ANALISIS KEMAMPUAN SELF HEALING PADA LAPIS ASPAL BETON DENGAN LIMBAH BUBUTAN BAJA SEBAGAI BAHAN TAMBAH

Steel waste is waste generated from a large or small amount of steel production process. The results of steel waste disposal can pollute the environment if not done a good treatment and countermeasure so that it has value benefits. This study uses steel lathe waste additives to determine the self-healing ability of asphalt in the AC-WC mixture. Steel lathe waste used with varying degrees of steel lathe 0%, 0,25%, 0,5%, 0,75%, 1% and asphalt content used by 5,5%. After obtaining the data used in the study, samples were made for asphalt mixtures with varying degrees. Then the finished sample is divided into 4 parts to be tested for temperature rise on each steel lathe mixture using a thermal camera. And tested using a threepoint bending test to determine the ability of asphalt selfhealing in the AC-WC mixture that occurs for 5 cycles with a heating duration of 20 seconds, 40 seconds, 60 seconds. From the results of the research on the content of a mixture of 0% steel lathe proved the sample can do self-healing but the results obtained are not as good as when using variations in the added ingredients of steel fiber mixture 0,25%, 0,5%, 0,75% and 1%. ABSTRAKLimbah baja adalah buangan yang dihasilkan dari suatu proses produksi baja baik dalam jumlah yang besar atau sedikit. Hasil buangan limbah baja dapat mecemari lingkungan apabila tidak dilakukan pengolahan dan penanggulangan yang baik sehingga memiliki nilai manfaat. Penelitian ini menggunakan bahan tambahan limbah bubutan baja untuk dapat mengetahui kemampuan self healing aspal pada campuran AC-WC. Limbah bubutan baja yang digunakan dengan kadar variasi bubutan baja 0%, 0,25%, 0,5%, 0,75%, 1% dan kadar aspal yang dipakai sebesar 5,5%. Setelah didapatkan data yang dipakai dalam penelitian dilakukan pembuatan sampel terhadap campuran aspal dengan variasi kadar. Kemudian sampel yang telah jadi di belah menjadi 4 bagian untuk diuji kenaikan temperatur pada setiap campuran bubutan baja dengan menggunakan kamera thermal. Serta diuji dengan menggunakan alat threepoint bending test untuk mengetahui kemampuan selfhealing aspal pada campuran AC-WC yang terjadi selama 5 siklus dengan durasi pemanasan 20 detik, 40 detik, 60 detik. Dari hasil penelitian pada kadar campuran bubutan baja 0% terbukti sampel dapat melakukan self healing tetapi hasil yang didapatkan tidak sebaik ketika menggunakan variasi bahan tambah campuran serat baja 0,25%, 0,5%, 0,75% dan 1%.

Effect of Heating Duration at High Temperature on the Strength and Integrity of Fly Ash-Based Geopolymer Concrete

Fire is one of the most severe environmental conditions that concrete structures might be subjected to, especially in closed conduct structures, such as tunnels. Concrete in general can withstand fire but its properties degrade when exposed to fire at high temperatures. The effect of heating duration, at a high temperature, on the performance of fly ash-based geopolymer concrete is presented. Cubes of low, medium and high strength grades of geopolymer concrete that had been cured for 28 days, were exposed to a fire flame at 1000 °C for 30, 60, 90, 120, 150 and 180 min. After the fire exposure, the cubes were cooled to the ambient temperature before further testing. A visual observation was performed on the cubes to detect any colour change, cracking and spalling. The losses of mass and residual compressive strength of the cubes were recorded. The results showed that as the heating duration increased from 30 to 90 min, the compressive strength of the cubes also increased. Contrarily, the compressive strength decreased as the heating duration increased beyond 90 min indicating that the extended heating duration induced the loss of free water and decomposition of aluminosilicate products in geopolymer concrete. The evaporation of water by virtue of the heating for the extended duration, at high temperature, led to a loss in the mass of concrete. The findings suggest that geopolymer concrete was able to sustain its structural integrity without any noticeable spalling and hence, it can be classified as a fire-resistant material.

