scholarly journals Blast Vibration Control in A Hydropower Station for the Safety of Adjacent Structure

2020 ◽  
Vol 10 (18) ◽  
pp. 6195
Author(s):  
Yuanjun Ma ◽  
Changwu Liu ◽  
Ping Wang ◽  
Jun Zhu ◽  
Xianliang Zhou

The transverse cofferdam in Xiangjiaba hydropower station was a water retaining concrete structure with a length of 126 m, a width of 12 m, and a height of 25.2 m, consisting of masonry, plain concrete structure (PC), and roller compacted concrete (RCC), which had to be demolished by blasting after the dam was built. There were many precise instruments nearby the cofferdam which had strict restrictions on blasting vibration. Therefore, the cofferdam was divided into six blasting regions, including land blasting and underwater blasting. Blasting parameters and blasting network structure were accurately designed and continuously optimized through blast-induced vibration test results. At nine measurement points in different locations, 57 blast vibration data were recorded. Consequently, 1386 holes with an explosive weight of 9641.3 kg were detonated in land blasting. The highest levels of vibration were recorded as 8.74 cm/s in the desilting tunnel on the right of the cofferdam. The explosives up to 11887.7 kg were detonated in an underwater blasting. According to the analysis of the law of vibration attenuation, the blast vibration value was reduced to 7.65 cm/s. The results showed that the research on the attenuation law of blasting vibration can effectively increase the charge weight per delay and control the blast-induced vibration. Consequently, the peak particle velocity (PPV) of underwater blasting could be predicted by analyzing the PPV of land blasting in same structure, which provided the basis for the design of underwater blasting parameters. A reliable method for cofferdam demolition in hydropower station was proposed, which provided a reference for similar projects.

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Yingguo Hu ◽  
Zhaowei Yang ◽  
Erlei Yao ◽  
Meishan Liu ◽  
Yu Rao

This paper focuses on the investigation and control of the blasting-induced ground vibration under cold condition. The mechanical performance and wave propagation characteristics of the frozen rock mass are quite different from that of the conventional condition. Laboratory tests were implemented to investigate the wave impedance of rock mass in the frozen, saturated, normal, and drying states. Results reveal the longitudinal wave velocity could be enlarged by 40 percent in the frozen state. Then long-term monitoring of blasting vibration was implemented based on the blasting excavation of the Fengman hydropower station reconstruction project in the north of China. Results demonstrate the PPV and frequency both attenuate much slower when the rock mass is frozen, and the obvious turning points of PPV could be found between different temperatures, where the change of the PPV relationship happens. At last, numerical simulation of the blasting seismic wave attenuation and the response in the protected structure was implemented. The equivalent freezing simulation method was proposed and verified with the site experiment data. Results demonstrate that the attenuation coefficient decreases obviously as the frozen depth of the rock mass increases. The dynamic degree response in structure is much stronger and the maximum charge weight per delay was limited more strictly under the frozen condition. A most adverse frozen depth was determined when the charge weight per delay gets the minimum value. With the above control approaches, a total of 676 blasting was completed in Fengman hydropower station reconstruction and no case of excessive measurement could be found.


Sensi Journal ◽  
2020 ◽  
Vol 6 (2) ◽  
pp. 236-246
Author(s):  
Ilamsyah Ilamsyah ◽  
Yulianto Yulianto ◽  
Tri Vita Febriani

The right and appropriate system of receiving and transferring goods is needed by the company. In the process of receiving and transferring goods from the central warehouse to the branch warehouse at PDAM Tirta Kerta Raharja, Tangerang Regency, which is currently done manually is still ineffective and inaccurate because the Head of Subdivision uses receipt documents, namely PPBP and mutation of goods, namely MPPW in the form of paper as a submission media. The Head of Subdivision enters the data of receipt and mutation of goods manually and requires a relatively long time because at the time of demand for the transfer of goods the Head of Subdivision must check the inventory of goods in the central warehouse first. Therefore, it is necessary to hold a design of information systems for the receipt and transfer of goods from the central warehouse to a web-based branch warehouse that is already database so that it is more effective, efficient and accurate. With the web-based system of receiving and transferring goods that are already datatabed, it can facilitate the Head of Subdivision in inputing data on the receipt and transfer of goods and control of stock inventory so that the Sub Head of Subdivision can do it periodically to make it more effective, efficient and accurate. The method of data collection is done by observing, interviewing and studying literature from various previous studies, while the system analysis method uses the Waterfall method which aims to solve a problem and uses design methods with visual modeling that is object oriented with UML while programming using PHP and MySQL as a database.


