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Sample records for dynamic lot sizing

  1. Capacitated dynamic lot sizing with capacity acquisition

    DEFF Research Database (Denmark)

    Li, Hongyan; Meissner, Joern

    2011-01-01

    batch, along with inventory carrying costs. The production per period is limited by a capacity restriction. The underlying capacity must be purchased up front for the upcoming season and remains constant over the entire season. We assume that the capacity acquisition cost is smooth and convex......One of the fundamental problems in operations management is determining the optimal investment in capacity. Capacity investment consumes resources and the decision, once made, is often irreversible. Moreover, the available capacity level affects the action space for production and inventory...... planning decisions directly. In this article, we address the joint capacitated lot-sizing and capacity-acquisition problems. The firm can produce goods in each of the finite periods into which the production season is partitioned. Fixed as well as variable production costs are incurred for each production...

  2. Competition under capacitated dynamic lot-sizing with capacity acquisition

    DEFF Research Database (Denmark)

    Li, Hongyan; Meissner, Joern

    2011-01-01

    Lot-sizing and capacity planning are important supply chain decisions, and competition and cooperation affect the performance of these decisions. In this paper, we look into the dynamic lot-sizing and resource competition problem of an industry consisting of multiple firms. A capacity competition...

  3. A Dynamic Lot-Sizing Model with Demand Time Windows

    NARCIS (Netherlands)

    C.Y. Lee (Chung-Yee); S. Çetinkaya; A.P.M. Wagelmans (Albert)

    1999-01-01

    textabstractOne of the basic assumptions of the classical dynamic lot-sizing model is that the aggregate demand of a given period must be satisfied in that period. Under this assumption, if backlogging is not allowed then the demand of a given period cannot be delivered earlier or later than the

  4. A dynamic lot-sizing model with demand time windows

    NARCIS (Netherlands)

    C.Y. Lee (Chung-Yee); S. Cetinkaya; A.P.M. Wagelmans (Albert)

    1999-01-01

    textabstractOne of the basic assumptions of the classical dynamic lot-sizing model is that the aggregate demand of a given period must be satisfied in that period. Under this assumption, if backlogging is not allowed then the demand of a given period cannot be delivered earlier or later than the

  5. A dynamic lot-sizing model with demand time windows

    NARCIS (Netherlands)

    C.Y. Lee (Chung-Yee); S. Cetinkaya; A.P.M. Wagelmans (Albert)

    1999-01-01

    textabstractOne of the basic assumptions of the classical dynamic lot-sizing model is that the aggregate demand of a given period must be satisfied in that period. Under this assumption, if backlogging is not allowed then the demand of a given period cannot be delivered earlier or later than the pe

  6. A Dynamic Lot-Sizing Model with Demand Time Windows

    NARCIS (Netherlands)

    C.Y. Lee (Chung-Yee); S. Çetinkaya; A.P.M. Wagelmans (Albert)

    1999-01-01

    textabstractOne of the basic assumptions of the classical dynamic lot-sizing model is that the aggregate demand of a given period must be satisfied in that period. Under this assumption, if backlogging is not allowed then the demand of a given period cannot be delivered earlier or later than the per

  7. Green Lot-Sizing

    NARCIS (Netherlands)

    M. Retel Helmrich (Mathijn Jan)

    2013-01-01

    textabstractThe lot-sizing problem concerns a manufacturer that needs to solve a production planning problem. The producer must decide at which points in time to set up a production process, and when he/she does, how much to produce. There is a trade-off between inventory costs and costs associated

  8. A Note on "Stability of the Constant Cost Dynamic Lot Size Model" by K. Richter

    NARCIS (Netherlands)

    S. van Hoesel (Stan); A.P.M. Wagelmans (Albert)

    1991-01-01

    textabstractIn a paper by K. Richter the stability regions of the dynamic lot size model with constant cost parameters are analyzed. In particular, an algorithm is suggested to compute the stability region of a so-called generalized solution. In general this region is only a subregion of the stabili

  9. Dynamic programming algorithm for economic lot-sizing problem with bounded inventory and out-sourcing

    Institute of Scientific and Technical Information of China (English)

    LIU Xiao; WANG Cheng-en

    2005-01-01

    This paper addresses a single item dynamic lot-sizing model with inventory capacity and out-sourcing. The goal is to minimize the total costs of production, setup, inventory holding and out-sourcing. Two versions of an out-sourcing model with time-varying costs are considered: stock out case and conservation case. Zero Inventory Order property has been found and some new properties are obtained in an optimal solution. Dynamic programming algorithms are developed to solve the problem in strongly polynomial time respectively. Furthermore, some numerical results demonstrate that the approach proposed is efficient and applicable.

  10. Meta-Heuristics for Dynamic Lot Sizing: a review and comparison of solution approaches

    NARCIS (Netherlands)

    R.F. Jans (Raf); Z. Degraeve (Zeger)

    2004-01-01

    textabstractProofs from complexity theory as well as computational experiments indicate that most lot sizing problems are hard to solve. Because these problems are so difficult, various solution techniques have been proposed to solve them. In the past decade, meta-heuristics such as tabu search, gen

  11. Coordinated Lot-sizing and Dynamic Prizing under a Supplier All-units Quantity Discount

    Directory of Open Access Journals (Sweden)

    Sandra Transchel

    2008-05-01

    Full Text Available We consider an economic order quantity model where the supplier offers an all-units quantity discount and a price sensitive customer demand. We compare a decentralized decision framework where selling price and replenishment policy are determined independently to simultaneous decision making. Constant and dynamic pricing are distinguished. We derive structural properties and develop algorithms that determine the optimal pricing and replenishment policy and show how quantity discounts not only influence the purchasing strategy but also the pricing policy. A sensitivity analysis indicates the impact of the fixed-holding cost ratio, the discount policy, and the customers' price sensitivity on the optimal decisions.

  12. A RELATIVE BENEFIT ALGORITHM FOR BASIC ECONOMIC LOT SIZE PROBLEM

    Institute of Scientific and Technical Information of China (English)

    马辉民; 张子刚; 周少甫; 黄卫来

    2001-01-01

    The paper develops an algorithm that solves economic lot size problem in O(n2) time in the Wagner-Whitin case. The algorithm is based on the standard dynamic programming approach which requires the computation of the maximal relative benefit for some possible subplans of the production plan. In this algorithm the authors have studied the forward property and decomposition properties which can make computation easy. The proposed algorithm appears to perform quite reasonably for practical application.

