Analisa Unjuk Kerja Mesin Honda Astrea C 800 dengan Bahan Bakar Ethanol

Perkembangan teknologi dan pertumbuhan ekonomi dunia begitu pesat saat ini. Seiring dengan itu kebutuhan energy tentunya semakin bertambah pada semua sektor. Dari sektor transportasi, misalnya pada kenderaan sepeda motor pertumbuhannya sangat signifikan, tentunyamembutuhkan banyak bahan bakar. Oleh karena itu perlu dicari bahan bakar alternatif sebagai pengganti bahan bakar minyak. Bahan bakar Honda Astrea C800 menggunakan premium atau pertamax, setelah dilakukan penelitian ternyata ethanol dapat dijadikan bahan bakar alternatif. Namun perlu dilakukan beberapa modifikasi pada enjin sehingga memberikan kenaikan efisiensi. Dapat dilihat dari beberapa indikasi Perubahan kenaikan torsi, daya, kerja dan mempengaruhi konsumsi bahan bakar. Penelitian ini menggunakan dua jenis bahan bakar yaitu pertamax dan ethanol. Dari hasil modifikasi enjin ternyata kondisi yang optimum tepat pada perbandingan kompresi 11,8 : 1.Kemudian dilakukan penelitian dengan berbagai variasi putaran mesin 3000 rpm, 3500rpm, 4000 rpm, 4500 rpm, 5000 rpm, 5500 rpm dan 6000 rpm. Dari hasil penelitian diperoleh bahwa penggunaan ethanol sangat sesuai bagi enjin sepeda motor Astrea C 800 dapat dilihat dari indikasi yang diperoleh dimana daya maksimal meningkat sebesar 0,45 HP dari penggunaan bahan bakar pertamax pada putaran 6000 rpm demikian pula konsumsi ethanol lebih irit 0,021 l/h dibandingkan denganpertamax

PENGARUH TINGKAT SUKU BUNGA, NILAI TUKAR, INFLASI, DAN PERTUMBUHAN LABA TERHADAP HARGA SAHAM (Studi pada Perusahaan Sektor Pertambangan Sub Sektor Batubara yang Terdaftar di Bursa Efek Indonesia periode 2011-2015)

ABSTRAK Harga saham di Bursa Efek Indonesia (BEI) tidak selamanya tetap, adakalanya meningkat dan bisa pula menurun, tergantung pada kekuatan permintaan dan penawaran. Terjadinya fluktuasi harga saham di pasar modal menjadikan bursa efek menarik bagi beberapa kalangan pemodal (investor). Penelitian ini bertujuan untuk mengetahui seberapa besar pengaruh tingkat suku bunga, nilai tukar, inflasi, dan pertumbuhan laba terhadap harga saham. Model penelitian yang digunakan adalah analisis deskriptif dan verifikatif. Populasi dari penelitian ini adalah perusahaan sektor pertambangan sub sektor batubara yang terdaftar di Bursa Efek Indonesia periode 2011-2015 berjumlah 24 perusahaan. Metode penelitian sampel menggunakan teknik purposive sampling dengan total sampel 14 perusahaan yang memenuhi kriteria. Analisis data dilakukan dengan menggunakan regresi linier berganda. Hasil penelitian menunjukkan bahwa secara parsial tingkat suku bunga berpengaruh terhadap harga saham dengan kontribusi pengaruh sebesar 24,6%. Nilai tukar berpengaruh terhadap harga saham dengan kontribusi pengaruh sebesar 14,1%. Inflasi berpengaruh terhadap harga saham dengan kontribusi pengaruh sebesar 33,2%. Sedangkan pertumbuhan laba berpengaruh terhadap harga saham dengan kontribusi pengaruh sebesar 13,5%. Secara simultan tingkat suku bunga, nilai tukar, inflasi, dan pertumbuhan laba berpengaruh terhadap harga saham dengan kontribusi pengaruh sebesar 85,4% pada perusahaan sektor pertambangan sub sektor batubara yang terdaftar di Bursa Efek Indonesia periode 2011-2015. Kata kunci: Tingkat Suku Bunga, Nilai Tukar, Inflasi, Pertumbuhan Laba, dan Harga Saham

Quantifying Killing of Orangutans and Human-Orangutan Conflict in Kalimantan, Indonesia

Human-orangutan conflict and hunting are thought to pose a serious threat to orangutan existence in Kalimantan, the Indonesian part of Borneo. No data existed prior to the present study to substantiate these threats. We investigated the rates, spatial distribution and causes of conflict and hunting through an interview-based survey in the orangutan's range in Kalimantan, Indonesia. Between April 2008 and September 2009, we interviewed 6983 respondents in 687 villages to obtain socio-economic information, assess knowledge of local wildlife in general and orangutan encounters specifically, and to query respondents about their knowledge on orangutan conflicts and killing, and relevant laws. This survey revealed estimated killing rates of between 750 and 1800 animals killed in the last year, and between 1950 and 3100 animals killed per year on average within the lifetime of the survey respondents. These killing rates are higher than previously thought and are high enough to pose a serious threat to the continued existence of orangutans in Kalimantan. Importantly, the study contributes to our understanding of the spatial variation in threats, and the underlying causes of those threats, which can be used to facilitate the development of targeted conservation management

RNAi-mediated COPS3 gene silencing inhibits metastasis of osteogenic sarcoma cells

Metastatic disease is the primary cause of mortality among patients with osteogenic sarcoma (OGS). In this study, we aimed to identify the relationship of COPS3 gene expression to metastasis. Immunohistochemical staining for COPS3 was performed on 65 OGS samples (37 without and 28 with metastatic disease); 18.9% (7/37) of specimens from patients with no metastasis and 57.1% (16/28) of specimens from patients with metastasis showed intense staining of COPS3. Comparison of COPS3 expression between a poorly metastatic osteosarcoma cell line (SAOS-2) and highly metastatic osteosarcoma cell line (HOS) showed stronger expression of COPS3 in HOS cells. Inhibiting COPS3 function by siRNA resulted in reduced proliferation and migration of HOS cells. Inhibition of COPS3 gene downregulated expression of the MAPK signaling pathway, which has an important role in metastasis of OGS. Our results suggested that overexpression of the COPS3 gene might have important roles in metastasis of osteosarcoma cells

Both-Bone Forearm Fractures in Children with Minimum Four Years of Growth Remaining: Can Cast Achieve a Good Outcome at Skeletal Maturity?

