Maintenance and sustainability: a systematic review of modeling-based literature

PurposeMaintenance is a critical business function with a great impact on economic, environmental and social aspects. However, maintenance decisions' planning has been driven by merely economic and technical measures with inadequate consideration of environmental and social dimensions. This paper presents a review of the literature pertaining to sustainable maintenance decision-making models supported by a bibliometric analysis that seeks to establish the evolution of this research over time and identify the main research clusters.Design/methodology/approachA systematic literature review, supported with a bibliometric and network analysis, of the extant studies is conducted. The relevant literature is categorized based on which sustainability pillar, or possibly multiple ones, is being considered with further classification outlining the application area, modeling approach and the specific peculiarities characterizing each area.FindingsThe review revealed that maintenance and sustainability modeling is an emerging area of research that has intensified in the last few years. This fertile area can be developed further in several directions. In particular, there is room for devising models that are implementable, based on reliable and timely data with proven tangible practical results. While the environmental aspect has been considered, there is a clear scarcity of works addressing the social dimension. One of the identified barriers to developing applicable models is the lack of the required, accurate and timely data.Originality/valueThis work contributes to the maintenance and sustainability modeling research area, provides insights not previously addressed and highlights several avenues for future research. To the best of the authors' knowledge, this is the first review that looks at the integration of sustainability issues in maintenance modeling and optimization.

Performance and Environmental Impact Assessment of Diesel Engine Operating on High Viscous Punnai Oil - Diesel Blends

The increasing demand for energy consumption because of the growing population and environmental concerns has motivated the researchers to ponder about alternative fuel that could replace diesel fuel. A new fuel should be cheaply available, clean, efficient, and environmentally friendly. In this paper, the engine operated with neat punnai oil blends with diesel were investigated at various engine load conditions, keeping neat punnai oil and diesel as base fuels. The performance indicators such as Brake Specific Energy consumption (BSEC), Brake thermal efficiency (BTE) and Exhaust gas temperature (EGT); emission indicators such as Carbon monoxide (CO), Oxides of Nitrogen (NOx), smoke opacity; and combustion parameters like cylinder pressure and heat release rate were examined. The Brake thermal efficiency of diesel is 29.2% whereas, it was lower for neat punnai oil and its blends at peak load conditions. Concerning the environmental aspect, Oxides of Nitrogen emission showed a decreasing trend with higher smoke emissions for Punnai oil blends. Detailed combustion analysis showed that on smaller concentrations of punnai oil in the fuel blend, the duration of combustion has improved significantly. However, for efficiency and emissions, the P20 (20% Punnai oil and 80% Diesel) blend performs similar to that of diesel compared to all other blending combinations. When compared with diesel, the P20 blend shows an improvement in BSEC by 26.37%. It also performs closer in HC emission, a marginal increase in smoke opacity of 4% with reduced NOx and CO2 emission of 7.9% and 4.65% respectively. Power loss was noticed when neat punnai oil and higher blends were used due to the high density and low calorific value of punnai oil blends which leads to injecting more fuel for the same pump stroke.

СТАЛИЙ РОЗВИТОК СІЛЬСЬКОГО ГОСПОДАРСТВА ТА ЙОГО ВПЛИВ НА ПРОДОВОЛЬЧУ БЕЗПЕКУ УКРАЇНИ

The article attempts to explore the agriculture sustainability issues and its implications for food security in Ukraine. The study discusses a critical importance of agribusiness development for Ukraine's economy. However, it is observed that currently, this sector is facing a serious decline in production. A special emphasis is put that agriculture affects the national food security. In this context, the purpose of this study is to identify negative factors and offer pathways to enhance the agricultural sector productivity. To attain the research objectives, the empirical and theoretical scientific approaches as well as the research methods of observation, analysis and synthesis have been employed. This study also presents a ‘sustainable development’ concept interpretation along with revealing its core structural elements that characterize the contemporary state of agriculture from the three perspectives: economic, social and environmental. Accordingly, insights into each of these three aspects were provided that allowed to evaluate the agricultural performance, to assess a salary range in the industry as well as to examine soil fertility. The research findings have detected some negative trends in the agricultural sector development. In particular, the economic aspect perspective has demonstrated a yield decline and a reduction in livestock as well as a drop in labor productivity in agribusinesses. As it is reported, the social settings are characterized by large fluctuations in the payroll budgets in agricultural enterprises and the shortage in certain food products consumed by Ukrainians against physiologically justified norms of consumption of these products. The environmental aspect shows a decrease in the application of organic and mineral fertilizers which negatively affects the soil fertility. Given the above research outcomes, this study offers an action plan to promote sustainable development, boost productivity and enhance the agricultural industry efficiency.