The utilization of young-harvested purple corn for dodol processed to support functional food diversification

Young-harvested purple corn can be processed to some products, including traditional processed dodol in Indonesia, that very liked by all people until now. The superiority of purple corn dodol is it has component of anthocyanin that has antioxidant activities. The ingredient using young-harvested purple corn. The method using complete randomize design, factor I extractor water P (300ml, 400 ml, 500ml), factor II heating duration L (15 minutes, 25 minutes, 35 minutes), each intervention done by 3 times repeating, cooked in boiled temperature. The data analyze using Anova, and continue with DMRT test. The level of panelists’ acceptance using organoleptic test with display parameter of colour, smells, texture, and taste test. The result of this research showed that the intervention which very liked by panelists was P1L1 500g of corn extracted by 300 ml of water with heating duration about 15 minutes, with component of water 24.86%, ash 0.44%, protein 5.98%, and high relative anthocyanin 4.04 (μg/g). Dodol processed of purple corn can be developed to instant product, with proper packaging can support functional food product diversification that has high sale value.

A method for estimating scheduled and manual override heating behaviour and settings from measurements in low energy UK homes

PurposeThe purpose of this paper is to present a methodology for estimating scheduled and manual override heating events and heating settings from indoor air temperature and gas use measurements in UK homes.Design/methodology/approachLiving room air temperature and gas use data were measured in ten UK homes built to low energy standards. The temperature measurements are used to establish whether the central heating system is turned on or off and to estimate the heating setpoint used. The estimated heating periods are verified using the homes' average daily gas consumption profiles.FindingsUsing this method, the average number of heating periods per day was 2.2 (SD = 0.8) on weekdays and 2.7 (SD = 0.5) on weekends. The weekday mean heating duration was 8.8 h and for weekends, it was 9.8 h. Manual overrides of the settings occurred in all the dwellings and added an average of 2.4 h and 1.5 h to the heating duration on weekdays and weekends respectively. The mean estimated setpoint temperatures were 21.2 and 21.4°C on weekdays and weekends respectively.Research limitations/implicationsManual overrides of heating behaviours have only previously been assessed by questionnaire survey. This paper demonstrates an alternative method to identifying these manual override events and responds to a key gap in the current body of research that little is currently reported on the frequency and duration of manual heating overrides in UK homes.Practical implicationsThe results could be used to better inform the assumptions of space heating behaviour used in energy models in order to more accurately predict the space heating energy demands of dwellings.Originality/valueManual overrides of heating behaviours have only previously been assessed by questionnaire survey. This paper demonstrates an alternative method to identifying these manual override events and responds to a key gap in the current body of research that little is currently reported on the frequency and duration of manual heating overrides in UK homes.

The Disappearance of Coal Seams Recorded in Associated Gangue Rocks in the SW Part of the Upper Silesian Coal Basin, Poland

Coal seams in the Upper Silesian Coal Basin vanish within the Carboniferous Upper Silesian Sandstone Series and below an unconformity marking the Carboniferous top surface. Changes in the geochemical, mineralogical, petrological and palynological characteristics of gangue rocks associated with the vanished seams record what happened. The observed changes could have been caused by (1) coal-seam paleofire, (2) peat combustion, (3) igneous intrusion, (4) metasomatism and/or (5) weathering. Multifaceted research on samples collected at the Jas-Mos mining area, a part of the operating Jastrzębie-Bzie Coal Mine that are representative of different geological settings in the northern and southern parts of the mining area, point to intra-deposit paleofire as the most plausible reason for the disappearance. Biomarkers enabled recognition of differences in heating duration and oxygen access. Coal seams in the south burned quickly with abundant oxygen supply. Seams in the north pyrolyzed for an extended time under conditions of limited oxygen. Though other methods used proved less sensitive, all confirmed low (100–150 °C) paleotemperature heating. Overall, the reason for the local disappearance of the coal seams, making their exploitation difficult and unprofitable, can be assigned to a variety of different processes in a complex overlapping history of variable weathering, heating due to local endogenic fires and, probably, earlier peat combustion.

Influence of palm kernel variables on the yield and quality of oil expressed using an expeller

The objectives of this study were to establish the impact order of the oil-palm kernel processing variables, namely: kernel moisture content (KMC), kernel heating temperature (KHT), kernel heating duration (KHD), and kernel particle size (KPS) on the palm kernel oil (PKO) yield; to develop an empirical model for the PKO yield as influenced by the KMC, KHT and KHD; to investigate the effect of the KMC, KHT and KHD on the PKO quality; and to specify levels of the kernel variables for the maximum PKO yield with minimum variability. The study was undertaken using oil-palm kernels of unidentified variety from Nsukka, Nigeria. The statistical analysis of data was performed with Design-Expert 8P and Minitab 19 Software at P = 0.05. The impact order of the studied kernel variables on the PKO yield, using an expeller (MS-100), was found to be the KPS, KMC, KHD, and KHT. For the maximum PKO yield with minimum variability in the PKO yield, a KMC of 5% (wb), a KHT of 80 °C, a KHD of 10 min, and a KPS of 11 mm and above is recommended.

