Analisis Risiko Kesehatan Pajanan Pm10 pada Pekerja Industri Readymix PT. X Plant Kebon Nanas Jakarta Timur

Pajanan agen risiko kesehatan dari lingkungan kerja berdampak pada timbulnya risiko penyakit akibat kerja sehingga pekerja menjadi tidak produktif. Oleh karena itu, untuk mengestimasi risiko kesehatan dari pajanan agen risiko berupa PM10 dari lingkungan kerja, sebuah penelitian analisis risiko telah dilakukan pada 70 orang pekerja industri readymix PT. X Plant Kebon Nanas. Risiko kesehatan akibat pajanan PM10 dihitung dengan membandingkan asupan PM10 dengan dosis referensi. Konsentrasi PM10 diukur pada 6 titik dengan konsentrasi rata-ratayaitu 0,289 mg/m3.Perhitungan risiko yang diterima saat ini (realtime) terdapat 21,4% pekerja yang berada dalam kategori berisiko. Hasil estimasi risiko yang diterima seumur hidup (lifetime) hanya 2 orang pekerja yang dalam kategori tidak berisiko. Manajemen risiko yang dapat dilakukan adalah dengan menurunkan konsentrasi menjadi 0,08 mg/m3. Dengan konsentrasi tersebut pekerja diestimasikan aman bekerja selama 11 jam per hari dan 362 hari per tahun

Characterization of bio fouling in membrane bioreactor

Biofouling that formed in membrane bioreactor impacted the performance of membrane bioreactor. This study investigates the impact of biofouling in terms of the concentration of soluble microbial product on the characteristics and the fouling potential of lab scale membrane bioreactor. The performance of membrane bioreactor reduced significantly with reduction in the initial flux, and dramatic transformation in surface morphology and roughness occurred. The small size of residual organic substances further facilitates membrane fouling by pore blockage. It can be concluded that SMP influence fouling under certain condition of membrane bioreactor

Effects of SRT and HRT on Treatment Performance of MBR and Membrane Fouling

40L of hollow fiber membrane bioreactor with solids retention times (SRT) of 30, 15 and 4 days were setup for treating synthetic wastewater at hydraulic retention times (HRT) of 12, 8 and 4 hours. The objectives of the study were to investigate the effects of SRT and HRT on membrane fouling. A comparative analysis was carried out for physiochemical quality parameters (turbidity, suspended solids, COD, NH3-N and PO43-). Scanning electron microscopy (SEM), energy diffusive X-ray (EDX) analyzer and particle size distribution (PSD) were used to characterize the membrane fouling properties. The influence of SRT on the quality of effluent, activated sludge quality, and membrane fouling were also correlated. Lower membrane fouling and slower rise in trans-membrane pressure (TMP) were noticed at the longest SRT and HRT of 30d and 12h, respectively. Increasing SRT results in noticeable reduction of dissolved organic matters. The best removal efficiencies of COD, TSS, NH3-N and PO43- were 93%, 98%, 80% and 30% respectively. The high HRT with shorter SRT induced faster fouling rate. The main fouling resistance was cake layer. The most severe membrane fouling was observed at SRT and HRT of 4 and 12, respectively with thickness cake layer of 17mm as reflected by higher TMP, lower effluent removal and thick sludge cake layer

Effect of Unit Cell Type and Pore Size on Porosity and Mechanical Behavior of Additively Manufactured Ti6Al4V Scaffolds

Porous metal structures have emerged as a promising solution in repairing and replacing damaged bone in biomedical applications. With the advent of additive manufacturing technology, fabrication of porous scaffold architecture of different unit cell types with desired parameters can replicate the biomechanical properties of the natural bone, thereby overcoming the issues, such as stress shielding effect, to avoid implant failure. The purpose of this research was to investigate the influence of cube and gyroid unit cell types, with pore size ranging from 300 to 600 µm, on porosity and mechanical behavior of titanium alloy (Ti6Al4V) scaffolds. Scaffold samples were modeled and analyzed using finite element analysis (FEA) following the ISO standard (ISO 13314). Selective laser melting (SLM) process was used to manufacture five samples of each type. Morphological characterization of samples was performed through micro CT Scan system and the samples were later subjected to compression testing to assess the mechanical behavior of scaffolds. Numerical and experimental analysis of samples show porosity greater than 50% for all types, which is in agreement with desired porosity range of natural bone. Mechanical properties of samples depict that values of elastic modulus and yield strength decreases with increase in porosity, with elastic modulus reduced up to 3 GPa and yield strength decreased to 7 MPa. However, while comparing with natural bone properties, only cube and gyroid structure with pore size 300 µm falls under the category of giving similar properties to that of natural bone. Analysis of porous scaffolds show promising results for application in orthopedic implants. Application of optimum scaffold structures to implants can reduce the premature failure of implants and increase the reliability of prosthetics