of United Kingdom, Italy, and Denmark.Materials and methods: A hypothetical cost-consequence model was developed to estimate economic burden of Nd:YAG laser capsulotomy due to different single-piece acrylic monofocal IOLs. Cumulative incidence of Nd:YAG laser capsulotomy at 3 years after cataract surgery with five single-piece monofocal acrylic IOLs was sourced from retrospective data analysis of electronic medical records of cataract patients in the United Kingdom. Risk probability of post-Nd:YAG laser complications, ie, retinal detachment, glaucoma, and cystoid macular edema at 3 years was derived using published literature. Unit costs were taken from publicly available sources with all costs converted to euro (€). Number of cataract procedures per year for each country was sourced from Eurostat statistics.Results: For the estimated cataract procedures carried out nationally every year, single-piece monofocal hydrophobic AcrySof IOL was associated with substantially lower cases of Nd:YAG laser capsulotomy procedures and subsequent complications in 3 years after cataract surgery when compared to other single-piece monofocal acrylic IOLs. The total cost savings with the use of AcrySof over other IOLs in countries assessed ranged from €0.5 to €4.7 million (vs AMO Tecnis) and €2.1 to €17.9 million (vs Rayner C-/Super-flex).Conclusion: Incidence of Nd:YAG capsulotomy due to the choice of IOL could significantly affect healthcare budgets in the post-cataract surgery period. Our analysis indicates that single-piece monofocal AcrySof IOLs is the most cost-saving treatment option for health care systems when compared to other acrylic single-piece IOLs. Keywords: AcrySof, cost, Nd:YAG capsulotomy, cataract, PCO, IO