  13. Record Dynamics in the Parking Lot Model

    DEFF Research Database (Denmark)

    Sibani, Paolo; Boettcher, Stefan

    2016-01-01

    We study the aging dynamics in the parking lot model of granular relaxation with extensive numerical simulations. Our results reveal the log-Poisson statistics in the progression of intermittent events that lead to ever slower increases in the density. Defining clusters as domains of parked cars...

  14. New methodology for dynamic lot dispatching

    Science.gov (United States)

    Tai, Wei-Herng; Wang, Jiann-Kwang; Lin, Kuo-Cheng; Hsu, Yi-Chin

    1994-09-01

    This paper presents a new dynamic dispatching rule to improve delivery. The dynamic dispatching rule named `SLACK and OTD (on time delivery)' is developed for focusing on due date and target cycle time under the environment of IC manufacturing. This idea uses traditional SLACK policy to control long term due date and new OTD policy to reflect the short term stage queue time. Through the fuzzy theory, these two policies are combined as the dispatching controller to define the lot priority in the entire production line. Besides, the system would automatically update the lot priority according to the current line situation. Since the wafer dispatching used to be controlled by critical ratio that indicates the low customer satisfaction. And the overall slack time in the front end of the process is greater compared to that in the rear end of the process which reveals that the machines in the rear end are overloaded by rush orders. When SLACK and OTD are used the due date control has been gradually improved. The wafer with either a long stage queue time or urgent due date will be pushed through the overall production line instead of jammed in the front end. A demand pull system is also developed to satisfy not only due date but also the quantity of monthly demand. The SLACK and OTD rule has been implemented in Taiwan Semiconductor Manufacturing Company for eight months with beneficial results. In order to clearly monitor the SLACK and OTD policy, a method called box chart is generated to simulate the entire production system. From the box chart, we can not only monitor the result of decision policy but display the production situation on the density figure. The production cycle time and delivery situation can also be investigated.

  15. Penentuan Lot Size Pemesanan Bahan Baku Dengan Batasan Kapasitas Gudang

    Directory of Open Access Journals (Sweden)

    Dana Marsetiya Utama

    2016-07-01

    Full Text Available This paper explains the problem of determining the lot size of ordering raw materials with warehouse capacity limitation in order to minimize inventory costs. Generally, the lot size of ordering raw materials determined without considering warehouse capacity. The algorithm that used is Wagner Within (WW which is modified by adding a warehouse capacity as a constraint. The result shows the minimum of total inventory cost is 24,100 and the ordering raw materials at the week 3, 5 and 7.

  16. Lot-sizing algorithms with applications to engineering and economics

    DEFF Research Database (Denmark)

    Vidal, Rene Victor Valqui; Ferreira, Jose S.

    1984-01-01

    The paper presents two new solution procedures for a deterministic lot size problem, a matrix algorithm and a heuristic matrix method. The algorithm is based on the dual of a linear programming model formulation of the lot size problem, and it provides optimal solutions even in the general case...... of time-varying parameters. A comparison of the efficiency of the new solution procedures with well-known methods is developed. New applications of the techniques described within the fields of engineering (optimal design of a pump-pipe system) and economics (a model for import-planning) are referred to...

  17. The Lot Sizing and Scheduling of Sand Casting Operations

    NARCIS (Netherlands)

    Hans, Erwin; Velde, van de Steef

    2010-01-01

    We describe a real world case study that involves the monthly planning and scheduling of the sand-casting department in a metal foundry. The problem can be characterised as a single-level multi-item capacitated lot-sizing model with a variety of additional process-specific constraints. The main obje

  18. The Lot Sizing and Scheduling of Sand Casting Operations

    NARCIS (Netherlands)

    Hans, Elias W.; van de Velde, S.L.; van de Velde, Steef

    2011-01-01

    We describe a real world case study that involves the monthly planning and scheduling of the sand-casting department in a metal foundry. The problem can be characterised as a single-level multi-item capacitated lot-sizing model with a variety of additional process-specific constraints. The main

  19. The economic production lot size model with several production rates

    DEFF Research Database (Denmark)

    Larsen, Christian

    should be chosen in the interval between the demand rate and the production rate, which minimize unit production costs, and should be used in an increasing order. Then, given the production rates, we derive closed form solutions for the optimal runtimes as well as the minimum average cost. Finally we......We study an extension of the economic production lot size model, where more than one production rate can be used during a cycle. The production rates and their corresponding runtimes are decision variables. We decompose the problem into two subproblems. First, we show that all production rates...

  20. Optimal Method of Capacitated Lot-Sizing Planning in Manufacturing Systems

    Institute of Scientific and Technical Information of China (English)

    CHANG Jian-feng; ZHONG Yue-xian; HAN Zan-dong

    2006-01-01

    This paper analyzes the capacitated lot-sizing problem considering an individual machine's production capacity using a two-layer hierarchical method to minimize the sum of the dynamic inventory cost and the overtime penalty cost.The genetic algorithm,the parameter linear programming method,and a heuristic method were used in the developed methOd.The method uses the genetic operator to define the lot-sizing matrix(the first layer),linear prograrnming to determine each machine's schedule(the second layer)according to the lot-sizing matrix,and the heuristic method to verify the feasibility ofthe solutions by adiusting them to meet the constraint requirements.The scheduling of machines in a press shop demonstrates the effectiveness Of the algorithm.The result shows that the algorithm is convergent.

  1. LOT SIZING WITH NON-ZERO SETUP TIMES FOR REWORK

    Institute of Scientific and Technical Information of China (English)

    Rasoul HAJI; Alireza HAJI; Mehdi SAJADIFAR; Saeed ZOLFAGHARI

    2008-01-01

    In this paper we consider a single machine multi-product lot scheduling problem in which defective items are produced in any production run of each product. In each cycle after the normal production of each product the machine is setup for the rework of the defectives of the same product and then the rework process starts. We assume that the setup time for the normal production process as well as the rework process is non-zero. Further we consider the waiting time cost of defectives for rework. This paper has two objectives. The first objective is to obtain the economic batch quantity (EBQ) for a single product. The second objective is to extend the result of the first objective to the multi-product case. Adopting the common cycle scheduling policy we obtain optimal batch sizes for each product such that the total cost of the system per unit time is minimized.

  2. Effects of Breakdown, Backlog and Rework on Replenishment Lot Size

    Directory of Open Access Journals (Sweden)

    Tsu-Ming Yeh

    2012-11-01

    Full Text Available This study studies the effects of machine breakdown, backlog and rework on the replenishment lot size. In real-life manufacturing systems, random defective rate and breakdown of equipment are inevitable. When backlogging is permitted during a production run, a random machine failure may take place either in backlog filling stage or in inventory piling time; this study focuses on the former situation and considers all defective items produced are repairable through a rework process. The objective of this study is to determine the optimal run time that minimizes the long-run average production-inventory costs. The result can be directly applied to the practical production planning and control field to assist practitioner in production management cost reduction.

