Investigation of Polymer–Plasticizer Blends as SH-SAW Sensor Coatings for Detection of Benzene in Water with High Sensitivity and Long-Term Stability

We report the first-ever direct detection of benzene in water at concentrations below 100 ppb (parts per billion) using acoustic wave (specifically, shear-horizontal surface acoustic wave, SH-SAW) sensors with plasticized polymer coatings. Two polymers and two plasticizers were studied as materials for sensor coatings. For each polymer–plasticizer combination, the influence of the mixing ratio of the blend on the sensitivity to benzene was measured and compared to commercially available polymers that were used for BTEX (benzene, toluene, ethylbenzene, and xylene) detection in previous work. After optimizing the coating parameters, the highest sensitivity and lowest detection limit for benzene were found for a 1.25 μm thick sensor coating of 17.5%-by-weight diisooctyl azelate-polystyrene on the tested acoustic wave device. The calculated detection limit was 45 ppb, with actual sensor responses to concentrations down to 65 ppb measured directly. Among the sensor coatings that showed good sensitivity to benzene, the best long-term stability was found for a 1.0 μm thick coating of 23% diisononyl cyclohexane-1,2-dicarboxylate-polystyrene, which was studied here because it is known to show no detectable leaching in water. The present work demonstrates that, by varying type of plasticizer, mixing ratio, and coating thickness, the mechanical and chemical properties of the coatings can be conveniently tailored to maximize analyte sorption and partial chemical selectivity for a given class of analytes as well as to minimize acoustic-wave attenuation in contact with an aqueous phase at the operating frequency of the sensor device

Kinerja Guru Dipengaruhi oleh Kompetensi Guru dan Kepemimpinan Kepala Sekolah

This study examines the optimization of teacher performance by measuring the effect of teacher competence and principal leadership on economic teacher performance. The method used is survey method and total sampling. The research subjects consisted of 55 high school economics teachers in the city of Tasikmalaya. Conclusion, teacher competence and principal leadership have a positive influence on teacher performance where the higher the teacher competence and the more effective the principal's leadership, it will improve the quality of teacher performance. Keywords: Teacher Competence, Teacher Performance, Principal Leadershi

Strategic Assessment of Near Coastal Waters: Northeast Case Study

The Northeast Case Study has been undertaken to illustrate how data being developed in NOAA\u27s program of strategic assessments can be used for resource assessments of estuaries and near coastal waters throughout the contiguous USA. It was designed as a pilot project to assist the U.S. Environmental Protection Agency (EPA) in developing its Strategic Initiative for the Management of Near Coastal Waters. As part of this initiative, the coastal states and EPA are to identify estuarine and coastal waters that require management action. The project began in June 1987 as a cooperative effort by NOAA\u27s Office of Oceanography and Marine Assessment and EPA\u27s Office of Policy, Planning, and Evaluation and Office of Marine and Estuarine Protection. The Northeast was selected because NOAA\u27s data bases were more complete for the estuaries of this region at the time. Offshore areas are not included since information to characterize them has not been organized for a consistently defined set of spatial units. Preliminary and interim case study reports were completed in September and November 1987. In these reports, information was compiled by estuary for seven themes: (1) physical and hydrologic characteristics; (2) land use and population; (3) nutrient discharges; (4) classified shellfish waters; (5) toxic discharges and hazardous waste disposal sites; (6) coastal wetlands; and (7) public outdoor recreation facilities. Most of the information was compiled from NOAA\u27s National Coastal Pollutant Discharge Inventory, National Estuarine Inventory (Volumes 1 and 2), National Coastal Wetlands Inventory, and Public Outdoor Recreational Facilities Inventory. However, with the exception of the toxic discharges chapter in the interim report, only cursory explanations of the data and no data analyses were provided in the previous reports. Two chapters, nutrient and toxic discharges to estuaries, will be completed to illustrate fully the extent of available data, the methods used to develop the data, and the types of analyses that are possible. The data bases used to compile the information in the report are constantly being updated and improved. For example, during the course of the project, NOAA analyzed the susceptibility and status of all estuaries identified in its National Estuarine Inventory to nutrient and toxic discharges. This information, not in the preliminary and interim drafts of the case study, is emphasized in the chapters on nutrient and toxic discharges with special attention given to the estuaries in the Northeast. Case studies for other regions may be completed in the future depending on interest and available resources

Synergistic disruption of external male sex organ development by a mixture of four antiandrogens

