Inadequate Load Research Articles

Correlation between 3D microstructural and 2D histomorphometric properties of subchondral bone with healthy and degenerative cartilage of the knee joint.

Cartilage degeneration of the knee joint is considered to be a largely mechanically driven process. We conducted a microstructural and histomorphometric analysis of subchondral bone samples of intact cartilage and in samples with early and higher- grade arthritic degeneration to compare the different states and correlate the findings with the condition of hyaline cartilage. These findings will enable us to evaluate changes in biomechanical properties of subchondral bone during the evolution of arthritic degeneration, for which bone density alone is an insufficient parameter. From a continuous series of 80 patients undergoing implantation of total knee endoprosthesis 30 osteochondral samples with lesions macroscopically classified as ICRS grade 1b (group A) and 30 samples with ICRS grade 3a or 3b lesions (group B) were taken. The bone samples were assessed by 2D histomorphometry (semiautomatic image analysis system) and 3D microstructural analysis (high-resolution micro-CT system). The cartilage was examined using the semiquantitative real-time PCR gene expression of collagen type I and II and aggrecan. Both histomorphometry and microstructural and biomechanical analysis of subchondral bone in groups A and B consistently revealed progressive changes of both bone and cartilage compared with healthy controls. The severity of cartilage degeneration as assessed by RT PCR was significantly correlated with BV/TV (Bone Volume Fraction), Tb.Th (Trabecular Thickness) showed a slight increase. Tb.N (Trabecular Number), Tb.Sp (Trabecular separation) SMI (Structure Model Index), Conn.D (Connectivity Density) and DA (Degree of Anisotropy) were inversely correlated. We saw sclerotic transformation and phagocytic reticulum cells. Bone volume fraction decreased with an increasing distance from the cartilage with the differences compared with healthy controls becoming greater in more advanced cartilage damage. The density of subchondral bone alone is considered an unreliable parameter for classifying changes evolving over time. The progressive damage of subchondral bone seen in the present study correlates well with cartilage changes. Trabecular orientation is also impaired, which explains the changes in biomechanical parameters and the inadequate load transfer and excessive loading of cartilage. Besides subchondral bone density, which in turn correlates with cartilage thickness, other parameters such as structure model index and grade of anisotropy best reflect mechanical properties such as Young modulus, compressive strength, tensile stress, and failure energy. However, it remains unclear whether the mechanical interaction of the mineralized subchondral tissues with articular cartilage works vice versa. The possibility of a biochemical signalling from the degenerating cartilage via the synovial fluid and bone- cartilage crosstalks via subchondral pores may indeed explain a certain depth-dependency of subchondral bone changes.

Eccentric training as a new approach for rotator cuff tendinopathy: Review and perspectives.

Excessive mechanical loading is considered the major cause of rotator cuff tendinopathy. Although tendon problems are very common, they are not always easy to treat. Eccentric training has been proposed as an effective conservative treatment for the Achilles and patellar tendinopathies, but less evidence exists about its effectiveness for the rotator cuff tendinopathy. The mechanotransduction process associated with an adequate dose of mechanical load might explain the beneficial results of applying the eccentric training to the tendons. An adequate load increases healing and an inadequate (over or underuse) load can deteriorate the tendon structure. Different eccentric training protocols have been used in the few studies conducted for people with rotator cuff tendinopathy. Further, the effects of the eccentric training for rotator cuff tendinopathy were only evaluated on pain, function and strength. Future studies should assess the effects of the eccentric training also on shoulder kinematics and muscle activity. Individualization of the exercise prescription, comprehension and motivation of the patients, and the establishment of specific goals, practice and efforts should all be considered when prescribing the eccentric training. In conclusion, eccentric training should be used aiming improvement of the tendon degeneration, but more evidence is necessary to establish the adequate dose-response and to determine long-term follow-up effects.

Research on Influence Factor of Primary Frequency Regulation Performance for Thermal Power Plant

As a basic auxiliary service, primary frequency regulation (PFR) is provided with significant effect in secure and stable operation for grids. Thermal power plants undertake important task in PFR by virtue of it is main type in grid-connected power plants. However, some problems such as slow response, inadequate load variable quantity, or even reverse regulating effect exist in actual PFR process. In PFR relative control logic, PFR command, load variable quantity command and main steam pressures influence must be taken into consideration. Regulating valves flow characteristics and adjustment of overlap degree can result in imbalance of load regulating under different working point. Frequency data utilized by grid dispatching center and power plant are inconsistent so that PFR evaluation may be affected. On the premise of safe operation in power plant, energy storage can improve units load in a fast time. A series of optimization measurements are put forward on the basis of the above four influence factors. In accordance with respective influence characteristics, these measurements possess a certain reference significance to improve performance index of PFR.

