RECENT TRENDS IN THE DEVELOPMENT OF SENSORS FOR PRE-EXPLOSIVE CONCENTRATIONS OF FLAMMABLE GASES AND VAPORS OF FLAMMABLE LIQUIDS (REVIEW)

This paper presents a review of current trends in the development of manufacturing technologies of sensors of pre-explosive concentrations of flammable gases and vapors of flammable liquids. Various types of gas sensors are discussed, including catalytic, semiconductor, and optical sensor types, and the principles of their operation. The advantages and disadvantages of each type of gas sensor are highlighted. New and traditional technologies for manufacturing sensitive elements that improve sensor parameters such as processability, miniaturization and reduce energy consumption are discussed. In conclusion, this article suggests future trends and prospects for development and research to improve the sensitivity and selectivity of sensors.

Moving Beyond the Crypto-Currency Success of Blockchain: A Systematic Survey

Blockchain (BC) is a technology whose value today is estimated by the success of Bitcoin. However, the spectrum of Blockchain applications goes beyond the financial sector. It has displayed enormous potential for revamping the customary industry with its key merits like decentralization, persistency, anonymity, and auditability. In this paper we conduct a comprehensive survey on the blockchain technology, explaining its structure and functioning. This work has analyzed the potential of BC in seven crucial sectors vis. voting systems, supply chain management, the security of Internet of Things (IoT), healthcare, intelligent transportation systems, government services, and tourism. Moreover, this paper has critically evaluated the traditional technologies used in various sectors, the problems in them, and the benefits that will be provided by the employment of BC. With its future directions, this paper will help researchers to create and realize new value for various sectors that is beyond anything we can imagine with existing technologies.

Solar E-Cooking with Low-Power Solar Home Systems for Sub-Saharan Africa

The e-cooking feasibility was evaluated for two of the main staple foods across rural Sub-Saharan Africa (rice and maize porridge) considering basic solar home systems (SHS) of 100–150 W and using inexpensive market available low-power DC cooking devices (rice cooker and slow cooker). The coverage of e-cooking necessities was spatially evaluated for the African continent considering households of two, five, and eight people. While households of two people were able to be covered >95% of the days, the increase in e-cooking necessities implied that only larger PV generators (150 W) located in high irradiation sites (>2400 kWh/m2/year) were able to fulfill e-cooking, even in scenarios of households of five and eight people. Furthermore, the economic cost and the greenhouse gases emission factor (GHG) of e-cooking via small SHS were evaluated and benchmarked against traditional technologies with wood and charcoal considering three-stone and improved stoves and liquefied petroleum gas (LPG) cookers. The GHG for e-cooking was 0.027–0.052 kgCO2eq/kg.meal, which was strikingly lower than the other technologies (0.502–2.42 kgCO2eq/kg.meal). The e-cooking cost was in the range of EUR 0.022–0.078 person/day, which was clearly lower than LPG and within the range of the cost of cooking with wood and charcoal (EUR 0.02–0.48 person/day). The results provided a novel insight regarding market available technologies with a potential of changing cooking conditions in this region.

Technical particularities of weaving moldovan carpets

The paper presents the results of the study focused on the analysis of technologies used in the weaving of traditional carpets in their evolution, identifying their particularities of identity but also the influencing factors that determine them. The stages of preparation for weaving and weaving techniques are presented. The defining characteristics with implications on their technological solution were analyzed. The paper presents the results of the study within the State Program 20.8009.0807.17 „Education for revitalizing the national cultural heritage through the traditional technologies of processing used in the area of the Republic of Moldova, in the context of multiculturalism, diversity and European integration”.

Developing the operating principle and mathematical model of the downhole device for injecting scCO2 in productive formations

Traditional technologies are not economically efficient in term of processing heavy and extra-heavy oils. Technologies based on the use of supercritical fluids (SCF) may become one of the innovative directions in the production and processing of heavy and extra-heavy oils. Therefore, in this paper the operation principle of the downhole device for pumping scCO2 into a productive reservoir is developed. The mathematical model is developed either. Calculations with different heat flux densities on the channel wall are carried out. The dependences of the temperature distribution along the length of the heated section are obtained. The calculation results are compared with experimental data.