  3. Lot-sizing for inventory systems with product recovery

    NARCIS (Netherlands)

    R.H. Teunter (Ruud)

    2003-01-01

    textabstractWe study inventory systems with product recovery. Recovered items are as-good-as-new and satisfy the same demands as new items. The demand rate and return fraction are deterministic. The relevant costs are those for ordering recovery lots, for ordering production lots, for holding

  4. Lot-sizing for inventory systems with product recovery

    NARCIS (Netherlands)

    R.H. Teunter (Ruud)

    2003-01-01

    textabstractWe study inventory systems with product recovery. Recovered items are as-good-as-new and satisfy the same demands as new items. The demand rate and return fraction are deterministic. The relevant costs are those for ordering recovery lots, for ordering production lots, for holding recove

  5. Capacitated Dynamic Lot Sizing with Capacity Acquisition

    DEFF Research Database (Denmark)

    Li, Hongyan; Meissner, Joern

    One of the fundamental problems in operations management is to determine the optimal investment in capacity. Capacity investment consumes resources and the decision is often irreversible. Moreover, the available capacity level affects the action space for production and inventory planning decisions...... with inventory carrying costs. The production per period limited by a capacity restriction. The underlying capacity must be purchased up front for the upcoming season and remains constant over the entire season. We assume that the capacity acquisition cost is smooth and convex. For this situation, we develop...

  6. Record dynamics in the parking-lot model

    Science.gov (United States)

    Sibani, Paolo; Boettcher, Stefan

    2016-06-01

    We present an analytical and numerical study of the parking lot model (PLM) of granular relaxation and make a connection to the aging dynamics of dense colloids. As we argue, the PLM is a Kinetically Constrained Model which features astronomically large equilibration times and displays a characteristic aging behavior on all observable time scales. The density of parked cars displays quasi-equilibrium Gaussian fluctuations interspersed by increasingly rare intermittent events, quakes, which can lead to an increase of the density to new record values. Defining active clusters as the shortest domains of parked cars which must be rearranged to allow further insertions, we find that their typical length grows logarithmically with time for low enough temperatures and show how the number of active clusters on average gradually decreases as the system approaches equilibrium. We further characterize the aging process in terms of the statistics of the record-sized fluctuations in the interstitial free volume which lead to quakes and show that quakes are uncorrelated and that they can be approximately described as a Poisson process in logarithmic time.

  7. Some New Properties for Single Item Economic Lot Sizing Model with Inventory Capacity and Stockouts

    Institute of Scientific and Technical Information of China (English)

    Liu Xiao(刘晓); Wang Chengen; Chu Chengbin

    2004-01-01

    This paper deals with a single item inventory capacity economic lot sizing model and sale loss. Unsatisfied demand cannot be backlogged. Although the model with time-dependent bounds is a NP problem, however, when lost sale cost is non-increasing, some new properties are proved in an optimal solution, the problem becomes a stockout case. A dynamic programming algorithm is developed to solve the problem in strongly polynomial with O(T3) time. Some numerical results demonstrate that the approach proposed for stockout problem is efficient and applicable.

  8. A note on "Khouja and Park, optimal lot sizing under continuous decrease, Omega 31 "

    NARCIS (Netherlands)

    R.H. Teunter (Ruud)

    2004-01-01

    textabstractKhouja and Park (Omega 31, 539-545, 2003) analyze the problem of optimizing the lot size under continuous price decrease. They show that the classic EOQ formula can lead to far from optimal solutions and develop an alternative lot size formula using the software package Mathematica. This

  9. Determining Replenishment Lot Size and Shipment Policy for an EPQ Inventory Model with Delivery and Rework

    Directory of Open Access Journals (Sweden)

    Leopoldo Eduardo Cárdenas-Barrón

    2015-01-01

    Full Text Available The determination of production-shipment policies for a vendor-buyer system is dealt within this paper. The main objective is to derive the optimal replenishment lot size and shipment policy for an EPQ inventory model with multiple deliveries and rework. This inventory model contains two decision variables: the replenishment lot size and the number of deliveries. Previous researches solve this inventory model considering both variables to be continuous. However, the number of deliveries must be considered as a discrete variable. In this direction, this paper solves the inventory model considering two cases: Case 1: the replenishment lot size as a continuous variable and the number of shipments as a discrete variable and Case 2: the replenishment lot size and the number of shipments as discrete variables. The final results are two simple and easy-to-apply solution procedures to find the optimal values for the replenishment lot size and the number of deliveries for each case.

  10. Dynamic Lot Sizing Problem of Production and Outsourcing under the Environment of Different Customer Classes%不同顾客环境下生产及外包的动态批量问题

    Institute of Scientific and Technical Information of China (English)

    徐娟; 汪小京; 刘志学

    2014-01-01

    This paper considers a dynamic lot sizing problem of production and outsourcing with different kinds of customer class (e.g.,high valuable and low valuable one) demand in a finite time horizon.The firm can produce in house or outsourcing from outside in order to satisfy different customer demand,and then five service policies are obtained.The optimal outsourcing policy does not necessarily satisfy the Zero-Inventory-Outsourcing rule,and the optimal production policy does not necessarily satisfy the Zero-Inventory-Production rule.However,the set of production periods for high valuable customer must include the set for low valuable one.Based on this lemma,a polynomial algorithm is proposed to search out the optimal production and outsourcing policy,with time complexity O(N3),and a numeric example is given to illustrate the five service policies.At last,when the number of customer classes is larger,two heuristics are designed according to the special production and outsourcing rule.%在有限计划期内,考虑不同顾客(例如:高端和低端顾客)具有不同的缺货等待成本,企业可以采用生产或者外包的方式满足不同顾客需求.在生产和外包两种策略下,企业有五种不同的服务方式,而最优外包期不一定满足“零库存外包”规则,最优生产期不一定满足“零库存生产”规则,但满足高端顾客需求的生产期必须包含满足低端顾客需求的生产期.基于此性质,提出了一个多项式算法得到最优的生产及外包策略,并为每类顾客制定相应的服务策略,计算复杂度为O(N3),并通过算例分析了五种不同的服务策略.最后,拓展到多类顾客的需求环境,根据特殊的生产法则和顾客分类方法,分别设计了一种启发式算法,得到企业的生产及外包策略.

