Judul: Rancang Bangun dan Pengujian Mesin Pembeku Tipe Lempeng Sentuh dengan Suhu Media Pembeku Bertahap
Abstrak: Commercial freezer generally use fixed medium temperature during thefreezing process, which caused considerable destruction of exergy and is believedto be the source of energy inefficiency. Previous research has tried to design and analyse a contact plate freezer freezing process with stepping medium temperature. However, thermal losses was occured as caused by friction between the bottom of the produce with the freezing plate, and exerts 4-5 °C temperature is increased to the products. Therefore, it is necessary to design a freezer with stepping medium temperature without thermal losses. This study is devoted to the design of a contact plate freezer with variable medium temperature. The freezer is designed using one evaporator with three expansion valve, so that the temperature can be changed during the freezing process by changing the expansion valve to be used. The freezer was designed in laboratory scale using a compressor with refrigeration capacity of 718 watts. The freezing chamber has dimension of 25.1 cm × 24.7 cm × 14.8 cm with freezing plate made of copper material with a thickness of 3 mm. The results show that medium temperature of the freezer can be varied by the average temperature every stage is -4.88, -8.30, and -14.26 °C. The test results indicated that the COP of the freezer was 4.10. Pressure decrease along the evaporator ranges from 33.1 unti 100.5 kPa. Stepping medium temperature can increase the efficiency of exergy amounted 8.3 % by decreasing exergy loss amount 0.868 kJ.
Keyword: 

Judul: Kajian Eksergi Sistem Pembekuan Temulawak dengan Suhu Media Pembeku Bertahap pada Mesin Pembeku Tipe Lempeng Sentuh
Abstrak: Analyzingenergy and exergy is a way to find out the amount of freezing energy consumption and wasted energy of freezing process. This research aims to study the effects of changes in freezing medium temperature against exergy efficiency of extract Curcuma freezing, and relations between COP value and the efficiency of exergy produced. By the result of this research,it is known that the specific energy consumption is ranged from 307.23 kJ/kg to 387.58 kJ/kg. The average of loosing exergy is from 15.067 kJ/kg to 36.821 kJ/kg, so the largest efficiency of exergy produced is 68.36% at scenario 1 (Tma = -5˚C, Tmf = -10˚C,Tmb = -20˚C) and smallest one is 52.26 at scenario 5 (Tma = -20˚C, Tmf = -20˚C, Tmb = -20˚C). The Graphic of the relation between COP and exergy efficiency shows that COP is linearly proportional with the efficiency of exergy produced. Based on COP and exergy efficiency, known that the most optimum freezer medium temperature is scenario 1 with COP 5.17, energy efficiency 0.14%, exergy efficiency 68.36% and input energy 7.2 kWh.
Keyword: 

Judul: Pola Pernikahan Masyarakat Batak Karo di Perantauan
Abstrak: Pernikahan adalah budaya yang tidak akan pernah berhenti, pernikahan akan terjadi secara berkelanjutan Dasarnya, karena pernikahan merupakan kebutuhan biologis manusia. Indonesia adalah negara yang kaya akan budaya dan etnis. Setiap suku di Indonesia mempunyai tata cara/adat istiadat dalam pelaksanaan pernikahan itu sendiri. Begitupun dengan suku Batak karo yang mempunyai sendiri tata cara pelaksanaan pernikahan. Seiring dengan perkembangan zaman Karo Banyak masyarakat yang merantau ke berbagai daerah di Indonesia, salah satunya Bogor berjalan-jalan. Masyarakat Karo yang merantau ke wilayah Bogor pada umumnya akan berusaha melakukan adaptasi ke negara tempat tinggal baru. Keadaan ini juga terjadi pada perkawinan Karo dalam pola adaptasi di Bogor. Namun adaptasi pernikahan masyarakat Karo di Bogor berupaya menjaga nilai-nilai budaya Karo dan sakralisme perkawinan. Mereka do Karo Dimodifikasi pada pola perkawinan, dengan tetap menjaga nilai budaya pernikahan.
Keyword: Weddings Karo, Adaptation marriage patterns, Attitudes