Behaviour of Listeria monocytogenes and Natural Microflora during the Manufacture of Riojano Chorizo (Spanish Dry Cured Sausage)

Riojano chorizo is a dry cured sausage manufactured with traditional technologies without adding starter cultures at low temperatures. Its characteristics differ from other types of chorizo since sugars and nitrites are no added and processing temperatures are low- This work evaluates the behaviour of Listeria monocytogenes during the processing of inoculated Riojano chorizo as well as the natural microflora that can play a technological role or be of interest as indicators. The sausage mixture was inoculated with a cocktail of three selected strains of L. monocytogenes (CECT 932, CECT 934 and CECT 4032) (4 log10 CFU/g) and after processed following the traditional production method. Samples were taken before inoculation, after inoculation, after stuffing (day 0) and on days 6, 13, 21 and 28 of processing. L. monocytogenes, mesophiles, Micrococcaceae, lactic acid bacteria, Enterobacteriaceae, S. aureus, sulfite-reducing clostridia and molds and yeast counts were evaluated. Furthermore, pH, water activity and humidity were determined. No growth of L mocytogenes was observed during the first 6 days, when the temperature of processing was 4 °C. The low temperature in the initial stages was a relevant hurdle to control L. monocytoegenes growth. A significant decrease (p ≤ 0.05) in L. monocytogenes counts was observed on day 13 compared to the initial counts. During drying (days 6 to 21) a reduction in this pathogen of 1.28 log CFU/g was observed. The low water activity below 0.92 on day 13 and 0.86 on day 21 seems to be critical for the reduction of L. monocytogenes.

Technological Solutions and Specific Equipment for Improving the Degraded Grasslands by Total Reseeding

The scientific basis and the development of research on new solutions for organic production of fodder and their conversion into animal products with high biological value, maintaining biodiversity and environmental protection, have created the premises for promoting new technologies to improve, rehabilitate and enhance the grasslands, which are in accordance with a sustainable and efficient agriculture practice. In this chapter the technological solutions and technical equipment for improving the permanent grasslands by total renovation, specific to each stationary area conditions, are presented. The basis of new technologies or technological sequences for improving the degraded grasslands is composition and utilization of complex aggregates, consisting of specific machines and equipment, using the recent research achievements in the field of grassland farming. It is also intended that the proposed technological solutions eliminate or limit the effect of external restrictive factors so as to ensure a high feed production and a high feed value, meeting the agrotechnical requirements for each agricultural component operation. For highlighting the advantages of using the specific machines, traditional technologies, within are used common farming machines and new technologies, when are used specific machinery for grassland farming, are analyzed in comparison. To improve the degraded grasslands by reseeding method, new technologies and technological sequences use different complex aggregates, which perform in a pass 2 or even 3 operations, such as: clearing of non-valuable vegetation, hillocks and liming; tillage and liming; seedbed preparation and spreading the chemical fertilizers; rolling before sowing, sowing, rolling after sowing; the destruction of the old grass carpet, seedbed preparing, sowing and rolling after sowing and fertilization with chemical fertilizers; fertilization with chemical fertilizers, rolling before sowing, sowing and rolling after sowing. Compared to traditional technologies, new technologies and technological sequences for improving the degraded grasslands, require reduced fuel consumption and labor, with a lower number of aggregate passes.

Investigation of Significant Parameters during Abrasive Waterjet Turning

This paper presents an investigation of abrasive waterjet turning (AWJT). The purpose of the article was to investigate significant parameters of the turning process and to evaluate their impact on the turning product. The influence of the traverse speed, the rotational speed, and the relative position of the jet to the specimen (lateral jet shift) were investigated. Based on the previous research done in this field, the multi-pass tangential turning method was selected. Rotational speed does not seem to have a significant impact on the AWJ turning process. However, the relative position of the jet is a key parameter for improving the efficiency of the process. Increasing the lateral jet shift causes the volume of the material removed to increase until the optimal impact angle is reached. These findings need to be extended in order to adjust AWJT. Without these improvements, a comparison of jet to traditional technologies is inappropriate.