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Tolerance design technique balances the expected quality loss due to variations of the system performance and the cost due to controlling these variations. Measures of quality are discussed and quality loss function is used for tolerance design. The goal is to minimize the total loss that consists of the quality loss to the customer and the cost increase to the producer. The design methodologies are presented for the tolerances of products before shipping to the customer and the tolerances of lower-level characteristics. The approaches to tolerance design for components and subsystems are also demonstrated using the variation transfer function. Examples are given as illustrations of the methodology.

Cryogenic treatments have been applied to enhance both wear and abrasion resistance for the cutting inserts. Therefore, many investigations focused on the shallow and deep cryogenic treatments in terms of their performance on the machinability criteria. This paper presents a detailed analysis on machinability investigation of cryogenically treated hardened 4140 steel (55 HRC), and sustainability assessment in hard machining on finishing mode carried out at dry cutting regime. A series of machining trials have been performed under varied cutting conditions (feed, depth of cut and speed) following the L₉ orthogonal array design experimental layout for analysis of various responses along with cost estimation in hard turning. Moreover, the machining parameters are optimized and mathematically formulated for the minimization of various responses using a multi-objective optimization method. Finally, considering the motivational idea of “Go green–Think green–Act green”, a unique novel approach has been proposed concerning economic evaluation and sustainability assessment in hard turning for safer and cleaner approach of environment friendly manufacturing. According to statistical analysis, feed influenced both surface roughness and cutting force significantly. Because of cryogenic treatment both surface roughness and cutting force diminished. It is noticed that with high speed, low feed, and depth of cut both force and roughness value declined. The tool life of CBN was 44min and considering the same, Gilbert’s machining economic model calculated the overall machining cost per part of 80.86 in the machining of hardened AISI 4140 steel. The outcomes clearly established that machining under dry conditions provides environment friendliness, technologically viable, and economically feasible to improve sustainability.

The present study addresses the machinability investigation in finish dry hard turning of high strength low alloy steel with coated ceramic tool by considering cutting speed, feed and depth of cut as machining parameters. The technological parameters like surface roughness, flank wear, chip morphology and economical feasibility have been considered to investigate the machinability performances. Twenty seven set of trials according to full factorial design of experiments are performed and analysis of variance, multiple regression method, Taguchi method, desirability function approach and finally Gilbert’s approach are subsequently applied for parametric influence study, mathematical modeling, multi-response optimization, tool life estimation and economic analysis. Results indicated that feed and cutting speed are the most significant controlled as well as dominant factors for hard turning operation if the minimization of the machined surface roughness and tool flank wear is considered. Abrasions, adhesion followed by plastic deformation have been observed to be the principal wear mechanism for tool life estimation and observed tool life for coated ceramic insert is 47min under optimum cutting conditions. The total machining cost per part is ensued to be lower ($0.29 only) as a consequence of higher tool life, reduction in downtime and enhancement in savings, which finds economical benefits in hard turning. The current work demonstrates the substitution of conventional, expensive and slow cylindrical grinding process, and proposes the most expensive CBN tool alternative using coated ceramic tools in hard turning process considering techno-economical and ecological aspects.

We performed a cost-benefit analysis for bioethanol production using biomass of Ulva rigida, a marine macroalga (seaweed), co-cultured with fish in an intensive offshore aquaculture unit. This is the first report for such analysis that takes into consideration offshore seaweed cultivation and uses a recently developed, novel and simplified ethanol production technology that is devoid of costly pre-treatments imposed to the seaweed biomass. By simultaneously producing ethanol with valuable Dried Distillers Grains with Solubles (DDGS) by-products such as animal feed, the economic viability of this system is plausible over a production range of 77–240 dry tons of seaweed per day. As such, applying the model to suggested future scenarios for the Israeli Mediterranean shorelines, which limits aquaculture to ca. 600 ha, results in unprofitability. Further, sensitivity analyses place profitability as mainly dependent on DDGS prices and on the daily growth rate (biomass yield) of the macroalga. These two are key factors to achieve profitability at the 600-ha scenario.

Globally, billions of people rely on piped water and sanitation services delivered by municipal water utilities, but many of these systems, particularly in low- and middle-income countries (LMICs) are plagued by chronic problems of inequitable access, intermittent supply, and poor water quality. While improving service quality in these persistently underperforming systems will certainly require substantial infrastructure investment and supportive maintenance, a parallel strengthening of utilities and regulators’ capacity and management is at least as fundamental. And though prior research highlights the lack of capacity, misaligned incentives, and ineffective policies that lead LMIC utilities to perform so poorly, the identification of sustainable and replicable solutions to these problems, that extends beyond a small set of cases, has proven difficult. This paper argues for greater use of systems dynamics models to facilitate more holistic thinking about the potential of different intervention strategies, acknowledging that the behavior of utility-based water management systems is defined by complex interactions. This complexity plays out in reinforcing and balancing feedback between variables, lagged responses, and dynamics that often preclude moving past critical thresholds that define poverty or low performance traps. The paper then discusses how several basic archetypes relate to experiences of institutional reform failure and success described in the broader literature, with the goal of motivating future application of these methods for comparative analysis of different utility water system improvements.

In order to promote the construction and development of rural energy Internet, this paper designs corresponding business models for the three stages of rural energy Internet investment - construction - operation, and establishes cost and value measurement models. Based on the actual data in Shandong, five different scenarios are set up to measure the cost and value, and the best means to improve the economic efficiency of rural industries are identified through sensitivity analysis. The results of the example show that considering multiple benefits can bring a better economy to the rural energy industry, and increasing the percentage of direct energy supply is the best way to improve the economy of the rural energy industry.

To solve the problem of forming fixed cover plastic parts, plastic materials and the molding process are analyzed with a mold scheme demonstration, structural analysis and economic analysis. The main runner, cold slug well, pull rod, and runner and gate of the gating system are also thus designed. The ejection force is calculated, and the cooling system designed. An assembly diagram of the special injection mould is given. Practical tests have shown that the shell shaped piece injection mould structure is economical, reliable, has a good machining quality and a high production efficiency.

The energy consumption of building accounts for a significant proportion in the total consumption of the world. The use of new materials may bring obvious energy-saving effect. In this paper, a mathematical model is constructed by economic method. This model can consider synthetically energy consumption of building and the cost of wall, and determine the criterion of selecting wall materials and wall thickness.

As a promising industry, the biomass power generation has a good prospect for development. This paper analyzed the current status of domestic and foreign biomass power generation, and makes an economic analysis and generation costs structure model of biomass power generation of Jilin province. The existing problems of the current biomass power generation were investigated in detail, and the development strategy of biomass power generation of Jilin province was proposed.