Energy and Environmental Analysis of a Solar Evacuated Tube Heat Pipe Integrated Thermoelectric Generator Using IoT

This paper investigates the solar evacuated tube heat pipe system (SEHP) coupled with a thermoelectric generator (TEG) using the internet of things (IoT). The TEGs convert heat energy into electricity through the Seebeck effect that finds application in the waste heat recovery process for the generation of power. The present work deals with the theoretical study on solar evacuated tube heat pipe integrated TEG and it is validated experimentally using with and without parabolic trough concentrating collector. And the carbon credit of the TEG system is determined to find its potential in the environmental aspect. Also, the boost type converter is used to raise the power output by increasing the voltage from the TEG for rural electrifications. However, it is found that the maximum power output due to the influence of the parabolic trough concentrator results in increased efficiency when compared with the non-concentrating SEHP-TEG system. The TEG output power can be boosted up to a maximum of 5.98 V using a power electronic boost converter. Besides, the recorded real sensor data with Arduino is implemented in the experimental process for automatic remote monitoring of the temperature.

DEVELOPMENT OF LOGISTIC POTENTIAL OF NATIONAL SUPPLY CHAINS FOR THE PURPOSE OF THEIR INTEGRATION INTO GLOBAL SUPPLY CHAINS

The article presents the list of development factors of the logistics potential of supply chains that have a direct and indirect impact on the components of the logistics potential both in the internal and external environment of the chain. As such development factors, were proposed: the introduction of new logistics technologies for the delivery of goods and storage of goods in warehouses, the active development of information systems and their implementation in the field of logistics and supply chain management, the development of the logistics services market, including integrated logistics support, resourcesaving policies of enterprises, increasing the importance of the environmental aspect of doing business in the framework of states' aspirations for sustainable development. The above factors will make it possible to determine the reserves for building up the logistics potential for national supply chains in order to integrate them into global supply chains.

Implementation of Sustainable Tourism Development of Tourism Villages in Langkat Regency

This research is applied research, which seeks to encourage research to develop and manage destinations with the concept of sustainable tourism development (STD). STD is a concept that integrates the four pillars of tourism destination governance. This concept has been stated in the Regulation of the Minister of Tourism of the Republic of Indonesia Number 14 of 2016. The STD concept consists of four variables, among others; a) the implementation of effective management that is integrated and sustainable, b) strengthening the impact and economic benefits for local communities, c) strengthening and preserving socio-cultural, and d) paying attention to environmental sustainability around tourist destinations. This research aims to apply the STD concept for the development of tourism village potential. Specifically, this research is intended to encourage tourism village potentials in Sei Bingai and Tanjung Pura Districts, Langkat Regency, North Sumatra Province. So that in the end, it is hoped that Langkat Regency can have a well-managed tourist village based on the STD concept. The results showed that, based on the results of Confirmatory Factor Analysis (CFA) using AMOS 22 software, it was found that the existing variables were indeed relevant for analyzing the application of sustainable tourism development. Furthermore, based on the scoring carried out in the Focus Group Discussion (FGD) activities with key stakeholders, a ranking is carried out. Of the four existing aspects, the environmental aspect is in the good category (based on the excellent, good, average, and poor categories), while the sustainable integrated management variable, the variable economic benefits for the surrounding community, and the environmental conservation variable are in the good category. The results of the FGD also concluded that the majority of key stakeholders agreed that in Rumah Galuh Village and Pematang Serai Village, Langkat Regency would continue to be developed into a tourist village with a sustainable tourism development model.

