Novel Lubricant Compressor For Automotive Air Conditioning System

Outside Temperature increase – Global warming, El-Nino, etc. Cooling capacity reduce – Compressor work increase Automotive Air Conditioning (AAC) – increase fuel Consumption up to 20% & Greenhouse gas NOx (80%) & CO (70%) Current AAC system is been optimized but still could not cope with today’s weather condition

Effects of Controller and Nonuniform Temperature Profile on the Onset of Rayleigh-Bénard-Marangoni Electroconvection in a Micropolar Fluid

Linear stability analysis is performed to study the effects of nonuniform basic temperature gradients on the onset of Rayleigh-Bénard-Marangoni electroconvection in a dielectric Eringen’s micropolar fluid by using the Galerkin technique. In the case of Rayleigh-Bénard-Marangoni convection, the eigenvalues are obtained for an upper free/adiabatic and lower rigid/isothermal boundaries. The influence of various parameters has been analysed. Three nonuniform basic temperature profiles are considered and their comparative influence on onset of convection is discussed. Different values of feedback control and electric number are added up to examine whether their presence will enhance or delay the onset of electroconvection

Model Peraga Sebagai Media Pembelajaran Pada Mata Pelajaran Sains Dan Matematika Di Sekolah Menengah Pertama

Salah satu tujuan pembelajaran sains dan matematika di sekolah menengah pertama adalah untuk meningkatkan pengetahuan, konsep, dan keterampilan sains dan matematika siswa sebagai dasar untuk melanjutkanpendidikan ke jenjang selanjutnya. Keberadaan media dalam pembelajaran sangat diperlukan mengingat sains dan matematika memiliki konsep-konsep abstrak yang seringkali menjadi alasan sulitnya mempelajari materi kedua mata pelajaran tersebut. Media tiga dimensi dalam sains maupun alat peraga dalam matematika merupakan model peraga yang dapat dijadikan media dalam pembelajaran. Media tiga dimensi dapat berupa gambar yang setidaknya memiliki tiga sisi (depan, belakang dan samping) sehingga sebuah gambar tiga dimensi dapat dilihat dari berbagai arah. Peranan alat peraga dalam matematika adalah meletakkan ide-ide dasar konsep sehingga dengan bantuan alat peraga yang sesuai, siswa dapat memahami ide-ide dasar yang melandasi sebuah konsep, mengetahui cara membuktikan suatu rumus atau teorema, dan dapat menarik suatu kesimpulan dari hasil pengamatannya. Dengan demikian, model peraga dapat digunakan sebagai alat peraga untuk menerangkan konsep materi pelajaran sehingga siswa menjadi lebih tertarik, berminat dan memiliki motivasi belajar yang pada akhirnya akan meningkatkan prestasi belajar siswa.Kata-kata kunci : model peraga, media pembelajaran.Abstract : One goal of learning science and mathematics in secondary schools is to improve the knowledge, concepts, and skills of science and mathematics students as a basis for continuing their education to the next. The presence of media in learning is necessary considering the science and mathematics have the abstract concepts that are often the reason for the difficulty of studying the material both these subjects. Three-dimensional media in science andmathematics teaching aids in a visual model that can be used as media of learning. Media can be either three-dimensional image that has at least three sides (front, rear and side) so that a three-dimensional images can be viewed from various directions. The role of teaching aids in mathematics is to put the basic ideas of the concept that with the aid of appropriate props, students can grasp the basic ideas underlying the concept, knowing how to prove a formula or theorem, and can draw a conclusion from the results of his observations. Thus, the model can be used as a visual prop to explain the concept of subject matter so that students become more interested, interested and motivated to learn, which in turn will improve student achievement

Pengaruh Pemberian Jenis Pakan Yang Berbeda Terhadap Mutu Gonad Calon Induk Ikan Ingir-ingir (Mystus Nigriceps)

The research was conducted from January to March 2016 at the Fish Hatchery and Breeding Laboratory, Faculty of Fisheries and Marine Science University of Riau Pekanbaru. The aim of this research was to evaluate suitable feed for the maturation of the gonad of bagrid catfish (Mystus nigriceps) reared with different feeding treatment (Commercial feed; cookle meat; soilworm(annelid) and chopped fresh fish. The research method used was Completely Randomized Design (CDR) with four treatments and three replications. The result showed that chopped fresh fish (Poecilia reticulata) and commercial dry food were the best food for maturating the fish gonad of bagrid catfish (Mystus nigriceps). Total fish reached matured stage IV was 16 fish (88,89%), gonad somatic index 9,06 %, relative fecundity 835 eggs/g fish, egg diameter 0,85 mm. The temperature range from 28 – 310C, pH 5 – 6, DO 5,7 – 6,8 ppm

Proteksi Panas Lebih pada Generator Berbasiskan Smart Relay

One of abnormal conditions that may happen when operating synchronous generator is overheating at armature winding. Therefore, this condition is needed to overcome to avoid further damage in the generator by designing and implementing smart relay based overheating protection. Temperature at armature winding is as an input of the smart relay where it was measured by using LM35DZ sensor. Magnetic contactor was used as switch, where it will open when the temperature higher then setting value. The overheat protection design was implemented successfully where it can trip (disconnect generator from the system by opening magnetic contactor) when the armature winding temperature is higher than 60° C

Performance of Al2O3-SiO2/PAG employed composite nanolubricant in automotive air conditioning (AAC) system

Automotive Air conditioning (AAC) system is the contributor of harmful gasses emission and global warming. In order to solve the issues, investigation on potential improvement in lubrication used in air conditioning system is done to improve the system performance and efficiency. The performance of AAC system namely cooling capacity, compressor work, coefficient of performance (COP) and power consumption was investigated by comparing pure lubricant and Al2O3-SiO2/PAG nanolubricants. Performance of AAC by using different ranges of refrigerant charges (95 to 155 g) and speeds (1200 and 1800 rpm) was investigated. The result shows that the cooling capacity and COP of pure lubricant were relatively lower than Al2O3-SiO2/PAG nanolubricants. The compressor work and power consumptions of Al2O3-SiO2/PAG nanolubricants were greatly reduced. Cooling capacity and COP are enhanced by 102.99% and 23% respectively. The compressor work and power consumption are reduced by 25.9% and 28.24% respectively. From the results, nanolubricants gives more advantages in AAC performance over pure lubricant. Therefore, Al2O3-SiO2/PAG composite nanolubricants is recommended to be used as the compressor lubrication to enhance AAC performances system

Properties of Polyurethane Foam/Coconut Coir Fiber as a Core Material and as a Sandwich Composites Component

This research focuses on the fabrication and characterization of the sandwich composites panel using glass fiber composite skin and polyurethane foam reinforced coconut coir fiber core. The main objectives are to characterize the physical and mechanical properties and to elucidate the effect of coconut coir fibers in polyurethane foam cores and sandwich composites panel. Coconut coir fibers were used as reinforcement in polyurethane foams in which later were applied as the core in sandwich composites ranged from 5 wt% to 20 wt%. The physical and mechanical properties found to be significant at 5 wt% coconut coir fiber in polyurethane foam cores as well as in sandwich composites. It was found that composites properties serve better in sandwich composites construction