Silicon production process evaluations

Chemical engineering analysis of the HSC process (Hemlock Semiconductor Corporation) for producing silicon from dichlorosilane in a 1,000 MT/yr plant was continued. Progress and status for the chemical engineering analysis of the HSC process are reported for the primary process design engineering activities: base case conditions (85%), reaction chemistry (85%), process flow diagram (60%), material balance (60%), energy balance (30%), property data (30%), equipment design (20%) and major equipment list (10%). Engineering design of the initial distillation column (D-01, stripper column) in the process was initiated. The function of the distillation column is to remove volatile gases (such as hydrogen and nitrogen) which are dissolved in liquid chlorosilanes. Initial specifications and results for the distillation column design are reported including the variation of tray requirements (equilibrium stages) with reflux ratio for the distillation

Silicon production process evaluations

Engineering design of the third distillation column in the process was accomplished. The initial design is based on a 94.35% recovery of dichlorosilane in the distillate and a 99.9% recovery of trichlorosilane in the bottoms. The specified separation is achieved at a reflux ratio of 15 with 20 trays (equilibrium stages). Additional specifications and results are reported including equipment size, temperatures and pressure. Specific raw material requirements necessary to produce the silicon in the process are presented. The primary raw materials include metallurgical grade silicon, silicon tetrachloride, hydrogen, copper (catalyst) and lime (waste treatment). Hydrogen chloride is produced as by product in the silicon deposition. Cost analysis of the process was initiated during this reporting period

Silicon production process evaluations

Chemical engineering analysis was continued for the HSC process (Hemlock Semiconductor Corporation) in which solar cell silicon is produced in a 1,000 MT/yr plant. Progress and status are reported for the primary engineering activities involved in the preliminary process engineering design of the plant base case conditions (96%), reaction chemistry (96%), process flow diagram (85%), material balance (85%), energy balance (60%), property data (60%), equipment design (40%), major equipment list (30%) and labor requirements (10%). Engineering design of the second distillation column (D-02, TCS column) in the process was completed. The design is based on a 97% recovery of the light key (TCS, trichlorosilane) in the distillate and a 97% recovery of the heavy key (TET, silicon tetrachloride) in the bottoms. At a reflux ratio of 2, the specified recovery of TCS and TET is achieved with 20 trays (equilibrium stages, N=20). Respective feed tray locations are 9, 12 and 15 (NF sub 1 = 9, NF sub 2 = 12,, and NF sub 3 = 15). A total condenser is used for the distillation which is conducted at a pressure of 90 psia

Silicon production process evaluations

Chemical engineering analyses involving the preliminary process design of a plant (1,000 metric tons/year capacity) to produce silicon via the technology under consideration were accomplished. Major activities in the chemical engineering analyses included base case conditions, reaction chemistry, process flowsheet, material balance, energy balance, property data, equipment design, major equipment list, production labor and forward for economic analysis. The process design package provided detailed data for raw materials, utilities, major process equipment and production labor requirements necessary for polysilicon production in each process

What do we want to get out of this?:a critical interpretive synthesis of the value of process evaluations, with a practical planning framework

BACKGROUND: Process evaluations aim to understand how complex interventions bring about outcomes by examining intervention mechanisms, implementation, and context. While much attention has been paid to the methodology of process evaluations in health research, the value of process evaluations has received less critical attention. We aimed to unpack how value is conceptualised in process evaluations by identifying and critically analysing 1) how process evaluations may create value and 2) what kind of value they may create. METHODS: We systematically searched for and identified published literature on process evaluation, including guidance, opinion pieces, primary research, reviews, and discussion of methodological and practical issues. We conducted a critical interpretive synthesis and developed a practical planning framework. RESULTS: We identified and included 147 literature items. From these we determined three ways in which process evaluations may create value or negative consequences: 1) through the socio-technical processes of ‘doing’ the process evaluation, 2) through the features/qualities of process evaluation knowledge, and 3) through using process evaluation knowledge. We identified 15 value themes. We also found that value varies according to the characteristics of individual process evaluations, and is subjective and context dependent. CONCLUSION: The concept of value in process evaluations is complex and multi-faceted. Stakeholders in different contexts may have very different expectations of process evaluations and the value that can and should be obtained from them. We propose a planning framework to support an open and transparent process to plan and create value from process evaluations and negotiate trade-offs. This will support the development of joint solutions and, ultimately, generate more value from process evaluations to all. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12874-022-01767-7

Can Economic Development Programs Be Evaluated?