2013 ◽  
Vol 19 (1) ◽  
pp. 28
Author(s):  
Hamda Situmorang ◽  
Manihar Situmorang

Abstract Implementation of demonstration method in the teaching of chemistry is assigned as the right strategy to improve students’ achievement as it is proved that the method can bring an abstract concept to reality in the class. The study is conducted to vocational high school students in SMKN1 Pargetteng getteng Sengkut Pakfak Barat at accademic year 2013. The teaching has been carried out three cycles on the teaching of chemistry topic of colloid system. In the study, the class is divided into two class, experiment class and control class. The demontration method is used to teach students in experimental class while the teaching in control class is conducted with lecture method. Both are evaluated by using multiple choise tests before and after the teaching procedures, and the ability of students to answer the problems are assigned as students’ achievements. The results showed that demonstration method improved students’ achievement in chemistry. The students in experimental class who are taughed with demonstration method (M=19.08±0.74) have higher achievements compare with control class (M=12.91±2.52), and both are significantly different (tcalculation 22.85 > ttable 1.66). The effectivity of demostration method in experimental class (97%) is found higer compare to conventional method in control class (91%).


2020 ◽  
Author(s):  
Isra Revenia

This article is made to know the destinantion and the administrasi functions of the school in order to assist the leader of an organazation in making decisions and doing the right thing, recording of such statements in addition to the information needs also pertains to the function of accountabilitty and control functions. Administrative administration is the activity of recording for everything that happens in the organization to be used as information for leaders. While the definition of administration is all processing activities that start from collecting (receiving), recording, processing, duplicating, minimizing and storing all the information of correspondence needed by the organization. Administration is as an activity to determine everything that happens in the organization, to be used as material for information by the leadership, which includes all activities ranging from manufacturing, managing, structuring to all the preparation of information needed by the organization.


2019 ◽  
Vol 8 (4) ◽  
pp. 9538-9542

In vision of searching for the right Unmanned Aerial System (UAS) for a specific mission, there are multiple factors to be considered by the operator such as mission, endurance, type of payload and range of the telemetry and control. This research is focusing on extending control range of the UAS by using 4G-LTE network to enable beyond-line-of-sight flying for the commercial UAS. Major UAS such Global Hawk, Predator MQ-1 are able to fly thousands of kilometers by the use of satellite communication. However, the satellite communication annual license subscription can be very expensive. With this situation in mind, a new type of flight controller with 4G-LTE communication has been developed and tested. Throughout the research, blended-wing-body (BWB) Baseline B2S is used as the platform for technology demonstrator. Result from this analysis has proven that the proposed system is capable to control a UAS from as far as United Kingdom, with a latency less than 881 ms in average. The new added capability can potentially give the commercial UAS community a new horizon to be able to control their UAS from anywhere around the world with the availability of 4G-LTE connection


2020 ◽  
Vol 18 (3) ◽  
pp. 254-261
Author(s):  
Thomas F. Whayne

Supplementary estrogen plays important roles for female patients as convenient birth control, relief of postmenopausal symptoms, and in the management of other selected problems. However, as is the case for essentially all medications, there are side effects. Short of a major pulmonary embolus, the most severe side effect of estrogen would appear to be sporadic, rare, and severe hypertriglyceridemia associated with acute pancreatitis. The occurrence of this fortunately rare problem usually happens in the presence of some preexisting and usually mild increase in triglycerides (TG). A case of chronic and severe recurrent acute pancreatitis is described in the introduction and the management was complete estrogen avoidance. Started close to menopause and continued for a relatively short period, estrogens may have some cardiovascular (CV) benefit but the general recommendation is not to prescribe them for CV disease prevention. Estrogens may contribute to decreased diabetes mellitus (DM) risk and control. Administration of estrogens by the transdermal route may decrease some problems such as venous thromboembolism (VTE) and elevation of TG. Administration of estrogen in the right situation brings significant benefit to the female patient but skillful, careful, and knowledgeable use is essential.