  11. MODEL JOINT ECONOMIC LOT SIZE PADA KASUS PEMASOK-PEMBELI DENGAN PERMINTAAN PROBABILISTIK

    Directory of Open Access Journals (Sweden)

    Wakhid Ahmad Jauhari

    2009-01-01

    Full Text Available In this paper we consider single vendor single buyer integrated inventory model with probabilistic demand and equal delivery lot size. The model contributes to the current literature by relaxing the deterministic demand assumption which has been used for almost all integrated inventory models. The objective is to minimize expected total costs incurred by the vendor and the buyer. We develop effective iterative procedures for finding the optimal solution. Numerical examples are used to illustrate the benefit of integration. A sensitivity analysis is performed to explore the effect of key parameters on delivery lot size, safety factor, production lot size factor and the expected total cost. The results of the numerical examples indicate that our models can achieve a significant amount of savings. Finally, we compare the results of our proposed model with a simulation model. Abstract in Bahasa Indonesia: Pada penelitian ini akan dikembangkan model gabungan pemasok-pembeli dengan permintaan probabilistik dan ukuran pengiriman sama. Pada model setiap lot pemesanan akan dikirim dalam beberapa lot pengiriman dan pemasok akan memproduksi barang dalam ukuran batch produksi yang merupakan kelipatan integer dari lot pengiriman. Dikembangkan pula suatu algoritma untuk menyelesaikan model matematis yang telah dibuat. Selain itu, pengaruh perubahan parameter terhadap perilaku model diteliti dengan analisis sensitivitas terhadap beberapa parameter kunci, seperti ukuran lot, stok pengaman dan total biaya persediaan. Pada penelitian ini juga dibuat model simulasi untuk melihat performansi model matematis pada kondisi nyata. Kata kunci: model gabungan, permintaan probabilistik, lot pengiriman, supply chain

  12. CAPACITATED LOT SIZING AND SCHEDULING PROBLEMS USING HYBRID GA/TS APPROACHES

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The capacitated lot sizing and scheduling problem that involves in determining the production amounts and release dates for several items over a given planning horizon are given to meet dynamic order demand without incurring backloggings. The problem considering overtime capacity is studied. The mathematical model is presented, and a genetic algorithm (GA) approach is developed to solve the problem. The initial solutions are generated after using heuristic method. Capacity balancing procedure is employed to stipulate the feasibility of the solutions. In addition, a technique based on Tabu search (TS) is inserted into the genetic algorithm to deal with the scheduled overtime and help the convergence of algorithm. Computational simulation is conducted to test the efficiency of the proposed hybrid approach, which turns out to improve both the solution quality and execution speed.

  13. Classifying and modeling setups and cleanings in lot sizing and scheduling

    NARCIS (Netherlands)

    Stefansdottir, Bryndis; Grunow, Martin; Akkerman, Renzo

    2017-01-01

    Much attention in the lot sizing and scheduling literature has been focused on reducing the number and size of setups. Cleanings, in contrast, remain a key cost driver in large parts of the process industries such as the food and pharmaceutical sectors. Here, quality and safety considerations lead

  14. Heuristic procedures for a stochastic lot-sizing problem in make-to-order manufacturing

    NARCIS (Netherlands)

    N.P. Dellaert (Nico); M.T. Melo

    1995-01-01

    textabstractWe consider a single item, uncapacitated stochastic lot-sizing problem motivated by a Dutch make-to-order company producing steel pipes. Since no finished goods inventory is kept, a delivery date is fixed upon arrival of each order. The objective is to determine the optimal size of

  15. Effects of Imperfect Quality and Defective Items on Economic Production Lot Size

    Institute of Scientific and Technical Information of China (English)

    Raafat; N; Ibrahim; Paul; Lochert

    2002-01-01

    The classical EPQ model has been used for a long ti me and is widely accepted and implemented. Nevertheless, the analysis for finding an economic lot size has based on a number of unrealistic assumptions. A common unrealistic assumption in using EPQ is that all units produced are of good quali ty. The classical EPQ model shows that the optimal lot size will generate minimum ma nufacturing cost, thus producing minimum setup cost and inventory cost. However, this is only true if all products manufactured...

  16. Solving a combined cutting-stock and lot-sizing problem with a column generating procedure

    DEFF Research Database (Denmark)

    Nonås, Sigrid Lise; Thorstenson, Anders

    2008-01-01

    procedure for this problem that works well on both small and large-sized problems. The procedure includes characteristics from both the column generating procedure in Nonås and Thorstenson, which works well on small-sized problems, and from the sequential heuristic due to Haessler [A heuristic programming......In Nonås and Thorstenson [A combined cutting stock and lot sizing problem. European Journal of Operational Research 120(2) (2000) 327-42] a combined cutting-stock and lot-sizing problem is outlined under static and deterministic conditions. In this paper we suggest a new column generating solution...... solution to a nonlinear cutting stock problem, Management Science 17(12) (1971) 793-802], which works well on large-sized problems. Numerical results are presented that show that the new heuristic performs better than both of the earlier procedures. Comparisons with results obtained by other authors...

  17. Fully Polynomial Approximation Schemes for Single-Item Capacitated Economic Lot-Sizing Problems

    NARCIS (Netherlands)

    C.P.M. van Hoesel; A.P.M. Wagelmans (Albert)

    1997-01-01

    textabstractNP-hard cases of the single-item capacitated lot-sizing problem have been the topic of extensive research and continue to receive considerable attention. However, surprisingly few theoretical results have been published on approximation methods for these problems. To the best of our kno

  18. A mathematical model for the product mixing and lot-sizing problem by considering stochastic demand

    Directory of Open Access Journals (Sweden)

    Dionicio Neira Rodado

    2016-11-01

    Full Text Available The product-mix planning and the lot size decisions are some of the most fundamental research themes for the operations research community. The fact that markets have become more unpredictable has increaed the importance of these issues, rapidly. Currently, directors need to work with product-mix planning and lot size decision models by introducing stochastic variables related to the demands, lead times, etc. However, some real mathematical models involving stochastic variables are not capable of obtaining good solutions within short commuting times. Several heuristics and metaheuristics have been developed to deal with lot decisions problems, in order to obtain high quality results within short commuting times. Nevertheless, the search for an efficient model by considering product mix and deal size with stochastic demand is a prominent research area. This paper aims to develop a general model for the product-mix, and lot size decision within a stochastic demand environment, by introducing the Economic Value Added (EVA as the objective function of a product portfolio selection. The proposed stochastic model has been solved by using a Sample Average Approximation (SAA scheme. The proposed model obtains high quality results within acceptable computing times.

