Environmantal Science and Technology

A rapid growth of the vehicles as a transportation mode has resulted in an increase production of waste tires which potentially causes the environmental problems. The aim of this study is to convert waste tires into alternative fuels via pyrolysis. This paper studied the effect of temperature, material, and catalyst on the product yields and physical properties of the liquid products. The experiments were conducted by using rotary kiln reactor in a batch system. The rotary kiln diameter and the length were 260 mm and 400 mm, respectively. The pyrolysis experiments were carried out at the reactor temperature of 250oC, 300oC, and 350oC. The results show that increasing the pyrolysis temperature has resulted in an increase of the liquid and gaseous products while the solid resiude decreased. The maximum oil production were obtained at the pyrolysis temperature of 350oC for waste inner tube (10,92%) and waste tire (13,6%). Waste tires produced higher fraction of oil than those of inner tubes. The catalyst presence (natural zeolite) slightly affected the oil yields for both waste tires and waste inner tubes. The viscosity and density of the pyrolytic oil from waste tires have the similar value with the standard value for diesel fuel (solar) whereas the heating value of waste tire lower than those of diesel and other fuels. The use of pyrolytic oil for fueling the pressurized stove and burner have the potential in the near future so that the infrastructure and regulation for implementing this technology need to be prepared.

Electrification ratio in Special Distric of Yogyakarta in 2015 still under 100%, but 100% villages has been electrified. It shows that several houses which far from village which has not been electrified. The alternative solution is to build a small power plant by utilizing rice husks which are quite abundant in Yogyakarta. Diesel Power Plant (PLTD) by dual fuel system studied had a capacity of 50 kVA. Dual fuel system is combination of diesel fuel and synthetic gas from gasification of rice husks. This study is discussed about potential of rice husks, gasification equipment design, electrical distribution, and economic feasibility studies. The results showed that 0.2% of rice husks in Yogyakarta is enough to fulfill fuel requirements of PLTD by dual fuel system. Comparison of fuel requirements in PLTD by dual fuel system is 40% or about 4.72 liters/hour of diesel fuel and 60% synthetic gas from gasification of rice husk as much as 33.19 kgs/hour. Reactor is designed to fulfill gasification process for 2 hours every batch. The system produced 31.68 kWh distributed to 2 home industries, 48 households with each capacity is 450 VA, and street lighting. Investment to build PLTD by dual fuel system is Rp. 700,310,500.00 and operational & maintenance costs is Rp. 458,196,000.00 per year. The economic feasibility study to build PLTD by dual fuel system is claimed feasible if minimum price of electricity is Rp. 2,417.00 which gain NPV and IRR of Rp. 568,819.00 and 12.03%,respectively and payback period of 4 years.

– In this study, biodiesel fuel produced from waste cooking oil was blended in 20%, 30%, 40% and 50% with the commercial diesel fuel. The biodiesel was collected from a company near Yogyakarta city. It was produced from transesterification process in a commercial scale reactor. The diesel-biodiesel mixtures were tested in a four-cylinder and four-stroke diesel engine with the compression ratio of 18 and water cooling system. The results show that the thermal efficiency of diesel engine increased with increasing the engine speed. The present of biodiesel also increased the thermal efficiency of the diesel engine. A mixture of 40% (B40) and 50% (B50) biodiesel resulted in the highest thermal efficiency. The brake mean effective pressure also increased with increasing the engine speed and biodiesel mixture. The specific fuel consumption showed a decrease in its value as a function of engine speed. Low specific fuel consumption means the high thermal efficiency of the diesel engine.