Author(s):  
Asha Bajpai

Custody refers to the physical care and control of a minor whereas guardianship is a wider term and includes rights and duties with respect to the care and control of minor’s person and property, and includes the right to make decisions relating to the minor. The present legal regime relating to guardianship and custody of children is discussed, including the Guardians and Wards Act, 1890, the Hindu Minority and Guardianship Act, 1956, the personal and matrimonial laws, and relevant provisions in the Family Courts Act and Protection of Women against Domestic Violence Act, 2005. The emerging concepts of shared parenting, joint custody, and the interparental child removal or abduction of child is included. There is review and analysis of some major reported judicial decisions. A comparative survey of international laws and trends has been done. Suggestions for law reform in the best interest of the child have been given.


2021 ◽  
pp. 1-8
Author(s):  
Sevde Aksu ◽  
Pelin Palas Karaca

<b><i>Aim:</i></b> The research was conducted as a randomized controlled pilot study to evaluate the effects of reflexology on lactation in mothers who delivered by cesarean section (CS). <b><i>Methods:</i></b> A single-blind randomized controlled experimental study was conducted with a total of 60 postpartum women in the reflexology application (<i>n</i> = 30) and control groups (<i>n</i> = 30). After the CS, the mothers in the control group were given approximately 3-h routine nursing care after recovering from the effects of anesthesia; the introductory information form was applied, and the Breastfeeding Charting System and Documentation Tool (LATCH) and visual analog scale (VAS) for the signs of the onset of lactation were implemented on the first and second days. Reflexology was applied to the women in the intervention group after an average of 3 h following the mother’s condition had become stable and she had recovered from the effects of anesthesia. Reflexology was applied a total of 20 min – 10 min for the right foot, 10 min for the left foot – twice a day with 8-h intervals on the first and second days after CS. After the last reflexology application, the LATCH and VAS for the signs of the onset of lactation were applied. <b><i>Results:</i></b> Of the women, 70% breastfed their babies within 60 min after delivery; 46.7% of the mothers received breastfeeding training and 81.7% needed support for breastfeeding after the CS. The LATCH breastfeeding scores of the women in the intervention group on both days were significantly higher compared to those of the women in the control group (<i>p</i> &#x3c; 0.001). On the first day after the CS, apart from breast pain, there was no significant difference between the two groups in terms of breast heat and breast tension (<i>p</i> &#x3e; 0.05). On the second day after the CS, apart from breast tension, there was no significant difference between the groups in terms of breast heat and breast pain (<i>p</i> &#x3c; 0.05). In the study, women in the intervention group were found to have higher scores in terms of all three symptoms compared to the control group (<i>p</i> &#x3c; 0.05). <b><i>Conclusions:</i></b> In the study, it was determined that LATCH scores and signs of the onset of breastfeeding increased in the mothers who received reflexology after CS.


2018 ◽  
Vol 38 ◽  
pp. 03020 ◽  
Author(s):  
Zheng Si ◽  
Qian Zhang ◽  
Ling Zhi Huang ◽  
Dan Yang

Most existing temperature field calculation programs have relative defects. In the present paper, based on merits of ANSYS platform, a temperature field calculation program of mass concrete structure is developed and demonstrated. According to actual pouring progress and thermodynamic parameters, a roller-compacted concrete dam is simulated. The difference of maximum temperature between calculated and measured values of measuring points is less than 1.8°C. Furthermore, the relative difference is -5%–5%. This result shows that the calculation program developed based on ANSYS platform can simulate and calculate the temperature field of mass concrete structure.


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