Field Jet Erosion Tests on Benbrook Dam, Texas

This report summarizes the results of eight field Jet Erosion Tests (JETs) performed on Benbrook Dam, TX. The results from these tests will be used by the U.S. Army Corps of Engineers, Fort Worth District, in assessments of the erosion resistance of the Benbrook Dam with regards to possible overtopping by extreme flooding. The JETs were performed at four different locations, i.e., two locations at the lowest crest elevation and two locations at the mid-slope face of the downstream embankment. Variations in estimated critical hydraulic shear stress and erosion rate values may have been caused by differences in soil composition, i.e., when the material changed from silt/sand to clay. The resulting values of the Erodibility Coefficient, Kd, and Critical Stress, τc, are very useful information in assessing the stability of Benbrook Dam during an overtopping event. Because of the observed natural variability of the materials, combining the erosion parameters presented in this report with the drilling logs and local geology will be imperative for assessing erosion-related failure modes of Benbrook Dam.

Pemeliharaan Mesin Hydraulic Shear Menggunakan Pendekatan Reliability Centered Maintenance dan Manajemen Suku Cadang

Production equipment that has a high operating time becomes a vital aspect in supporting the operational system, and its maintenance becomes a critical point that must be planned. This research discusses maintenance policies that focus on machine reliability and parts availability to produce proper maintenance actions, optimal maintenance scheduling and good spare-parts management. The research was conducted on a developing manufacturing company engaged the field of agricultural aids in the city of Bekasi. This study focused on hydraulic shear machines because they have the largest downtime value of 8,344.8 minutes. This problem has a negative impact on the company because it can reduce the yield. Based on these conditions, the study was conducted using the Reliability Centered Maintenance method to update the maintenance patterns and Poisson Process to determine the number of component requirements needed for the next one year. The data obtained in the form of historical damage to the machine, component cost, labor cost and production cost. This research produces an optimal preventive replacement time interval that is every 154 hours for the oil seal component, 242 hours for the shear blade component, and 324 hours for the oil hydraulic hose (1/2") component. While the number of critical components required for the next 1 year is 37 units for oil seal component, 10 units for shear blade components, and 7 units for oil hydraulic hose (1/2") component.

Activation of NOTCH1 by Shear Force Elicits Immediate Cytokine Expression in Human Chondrocytes

Osteoarthritis is caused by overloading of joints and is characterized by inflammation-induced disruption of cartilage structure. Current treatment strategy aims to relieve inflammation and prevent further deterioration of joint function. However, how mechanical force leads to inflammation and deterioration of chondrocyte function still remains incompletely understood. To explore the force-regulated molecular mechanism, an in vitro hydraulic shear force experiment to simulate the condition of force loading was required. The result demonstrated that multiple cytokines and immune regulators, including interleukin 8, interferon β, TRAF1 and TNFAIP3, were significantly increased by shear force within two hours of treatment. Moreover, JAG1 and HES1 were drastically upregulated as well, suggesting that NOTCH1 signaling is activated by shear force. Short-term expression of NOTCH1 intracellular domain activated a similar set of cytokines, indicating that NOTCH1 responds to shear force and activates downstream genes. When incubated under the medium conditioned by NOTCH1-activated chondrocyte, osteoblasts expressed higher levels of interferon β and interferon λ. Together, our results indicated that NOTCH1 functions as a force sensor and promotes expression of cytokines and immune regulators from shear-force bearing chondrocytes.

The Important Role of Dissolved Oxygen Supply Regulated by the Hydraulic Shear Force during the Biosynthesis of Iron Hydroxysulfate Minerals

The severity of environmental pollution from acid mine drainage (AMD) is increasingly garnering attention. In this study, the effects of hydraulic shear forces (achieved by regulating the shaking table’s rotation speed) on Fe2+ bio-oxidation and Fe3+ hydrolytic mineralization in an acidic 9K medium-FeSO4-Acidithiobacillus ferrooxidans system (simulated AMD) are investigated. Results reveal that a higher shaking speed favors a higher oxidation rate of Fe2+, whereas a very low or high shaking speed restricts the removal of Fe3+. Shaking table rotation speeds of 120–180 rpm were preferred for biomineralization treatment in the simulated AMD. As the initial concentration of Fe2+ in the system decreased from 9.67 to 0 g/L in 40 h, the dissolved O2 (DO) in the solution dropped to its lowest concentration after 20 h and then increased to its initial level between 40 and 120 h. However, the corresponding total Fe (TFe) precipitation efficiency increased with the increasing mineralization time after 40 h. The effect of O2 supply time on biomineralization revealed that DO was mainly used in Fe2+ bio-oxidation. After Fe2+ was completely oxidized by A. ferrooxidans, the precipitation efficiency of TFe was independent of the O2 supply.

Structural characteristics and functional properties of fiber-rich by-products of white cabbage modified by high-energy wet media milling

The recovery of residues and by-products of the food industry plays an important role in terms of sustainable management. For this reason, the aim of this study was to analyse the effect of wet milling parameters on dietary fiber concentrates of white cabbage by products or, more precisely, the stalks of cabbage. The input of hydraulic shear-energy during wet milling process leads to a partial modification of the structure of fiber components to obtain compounds with high water- and oil-binding properties. Furthermore, the wet milling parameters affect the functional properties of the fiber concentrates. A mathematical model was developed which relates the functional properties to the parameters of the colloid mill such as slurry concentration, milling time, agitation speed and particle size distribution. A slurry of the grounded material is forced into the milling gap. Grinding is autogenous as a result of collisions between rotating particles. All of the material in the process stream is being grounded finer than the gap setting and grinding can be optimized by adjusting mill operating parameters. The identification of the relations between milling parameters and functional properties is necessary in order to comprehend the processing characteristics of the material in the context of fiber enriched food products manufacturing.