The main objective is to assess effectiveness of continuous solar dryer integrated with desiccant thermal storage for drying cocoa beans. Two type of desiccants were tested, molecular sieve 13× (Na86 [(AlO2)86·(SiO2)106]·264H2O) as an adsorbent type and CaCl2 as an absorbent type. The results revealed that during sunshine hours, the maximum temperature within the drying chamber varied from 40 °C to 54 °C. In average, it was 9–12 °C higher than ambient temperature. These temperatures are very suitable for drying cocoa beans. During off-sunshine hours, humidity of air inside the drying chamber was lower than ambient because of the desiccant thermal storage. Drying times for intermittent directs sun drying, solar dryer integrated with adsorbent, and solar dryer integrated with absorbent were 55 h, 41 h, and 30 h, respectively. Specific energy consumptions for direct sun drying, solar dryer integrated with adsorbent, and solar dryer integrated with absorber were 60.4 MJ/kg moist, 18.94 MJ/kg moist, and 13.29 MJ/kg moist, respectively. The main conclusion can be drawn here is that a solar dryer integrated with desiccant thermal storage makes drying using solar energy more effective in term of drying time and specific energy consumption

The utilization of bagasse and banana stem as activated carbon precursors has been conducted. In this study, the dried samples were impregnated using phosphoric acid (H₃PO₄) solution as the activator at a ratio of sample to the activator (w/w) was 1:1. The impregnation was conducted at room temperature for 24 hours. The samples then carbonized at 400 °C for 30, 45 and 60 minutes and finally washed and dried to obtain the activated carbon. The research aimed to investigate the effects of time of carbonization on the characteristics of activated carbon produced from bagasse and banana stem. The result showed that yield of activated carbon was in the range of 40.03 – 46.73 % with a high content of carbon as high 90.33 %. The result of BET analysis showed that the highest surface area reached1130.465 m²/g.

Objectives: This study aims to develop better solar dryer for paddy drying. Methods and Analysis:The design and fabrication of a parabolic cylinder type collector-drying unit has been developed. Paddy is dried by the variation which took place into four batches starting from batch 1 (08:30 - 09:20), batch 2 (09:30- 10:10), batch 3 (10:20 - 11:10) and batch 4 (11:40 - 12:20) Western Indonesia Time (GMT +7), with a capacity of 5 kg of paddy/batch and solar radiation is in the range of 408.5 - 547.2 Watt/m2. The highest irradiation takes place in batch 2 with the maximum temperature inside the dryer reaching 74◦C. Findings: Overall the experiments achieved that paddy temperature are in the range of 43 – 45◦C, with the shortest drying time achieved in batches 2 and batch 4 i.e. 40 minutes. Thermal efficiency are in the range of 37.91% - 50.35%, SEC of 5.318 - 7.042 MJ/kg H2O evaporated and drying rate of 1.06 - 1.38 kg/hrs. Thus, this solar dryer is more effective than industrial inclined bed dryer or theindustrial horizontal rotary dryer. Novelty: The solar dryer using a parabolic cylinder type solar collector with a screw conveyor has been designed which can reduce drying time and moisture content better. Keywords: Solar dryer; parabolic collector; paddy; efficiency

This study aims to obtain the best operating conditions including pyrolysis time and amount of catalyst in oil fuel production from reject plastic as raw material with coal fly ash as catalyst based on its yield and characteristics. Both reject plastic and coal fly ash are waste originating from a paper industry in Medan. This research was carried out in three steps: preparation of reject plastic and coal fly ash, oil fuel production and characterization (composition of coal fly ash and density, viscosity and heating value of oil fuel). The main components in the coal fly ash are SiO₂, C and Al₂O₃ that are 30.36%, 27.11% and 24.04% respectively. The yields of oil fuel are in the range of 14.18% - 26.58%. From 12 samples, 10 samples meet the standard density whereas 8 samples meet the standard viscosity for diesel fuel based on ASTM D-975. The best operating condition is achieved when using 15% catalyst with 2 h pyrolysis time that produce oil fuel with the highest heating value.

