PENGENDALIAN SISTEM PEMBENGKOK MATERIAL PADA SIMULATOR MESIN PEMBENGKOK BATANG SILINDER

Dalam dunia industri saat ini, sistem pengendalian proses produksi biasanya merujuk pada penggunaan sistem pengendalian otomatis. Pengendalian sistem kontrol secara otomatis dapat meningkatkan kinerja mesin. Salah satu aplikasi sistem pengendali otomatis dapat diterapkan pada mesin pembengkok (bending machine). Pada sistem kontrol otomatis, komputer berperan sebagai perangkat pengendali yang sebelumnya dilakukan secara manual. Sistem kontrol otomatis ditujukan untuk proses yang berulang-ulang tanpa menurunkan kualitas produksi. Sistem kontrol otomatis sendiri prosesnya lebih teliti dibandingkan sistem kontrol secara manual. Pada tugas akhir, dibuat suatu simulator pembengkok otomatis menggunakan microcontroller ATMega 8535 sebagai sistem pengendali utama. Microcontroller digunakan sebagai pengendali mekanisme pembengkok pada simulator mesin pembengkok batang silinder yang berada di laboratorium Otomasi dan Robotika. Prinsip kerja sistem ini yaitu dengan cara microcontroller memberikan perintah berupa sinyal keluaran yang telah diolah menuju rangkaian sistem pembengkok. Rangkaian sistem pembengkok merupakan rangkaian komponen yang terlebih dahulu menerima perintah dari microcontroller kemudian keluaran dari sistem rangkaian digunakan untuk menggerakan mekanisme mesin pembengkok (Aktuator)

PENGENDALIAN SISTEM PEMBENGKOK MATERIAL PADA SIMULATOR MESIN PEMBENGKOK BATANG SILINDER

Dalam dunia industri saat ini, sistem pengendalian proses produksi biasanya merujuk pada penggunaan sistem pengendalian otomatis. Pengendalian sistem kontrol secara otomatis dapat meningkatkan kinerja mesin. Salah satu aplikasi sistem pengendali otomatis dapat diterapkan pada mesin pembengkok (bending machine). Pada sistem kontrol otomatis, komputer berperan sebagai perangkat pengendali yang sebelumnya dilakukan secara manual. Sistem kontrol otomatis ditujukan untuk proses yang berulang-ulang tanpa menurunkan kualitas produksi. Sistem kontrol otomatis sendiri prosesnya lebih teliti dibandingkan sistem kontrol secara manual. Pada tugas akhir, dibuat suatu simulator pembengkok otomatis menggunakan microcontroller ATMega 8535 sebagai sistem pengendali utama. Microcontroller digunakan sebagai pengendali mekanisme pembengkok pada simulator mesin pembengkok batang silinder yang berada di laboratorium Otomasi dan Robotika. Prinsip kerja sistem ini yaitu dengan cara microcontroller memberikan perintah berupa sinyal keluaran yang telah diolah menuju rangkaian sistem pembengkok. Rangkaian sistem pembengkok merupakan rangkaian komponen yang terlebih dahulu menerima perintah dari microcontroller kemudian keluaran dari sistem rangkaian digunakan untuk menggerakan mekanisme mesin pembengkok (Aktuator)

KAJIAN PERBANDINGAN EKSTRAK Tribulus Terrestris DENGAN KELOMPOK BUNGA ROSELA (Hibiscus Sabdariffa) TERHADAP KARAKTERISTIK MINUMAN HERBAL