  19. Two parameter-tuned metaheuristic algorithms for the multi-level lot sizing and scheduling problem

    Directory of Open Access Journals (Sweden)

    S.M.T. Fatemi Ghomi

    2012-10-01

    Full Text Available This paper addresses the problem of lot sizing and scheduling problem for n-products and m-machines in flow shop environment where setups among machines are sequence-dependent and can be carried over. Many products must be produced under capacity constraints and allowing backorders. Since lot sizing and scheduling problems are well-known strongly NP-hard, much attention has been given to heuristics and metaheuristics methods. This paper presents two metaheuristics algorithms namely, Genetic Algorithm (GA and Imperialist Competitive Algorithm (ICA. Moreover, Taguchi robust design methodology is employed to calibrate the parameters of the algorithms for different size problems. In addition, the parameter-tuned algorithms are compared against a presented lower bound on randomly generated problems. At the end, comprehensive numerical examples are presented to demonstrate the effectiveness of the proposed algorithms. The results showed that the performance of both GA and ICA are very promising and ICA outperforms GA statistically.

  20. A joint lot-sizing and marketing model with reworks, scraps and imperfect products

    Directory of Open Access Journals (Sweden)

    Mohsen Fathollah Bayati

    2011-04-01

    Full Text Available In this paper, we establish an economic production quantity (EPQ based inventory model by considering various types of non-perfect products .We classify products in four groups of perfect, imperfect, defective but reworkable and non-reworkable defective items. The demand is a power function of price and marketing expenditure and production unit cost is considered to be a function of lot size. The objective of this paper is to determine lot size, marketing expenditure, selling price, set up cost and inventory holding cost, simultaneously. The problem is modeled as a nonlinear posynomial geometric programming and an optimal solution is derived. The implementation of the proposed method is demonstrated using a numerical example and the sensitivity analysis is also performed to study the behavior of the model.

  1. Quality Costs (IRR Impact on Lot Size Considering Work in Process Inventory

    Directory of Open Access Journals (Sweden)

    Misbah Ullaha

    2014-06-01

    Full Text Available Economic order quantity model and production quantity model assume that production processes are error free. However, variations exist in processes which result in imperfection particularly in high machining environments. Processes variations result in nonconformities that increase quality costs in the form of rework, rejects and quality control techniques implementations to ensure quality product delivery. This paper is an attempt towards development of inventory model which incorporate inspection, rework, and rejection (IRR quality costs in optimum lot size calculation focusing work in process inventory. Mathematical model is derived for optimum lot size based on minimum average cost function using analytical approach. This new developed model (GTOQIRR assume an imperfect production environment. Numerical examples are used to visualize the significant effect of quality cost in the proposed model in comparison to the previously developed models. The proposed model is highly recommendable for quality based high machining manufacturing environments considering work in process inventories.

  2. A Mixed Integer Programming Model Formulation for Solving the Lot-Sizing Problem

    CERN Document Server

    Mohammadi, Maryam

    2012-01-01

    This paper addresses a mixed integer programming (MIP) formulation for the multi-item uncapacitated lot-sizing problem that is inspired from the trailer manufacturer. The proposed MIP model has been utilized to find out the optimum order quantity, optimum order time, and the minimum total cost of purchasing, ordering, and holding over the predefined planning horizon. This problem is known as NP-hard problem. The model was presented in an optimal software form using LINGO 13.0.

  3. Exponential Smoothing for Multi-Product Lot-Sizing With Heijunka and Varying Demand

    OpenAIRE

    Grimaud Frédéric; Dolgui Alexandre; Korytkowski Przemyslaw

    2014-01-01

    Here we discuss a multi-product lot-sizing problem for a job shop controlled with a heijunka box. Demand is considered as a random variable with constant variation which must be absorbed somehow by the manufacturing system, either by increased inventory or by flexibility in the production. When a heijunka concept (production leveling) is used, fluctuations in customer orders are not transferred directly to the manufacturing system allowing for a smoother production and better production capac...

  4. Multi-product valid inequalities for the discrete lot-sizing and scheduling problem

    OpenAIRE

    Gicquel, Céline; Minoux, Michel

    2015-01-01

    International audience; We consider a problem arising in the context of industrial production planning, namely the multi-product discrete lot-sizing and scheduling problem with sequence-dependent changeover costs. We aim at developing an exact solution approach based on a Cut & Branch procedure for this combinatorial optimization problem. To achieve this, we propose a new family of multi-product valid inequalities which corresponds to taking into account the conflicts between different produc...

  5. A Study of the Optimum Lot Size and the Newsboy Problem Under Random Demands

    Directory of Open Access Journals (Sweden)

    Sira Allende Alonso

    2004-02-01

    Full Text Available The determination of the optimum lot size is a stochastic problem because of the randomness of the demands. The usual approaches consider that the involved distributions are known. We consider the case in which they are unknown. The optimization problem is probabilistic constraint program. The demands are modeled by an autoregressive process and the needed quantiles are derived. The newsboy problem is revisited using the derived results.

  6. A genetic algorithm-based approach to flexible flow-line scheduling with variable lot sizes.

    Science.gov (United States)

    Lee, I; Sikora, R; Shaw, M J

    1997-01-01

    Genetic algorithms (GAs) have been used widely for such combinatorial optimization problems as the traveling salesman problem (TSP), the quadratic assignment problem (QAP), and job shop scheduling. In all of these problems there is usually a well defined representation which GA's use to solve the problem. We present a novel approach for solving two related problems-lot sizing and sequencing-concurrently using GAs. The essence of our approach lies in the concept of using a unified representation for the information about both the lot sizes and the sequence and enabling GAs to evolve the chromosome by replacing primitive genes with good building blocks. In addition, a simulated annealing procedure is incorporated to further improve the performance. We evaluate the performance of applying the above approach to flexible flow line scheduling with variable lot sizes for an actual manufacturing facility, comparing it to such alternative approaches as pair wise exchange improvement, tabu search, and simulated annealing procedures. The results show the efficacy of this approach for flexible flow line scheduling.

  7. Formulation and Solution ofTwo-Level Capacitated Lot-Sizing Problem

    Directory of Open Access Journals (Sweden)

    Mohsen Basti

    2016-06-01

    Full Text Available The integration of sequencing decisions in lot-sizing and scheduling problems has received an increased attention from the research community due to its inherent applicability to the real-world problems. In this paper, we develop and solve a synchronized and integrated two-level lot-sizing and scheduling problem motivated by a real-world problem arisen in the soft drink production. The soft drink production process has two main stages: flavor preparation (Stage1 and bottling (Stage2. In Stage 1, the liquid flavor (concentrated syrup plus some water is prepared in tanks with various capacities. In Stage 2 in which the liquid flavors are bottled at the filling lines. we considered stock capacityconstraint, and shortages of the combination(shortages backlog and lost sales added to the model. The aim is to determine the lot-sizing and scheduling raw materials and products so that the soft drink flavors and bottle types are assigned to the tanks and bottling lines, respectively, in order to meet a known weekly product demand. Finally, we implement LINGO solver to solve this model.