Reproduced with permission from Environmental Health Perspectives.Background: By disrupting the action of androgens during gestation, certain chemicals present in food, consumer products, and the environment can induce irreversible demasculinization and malformations of sex organs among male offspring. However, the consequences of simultaneous exposure to such chemicals are not well described, especially when they exert their actions by differing molecular mechanisms. Objectives: To fill this gap, we investigated the effects of mixtures of a widely used plasticizer, di(2-ethylhexyl) phthalate (DEHP); two fungicides present in food, vinclozolin and prochloraz; and a pharmaceutical, finasteride, on landmarks of male sexual development in the rat, including changes in anogenital distance (AGD), retained nipples, sex organ weights, and malformations of genitalia. These chemicals were chosen because they disrupt androgen action with differing mechanisms of action. Results: Strikingly, the effect of combined exposure to the selected chemicals on malformations of external sex organs was synergistic, and the observed responses were greater than would be predicted from the toxicities of the individual chemicals. In relation to other hallmarks of disrupted male sexual development, including changes in AGD, retained nipples, and sex organ weights, the combined effects were dose additive. When the four chemicals were combined at doses equal to no observed adverse effect levels estimated for nipple retention, significant reductions in AGD were observed in male offspring. Conclusions: Because unhindered androgen action is essential for human male development in fetal life, these findings are highly relevant to human risk assessment. Evaluations that ignore the possibility of combination effects may lead to considerable underestimations of risks associated with exposures to chemicals that disrupt male sexual differentiation.European Union and the Danish Environmental Protection Agency

EPA Superfund Record of Decision: Murray Smelter Murray City, UT

The Murray Smelter Site ( the Site ) is located in the city of Murray, Utah, in Salt Lake County as illustrated on Figure 1. The Site includes the former operational areas of the Murray Smelter and adjacent Germania Smelter which are referred to as the on-facility area., as well as surrounding residential and commercial areas where airborne emissions from the smelters impacted the environment or where contamination in shallow ground water may be transported in the future. These surrounding areas are referred to as the off-facility area. The on-facility area is approximately 142 acres. Its boundaries are 5300 South Street to the south, State Street to the east, Little Cottonwood Creek to the north, and the west set of Union Pacific railroad tracks to the west. The off-facility area is approximately 30 acres to the west of the on-facility area, approximately 106 acres south and southeast of the on-facility area., an: a small area between 5200 South Street and Little Cottonwood Creek to the east of the on-facility area. The west portion of the off-facility area is bounded by Little Cottonwood Creek to the north, 300 West Street to the west, 5300 South Street to the south, and the on-facility boundary to the east. The south/southwest portion is bounded by 5300 South Street to the north and Wilson Avenue to the south. The off-facility boundaries were determined by EPA based on the results of air dispersion modeling performed in November, 1994. The purpose of the modeling was to identify the area that potentially would have received the greatest amount of deposition resulting from lead and arsenic emissions from the Murray Smelter during its operating period. For environmental Sampling, risk assessment, and risk management purposes. the Site was divided into smaller areas to represent realistic areas of humar and ecological exposure. The 142 acre on-facility area was divided into eleven exposure units (EU\u27s) and the 136 acre off-facility area was divided into eight initial study zones (ISZ\u27s). The riparian area along Little Cottonwood Creek was delineated as the ecological study area

MS4 Resource: BMP Crosswalk

A cross-walk to assist designers and modelers to match common BMPs identified in the MA and NH Stormwater Manual with the BMPs modeled in the MS4 permit and documented in appendix

PENGARUH MEKANISME CORPORATE GOVERNANCE DAN PROGRAM OPSI SAHAM KARYAWAN TERHADAP MANAJEMEN LABA (EARNINGS MANAGEMENT)

Penelitian ini bertujuan untuk mengetahui pengaruh dari mekanisme corporate governance dan program opsi saham karyawan terhadap manajemen laba. Penerapan corporate governance di ukur dengan lima variabel yaitu Kepemilikan manajerial,kepemilikan institusional,ukuran dewan direksi, ukuran dewan komisaris, dan komite audit dan di tambah dengan program opsi saham karyawan. Penelitian ini menggunakan data empiris perusahaan manufaktur di Bursa Efek Indonesia dari tahun 2007 sampai tahun 2008 dengan sampel 54 perusahaan. Metode penelitian yang digunakan adalah uji asumsi klasik dan pengujian hipotesis. Berdasarkan hasil penelitian, ditemukan bahwa variabel yang mempunyai pengaruh yang signifikan terhadap besaran manajemen laba adalah Kepemilikan institusional,ukuran dewan komisaris, komite audit, dan program opsi saham karyawan. Dimana semakin besar proporsi kepemilikan institusional,ukuraan dewan komisaris, komite audit dan program opsi saham maka manajer cenderung menurunkan laba. Variabel kepemilikan manajerial, dan ukuran dewan direksi tidak terbukti mempunyai pengaruh yang signifikan terhadap besaran manajemen laba