Minuman herbal adalah minuman yang dibuat dari ramuan bunga, daun, biji, akar, atau buah kering yang biasa disebut simplisia. Tujuan dari penelitian adalah untuk mempelajari perbandingan ekstrak tribulus terrestris dan kelopak bunga rosella (hibiscus sabdariffa) terhadap karakteristik minuman herbal. Maksud dari penelitian ini adalah untuk memanfaatkan tanaman tribulus terrestris dan kelopak bunga rosella (hibiscus sabdariffa) menjadi suatu bentuk olahan pangan fungsional yang praktis dan bermanfaat bagi kesehatan dengan membuat minuman herbal. Metode penelitian yang dilakukan dalam dua tahap meliputi penelitian pendahuluan dan penelitian utama. Penelitian pendahuluan dimaksudkan menentukan pemanis dan perlakuan ekstrak yang terpilih yang akan dijadikan acuan untuk penelitian utama. Penelitian utama bertujuan untuk mengetahui pengaruh perbandingan ekstrak tribulus terrestris dan kelopak bunga rosella (hibiscus sabdariffa) terhadap karakteristik minuman herbal. Rancangan percobaan yang digunakan dalam penelitian ini adalah Rancangan Acak Kelompok (RAK) dengan pola faktorial 3x3 sebanyak tiga kali ulangan yang dilanjutkan dengan uji lanjut duncan. Variabel percobaan terdiri dari ekstrak tribulus terrestris (P) yaitu (110 mL ,120 mL ,130 mL) dan ekstrak kelopak bunga rosella (hibiscus sabdariffa) (G) yaitu (20 mL ,30 mL ,40 mL). Hasil uji organoleptik dan analisis saponin serta vitamin c kuantitatif pada penelitian pendahuluan, diperoleh hasil bahwa madu perhutani lengkeng merupakan pemanis terpilih dan perlakuan ekstrak dengan direbus yang akan digunakan dalam penelitian utama. Hasil analisis kimia pada penelitian utama ekstrak tribulus terrestris minuman herbal berpengaruh nyata terhadap seluruh respon kimia yaitu kadar vitamin C, derajat keasaman (pH), kadar saponin, dan kadar total antosianin. Sedangkan hasil uji organoleptik pada penelitian utama pada atribut rasa berbeda nyata tetapi pada atribut warna dan aroma tidak berpengaruh nyata. Ekstrak kelopak bunga rosella (hibiscus sabdariffa) minuman herbal berpengaruh nyata terhadap seluruh respon kimia yaitu kadar vitamin C, derajat keasaman (pH), kadar saponin, dan kadar total antosianin. Sedangkan hasil uji organoleptik pada penelitian utama pada seluruh atribut rasa, aroma, dan warna berbeda nyata. Interaksi antara ekstrak tribulus terrestris dan ekstrak kelopak bunga rosella (hibiscus sabdariffa) herbal berpengaruh nyata terhadap respon kimia derajat keasaman (pH) dan kadar vitamin C sedangkan pada kadar saponin dan kadar total antosianin tidak berpengaruh nyata. Sedangkan hasil uji organoleptik pada penelitian utama pada seluruh atribut rasa, aroma, dan warna berbeda nyata

Water dispersible microbicidal cellulose acetate phthalate film

BACKGROUND: Cellulose acetate phthalate (CAP) has been used for several decades in the pharmaceutical industry for enteric film coating of oral tablets and capsules. Micronized CAP, available commercially as "Aquateric" and containing additional ingredients required for micronization, used for tablet coating from water dispersions, was shown to adsorb and inactivate the human immunodeficiency virus (HIV-1), herpesviruses (HSV) and other sexually transmitted disease (STD) pathogens. Earlier studies indicate that a gel formulation of micronized CAP has a potential as a topical microbicide for prevention of STDs including the acquired immunodeficiency syndrome (AIDS). The objective of endeavors described here was to develop a water dispersible CAP film amenable to inexpensive industrial mass production. METHODS: CAP and hydroxypropyl cellulose (HPC) were dissolved in different organic solvent mixtures, poured into dishes, and the solvents evaporated. Graded quantities of a resulting selected film were mixed for 5 min at 37°C with HIV-1, HSV and other STD pathogens, respectively. Residual infectivity of the treated viruses and bacteria was determined. RESULTS: The prerequisites for producing CAP films which are soft, flexible and dispersible in water, resulting in smooth gels, are combining CAP with HPC (other cellulose derivatives are unsuitable), and casting from organic solvent mixtures containing ≈50 to ≈65% ethanol (EtOH). The films are ≈100 µ thick and have a textured surface with alternating protrusions and depressions revealed by scanning electron microscopy. The films, before complete conversion into a gel, rapidly inactivated HIV-1 and HSV and reduced the infectivity of non-viral STD pathogens >1,000-fold. CONCLUSIONS: Soft pliable CAP-HPC composite films can be generated by casting from organic solvent mixtures containing EtOH. The films rapidly reduce the infectivity of several STD pathogens, including HIV-1. They are converted into gels and thus do not have to be removed following application and use. In addition to their potential as topical microbicides, the films have promise for mucosal delivery of pharmaceuticals other than CAP