Diagnostic of the Cooking and Storage Systems of a Cassava-Derived Food Locally Called “fufu” in the City of Yaoundé, Cameroon

Fufu is among the most consumed traditional dishes derived from cassava in Cameroon. However, the processing of cassava into flour used in the preparation of fufu, the home storage of that flour and the cooking practices might lead to microbial contamination and hence constitute a potential health risk for consumers. The aim of this study was to diagnose the cooking systems of fufu in the city of Yaoundé taking into consideration the processing of granules, its storage systems and the cooking practices. A cross-sectional study was conducted in the city of Yaoundé. A total of 74 participants were submitted to a survey by the means of a structured questionnaire. Information on the socio-demographic characteristics of the population, the nature and quality of raw material used to cook fufu, the cooking processes, the storage of cooked fufu and complaints associated with the consumption of fufu were collected and statistically analyzed. Results showed that the majority of participants were women (82.4%) with university education level (73%). Most of the participants preferred granules of fermented cassava as raw material. The odor was the main purchasing criteria of raw materials which were generally stored at room temperature (25±2°C) in the household for 1 to 2 weeks. 76.05% of participants were aware of the impact of microorganisms on the color and odor of the raw material. Two cooking processes of fufu were identified, the heating duration being the main difference. The majority of participants used a heating duration of less than 15 min as it leads to slightly rigid, less elastic and not sticky fufu highly appreciated in the Centre and Sud regions of Cameroon. Leftovers fufu eaten by participants without any heating process and leftovers fufu reheated for a short duration before being consumed might be the causes of digestive troubles associated with its consumption. Prospective studies should be conducted to optimize the cooking process of fufu taking into consideration its microbiological (sporulated microflora) and sensorial quality.

Establishing rational conditions for obtaining potassium glycerate

This paper reports a study into the dependence of efficient glycerate potassium production involving glycerin and potassium hydroxide solution on the process conditions. The concentration of potassium glycerate in the resulting product has been used as a parameter of the efficient glycerate potassium production process. Glycerates of metals are applied to produce articles in the construction industry, electronics, medicine; they are employed as transesterification catalysts to obtain special fats for various purposes, as well as biodiesel fuel. In order to derive potassium glycerate, heating was applied while agitating a mixture of glycerin and potassium hydroxide. The analysis of potassium hydroxide was performed, in which the basic substance mass fraction was 85.5 %, the mass fraction of carbonate potassium – 0.9 %. The p.a.-grade glycerin was applied in this work, whose basic substance mass fraction was 99.5 %. The effect of the heating temperature of the reaction mixture on the concentration of potassium glycerate in the product has been determined. It has been shown that the rational heating temperature is 145 °C. The dependence of potassium glycerate concentration in the resulting product on the following conditions of the process has been established: a change in the molar concentration of glycerin and a reaction mixture heating duration. Such rational conditions for obtaining potassium glycerate have been defined as a molar concentration of glycerin of 60 % and a heating duration of 4 hours. The experimentally established concentration of potassium glycerate in the product under these conditions was 75.77 %. For potassium glycerate, the melting point (69 °C) and the mass fraction of moisture (0.8 %) have been determined. The results of experimental studies would make it possible to obtain potassium glycerate directly at enterprises where the glycerates of metals are used, from available raw materials, under rational conditions. The defined conditions for obtaining potassium glycerate could make it possible to efficiently utilize material and energy resources.

The formation conditions of birch tar in oxygen-depleted environments

Birch tar is the oldest manmade adhesive dating back to the European Middle Palaeolithic. Its study is of importance for understanding the cognitive capacities and technical skills of Neanderthals and the aceramic production systems employed in the European Palaeolithic and Mesolithic. Several methods may have been used to make birch tar, the most common proposition being dry distillation in oxygen-depleted atmospheres. One of the major impediments for our understanding of the conditions employed to make Neanderthal birch tar, and ultimately the technique used, is that it remains unknown at which temperatures exactly birch tar forms. The relationship between heating duration and tar formation is also unknown. To address these questions, we conduct a laboratory heating experiment, using sealed glass tubes and an electric furnace. We found that birch tar is only produced at a narrow temperature interval (350 °C and 400 °C). Heating times longer than 15 min have no effect on the quantity of tar produced. These findings, notwithstanding previous propositions of necessarily long heating times and larger tolerances for temperature, have important implications for our understanding of the investment in time needed for Palaeolithic birch tar making.