  8. Exponential Smoothing for Multi-Product Lot-Sizing With Heijunka and Varying Demand

    Directory of Open Access Journals (Sweden)

    Grimaud Frédéric

    2014-06-01

    Full Text Available Here we discuss a multi-product lot-sizing problem for a job shop controlled with a heijunka box. Demand is considered as a random variable with constant variation which must be absorbed somehow by the manufacturing system, either by increased inventory or by flexibility in the production. When a heijunka concept (production leveling is used, fluctuations in customer orders are not transferred directly to the manufacturing system allowing for a smoother production and better production capacity utilization. The problem rather is to determine a tradeoff between the variability in the production line capacity requirement and the inventory level.

  9. A Multi-Product Lot-Sizing Model for a Manufacturing Company

    Directory of Open Access Journals (Sweden)

    Gómez-Herrera Juan Alejandro

    2013-06-01

    Full Text Available This paper presents an Integer Linear Programming model for a multi-product lot-sizing problem. The problem considers demands, inventory policies, backorder costs and the search of an efficient use of resources (machines and workers. The real-world case used to illustrate the model is from a Colombian company, which produces raw material for the bakery industry. The short term planning for the company under study is critical, because there is a multi-product environment whit shared resources by different products and processes. The computational experiments show the effectiveness of the proposed model.R

  10. The economic production lot size model extended to include more than one production rate

    DEFF Research Database (Denmark)

    Larsen, Christian

    2001-01-01

    btween the demand rate and the production rate which minimizes unit production costs, and should be used in an increasing order. Then, given the production rates, we derive closed-form expressions for all optimal runtimes as well as the minimum average cost. This analysis reveals that it is the size......We study an extension of the economic production lot size model, where more than one production rate can be used during a cycle. Moreover, the production rates, as well as their corresponding runtimes are decision variables. First, we show that all production rates should be choosen in the interval...... of the setup cost that determines the need for being able to use several production rates. Finally, we show how to derive a near-optimal solution of the general problem....

  11. The economic production lot size model extended to include more than one production rate

    DEFF Research Database (Denmark)

    Larsen, Christian

    2005-01-01

    production rates should be chosen in the interval between the demand rate and the production rate which minimizes unit production costs, and should be used in an increasing order. Then, given the production rates, we derive closed-form expressions for all optimal runtimes as well as the minimum average cost......We study an extension of the economic production lot size model, where more than one production rate can be used during a cycle. Moreover, the production rates, as well as their corresponding runtimes are decision variables. We decompose the problem into two subproblems. First, we show that all....... This analysis reveals that it is the size of the setup cost that determines the need for being able to use several production rates. We also show how to derive a near-optimal solution of the general problem....

  12. Optimal pricing and lot-sizing decisions under Weibull distribution deterioration and trade credit policy

    Directory of Open Access Journals (Sweden)

    Manna S.K.

    2008-01-01

    Full Text Available In this paper, we consider the problem of simultaneous determination of retail price and lot-size (RPLS under the assumption that the supplier offers a fixed credit period to the retailer. It is assumed that the item in stock deteriorates over time at a rate that follows a two-parameter Weibull distribution and that the price-dependent demand is represented by a constant-price-elasticity function of retail price. The RPLS decision model is developed and solved analytically. Results are illustrated with the help of a base example. Computational results show that the supplier earns more profits when the credit period is greater than the replenishment cycle length. Sensitivity analysis of the solution to changes in the value of input parameters of the base example is also discussed.

  13. Efeito da redução do tamanho de lote e de programas de Melhoria Contínua no Estoque em Processo (WIP e na Utilização: estudo utilizando uma abordagem híbrida System Dynamics - Factory Physics Effect of lot size reduction and Continuous Improvement on Work In Process and Utilization: study using a combined System Dynamics and Factory Physics approach

    Directory of Open Access Journals (Sweden)

    Moacir Godinho Filho

    2009-04-01

    Full Text Available O presente trabalho apresenta um modelo quantitativo que utiliza de forma híbrida as abordagens System Dynamics - SD (FORRESTER, 1962 e Factory Physics (HOPP; SPEARMAN, 2001 objetivando estudar o efeito conjunto de seis programas de Melhoria Contínua - CI (variabilidade na taxa de chegada, variabilidade do processo, qualidade, tempo até a falha, tempo de reparo e tempo de set up e de redução de tamanhos de lote de produção nos níveis médios de Estoque em Processo (WIP e Utilização em um ambiente produtivo com uma única máquina que processa múltiplos produtos. Os resultados dos experimentos realizados utilizando-se o modelo desenvolvido fornecem insights e subsídios que dão suporte a uma série de modernas ferramentas e filosofias de gestão da manufatura, tais como programas de redução da variabilidade do processo como, por exemplo, Seis Sigma; programas de redução de set up, como por exemplo os programas SMED (Single Minute Exchange of Die, Sistema Toyota de Produção/Manufatura Enxuta e Quick Response Manufacturing (QRM. Além disso, o modelo também serve para auxiliar na escolha de diferentes possibilidades de programas de Melhoria Contínua no chão de fábrica.This paper builds a quantitative model, which is a result of a combination of System Dynamics (FORRESTER, 1962 and Factory Physics (HOPP; SPEARMAN, 2001 approaches aiming to examine how six Continuous Improvement (CI programs (arrival variability, process variability, quality (defect rate, time to failure, repair time, and set up time, together with lot size reduction, affect Work In Process (WIP and Utilization in a multi-product, single-machine environment. Results of the paper provides support for: i the importance of implementing set up reduction programs; ii Lean Manufacturing (LM philosophy regarding the implementation of small CI programs in a lot of variables and areas of the shop floor; iii Quick Response Manufacturing (QRM philosophy regarding the

  14. Stochastic Lot-Sizing under Carbon Emission Control for Profit Optimisation in MTO Manufacturing

    Directory of Open Access Journals (Sweden)

    Qiao A.