Awareness, willingness and use of Voluntary HIV testing and counseling services by students of a university in south-south Nigeria

Background: HIV testing and counseling (HTC) is the entry point to HIV prevention, treatment, care, and support services. HTC can be voluntary or mandatory. This study aimed to determine the awareness, willingness, and use of voluntary HTC (VHTC) services by students of the Niger Delta University, Bayelsa State Nigeria.Method:  A cross sectional descriptive study was conducted in June 2012 using multi-stage random sampling to select 423 students who were administered a pre-tested, structured self-administered questionnaire adapted from the UNAIDS knowledge indicator questionnaire. Information about awareness, willingness and use of VHTC services were elicited from the respondents. Epi-Info 3.5.3 was used for data entry and analysis.Result:  There was almost universal awareness of HIV (99%) by respondents but a lower proportion (78.4%) were aware of VHTC services and a much lower proportion (14.8%) knew the services were available on the university campus. Furthermore, just about a half (53.8%) had ever undergone HIV testing (Female/male: OR=1.02, 95%CI: 0.68-1.55) and only 26.5% had voluntary HTC (Female/male: OR=1.34, 95%CI: 0.75-2.40). Majority (73.8%) of all respondents expressed willingness to undergo VHTC (significantly more females than males, OR=1.67, 95%CI: 1.04-2.68). Fear of positive result (39.1%) and stigma (25.7%) were the leading demotivators for those unwilling to have VHTC.Conclusion: Despite high awareness of HIV and voluntary HTC, actual use of VHTC services was low. There is a strong need for more education of the students and indeed the community at large as this would engender a more positive attitude and increased use of available VHTC services on campus.Keywords: HIV/AIDS, Voluntary HIV testing and counselling, HTC, undergraduate students, Niger Delta University, Bayelsa Stat

Fungal iron availability during deep seated candidiasis is defined by a complex interplay involving systemic and local events

Peer reviewedPublisher PD

ANALISIS KESULITAN MEMBACA PERMULAAN SISWA KELAS II DI SEKOLAH DASAR

This study aims to describe the analysis of the difficulties of beginning reading of grade II students at SDN Panyingkiran II.  This research uses a qualitative approach with a case study type of research. Data was obtained from the class teacher and grade II students of SDN Panyingkiran II. The data collection techniques used in this study were observation, interviews, and documentation. The data obtained was analyzed through the stages of data reduction, data presentation, and drawing conclusions. The results showed that of the 4 grade II students of SDN Panyingkiran II, it was found that RP, SM, AN, and MP had problems in beginning reading. The problems experienced, namely: not yet able to recognize letters, distinguish letters, spell words, and assemble words into sentences

Potential health impacts of heavy metals on HIV-infected population in USA.

Noninfectious comorbidities such as cardiovascular diseases have become increasingly prevalent and occur earlier in life in persons with HIV infection. Despite the emerging body of literature linking environmental exposures to chronic disease outcomes in the general population, the impacts of environmental exposures have received little attention in HIV-infected population. The aim of this study is to investigate whether individuals living with HIV have elevated prevalence of heavy metals compared to non-HIV infected individuals in United States. We used the National Health and Nutrition Examination Survey (NHANES) 2003-2010 to compare exposures to heavy metals including cadmium, lead, and total mercury in HIV infected and non-HIV infected subjects. In this cross-sectional study, we found that HIV-infected individuals had higher concentrations of all heavy metals than the non-HIV infected group. In a multivariate linear regression model, HIV status was significantly associated with increased blood cadmium (p=0.03) after adjusting for age, sex, race, education, poverty income ratio, and smoking. However, HIV status was not statistically associated with lead or mercury levels after adjusting for the same covariates. Our findings suggest that HIV-infected patients might be significantly more exposed to cadmium compared to non-HIV infected individuals which could contribute to higher prevalence of chronic diseases among HIV-infected subjects. Further research is warranted to identify sources of exposure and to understand more about specific health outcomes