INTRODUCTION: Both-bone forearm fractures in children can be treated non-operatively with a cast. Most previous studies have shown favourable outcome; however, information on the functional outcome after skeletal maturity is still scanty. Therefore, this study was conducted to determine the functional outcome after skeletal maturity in fractures with at least four years of growth remaining. MATERIALS AND METHODS: This retrospective study was conducted from March 2012 until March 2013. Age at the time of fracture was taken as until 10 years for females and until 12 years old for males with at least four years of growth remaining. Fractures occurring in the diaphysis were included in the study. Functional outcomes were assessed at or after skeletal maturity. RESULTS: Forty-four children fulfilled the criteria. The ages of the youngest and the oldest at the time of fracture was five and 12 years old respectively. Follow-up of the male and female patients were 7.4 years and 5.5 years respectively. There was a significant difference between post-reduction angulation and angulation at skeletal maturity of the radius and ulna (p<0.001). Out of 44 patients, 39 had excellent and five had good functional outcomes. No patient had fair or poor functional outcome. There was no association between the functional outcome and the angulation of forearm bones after skeletal maturity. Age at the time of fracture had a significant association with the functional outcome. CONCLUSION: Non-operative treatment of both-bone diaphyseal forearm fractures in a cast has good to excellent functional outcomes in children who still have four years of growth remaining

Nonunion of Lateral Humeral Condylar Fracture in A Child with Cubitus Varus

Patients with cubitus varus deformity secondary to malunited supracondylar fracture are at risk for lateral humeral condylar (LHC) fracture. This report describes a child presenting with preexisting malunion of supracondylar fracture presenting along with nonunion of a LHC fracture following a recent injury. The patient underwent resection osteotomy of the metaphyseal proximal fragment of the fracture surface, reduction of the displaced LHC fragment and screw fixation. This procedure corrected the cubitus varus and treated the nonunion of the lateral condyle thus avoiding a supracondylar osteotomy procedure. Treatment resulted in solid union, good range of motion and no avascular necrosis

Clinical Measurement of the Tibio-femoral Angle in Malay Children

Background: This study was conducted to find out the age when tibiofemoral angle starts to be in valgus and reaches maximum angle. The differences of the angles between genders were also studied. Methodology: This cross sectional study on tibiofemoral angle was conducted among 160 normal healthy children using clinical measurement method. The children between 2 18 months to 6 years old were assigned to 5 specific age groups of 32 children with equal sex distribution. Result: This study had shown a good inter-observer reliability of tibiofemoral angle measurement with intraclass correlation coefficient (ICC) of 0.87 with narrow margin of 95% confident interval (95% CI: 0.73, 0.94). The mean tibiofemoral angle for children at 2 , 3 , 4 , 5 and 6 years old were 2.25o (SD=0.53), 8.73o (SD=0.95), 7.53o (SD=1.40), 7.27o (SD=1.14) and 6.72o (SD=0.98) respectively. The age when they achieved maximum valgus tibiofemoral angle was 3 years old. The maximum mean (SD) tibiofemoral angle for boys, girls and all children were 8.91o (SD=1.17) , 8.56o (SD=0.62) and 8.73o (SD=0.95) respectively. The mean tibiofemoral angle showed no statistically significant difference between girls and boys except for the 5-year-old group, in which the mean TF angle for girls was 7.560 (SD=0.95) and for the boys was 6.970 (SD=1.26) with p-value of 0.037. Conclusion: Measurement of tibiofemoral angle using the clinical method had a very good inter-observer reliability. The tibiofemoral angle in Malay population was valgus since the age of 2 years with maximum angle of 8.730 (SD=0.95) achieved at the age of 3 years

Microrheological measurement of microcrystalline cellulose solution using single particle tracking

The aim of the research was to develop micro rheological measurement system to determine the alpha apparent and the complex shear modulus of microcrystalline cellulose (MCC) solutions based on a single particle tracking technique (SPT) using video microscopy (VM). The temporal displacement of a micro particle, acted as a probe in MCC solution was recorded, tracked and analyzed using custom-made MATLAB program. Videos were recorded at 30 fps resulted in the output of radial frequency range from 0.4 rad/s to 10 rad/s. The results from the local measurement in MCC solutions were compared with the bulk measurement using rheometer. The measurements were dependent on the local position of the probe in the solution. The results from the developed SPT-based measurement system were comparable to the common measurement using rheometer

Q-switched dual-wavelength erbium-doped fiber laser using graphene as a saturable absorber

We proposed stable Q-switched dual-wavelength initiated by graphene as saturable absorber inside erbium-doped fiber laser cavity. Continuous-wave and pulse spectrum of erbium-doped fiber laser (EDFL) was successfully demonstrated and analysed where the lasing starts at a pump power of 50.4 mW. Threshold pump power generates continuous-wave at 1560 nm which is then shifted to 1558.7 nm as the SA is inserted. Q-switched EDFL generates a maximum repetition rate of 115.9 kHz which corresponds to a pulse width of 41 μs. The generation of dual-wavelength at two different wavelengths are also demonstrated in these works