Competing with successful products has become perplexing with several uncertainties and transmutes from time to time as customers＇ expectations are dynamic.That is why manufacturing firms exhaustively strive to look ...Competing with successful products has become perplexing with several uncertainties and transmutes from time to time as customers＇ expectations are dynamic.That is why manufacturing firms exhaustively strive to look for a better competitive frontier using wellestablished and innovative product development（PD）processes.In this paper,we would like to answer three research questions：（i）What would be the effects of frontloading in PD？（ii）Can we improve our PD process endlessly？（iii）When is the critical time that the firm should take remedial action for improvements？As a contribution to the vast numbers of improvement methods in new product development（NPD）,this paper investigates the effects of front-loading using set-based concurrent engineering（SBCE）on cost and lead time.Models are developed and treated using a system dynamics（SD）approach.We assign a hypothetical upfront investment for SBCE and compare its effects on total cost and lead time of the development process.From the research,it is found that the total cost of PD is reduced almost by half-although the front loading is higher in order to encompass multiple design alternatives.The total product lead time is reduced by almost 20%.The model reveals the critical time for improvement of the PD process.We use SD tool（e.g.,STELLA）for simulation and visualization of the complex PD model,using SBCE as one of several strategies to frontload activities in the NPD process.展开更多
The extensive use of traditional cooking and heating stoves to meet domestic requirements creates a serious problem of indoor and outdoor air pollution.This study reports the impacts of two fuel feeding methods-front-...The extensive use of traditional cooking and heating stoves to meet domestic requirements creates a serious problem of indoor and outdoor air pollution.This study reports the impacts of two fuel feeding methods-front-loading and top-loading on the thermal and emissions performance of a modern coal-fired water-heating and cooking stove using a contextual test sequence that replicates typical patterns of domestic use.Known as a low-pressure boiler,when this stove was fueled with raw coal,the findings indicate that front-loading the fuel,which devolatilizes the new fuel gradually,produced consistently higher space heating efficiency and lower emission factors than top-loading the same stove,which devolatilizes new fuel all at once.Comparing the performance at both high and low power gave the similar results:front-loading with raw coal produced consistently better results than top-loading.The average water heating efficiency when front-loading was(58.6±2.3)%and(53.4±1.8)%for top-loading.Over the sixteen-hour test sequence,front-loading produced 22%lower emissions of PM2.5(3.9±0.6)mg/MJNET than top-loading(4.7±0.9)mg/MJNET.The same pattern was observed for carbon monoxide and the CO/CO2 ratio.CO was reduced from(5.0±0.4)g/MJNET to(4.1±0.5)g/MJNET.The combustion efficiency(CO/CO2 ratio)improved from(8.2±0.8)%to(6.6±0.6)%.Briquetted semi-coked coal briquettes are promoted as a raw coal substitute,and the tests were replicated using this fuel.Again,the same pattern of improved performance was observed.Front loading produced 3.5%higher heating efficiency,10%lower CO and a 0.9%lower CO/CO2 ratio.It is concluded that,compared with top loading,the manufacturers recommended front-loading refueling behavior delivered better thermal,emissions and combustion performance under all test conditions with those two fuels.展开更多
文摘Competing with successful products has become perplexing with several uncertainties and transmutes from time to time as customers＇ expectations are dynamic.That is why manufacturing firms exhaustively strive to look for a better competitive frontier using wellestablished and innovative product development（PD）processes.In this paper,we would like to answer three research questions：（i）What would be the effects of frontloading in PD？（ii）Can we improve our PD process endlessly？（iii）When is the critical time that the firm should take remedial action for improvements？As a contribution to the vast numbers of improvement methods in new product development（NPD）,this paper investigates the effects of front-loading using set-based concurrent engineering（SBCE）on cost and lead time.Models are developed and treated using a system dynamics（SD）approach.We assign a hypothetical upfront investment for SBCE and compare its effects on total cost and lead time of the development process.From the research,it is found that the total cost of PD is reduced almost by half-although the front loading is higher in order to encompass multiple design alternatives.The total product lead time is reduced by almost 20%.The model reveals the critical time for improvement of the PD process.We use SD tool（e.g.,STELLA）for simulation and visualization of the complex PD model,using SBCE as one of several strategies to frontload activities in the NPD process.
基金This research was supported by the National Natural Science Foundation of China(Grant No.51806242)the Chinese Universities Scientific Fund(No.2019TC010)+3 种基金the Chinese Universities Scientific Fund-Special Project for"Double First-Class"Initiative of College of Engineering,China Agricultural University,"the Characteristics of Thermal and Mass Flow for Clean Space-heating of Rural Households using Biofuels"the Agricultural Product Quality Inspection Bureau,Ministry of Agriculture and Rural Affairs,China,Agricultural Industry Standard Development Project-"Determination method of major atmospheric pollutants from rural household stoves"(No.181721301092371112)the bilateral China-South Africa MoST-NRF joint project“Development of Scientifically Robust and Culturally Appropriate Metrics and Protocols for Evaluating Clean(Combustion)Cooking Stoves”,sponsored by Ministry of Science and Technology,ChinaInvestigation on South-South Cooperation in Climate Change through Clean Stove Alliance,sponsored by Ministry of Ecology and Environment and Administrative Center for China's Agenda 21(No.0201835).
文摘The extensive use of traditional cooking and heating stoves to meet domestic requirements creates a serious problem of indoor and outdoor air pollution.This study reports the impacts of two fuel feeding methods-front-loading and top-loading on the thermal and emissions performance of a modern coal-fired water-heating and cooking stove using a contextual test sequence that replicates typical patterns of domestic use.Known as a low-pressure boiler,when this stove was fueled with raw coal,the findings indicate that front-loading the fuel,which devolatilizes the new fuel gradually,produced consistently higher space heating efficiency and lower emission factors than top-loading the same stove,which devolatilizes new fuel all at once.Comparing the performance at both high and low power gave the similar results:front-loading with raw coal produced consistently better results than top-loading.The average water heating efficiency when front-loading was(58.6±2.3)%and(53.4±1.8)%for top-loading.Over the sixteen-hour test sequence,front-loading produced 22%lower emissions of PM2.5(3.9±0.6)mg/MJNET than top-loading(4.7±0.9)mg/MJNET.The same pattern was observed for carbon monoxide and the CO/CO2 ratio.CO was reduced from(5.0±0.4)g/MJNET to(4.1±0.5)g/MJNET.The combustion efficiency(CO/CO2 ratio)improved from(8.2±0.8)%to(6.6±0.6)%.Briquetted semi-coked coal briquettes are promoted as a raw coal substitute,and the tests were replicated using this fuel.Again,the same pattern of improved performance was observed.Front loading produced 3.5%higher heating efficiency,10%lower CO and a 0.9%lower CO/CO2 ratio.It is concluded that,compared with top loading,the manufacturers recommended front-loading refueling behavior delivered better thermal,emissions and combustion performance under all test conditions with those two fuels.