IFSS, TG, FT-IR spectra of impregnated sugar palm (Arenga pinnata) fibres and mechanical properties of their composites.

This study aimed to investigate the effect of resin impregnation on the interfacial shear strength (IFSS), thermogravimetric (TG) and fourier transform infrared (FT-IR) of sugar palm (Arenga pinnata) fibres. In addition, the effect of resin impregnation on the mechanical properties of sugar palm fibre reinforced unsaturated polyester (UP) composites was also studied. The fibres were impregnated with UP via vacuum resin impregnation process at a pressure of 600 mmHg for 5 min. Composites of 10, 20, 30, 40 and 50 % fibre loadings were fabricated and tested for tensile and flexural properties. It was observed that the impregnation process caused the fibres to be enclosed by UP resin and this gave a strong influence to the increase of its interfacial bonding by the increase of its IFSS from single fibre pull-out test. It was also observed with TG and FT-IR spectra that the impregnated fibre had lower moisture uptake than the control and there was no significant increase in thermal stability of the impregnated fibre. The sequence of fibre decomposition started from the evaporation of moisture, hemicelluloses, cellulose, lignin and finally ash content and the presence of these components were proven by FT-IR spectra. For the composite specimens, due to the high interfacial bonding of the impregnated fibre and the matrix, the impregnated composites showed consistently higher tensile strength, tensile modulus, elongation at break, flexural strength, flexural modulus and toughness than the control samples. It was also observed that 30 % fibre loading gave optimum properties

Quantitative cross-species extrapolation between humans and fish: The case of the anti-depressant fluoxetine

This article has been made available through the Brunel Open Access Publishing Fund.Fish are an important model for the pharmacological and toxicological characterization of human pharmaceuticals in drug discovery, drug safety assessment and environmental toxicology. However, do fish respond to pharmaceuticals as humans do? To address this question, we provide a novel quantitative cross-species extrapolation approach (qCSE) based on the hypothesis that similar plasma concentrations of pharmaceuticals cause comparable target-mediated effects in both humans and fish at similar level of biological organization (Read-Across Hypothesis). To validate this hypothesis, the behavioural effects of the anti-depressant drug fluoxetine on the fish model fathead minnow (Pimephales promelas) were used as test case. Fish were exposed for 28 days to a range of measured water concentrations of fluoxetine (0.1, 1.0, 8.0, 16, 32, 64 μg/L) to produce plasma concentrations below, equal and above the range of Human Therapeutic Plasma Concentrations (HTPCs). Fluoxetine and its metabolite, norfluoxetine, were quantified in the plasma of individual fish and linked to behavioural anxiety-related endpoints. The minimum drug plasma concentrations that elicited anxiolytic responses in fish were above the upper value of the HTPC range, whereas no effects were observed at plasma concentrations below the HTPCs. In vivo metabolism of fluoxetine in humans and fish was similar, and displayed bi-phasic concentration-dependent kinetics driven by the auto-inhibitory dynamics and saturation of the enzymes that convert fluoxetine into norfluoxetine. The sensitivity of fish to fluoxetine was not so dissimilar from that of patients affected by general anxiety disorders. These results represent the first direct evidence of measured internal dose response effect of a pharmaceutical in fish, hence validating the Read-Across hypothesis applied to fluoxetine. Overall, this study demonstrates that the qCSE approach, anchored to internal drug concentrations, is a powerful tool to guide the assessment of the sensitivity of fish to pharmaceuticals, and strengthens the translational power of the cross-species extrapolation