    2017-01-01

    Full Text Available Aggravating global warming has heightened the imminent need by the world to step up forceful efforts on curbing emission of greenhouse gases. Although manufacturing is a major resource of carbon emission, few research works have studied the impacts of carbon constraints on manufacturing, leading to environmentally unsustainable production strategies and operations. This paper incorporates carbon emission management into production planning for make-to-order (MTO manufacturing. This paper proposes a model that solves lot-sizing problems to maximise profits under carbon emission caps. The model adopts stochastic interarrival times for customer orders to enhance the practicality of the results for real-world manufacturing. Numerical experiments show that reducing carbon emission undercuts short-term profits of a company. However, it is conducive to the company’s market image as being socially responsible which would attract more customers who concern about environmental protection. Hence, reducing carbon emission in manufacturing is beneficial to long-term profitability and sustainability. The results provide managerial insights into manufacture operations for balancing profitability and carbon control.

  15. Benders-based approach for an integrated Lot-Sizing and Scheduling problem

    Directory of Open Access Journals (Sweden)

    ouerfelli hala

    2012-07-01

    Full Text Available The main concern of the current paper is to present mathematical model and a decision method for production planning issues of a manufacturing organization. We aim at integrating the medium term and the short term as two levels of decision. These consist in periodical planning with determining the intended produced quantity and scheduling the functioning of machines. It is worth noting that in the literature there exist only few works on the issue of integration because of the shortage of numerical results. Thus, the integrated model presented here allows us to take into consideration the scheduling constraints in the Lot-sizing model. A recent algorithm, based on a heuristic approach to find a production planning with a feasible schedule for each period, has recently been published in which the two levels of decision were applied. In this paper, some of these ideas are developed in order to get an optimal solution. For this, an exact algorithm of Benders’ decomposition method is adopted to the integration problem. This has been proved efficient with reliance primarily on modeling view and the link between the two levels of decision and secondly on the numerical view.

  16. Determination of optimal lot size and production rate for multi-production channels with limited capacity

    Science.gov (United States)

    Huang, Yeu-Shiang; Wang, Ruei-Pei; Ho, Jyh-Wen

    2015-07-01

    Due to the constantly changing business environment, producers often have to deal with customers by adopting different procurement policies. That is, manufacturers confront not only predictable and regular orders, but also unpredictable and irregular orders. In this study, from the perspective of upstream manufacturers, both regular and irregular orders are considered in coping with the situation in which an uncertain demand is faced by the manufacturer, and a capacity confirming mechanism is used to examine such demand. If the demand is less than or equal to the capacity of the ordinary production channel, the general supply channel is utilised to fully account for the manufacturing process, but if the demand is greater than the capacity of the ordinary production channel, the contingency production channel would be activated along with the ordinary channel to satisfy the upcoming high demand. Besides, the reproductive property of the probability distribution is employed to represent the order quantity of the two types of demand. Accordingly, the optimal production rates and lot sizes for both channels are derived to provide managers with insights for further production planning.

  17. A multi-phase algorithm for a joint lot-sizing and pricing problem with stochastic demands

    DEFF Research Database (Denmark)

    Jenny Li, Hongyan; Thorstenson, Anders

    2014-01-01

    item over a finite multi-period planning horizon. Thece-dependent demands. The stochastic demand is captured by the scenario analysis approach, and this leads to a multiple-stage stochastic programming problem. Given the complexity of the stochastic programming problem, it is hard to determine optimal...... prices and lot sizes simultaneously. Therefore, we decompose the joint lot-sizing and pricing problem with stochastic demands and capacity constraints into a multi-phase decision process. In each phase, we solve the associated sub-problem to optimality. The decomposed decision process corresponds...... that the multi-phase heuristic algorithm solves the example problems effectively....

  18. Retailer’s lot-sizing policy under two warehouses and two levels of delay permitted using algebraic method

    Directory of Open Access Journals (Sweden)

    Huang Yung-Fu

    2007-01-01

    Full Text Available The main purpose of this paper is to modify Huang’s model [13] by considering two warehouses. In addition, we try to use algebraic method to determine the optimal lot-sizing policy for the retailer under two warehouses and two levels of delay permitted. This paper provides this algebraic approach that could be used easily to introduce the basic inventory theories to younger students who lack the knowledge of calculus. Furthermore, we develop three easy-to-use theorems to efficiently determine the optimal cycle time and optimal lot sizing for the retailer. As a result, we deduce some previously published results of other researchers as special cases. Finally, a numerical example is given to illustrate these theorems obtained in this paper. In addition, we obtain a lot of managerial insights from this numerical example.

  19. A holding cost bound for the economic lot-sizing problem with time-invariant cost parameters

    NARCIS (Netherlands)

    W.J. van den Heuvel; A.P.M. Wagelmans (Albert)

    2008-01-01

    textabstractIn this paper we derive a new structural property for an optimal solution of the economic lot-sizing problem with time-invariant cost parameters. We show that the total holding cost in an order interval of an optimal solution is bounded from above by a quantity proportional to the setup

  20. 蚁群算法在单级多时段多资源约束的生产批量问题中的应用研究%Application of an Improved Ant Colony Optimization Algorithm for Solving Single-level Multi-period Capacitated Dynamic Lot-sizing Problem

    Institute of Scientific and Technical Information of China (English)

    李英俊; 陈志祥

    2012-01-01

    One algorithm structure of an ant colony optimization(ACO) for solving multi -periods continuous and mixed integer programming problem was first designed herein and then its application in the single-level multi -period capacitated dynamic lot-sizing problem(CLSP) was introduced. The algorithm was based on the model characteristics of CLSP and improvements of traditional ant colony algorithm. Compared with other algorithms of other literature, the algorithm presented herein performs better than that the traditional genetic algorithm and the hybrid of simulated annealing penalty and genetic algorithm do;it has higher ability of obtaining optimal value. The application results show the method is feasible and effective for solving this kind problem.%设计了一个用于求解具有多时段连续与整数混合规划问题的算法结构,并以单级多时段多资源约束的生产批量问题(CLSP)的模型为背景进行了应用研究,根据此类问题的特点设计了新颖的蚁群算法,阐明了算法的具体实现过程.通过对其他文献中的例子进行计算和结果比较,表明提出的改进蚁群算法在寻优方面比退火惩罚混合遗传算法和传统的遗传算法要好,验证了所提算法对解决此类问题的可行性和适用性.

