ANALISIS BAHAYA, LINTASAN, DAN SISTEM PROTEKSI TERHADAP POTENSI LONGSORAN TIPE JATUHAN BATU PADA LERENG BANGUNAN PELIMPAH BENDUNGAN TUGU, JAWA TIMUR

The construction of the Tugu Dam spillway does not escape the problem of slope instability, especially the rock fall type landslide as a result of the rock slope cutting work at STA+80. The purpose of this study was to determine the characteristics of the rock discontinuity area and the solutions needed to address the potential hazards of rock fall on the slopes of spillway structure. In this study, a semi-quantitative method conducted based on the Rockfall Hazard Rating System (RHRS) which is carried out by identifying outcrops on rock slopes. Determination of the rock fall trajectory, was conducted by statistical methods on rock mass based on changes in velocity when rocks roll, slide, and bounce. Geologically, the research area belongs to the Mandalika Formation. Based on the RHRS weighting, the total score on the STA+80 slope is 399, which means that the slope needs to be repaired or given safely with a moderate level of urgency. The rock fall trajectory modeling at the measurement location X = 121,875 has a kinetic energy of 973.14 kJ andesite and 72.59 kJ of volcanic breccia, for high results of 0.43 meters of andesite reflection and 2.04 meters of volcanic breccia, and velocity results translational velocity obtained at 33.8 m/s andesite and 8.67 m/s volcanic breccia. The potential for rock fall requires a safety system with a type of retained flexible barriers with a height of 5 meters that can be applied to the toe of the slope.Keywords: rock fall, discontinuity, trajectory, protection system, Tugu Dam

IMPLEMENTASI PENILAIAN RISIKO KESEHATAN TERKAIT PAJANAN BTX DI LABORATORIUM PENGUJIAN MIGAS PT. SCI

Laboratorium merupakan tempat kerja untuk melakukan percobaan atau eksperimen uji dimana bekerja di tempat tersebut membutuhkan perilaku kehati-hatian dalam menggunakan peralatan dan bahan. Salah satu jenis bahan kimia yang terdapat di laboratorium adalah pelarut organik yang memiliki fungsi sebagai pelarut bahan kimia lainnya. Potensi risiko kanker payudara pada pekerja wanita di laboratorium pada studi kohort ini adalah paparan pelarut organik. Pelarut organik yang sering digunakan di laboratorium adalah benzene, toluene dan xylene (BTX). Dengan adanya pajanan bahan kimia BTX di tempat kerja dan risiko kesehatan yang ditimbulkan, maka perlu dilakukan penilaian tingkat risiko pajanan bahan kimia terhadap kesehatan pekerja di laboratorium melalui inhalasi secara kuantitatif dengan menggunakan metode CHRA DOSH Malaysia tahun 2018. Penelitian dimulai dengan pengambilan sampel inhalasi dan udara di lingkungan kerja. Data hasil sampling diolah untuk mengetahui Tingkat Bahaya (Hazard Rating), Tingkat Pajanan (Exposure Rating), dan Tingkat Risiko (Risk Rating) secara kualitatif dan kuantitatif. Tingkat risiko pajanan melalui inhalasi secara kualitatif diperoleh nilai tingkat risiko pajanan (RR) benzene, toluene dan xylene secara bertutut-turut RR= 20, 12, dan 8. Tingkat risiko pajanan melalui inhalasi untuk benzene memiliki risiko tinggi sedangkan toluene dan xylene memiliki risiko moderat. Tingkat risiko pajanan melalui inhalasi secara kuantitatif dengan metode CHRA. nilai tingkat risiko pajanan (RR) benzene, toluene dan xylene secara kuantitatif secara berturut-turut adalah RR= 5, 3, dan 2. Berdasarkan metode kuantitatif, nilai tingkat risiko pajanan melalui inhalasi untuk benzene memiliki risiko moderat sedangkan toluene dan xylene memiliki risiko rendah terhadap pekerja di laboratorium pengujian migas PT SCI

An improved hazard assessment chart for rock falls in near vertical blocky rock environments

The purpose of the study was to perform rockfall stability analysis and develop an improved rockfall hazard matrix chart using the R518 road in Limpopo as the case study. The study entailed structural mapping, wedge simulation using stereonet plots. The RocFall software was then used to identify the parameters that influence the occurrence of rockfall. The software was also used to monitor the variations in the kinetic energy of rolling, bouncing or falling rocks. The effects of the initial height and velocity of falling rocks on the final destination of fragments were also explored. Results showed that the selected area along the R518 road consists of joints and bedding planes. These features weaken the rock mass and create wedges that can potentially fall. Simulations with RocFall, on the other hand, indicated that slope height, vegetation density, slope angle, the velocity of the falling rock largely contribute to the extent that the broken rock could reach. From the empirical and numerical findings, an improved rockfall hazard rating chart was proposed. The chart was found to be suitable for the rating of level of rockfall hazard along highways and roads.

Empirical assessment of rockfall and debris flow risk along the Karakoram Highway, Pakistan

The Karakoram Highway links north Pakistan with southwest China. It passes through unique geomorphological, geological and tectonic setting. This study focused 200-km-long section of the highway starting from Besham until Chilas. Landslides are frequent and are mostly triggered by torrential rain during Monsoon and Westerlies, leading to highway blockade. Rockfall and debris flow are prime mode of slope failures. Regional to site-specific approach was implemented to assess risk associated with these two modes. Remote sensing-based techniques were used to identify potential hazardous sites, which were further investigated for risk assessment. Modified Pierson’s rockfall hazard rating system (RHRS) rated potential rockfalls, whereas semi-quantitative technique was employed to assess debris flows. Normalized scores of each site shaped the final map, further classified into four zones: very high, high, intermediate and low risk.