Sustainable eating behavior

With the growing impact of agriculture and modern food processing on the natural environment and growing concerns about all aspects of their sustainability, urgent solutions are required to promote healthy, low-impact diets. Sustainable diets are those with low environmental impact and high availability that ensure food and nutritional security. A comprehensive overview of different approaches to the analysis of sustainable eating behavior is provided. It is argued that preserving the environment is critical, including in designing programs to improve health, address inequalities in affordability, food access and availability in food system models. However, dietary advice and food policy should not be based solely on the environmental aspect of sustainability and should be carefully formulated. Economy, culture and other sociological factors should be taken into account in appropriate policies when planning ways to provide adequate nutrition to the population. It is emphasized that building sustainable food systems that support healthy communities requires a multidimensional, interdisciplinary approach. A sustainable healthy diet is based on improving the energy balance and changing the diet towards a predominantly plant-based diet, which is in line with the data on healthy eating. Updating national guidelines to reflect the latest data on healthy diets may in itself be important for improving health and reducing environmental impact, and may not only clearly define but expand the criteria for sustainability. Key principles of environmental sustainability and well-being are applied in shaping a national sustainable food strategy and are directly related to food production and consumption. To implement an integrated health and environment modeling framework, it is necessary to take different approaches to sustainable nutrition, motivating environmental, food security and public health goals. To develop a methodology for assessing indicators of sustainable nutrition, it is important to simultaneously take into account all aspects: nutritional value of products, indicators of environmental impact, availability of products, climatic, geographic and national characteristics. This methodology will allow to make competent decisions in the field of food production and consumption, will help to minimize the negative impact on the natural environment through sustainable eating behavior.

Efficient Extraction of Fermentation Inhibitors by Means of Green Hydrophobic Deep Eutectic Solvents

The methods for hydrogen yield efficiency improvements, the gaseous stream purification in gaseous biofuels generation, and the biomass pretreatment are considered as the main trends in research devoted to gaseous biofuel production. The environmental aspect related to the liquid stream purification arises. Moreover, the management of post-fermentation broth with the application of various biorefining techniques gains importance. Chemical compounds occurring in the exhausted liquid phase after biomass pretreatment and subsequent dark and photo fermentation processes are considered as value-added by products. The most valuable are furfural (FF), 5-hydroxymethylfurfural (HMF), and levulinic acid (LA). Enriching their solutions can be carried with the application of liquid–liquid extraction with the use of a suitable solvent. In these studies, hydrophobic deep eutectic solvents (DESs) were tested as extractants. The screening of 56 DESs was carried out using the Conductor-like Screening Model for Real Solvents (COSMO-RS). DESs which exposed the highest inhibitory effect on fermentation and negligible water solubility were prepared. The LA, FF, and HMF were analyzed using FT-IR and NMR spectroscopy. In addition, the basic physicochemical properties of DES were carefully studied. In the second part of the paper, deep eutectic solvents were used for the extraction of FF, LA, and HMF from post-fermentation broth (PFB). The main extraction parameters, i.e., temperature, pH, and DES: PFB volume ratio (VDES:VPFB), were optimized by means of a Box–Behnken design model. Two approaches have been proposed for extraction process. In the first approach, DES was used as a solvent. In the second, one of the DES components was added to the sample, and DES was generated in situ. To enhance the post-fermentation broth management, optimization of the parameters promoting HMF, FF, and LA extraction was carried under real conditions. Moreover, the antimicrobial effect of the extraction of FF, HMF, and LA was investigated to define the possibility of simultaneous separation of microbial parts and denatured peptides via precipitation.

Faktor Risiko Demam Berdarah di Negara Tropis

Tropical countries are the largest contributor to the incidence of Dengue HemorrhagicFever (DHF), but research on risk factors is still independent in various countries, it cannot beconcluded holistically. Through the research design, a systematic review is able to summarize andanswer the causes of DHF in this tropical country. This research method is a systematic review withguidelines following the 2009 PRISMA Checklist. In the initial search, 1,680 articles were foundusing the keyword “risk factors for Dengue Hemorrhagic Fever”, reduced to 274 article titles afteradding the keyword “tropical country”. Furthermore, the relevant abstracts were fi ltered and found37 selected article items. Through critical appraisal of the full text of the article, it was found that 17articles met the selection criteria for further review in this study. The results showed that there were5 major groups of risk factors that were widely studied, namely sociodemography, climatology, placeof dwelling, environment, and behavior. The sociodemographic factor associated with the incidenceof DHF in tropical countries is age. In terms of climatology, temperature and rainfall are importantfactors in the vector breeding process. Rural areas (rural areas) are the place of dwelling with the mostcases of DHF found. The environmental aspect that has been widely studied is mosquito breeding. Themost signifi cant risk behavior factor in transmission was the behavior of hanging clothes. Of the 17articles, it was found that 77.8% of the articles examined environmental variables.