Pengaruh Konsentrasi Aktivator Terhadap Kualitas Karbon Aktif dari Batubara Lignit

Activated carbon has been widely used in everyday life. One of them is in water purification. Materials for making activated carbon have been made and researched. Coal is one of the materials that can be processed into activated carbon. The availability of coal in Indonesia is quite abundant and has the potential to be used as activated carbon. The coal used is lignite. This coal is categorized as light coal where its use is only used as fuel in industry. It is hoped that the activated carbon from this coal will become an alternative source of coal use in Indonesia. Activated carbon from coal uses a variable concentration of 0.5 M, 1 M, 1.5 M, 2 M, 2.5 M, 3 M with HCL activator solution. It is hoped that the results of this study are in accordance with the quality standard of SNI 06-3730-1995.

A Novel Metaheuristic Moss-Rose-Inspired Algorithm with Engineering Applications

Every day, a moss rose generates new flowers with variable diameters. Two flowering mechanisms are controlled by exposure to sunlight, namely, a variable concentration of florigen based on photoreceptors called phytochromes, and the biological clock, which is responsible for the changing diameters of the plant flowers at night and some hours during the day. By explaining and idealizing the flowering mechanisms of the moss rose in nature, a new sort of nature-inspired optimization algorithm called the moss rose optimization algorithm (MROA) was proposed in this study. The MROA was benchmarked using three methods. First, 18 benchmark functions were utilized to evaluate the effectiveness of the MROA. Second, the MROA was used for planning a smart antenna system (SA) as an online solution to find unknown weights. Third, the MROA was used to find the optimal dimensions for a microstrip antenna for the frequency (2.4 GHz) as an offline solution. The MROA was compared with other algorithms. The results show the capacities and proficiencies of the proposed algorithm regarding finding the ideal solutions. The promising arrangements for smart antenna identification and microstrip antenna design highlight the importance of this algorithm for resolving current issues with unknown fields of investigation.

A comparative study and graphical analysis in designing and operation of Solar Thermal circular concentrator for enhancing efficiency of solar concentrating system

The present line concentrator system with constant concentration ratio exhibits rise in temperature of working media, however if the difference between outlet and inlet temperature of working media is large then they exhibit lower efficiency. Also the rate of fall of efficiency with increase in its temperature difference is high. To overcome this problem it is proposed to have a variable concentration ratio concentrator system. The variable concentration ratio is achieved by employing receiver consisting of the pipes having different diameters; with the larger diameter pipe at start followed by small diameter receiver. Thus, the concentrator system will have different diameter receivers offering variable concentration ratio system. This concept is confirmed with the help of G.O. Lof, Fester and Duffie Beck paper. The present paper describes above concept by graphical analysis carried out for the newly proposed circular line concentrator with variable concentration ratio. The results of superimposition of graphs leads to confirmation for the promisingly use of variable concentration ratio receivers for enhancing efficiency of solar concentrating system.

Filtrasi Ampas Jahe Menggunakan Filter Press

Ampas jahe hasil buangan proses industri jamu masih mengandung sari jahe. Pengolahan ulang dengan pelarutan dan penyaringan dengan plate and frame filter press dapat dilakukan untuk mengisolasinya. Penggunaan variabel konsentrasi umpan 0,2 kg/liter, 0,4 kg/liter, dan 0,6 kg/liter. Menggunakan tekanan tetap 2 kg/cm2 dan laju alir 5,66x10-11 m/s2, dihitung nilai tahanan spesifik ampas (α), tahanan ampas (Rc), tahanan medium filter (Rm) untuk mengetahui efesiensi kinerja alat filter press. Proses filtrasi dilakukan secara batch. Hasil perhitungan menunjukkan nilai α, Rc, dan Rm tertinggi pada konsentrasi 0,6 kg/L yaitu α (4,98x106 m/kg), Rc (1,35x108 m-1), Rm (3,79x1011 m-1). Efektivitas produk yang dihasilkan diketahui melalui pengukuran konsentrasi sari jahe pada hasil filtrat. Pengujian konsentrasi menggunakan centrifuge dan analisa Total Suspended Solid (TSS). Hasil analisa centrifuge menyatakan bahwa semakin besar konsentrasi umpan, maka semakin besar pula konsentrasi produk. Konsentrasi sari jahe tertinggi yang didapat 6,67%, terdapat pada variable konsentrasi umpan 0,6 kg/liter. Begitu pula dengan uji TSS, konsentrasi umpan 0,6 kg/liter menghasilkan TSS terbesar yaitu 277 mg/l. Ginger pulp from the process of industrial herbs still contain ginger juice. Reprocessing ginger pulp with dissolving and filtering with plate and frame filter press can done to isolate it. Use feed variable concentration 0.2 kg/liter, 0.4 kg/liter, and 0.6 kg/liter. Fixed pressure used is 2 kg/cm2 and flow rate use 5.66x10-11 m/s2, will calculated the specific prisoner value of the pulp (α), Prisoner of Pulp (Rc), Prisoner of medium filter (Rm) to know the efficiency of the performance of filter press. Filtration process is done in batches. The results of the calculation show the highest value of α, Rc, and Rm at concentrations 0.6 kg/liter are α (4.98x106 m/kg), Rc (1.35x108 M-1), Rm (3.79x1011 M-1). Effectiveness of the resulting products is known through measurements of ginger juice concentrations in filtrate results. Concentration testing using centrifuge and Total Suspended Solid (TSS) analysis. Result of centrifuge analysis states that the greater concentration of feed, that the greater the concentration of product. The highest concentrations of ginger juice gained 6.67%, there is a variable concentration feed 0.6 kg/liter. Similarly, the test of TSS, the concentration feed 0.6 kg/liter resulted in the largest TSS 277 mg/l.

Спонтанные переходы в состояние высокой проводимости в композитных пленках поливинилхлорида

The results of experimental studies of conductivity anomalies in film samples of specially synthesized copolymer are analyzed, in which in PVC macromolecules the polyacetylene molecular fragments are embedded with a variable concentration. It has been experimentally established that spontaneous and stimulated conduction jumps occur in such samples by 13 orders of magnitude, and the life of each of these states can be very large from a few minutes to a day. In paper we propose a qualitative model describing the anomalous behavior of the conductivity of the PVC composite, comprising the mechanisms of stabilization of high conductivity state, the conditions of development of instability in the transitions between the states, as well as the reasons for long living state of high conductivity even when the applied voltage is switched off. Simple numerical estimates confirming the reality of the proposed mechanisms are also considered.