Strategies towards injectable, load-bearing materials for the intervertebral disc: a review and outlook

Currently available treatments for the degenerated intervertebral disc present disadvantages, such as surgical invasiveness and inadequate load distribution results. Load-bearing, injectable materials may be interesting for future therapies, but have not been studied in depth. In this study, the existing literature was screened for studies on injectable materials for the intervertebral disc and a rationale for load-bearing, injectable materials was formulated. Requirements for such a material were discussed, partly based on the experience of materials used for similar applications. Important properties were discussed and found to include biocompatibility, bioactivity, porosity, handling, injectability, working time, setting time, radiopacity, containment and mechanical properties, where several of these properties are linked to one another. In conclusion, there is a need for consensus on the properties of new materials developed for use in minimally invasive procedures in the spine. A substantial amount of attention may need to be given to non-toxic setting reactions.

TCP/IP Based Intelligent Load Management System in Micro-Grids Network Using MATLAB/Simulink

Computerized power management system with fast and optimal communication network overcomes all major dicrepencies of undue or inadequate load relief that were present in old conventional systems. This paper presents the basic perception and methodology of modern and true intelligent load management scheme in micro grids topology by employing TCP/IP protocol for fast and intelligent switching. The network understudy performs load management and power distribution intelligently in a unified network. Generated power is efficiently distributed among local loads through fast communication system of server in the form of source and clients in the form of loads through TCP/IP. The efficient use of information between server and clients enables to astutely control the load management in a power system of micro grids system. The processing time of above stated system comes out to be 10ms faster than others which ensure very less delay as compared to conventional methods. The Micro Grids system operating through TCP/IP control has been implemented in MATLAB/Simulink and results have been verified.

Intelligent Load Shedding Using TCP/IP for Smart Grids

Computerized power management system with fast and optimal communication network overcomes all major discrepancies of undue or inadequate load relief that were present in old conventional systems. This paper presents the basic perception and methodology of modern and true intelligent load shedding scheme in micro grids topology by employing TCP/IP protocol for fast and intelligent switching. The network understudy performs load management and power distribution intelligently in a unified network. Generated power is efficiently distributed among local loads through fast communication system of server in the form of source and clients in the form of loads through TCP/IP. The efficient use of information between server and clients enables to astutely control the load shedding in a power system of micro grids system. The processing time of above stated system comes out to be 10 ms faster than others which ensure very less delay as compared to conventional methods. The Micro Grids system operating through TCP/IP control has been implemented in MATLAB/SIMULINK and results have been verified.

Development of environmental monitoring satellite systems in China

With the increase in global environmental problems, the necessity and urgency of remote sensing technology being applied to environmental monitoring has been widely recognized around the world. China has launched the environment and disaster monitoring and forecasting small satellite constellation HJ-1A/B and the FY3 atmosphere and environmental satellite, but they still cannot fully satisfy requirements for environmental monitoring. This paper summarizes the current status of satellite environmental monitoring in China and the existing problems of inadequate load design and low data utilization efficiency, and discusses the demand for environmental monitoring satellites. Based on the development of foreign satellite systems for environmental monitoring, the future development and key tasks of the environmental monitoring satellite system in China is discussed, as are some related initiatives.

Comparison of OpenMP 3.0 and Other Task Parallel Frameworks on Unbalanced Task Graphs

The UTS benchmark is used to evaluate the expression and performance of task parallelism in OpenMP 3.0 as implemented in a number of recently released compilers and run-time systems. UTS performs parallel search of an irregular and unpredictable search space, as arises, e.g., in combinatorial optimization problems. As such UTS presents a highly unbalanced task graph that challenges scheduling, load balancing, termination detection, and task coarsening strategies. Expressiveness and scalability are compared for OpenMP 3.0, Cilk, Cilk++, Intel Thread Building Blocks, as well as an OpenMP implementation of the benchmark without tasks that performs all scheduling, load balancing, and termination detection explicitly. Current OpenMP 3.0 run time implementations generally exhibit poor behavior on the UTS benchmark. We identify inadequate load balancing strategies and overhead costs as primary factors contributing to poor performance and scalability.

Probing deformation of double-walled carbon nanotube (DWNT)/epoxy composites using FTIR and Raman techniques

Two of the limitations of carbon nanotube (CNT) polymer composites have been the low volume fraction of nanotubes and inadequate load transfer from the polymer to the stiff CNT. Here, we have utilized functionalized mats of double-walled nanotubes (DWNT) to obtain 10 wt.% DWNT in an epoxy matrix, with strength approaching those of quasi-isotropic carbon fiber composites. We used the transmission FTIR technique with in situ loaded specimens to monitor spectral shift per unit applied stress for understanding load transfer behavior at the nanotube–epoxy interface. Tests show that in most cases a tensile stress causes negative FTIR peak shift in the neat epoxy, but this behavior is not always observed for the epoxy matrix in the composite. The FTIR data can be used successfully to estimate the average matrix stress in the composite and thereby the average stress in the nanotubes. In situ Raman studies using the G′ peak are also conducted to obtain complementary information on average tensile stress in the DWNT in the loading direction. The shift response is found to be ∼37 cm −1/GPa.