Automotive industry is one of the promising sector which is growing very fast recently. One of the important automotive component products is exhaust muffler. The present work aims to experimentally study the noise level generated from the racing type of muffler produced from small and medium industry compared with the standard type from the original products. The noise level measurement of motorcycle muffler has been conducted with several parameters including muffler types, glasswool filling, and silencers. The results showed that the increase in engine speed increased the noise generated from motorcycle muffler. Furthermore, the results also showed that the muffler noise level of racing type muffler is much higher than those of the standard muffler noise level. The highest noise level is obtained by HRP muffler, while the lowest is Tegal muffler. Glasswool filling in the muffler reduced the noise level for all four types of racing type mufler. Full glasswool filling can reduce the noise level significantly. The number and dimension of the silencer in the muffler have the prominent effect on the noise level. The increase of hole number in the silencer will be able to reduce the noise level.

Gula Semut is a sugar made from palm nectar or also called Neera that has gone through several processes before it is ready in a form that convenience for us to consume. This study aims to design and fabricate the vibrating sieve machine to separate gula semut (crystalized sugar) based on particle size. The machine has a capacity of 50 kg/h depending on the raw material. The machine consists of several main parts such as siever, electric motor, vibrating spring, balancer and frame. Simple calculation has been conducted to meet the capacity of the machine. The machine was made of food grade stainless steel to prevent contamination in gula semut due to corrosion. A preliminary experiment has been carried out to evaluate the performance of the machine including adjusting the balancer position. Finally, the machine will increase the productivity of gula semut industry in Kulonprogo District.

This study aims to investigate the thermal and catalytic pyrolysis of crushed instant noodle packs (CINP) and crushed coffee sachets (CCS) with and without calcined-natural zeolite catalysts. The experimental works were conducted using a small scale vertical tubular reactor heated by an electrical heater. The thermal pyrolysis experiments were carried out at the reactor temperature of 400, 450, and 500°C. In the second experiments, catalyst was loaded on the upper side of the reactor at various catalyst to plastic ratio. The results show that CINP produced higher liquid product at lower temperature while CCS produced higher liquid product at higher temperature. The maximum liquid oil yield obtained up to 65% on CCS pyrolysis at the temperature of 500°C. The presence of catalyst reduced the liquid fraction for both feedstocks and modified the chemical composition of the pyrolytic oil. The heating value of the pyrolytic oil was high enough for fueling the engine and other external combustion engines. CCS pyrolysis also produced much more solid product compared to CINP.

This paper presents the improvement of analytical methods for intramolecular carbon isotope compositions (δ 13 C) of pyruvate. Decarboxylated by H 2 O 2, pyruvate yields acetic acid and CO 2. Headspace solid phase micro-extractiongas chromatography-pyrolysis-gas chromatography-combustion-isotope ratio mass spectrometry (HS-SPME-GC-Py-GC-C-IRMS) was used to measure the intramolecular δ 13 C values of acetic acid. δ 13 C value of CO 2 can be later calculated using mass balance equation. The method's consistency was confirmed by comparison of the δ 13 C value of CO 2 from calculation to its direct measurement. Results of this study confirmed the method improvement because pyruvate 13 C intramolecular distribution patterns were obtained. Two intramolecular 13 C distribution patterns for commercial chemical reagents were found using this developed method. Intramolecular 13 C distribution patterns for pyruvate were found for application in dietary supplements. Its origin was inferred. The method presented herein is expected to be a useful tool for categorization of pyruvate into different intramolecular 13 C distribution patterns, which might indicate different production processes or raw materials.

In the past decade, Indonesia has successfully increased their GDP for about more than 6%. This situation move along side with population growth. Being the 4 th highest population on earth with 246.813.000 people live in 1.919 million km² land area, Indonesia still has about 2.1 energy elasticity, which is mean that there are still places with no access to electricity. Currently, Indonesia electricity consumption is about 573.32 kWh/capita but the production is about 543.2 kWh/capita. This power shortage forced the government to make a new plan for Indonesia future energy.