Agent-based modelling of pedestrian responses during flood emergency: mobility behavioural rules and implications for flood risk analysis

An agent-based model (ABM) for simulating the interactions between flooding and pedestrians is augmented to more realistic model responses of evacuees during floodwater flow. In this version of the ABM, the crowd of pedestrians have different body heights and weight, and extra behavioural rules are added to incorporate pedestrians’ states of stability and walking speed in floodwater. The augmented ABM is applied to replicate an evacuation scenario for a synthetic test case of a flooded shopping centre. Simulation runs are performed with increasingly sophisticated configuration modes for the pedestrians’ behavioural rules. Simulation results are analysed based on spatial and temporal indicators informing on the dynamic variations of the flood risk states of the flooded pedestrians, i.e. in terms of a commonly used flood Hazard Rating (HR) metric, variable walking speed, and instability due to toppling and/or sliding. Our analysis reveals significantly prolonged evacuation times and risk exposure levels as the stability and walking speed behavioural rules become more sophisticated. Also, it allows us to identify more conservative HR thresholds of pedestrian instability in floodwater, and a new formula relating walking speed states to the HR for stable pedestrians in floodwater. Accompanying details for software accessibility are provided.

Flood Hazard Mapping in Residential Area Using Hydrodynamic Model HEC-RAS 5.0

The flood hazard rating is one of the essential variables in flood risk analysis. The identification of flood-prone areas urgently requires information about flood hazard zones. This research explains the method to develop flood hazard map by using hydrodynamic modeling in the residential areas. The hydrodynamic model used in this research is HEC-RAS 5.0, which can simulate the one- and two-dimensional flow regimes. The study area is Bukit Sejahtera and Tanjung Rawa residences located in Palembang City with a total area of about 200 ha, where the Lambidaro River was frequently overflowing caused flood inundation in the area. There are five indicators of flood hazard being analyzed, i.e., 1) flood depth, 2) flow velocity, 3) energy head, 4) flow force, which is the result of multiplication between flood depth and the square of flow velocity, and 5) intensity, which is the result of multiplication between flood depth and the flow velocity. The simulation results show that the flood hazard rating in the study area ranges from high to low level. The zones with a high flood hazard rating are dominated by the area around or near to the river, whereas the further zones have a moderate and low level of flood hazard rating. The flood depth indicator has a more significant influence than the flow velocity on the flood hazard level in the study area. This research is expected can contribute to the development of flood map and flood control methods in advance.

Comparison of restaurant inspection report results and its corresponding star ratings on Yelp and Google Reviews

Background: In the current culture of dining-out, there is a greater emphasis on the overall dining experience at restaurants and less of a concern regarding food safety. The public often relies on consumer-generated review websites, such as Yelp and Google Reviews, to decide on where to eat. Each restaurant is often rated out of 5-stars based on factors such as customer service and food quality. The public perceives a restaurant with a 1-star rating poorly, whereas a restaurant with a 5-star rating is seen as excellent. Moreover, the aspect of food safety is determined by Environmental Health Officers (EHOs) who conduct inspections and assign hazard ratings to restaurants, which describe them as a low, moderate, or high-risk food premises. These inspection report results can be disseminated to the public online or through a placard system by the health authority. Currently, in most cities, there is no linkage or display of inspection report results on consumer-generated review websites. Methods: Secondary data was collected from publicly available online sources: Fraser Health’s restaurant inspection reports and two consumer-generated restaurant review websites – Yelp and Google Reviews. The author analyzed 170 randomly selected restaurants from the three most populous cities under Fraser Health’s jurisdiction (British Columbia, Canada): Surrey, Burnaby, and Abbotsford. Only independent restaurants and their routine inspection reports were considered in this study. The following data was obtained from each of the restaurant’s available routine inspection reports: current hazard rating, the average hazard score, and total number of critical violations (CVs). These variables were then compared to the current star rating found on Yelp and Google Reviews. Results: A total of six statistical analyses were conducted: two chi-square tests and four correlational analyses. When comparing the current hazard rating of the restaurant and their current star rating using chi-square tests, p = 0.0855 for Yelp and p = 0.0739 for Google Reviews. Furthermore, in all four correlational analyses, a negative linear relationship was observed, but only three resulted in statistically significant results. When comparing the average hazard score of the restaurant’s routine inspections and their current star rating, p = 0.0591 for Yelp (power = 47.21%) and p = 0.0000 for Google Reviews (power = 99.97%). When comparing the restaurant’s total CVs from routine inspections and their current star rating, p = 0.0001 for Yelp (power = 97.29%) and p = 0.0000 for Google Reviews (power = 100%). Conclusions: The findings of this study demonstrated that prescribed food safety evaluations largely align with the customer perception of restaurants. Although three out of six statistical tests resulted in statistically significant results, overall, it appears that restaurants with a higher star rating have lower number of CVs and lower average hazard scores. Even though this ideal relationship was established, the importance of safe food handling practices and serving safe food to the public should not be overlooked. Consumer-generated restaurant review websites are an excellent avenue to promote food safety within the overall culture of dining-out at restaurants.

A SiPM-Based Trinal Spectral Sensor Developed for Detecting Hazardous Discharges in High-Voltage Switchgear

Electric discharges seriously threat the safety of high-voltage switchgear. In this paper, a spectrum-based optical method is proposed for hazardous discharge monitoring. A SiPM-based trinal spectral sensor is developed with good performances in terms of sensitivity, defect resolution, and risk evaluation. Experiments carried out on two types of artificial discharges (i.e., partial discharge and arc discharge) demonstrate that the light intensities coupled in the three spectral bands account for different proportions and the ratio among the three components generally experiences a regular change with increase in severity of discharge. The typical spectral ratio values are then acquired for hazard rating of discharge and recognition of discharge types with high confidence.