The question addressed in this paper seems simple: Can economic development programs be evaluated? But the answer is not simple because of the nature of evaluation. To determine a program's effectiveness requires a sophisticated evaluation because it requires the evaluator to distinguish changes due to the program from changes due to nonprogram factors. The evaluator must focus on the outcomes caused by the program rather than the program's procedures. Evaluations can be divided into two categories process or formative evaluations and outcome, impact, or summative evaluations. Process evaluations focus on how a program is delivered. Impact evaluations focus on the program's results. Although process evaluations are important, the focus of this chapter is on program outcomes thus the concern with impact evaluations; however, both types of evaluations need to be defined.economic, development, programs, evaluate, Bartik, Bingham

Process Evaluations for a Multisite Nutrition Education Program

Process evaluations are an often-overlooked component of evaluating health promotion interventions, but can be essential for interpreting program outcomes. The purpose of this study was to report the results of two types of process evaluations conducted for Food Fit, a nutrition education program implemented to 58 3rd through 5th grade children (67% Caucasian) in 5 YMCA after school programs. To evaluate program fidelity, a trained observer watched each lesson and recorded program adherence using a standardized checklist, outlining essential components of the intervention. Attendance was recorded by asking each child to complete a small task before and after each lesson. Results showed that program adherence was perfect in most cases and attendance rates varied, but were generally high. Attendance rates were not associated with improvement in nutrition behaviors. Implications and recommendations for future use of process evaluations are discussed

The Utilization of Process Evaluations in Childhood Obesity Intervention Research: A Review of Reviews

Process evaluations are an essential component to evaluating health promotion programs, however they are consistently under-utilized and oftentimes not reported upon in the literature. This study reports the use of process evaluations in childhood obesity prevention interventions implemented over the past three decades. Seven meta-analyses and systematic reviews were located for this review or reviews, and from these, 119 unique references were identified. Each article was retrieved and read for appropriateness, and 20 were excluded for a variety of reasons (ex. not published in English language), resulting in 99 articles included for this study. Overall, process evaluations were not well reported upon. Only 38 studies reported the fidelity of program implementation, 25 studies tracked participant attendance, 29 studied evaluated participant satisfaction, and 49 studies reported how staff members were trained. Additionally, one-third of the studies did not report using a single type of process evaluation, and only 5 studies reported using all four types. Results from this study suggest that the use of process evaluations has been low in this area of research, which may explain why many obesity prevention studies have reported mixed or modest results. Suggestions for implementing simple, yet effective process evaluations in future studies will be presented

The generation of consensus guidelines for carrying out process evaluations in rehabilitation research

Abstract Background Although in recent years there has been a strong increase in published research on theories (e.g. realist evaluation, normalization process theory) driving and guiding process evaluations of complex interventions, there is limited guidance to help rehabilitation researchers design and carry out process evaluations. This can lead to the risk of process evaluations being unsystematic. This paper reports on the development of new consensus guidelines that address the specific challenges of conducting process evaluations alongside clinical trials of rehabilitation interventions. Methods A formal consensus process was carried out based on a modified nominal group technique, which comprised two phases. Phase I was informed by the findings of a systematic review, and included a nominal group meeting with an expert panel of participants to rate and discuss the proposed statements. Phase II was an in depth semi-structured telephone interviews with expert panel participants in order to further discuss the structure and contents of the revised guidelines. Frequency of rating responses to each statement was calculated and thematic analysis was carried out on all qualitative data. Results The guidelines for carrying out process evaluations within complex intervention rehabilitation research were produced by combining findings from Phase I and Phase II. The consensus guidelines include recommendations that are grouped in seven sections. These sections are theoretical work, design and methods, context, recruitment and retention, intervention staff, delivery of the intervention and results. These sections represent different aspects or stages of the evaluation process. Conclusion The consensus guidelines here presented can play a role at assisting rehabilitation researchers at the time of designing and conducting process evaluations alongside trials of complex interventions. The guidelines break new ground in terms of concepts and theory and works towards a consensus in regards to how rehabilitation researchers should go about carrying out process evaluations and how this evaluation should be linked into the proposed trials. These guidelines may be used, adapted and tested by rehabilitation researchers depending on the research stage or study design (e.g. feasibility trial, pilot trial, etc.)

Ethnographic methods for process evaluations of complex health behaviour interventions.

This is the final version of the article. Available from BioMed Central via the DOI in this record.This article outlines the contribution that ethnography could make to process evaluations for trials of complex health-behaviour interventions. Process evaluations are increasingly used to examine how health-behaviour interventions operate to produce outcomes and often employ qualitative methods to do this. Ethnography shares commonalities with the qualitative methods currently used in health-behaviour evaluations but has a distinctive approach over and above these methods. It is an overlooked methodology in trials of complex health-behaviour interventions that has much to contribute to the understanding of how interventions work. These benefits are discussed here with respect to three strengths of ethnographic methodology: (1) producing valid data, (2) understanding data within social contexts, and (3) building theory productively. The limitations of ethnography within the context of process evaluations are also discussed