Oracle Database Replay

This demonstration presents Oracle Database Replay, a novel approach to testing changes to the relational database management system component of an information system (software upgrades, hardware changes etc). Database Replay makes it possible to subject a test system to a real production workload, which helps identify all potential problems before implementing the planned changes on the production system. Any interesting workload period of a production database system can be captured with minimal overhead. The captured workload is used to drive a test system while maintaining the concurrency and load characteristics of the real production workload. The demonstration showcases how important maintaining the concurrency and load characteristics of the real workload is. The current testing solutions do not allow for synchronization based on data dependencies. Without proper synchronization the demonstration workload does not perform the work required and does not exercise the test system appropriately, leading to poor coverage and inadequate load. Thus many issues remain undetected. Database replay with its data based synchronization makes testing realistic and leads to the discovery of potential problems.

Cranes, Structures under Construction, and Temporary Facilities: Are We Doing Enough to Ensure They Are Safe?

As of the date of preparation of this editorial in mid-November, the National Transportation Safety Board NTSB had just released their report on the collapse of the I-35W Bridge in Minneapolis. The report indicated that the most probable cause of the collapse was inadequate load capacity due to a design error that resulted in the undersizing of as many as 24 of the bridge’s gusset plates. The NTSB notes that failure of the U10 plates was in part due to substantial weight increases on the bridge from previous modifications and concentrated construction loads from equipment and materials stored on the bridge, along with traffic on the bridge on the day of the collapse. Similar to many modern day structural failures, the lack of prevention of this collapse can be traced back to procedural flaws, but the fact remains that in this case, as with many other facilities under construction, the structure received its worst historical load case during the construction process. As a result of these findings, we are reminded once again that structures under construction are often more susceptible to collapse than at any other time during their lifespan.

Fuzzy rule-based methodology for residential load behaviour forecasting during power systems restoration

Inadequate load pickup during power system restoration can lead to overload and underfrequency conditions, and even restart the blackout process, due to thermal energy losses. Thus, load behaviour estimation during restoration is desirable to avoid inadequate pickups. This work describes an artificial intelligence method to aid the operator in taking decisions during system restoration by estimating residential load behaviour parameters such as overload in buses and the necessary time to recover steady-state power consumption. This method uses a fuzzy rule-based system to forecast the residential load, obtaining correct estimates with low computational cost. Test results using actual substation data are presented.

EFFECT OF FOLIAR APPLICATION AND FERTIGATION WITH SOME NUTRIENTS ON FRUIT MINERAL CONTENT OF YOUNG "GOLDEN DELICIOUS" APPLE TREES

Investigations of the effect of foliar application of some nutrients and fertigation in comparison with broadcast nitrogen fertilization on mineral fruit composition of young apple 'Golden Delicious', grafted on M9 rootstock was conducted in years 2000-2001. Two orchard experiments were established, one with 2-year and the other with 3-year old trees, grown at a spacing of 3.2 x 0.7 m and trained to super spindle. In year 2000 fruits were hand thinned on 2-year and 3-year trees to 20 and 50 fruits/tree respectively. In 2001 fruits were not thinned because of low fruit set. The results showed no significant beneficial effect of applied treatments on fruit mineral content in both experiments. Ratios of N/Ca, K/Ca and (Mg + K)/Ca in fruits indicated good storage quality as related to normal crop load. On the contrary, when treatments were applied on trees with inadequate crop load, no beneficial effect occurred and fruits showed low storage life. This result illustrates the important balance between vegetative growth and fruit load that occurs during tree establishment.

Variations in wear loss with respect to load and sliding speed under dry sand/rubber-wheel abrasion condition: a modeling study

The dry sand/rubber-wheel abrasion tester is widely used to evaluate the low-stress abrasion resistance of materials for the mining/mineral processing industry particularly for the oil sand mining industry. Since wear loss is usually proportional to the applied load, this test is often performed under a fixed load at a fixed sliding speed to rank materials. However, inaccurate or misleading information might be generated under an inadequate load. It has been observed that D2 tool steel exhibits very different responses to variations in the applied load. Above a certain load level, further increase in the applied load may lead to a decrease in wear loss of D2 steel. In order to understand this phenomenon, computer simulation was performed to investigate wear responses of several engineering materials, including D2 tool steel, stainless steel, Al 6061 and Cu 110, to variations in applied load under the dry sand/rubber-wheel abrasion condition. It was demonstrated that the decrease in wear loss of D2 tool steel with an increase in the applied load was attributed to failure of the abrasive sand. Wear losses of the materials with respect to the sliding speed were also investigated. The prediction from the simulation was compared to experimental observations.

