11,285 research outputs found
Observation of Damage Growth in Compressively Loaded Laminates
An experimental program to determine tie phenomenological aspects of composite-panel failure under simultaneous compressive n-plane loading and low-velocity transverse impact [C-75 m/s (0-250 ft/s)] is described. High-speed photography coupled with the shadow-moiré technique is used to record the phenomenon of failure propagation. The information gained from these records, supplemented by plate sectioning and observation for interior damage, has provided information regarding the failure-propagation mechanism.
The results show that the failure process can be divided roughly into two phases. In the first phase the plane is impacted, and the resulting response causes interlaminar separation. In the second phase the local damage spreads to the undamaged portion of the plate through a combination of laminae buckling and further delamination
Economic reforms and inequality in China
This paper investigates the theoretical relationship between economic reforms and inequalities in socialist countries and tests it empirically in the case of China. The paper argues that the issue of whether market oriented reforms are likely to increase or decrease inequality in the former socialist economies is an empirical question which cannot be settled by a priori reasoning. On the one hand, economic inequality may rise with the reintroduction of property income and incentive payments and the reduction of barriers to opportunity for labor and capital to fully realize their highest earning potentials, On the other hand, inequality may decline with the decentralization of property rights, information and the reduction of barriers to the movement of goods and productive factors. The Chinese experience shows that economic inequalities did not increase but decline slightly during the first stage of the reforms. But they rose during the second stage of the reforms. Hence, the Chinese experience is largely congruent with the Szelenyi-Manchin hypothesis
Adolescent Girl Writers: I can be good at it, if I like it
A common perception that girls are good at writing may lead educators to overlook girls. This study examined the writing engagement of three sixth grade girls and how their writing self-perception affected their attitudes in a writing classroom. Using a qualitative case study methodology, three themes emerged: the importance of writing tasks, the influence of reading interests on writing, and time as an external factor. Although these themes are important, the participants of this study alluded to a greater underlying factor; that of writing volition, i.e., desire to write. Volition was the key in engaging the girls as writers
Energy Management for a User Interactive Smart Community: A Stackelberg Game Approach
This paper studies a three party energy management problem in a user
interactive smart community that consists of a large number of residential
units (RUs) with distributed energy resources (DERs), a shared facility
controller (SFC) and the main grid. A Stackelberg game is formulated to benefit
both the SFC and RUs, in terms of incurred cost and achieved utility
respectively, from their energy trading with each other and the grid. The
properties of the game are studied and it is shown that there exists a unique
Stackelberg equilibrium (SE). A novel algorithm is proposed that can be
implemented in a distributed fashion by both RUs and the SFC to reach the SE.
The convergence of the algorithm is also proven, and shown to always reach the
SE. Numerical examples are used to assess the properties and effectiveness of
the proposed scheme.Comment: 6 pages, 4 figure
Feasibility of Using Discriminate Pricing Schemes for Energy Trading in Smart Grid
This paper investigates the feasibility of using a discriminate pricing
scheme to offset the inconvenience that is experienced by an energy user (EU)
in trading its energy with an energy controller in smart grid. The main
objective is to encourage EUs with small distributed energy resources (DERs),
or with high sensitivity to their inconvenience, to take part in the energy
trading via providing incentive to them with relatively higher payment at the
same time as reducing the total cost to the energy controller. The proposed
scheme is modeled through a two-stage Stackelberg game that describes the
energy trading between a shared facility authority (SFA) and EUs in a smart
community. A suitable cost function is proposed for the SFA to leverage the
generation of discriminate pricing according to the inconvenience experienced
by each EU. It is shown that the game has a unique sub-game perfect equilibrium
(SPE), under the certain condition at which the SFA's total cost is minimized,
and that each EU receives its best utility according to its associated
inconvenience for the given price. A backward induction technique is used to
derive a closed form expression for the price function at SPE, and thus the
dependency of price on an EU's different decision parameters is explained for
the studied system. Numerical examples are provided to show the beneficial
properties of the proposed scheme.Comment: 7 pages, 4 figures, 3 tables, conference pape
High-Efficient Parallel CAVLC Encoders on Heterogeneous Multicore Architectures
This article presents two high-efficient parallel realizations of the context-based adaptive variable length coding (CAVLC) based on heterogeneous multicore processors. By optimizing the architecture of the CAVLC encoder, three kinds of dependences are eliminated or weaken, including the context-based data dependence, the memory accessing dependence and the control dependence. The CAVLC pipeline is divided into three stages: two scans, coding, and lag packing, and be implemented on two typical heterogeneous multicore architectures. One is a block-based SIMD parallel CAVLC encoder on multicore stream processor STORM. The other is a component-oriented SIMT parallel encoder on massively parallel architecture GPU. Both of them exploited rich data-level parallelism. Experiments results show that compared with the CPU version, more than 70 times of speedup can be obtained for STORM and over 50 times for GPU. The implementation of encoder on STORM can make a real-time processing for 1080p @30fps and GPU-based version can satisfy the requirements for 720p real-time encoding. The throughput of the presented CAVLC encoders is more than 10 times higher than that of published software encoders on DSP and multicore platforms
Directed polymers in random media under confining force
The scaling behavior of a directed polymer in a two-dimensional (2D) random
potential under confining force is investigated. The energy of a polymer with
configuration is given by H\big(\{y(x)\}\big) = \sum_{x=1}^N \exyx
+ \epsilon \Wa^\alpha, where is an uncorrelated random potential
and \Wa is the width of the polymer. Using an energy argument, it is
conjectured that the radius of gyration and the energy fluctuation
of the polymer of length in the ground state increase as
and respectively with and for . A
novel algorithm of finding the exact ground state, with the effective time
complexity of \cO(N^3), is introduced and used to confirm the conjecture
numerically.Comment: 9 pages, 7 figure
POC Production and Export in the Indian Ocean Sector of the Southern Ocean: A US-China Collaborative Research Program
This proposed work is a study of the biological production and export flux of biogenic matter in response to ventilation of intermediate and deep water masses within the Polar Front zone. It is a collaborative work between the University of Maine and the Chinese Antarctic Research Expedition (CHINARE). The shipboard work is proposed for the Chinese antarctic resupply vessel off Prydz Bay in the Indian Ocean sector. In the austral Spring, this region experiences phytoplankton blooms that are thought to be the result of nutrient transport by the ventilation of intermediate and deep water masses. On an annual basis, it is believed that such blooms are the primary source of particulate organic carbon and biogenic silica flux to the ocean bottom. At this time however no data exists on the amount of particulate organic matter that sinks through the water column, leaving the quantitative relationships between production and export largely undefined in this region. The initial phase of the work consists of setting out a time-series sediment trap mooring at approximately 64 deg S latitude and 73 deg E longitude to take advantage of the historical data set that CHINARE has obtained in this area over the past decade. The biweekly to monthly trap samples will be analyzed for their organic constituents, and in conjunction with primary productivity observations will provide the basic data from which export values can be derived. This work will be carried out in collaboration with the State Oceanic Administration of the People\u27s Republic of China, and the Chinese Antarctic Research Expedition. In addition to providing time on the antarctic resupply vessel, the SOA will sponsor the shipboard primary productivity experiments and the supporting hydrographic measurements. The collaborating American scientists will provide guidance in making these observations to standards developed for the Joint Global Ocean Flux Study, and provide the hardware for the moored sediment trap. There will be a mutual sharing between the U.S. and Chinese investigators of all samples and data sets, and the data analysis will be carried out jointly
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