Life cycle assessment is a " cradle-to-grave " approach for assessing industrial systems. " Cradle-to-grave " begins with the gathering of raw materials from the earth to create the product and ends at the point when all materials are returned to the earth. LCA evaluates all stages of a product's life from the perspective that they are interdependent, meaning that one operation leads to the next. LCA enables the estimation of the cumulative environmental impacts resulting from all stages in the product life cycle, often including impacts not considered in more traditional analyses (e.g., raw material extraction, material transportation, ultimate product disposal, etc.). By including the impacts throughout the product life cycle, LCA provides a comprehensive view of the environmental aspects of the product or process and a more accurate picture of the true environmental trade-offs in product and process selection. The LCA process is a systematic, phased approach and consists of five components: aims and scopes, scoping, inventory analysis, impact assessment, and interpretation.

GEA countries have been a vital factor in trading since ancient time because of its strategic geographic position. On the age of colonialization, many western countries try to apply its economic model in this country; none of them has succeeded. In this modern age, GEA economic still developing on its own. Mainly adapt the form western economic. Meanwhile, in the western world, their economy is collapsing. EU and U.S. run into destruction because of huge debt. GEA countries should find a new model to replace currently economic. In the past, oriental countries have its own unique economic system. While occidental busy expanding their economy by increasing consumption, oriental economy looks like developing slowly because they have their own value in developing its economy. For example, Buddhist economics. It examines the psychology of the human mind and the anxiety, aspirations, and emotions that direct economic activity. A Buddhist understanding of economics aims to clear the confusion about what is harmful and beneficial in the range of human activities involving production and consumption, and ultimately tries to make human beings ethically mature. It tries to find a middle way between a purely mundane society and an immobile conventional society. In other word, Buddhist economy principle is to produce and use things according to needs, no more or less. Another example is Islam economics. The central features of an Islamic economy are often summarized as:

In order to establish more appropriate tourism strategies, the data on tourists' traveler behavior (e.g. tourist site destination choices, trip-chain making and tour choices, and dwelling time at each spot) would be quite informative. Traditional paper-based questionnaire survey or GPS-based survey methods may not be suitable for large spatial scale analysis of tourists' travel choices because of its high costs and inefficiency. On the other hand, there have been recent several applications of Wi-Fi based approach for human monitoring or travel survey. This study seeks applicability of Wi-Fi based continuous monitoring technology for collecting tourists’ travel behavior through the data analysis from two large-scale field experiments in Japan. Monitoring equipment has been located into some popular spots and transport nodes in two popular sightseeing districts (Central Hokkaido and Main Island of Okinawa) during tourist season. After appropriately cleansing the full records ...

Work and home under the COVID-19 pandemic The COVID-19 pandemic has altered the ways in which people live and work at home. New trajectories have emerged regarding the balance between work time and leisure. As pandemic lockdowns have confined people to their homes, the distinction between one's work life and home life has blurred. In turn, these changes have affected individuals' sense of their responsibility as workers and co-dwellers. How have people perceived this change? What new narratives have arisen to make sense of it? In this paper, we investigate how advertisements geared to national audiences represent Japanese and Norwegian households' ways of striking a balance between a new kind of work and home life. Specifically, we ask how advertisements envision balancing working at home during the pandemic while doing necessary housework and caregiving. We focus in particular on the perceptions of certain domestic tasks as gendered and narratives about the balance between work and home in everyday life. Work is gendered and situated in material practices. Where we work, how we work, what we work with and whom we work with intimately shapes human beings as individuals and as members of different social groups, such as households. As the COVID-19 pandemic emerged during the early months of 2020, societies across the globe began to change drastically in multiple ways, particularly regarding how work is enacted as a material practice. This global observation also holds true for Japan and Norway, the countries where we made our observations. Japan, with its customarily long workhours, strongly gendered barriers in the workplace and gendered division of domestic work may offer interesting ways in which a workforce faces the challenge of working from home. On the other side of the globe, the Norwegian workforce, with its short, efficient work hours, shows ways of working in the pandemic that are similar to but also quite different from those of the Japanese. The pandemic has changed societies in terms of where people work and how society envisions that workers will situate the socio-materiality of home and work. The challenges of this unexpected