Measured Temperature Characteristics of 152 mm Diameter Pivoted Shoe Journal Bearings with Flooded Lubrication

The steady-state performance characteristics of journal bearings sometimes impose limitations on the operation of high-speed rotating machinery. Such limitations in bearing performance might be the result of one or more of the following: inadequate load carrying capacity, unacceptably high operating temperatures, and inefficient component performance. Lowering operating temperatures helps to boost the bearing's load and/or speed capability, and reducing bearing power loss and/or oil flow requirements improves machine efficiency. In response to the need to improve bearing performance, the authors have conducted extensive testing of the pivoted shoe journal (PSJ) bearing. This paper describes work from the first phase of the study, in which the effects of independent design and operating variables on the metal temperatures of flooded lubricated, PSJ bearings are examined experimentally. These variables include pivot location, load orientation, shaft speed, and bearing load. In conclusion, it is shown that some of the independent variables have a significant influence on bearing performance, after comparing pad temperature profiles, isotherms, and maximum temperatures. The study was performed on a rig that measures steady-state performance under light to moderately heavy unit loads, and comparatively high operating speeds. These conditions are representative of modern-day rotating machinery, particularly new turbine and compressor designs. Presented at the 56th Annual Meeting Orlando, Florida May 20–24, 2001

An architecture for packet-striping protocols

Link-striping algorithms are often used to overcome transmission bottlenecks in computer networks. Traditional striping algorithms suffer from two major disadvantages. They provide inadequate load sharing in the presence of variable-length packets, and may result in non-FIFO delivery of data. We describe a new family of link-striping algorithms that solves both problems. Our scheme applies to any layer that can provide multiple FIFO channels. We deal with variable-sized packets by showing how fair-queuing algorithms can be transformed into load-sharing algorithms. Our transformation results in practical load-sharing protocols, and shows a theoretical connection between two seemingly different problems. The same transformation can be applied to obtain load-sharing protocols for links with different capacities. We deal with the FIFO requirement for two separate cases. If a sequence number can be added to each packet, we show how to speed up packet processing by letting the receiver simulate the sender algorithm. If no header can be added, we show how to provide quasi FIFO delivery. Quasi FIFO is FIFO except during occasional periods of loss of synchronization. We argue that quasi FIFO is adequate for most applications. We also describe a simple technique for speedy restoration of synchronization in the event of loss. We develop an architectural framework for transparently embedding our protocol at the network level by striping IP packets across multiple physical interfaces. The resulting stripe protocol has been implemented within the NetBSD kernel. Our measurements and simulations show that the protocol offers scalable throughput even when striping is done over dissimilar links, and that the protocol synchronized quickly after packet loss. Measurements show performance improvements over conventional round-robin striping schemes and striping schemes that do not resequence packets. Some aspects of our solution have been implemented in Cisco's router operating system (IOS 11.3) in the context of Multilink PPP striping.

A reliable and scalable striping protocol

Link striping algorithms are often used to overcome transmission bottlenecks in computer networks. Traditional striping algorithms suffer from two major disadvantages. They provide inadequate load sharing in the presence of variable length packets, and may result in non- FIFO delivery of data. We describe a new family of link striping algorithms that solves both problems. Our scheme applies to any layer that can provide multiple FIFO channels.We deal with variable sized packets by showing how fair queuing algorithms can be transformed into load sharing algorithms. Our transformation results in practical load sharing protocols, and shows a theoretical connection between two seemingly different problems. The same transformation can be applied to obtain load sharing protocols for links with different capacities. We deal with the FIFO requirement for two separate cases. If a sequence number can be added to each packet, we show how to speed up packet processing by letting the receiver simulate the sender algorithm. If no header can be added, we show how to provide quasi- FIFO delivery. Quasi- FIFO is FIFO except during occasional periods of loss of synchronization. We argue that quasi- FIFO is adequate for most applications. We also describe a simple technique for speedy restoration of synchronization in the event of loss.We develop an architectural framework for transparently embedding our protocol at the network level by striping IP packets across multiple physical interfaces. The resulting strIPe protocol has been implemented within the NetBSD kernel. Our measurements and simulations show that the protocol offers scalable throughput even when striping is done over dissimilar links, and that the protocol synchronizes quickly after packet loss. Measurements show performance improvements over conventional round robin striping schemes and striping schemes that do not resequence packets.