Indonesia merupakan penghasil limbah plastik terbesar kedua setelah Cina, sehingga telah menjadi isu lingkungan. Salah satu kemasan plastik yang banyak digunakan adalah kemasan untuk pembibitan terbuat dari plastik atau dikenal sebagai polybag. Guna membantu mengurangi penggunaan polybag, telah dilakukan percobaan skala laboratorium pembuatan paper bag dari pulp tandan kosong sawit (TKS) sebagai pengganti polybag. Penelitian ini bertujuan untuk mendapatkan formula pembuatan paper bag yang dapat memenuhi persyaratan penggunaan akhirnya. Kegiatan dimulai dari penggilingan pulp TKS, dilanjutkan dengan pembuatan lembaran dengan variasi gramatur 90 g/m2 dan 125 g/m2 pada rentang pH 7-8. Dua jenis bahan kimia penguat basah yang digunakan yakni polietilen imin (PEI) dan poliamin epiklorohidrin (PAE), ditambahkan dengan variasi dosis 1,0 – 2,0 % terhadap berat kering serat. Karakteristik lembaran dievaluasi melalui uji ketahanan tarik, daya regang, daya serap energi (tensile energy absorption atau TEA), ketahanan retak, ketahanan sobek, persen rendemen kekuatan setelah mengalami pembasahan, dan porositas. Uji biodegradabilitas dilakukan untuk melihat tingkat afiliasi bahan kimia yang ditambahkan terhadap lingkungan dan rasio C/N (rasio karbon/nitrogen) untuk mengetahui kontribusinya terhadap proses pengomposan. Hasil percobaan menunjukkan bahwa lembaran memiliki rendemen ketahanan tarik di atas 10%. Gramatur berkorelasi positif terhadap sifat kekuatan, dan negatif terhadap porositas. PAE memberikan sifat kekuatan lebih tinggi dibanding PEI, namun PEI memberikan persen rendemen ketahanan tarik lebih tinggi dibanding PAE. Seluruh bahan kimia yang ditambahkan dapat didegradasi lebih dari 60% dalam kurun waktu 28 hari namun uji rasio C/N menunjukkan hasil yang belum memadai. Formula optimum diperoleh pada gramatur 125 g/m2 dengan penambahan PEI 2%. Paper Bag Based on Empty Fruit Bunches Pulp as an Alternative for Polybag Substitute in Pre-Nursery Palm Oil PlantationAbstract Indonesia is the second-largest plastic waste producer after China, so it has become an environmental issue. One of the plastic packagings which are large in consumption for nursery packaging is known as polybag. Therefore, to reduce the use of plastic bag, the laboratory scale experiment of paper bag made from oil palm empty fruit bunches (EFB) as polybag substitutes has been done. This study aims to obtain a formula for paper bags that can meet the end using requirements. Laboratory scale started from beating the EFB pulp, then continued with handsheet making at grammage variation of 90 g/m2 and 125 g/m2 with a pH range of 7-8. Two types of wet strength agents were used, namely polyethyleneimine (PEI) and polyamine epichlorohydrin (PAE) which were varied from 1.0 to 2.0% (%db of fiber). Sheet properties were evaluated through tensile and bursting strength, stretch, TEA tests, tearing resistance, % yield of strength after wetting, opacity, and porosity. A biodegradability test was conducted to determine the chemical’s affiliation level to the soil and the C/N ratio to know its contribution to the composting process. The results showed that the paper bag has a tensile strength yield above 10%. Grammage is directly proportional to strength properties and inversely to porosity. PAE gave higher strength than PEI but is lower in % yield of tensile strength. All added chemicals can be degraded by more than 60% within 28 days but the C/N ratio test showed inadequate results. The optimum formula was obtained at 125 g/m2 and PEI of 2.0%.

Research on potato drying using the indirect solar dryer with flat-plate finned collector and forced convection has been done. The research was conducted at the outdoor field of Laboratory of Institute for Research and Standardization of Industry on June 14^th-23^rd, 2016 from 9:00 am to 4:00 pm. This research aims to obtain the drying kinetics model of potato (Solanumtuberosum L.) using an indirect solar dryer’s (ISD) with flat plate-finned collector and forced convection. The result will be compared to the open sun drying (OSD) method. Weather conditions during the drying process took place as follows; surrounding air temperature was in the range 27 to 34.7 °C, relative humidity (RH) 29.5 to 61.0% and the intensity of solar radiation 105.6 to 863.1 Watt/m². The dried potato thicknesses were 1.0 cm, 1.5 cm and 2.0 cm, with the average initial water content of 76.46%. The average temperature in the collector chamber ranged from 42.2 to 57.4 °C and the drying chamber was at 46.2 °C. The best drying result was obtained from a sample size of 1 cm thickness using the IDS method with an average drying rate of 0.018 kg H₂O per kg dry-weight.hour and the water content was constant at 5.02% in 21 hours of drying time. The most suitable kinetics model is Page model, equation MR = exp (−0.049 t^1,336) for 1.0 cm thickness, exp (−0.066 t^1,222) for 1.5 cm thickness and exp (−0.049 t^1,221) for 2.0 cm thickness. The quality of potato drying using ISD method is better than using OSD which can be seen from the color produced.