  1. A new Dantzig-Wolfe reformulation and branch-and-price algorithm for the capacitated lot-sizing problem with setup times

    NARCIS (Netherlands)

    Z. Degraeve (Zeger); R.F. Jans (Raf)

    2007-01-01

    textabstractAlthough the textbook Dantzig-Wolfe decomposition reformulation for the capacitated lot-sizing problem, as already proposed by Manne [Manne, A. S. 1958. Programming of economic lot sizes. Management Sci. 4(2) 115-135], provides a strong lower bound, it also has an important structural

  2. A new Dantzig-Wolfe reformulation and branch-and-price algorithm for the capacitated lot-sizing problem with setup times

    NARCIS (Netherlands)

    Z. Degraeve (Zeger); R.F. Jans (Raf)

    2007-01-01

    textabstractAlthough the textbook Dantzig-Wolfe decomposition reformulation for the capacitated lot-sizing problem, as already proposed by Manne [Manne, A. S. 1958. Programming of economic lot sizes. Management Sci. 4(2) 115-135], provides a strong lower bound, it also has an important structural de

  3. A new Dantzig-Wolfe reformulation and branch-and-price algorithm for the capacitated lot-sizing problem with setup times

    NARCIS (Netherlands)

    Z. Degraeve (Zeger); R.F. Jans (Raf)

    2007-01-01

    textabstractAlthough the textbook Dantzig-Wolfe decomposition reformulation for the capacitated lot-sizing problem, as already proposed by Manne [Manne, A. S. 1958. Programming of economic lot sizes. Management Sci. 4(2) 115-135], provides a strong lower bound, it also has an important structural de

  4. Detonation shock dynamics calibration for pBX 9502 with temperature, density, and material lot variations

    Energy Technology Data Exchange (ETDEWEB)

    Hill, Larry G [Los Alamos National Laboratory; Aslam, Tariq D [Los Alamos National Laboratory

    2010-01-01

    We present a methodology for scaling the detonation shock dynamics D{sub n}[{kappa}] calibration function to accommodate variations in the HE starting material. We apply our model to the insensitive TATB-based explosive PBX 9502, for which we have enough front curvature rate stick data to characterize three material attributes: initial temperature T{sub 0}, nominal density {rho}{sub 0}, and manufacturing lot (representing different microstructures). A useful feature of the model is that it returns an absolute estimate for the reaction zone thickness, {delta}. Lacking demonstrated material metrics(s), we express microstructural variation indirectly, in terms of its effect on {delta}. This results in a D{sub n}[{kappa}] function that depends on T{sub 0}, {rho}{sub 0}, and {delta}. After examining the separate effects of each parameter on D{sub n}[{kappa}], we compute an arc geometry as a validation problem. We compare the calculation to a PBX 9502 arc experiment that was pressed from one of the calibrated HE lots. The agreement between the model and experiment is excellent. We compute worst, nominal, and best-performing material parameter combinations to show how much difference accrues throughout the arc.

  5. A new approach for solving capacitated lot sizing and scheduling problem with sequence and period-dependent setup costs

    Directory of Open Access Journals (Sweden)

    Imen Chaieb Memmi

    2013-09-01

    Full Text Available Purpose: We aim to examine the capacitated multi-item lot sizing problem which is a typical example of a large bucket model, where many different items can be produced on the same machine in one time period. We propose a new approach to determine the production sequence and lot sizes that minimize the sum of start up and setup costs, inventory and production costs over all periods.Design/methodology/approach: The approach is composed of three steps. First, we compute a lower bound on total cost. Then we propose a three sub-steps iteration procedure. We solve optimally the lot sizing problem without considering products sequencing and their cost. Then, we determine products quantities to produce each period while minimizing the storage and variable production costs. Given the products to manufacture each period, we determine its correspondent optimal products sequencing, by using a Branch and Bound algorithm. Given the sequences of products within each period, we evaluate the total start up and setup cost. We compare then the total cost obtained to the lower bound of the total cost. If this value riches a prefixed value, we stop. Otherwise, we modify the results of lot sizing problem.Findings and Originality/value: We show using an illustrative example, that the difference between the total cost and its lower bound is only 10%. This gap depends on the significance of the inventory and production costs and the machine’s capacity. Comparing the approach we develop with a traditional one, we show that we manage to reduce the total cost by 30%.Research limitations/implications: Our model fits better to real-world situations where production systems run continuously. This model is applied for limited number of part types and periods.Practical implications: Our approach determines the products to manufacture each time period, their economic amounts, and their scheduling within each period. This outcome should help decision makers bearing expensive

  6. Analysis of the influence of the lot sizing on the efficiency of material flow in the supply chain

    Directory of Open Access Journals (Sweden)

    Roman Domański

    2017-09-01

    Full Text Available Background: Due to the rapidly changing needs of suppliers and customers classic methods of lot sizing do not work. Meanwhile, the target for logistics remains all the time the same: to realize the flow of materials in the supply chain as efficiently as possible. Today, efficiency is understood as the sum of two components: the effectiveness - understood as the degree of achieving the objective (i.e.  customer service level indicator and efficiency - understood as a way to achieve the objective, (i.e. total cost of the material flow in the supply chain. Simulation studies developed by authors was focused on the identification and analysis of both global and local conditions, the efficiency of material flow in the supply chain. Methods: Simulation of material flow in the supply chain was carried out using the spreadsheet. In the analysis of results, statistical software Minitab 17 was used. Using correlation analysis examined the relationship between the cost of the material flow and the realized customer service level. On the base of methods ANOVA and Tukey Pairwise Comparisons determined whether there is a statistically significant relationship between the lot size in flow between companies in supply chain and the cost of that flow through the whole chain. Results: The objective of the article is to identify the relations between the material flow lot size between particular companies in the supply chain and the flow costs and to identify the link in the supply chain that has the greatest impact on the customer service level and the flow total costs in the supply chain. Distribution of demand (category of goods has an impact on the cost of the material flow in the supply chain. In both analysed distributions of demand (normal and exponential was observed relationships proportional (what is beneficial for the whole supply chain is also beneficial to the each company in supply chain as well as the relationship inversely proportional (that which

  7. Optimal production lot sizing model in a supply chain with periodically fixed demand considering learning effect

    Institute of Scientific and Technical Information of China (English)

    熊中楷; SHEN; Tiesong

    2002-01-01

    This paper presents an optimal production model for manufacturer in a supply chain with a fixed demand at a fixed interval with respect to the learning effect on production capacity.An algorithm is employed to find theoptimal dela time for production and production time sequentially.It is found that the optimal delay time for production and the production time are not static,but dynamic and variant with time.It is important for a manufacturer to schedule the production so as to prevent facilities and workers from idling.

  8. Effect of Unequal Lot Sizes, Variable Setup Cost, and Carbon Emission Cost in a Supply Chain Model

    Directory of Open Access Journals (Sweden)

    Biswajit Sarkar

    2015-01-01

    Full Text Available Due to heavy transportation for single-setup multidelivery (SSMD policy in supply chain management, this model assumes carbon emission cost to obtain a realistic behavior for world environment. The transportation for buyer and vendor is considered along with setup cost reduction by using an investment function. It is assumed that the shipment lot size of each delivery is unequal and variable. The buyer inspects all received products and returns defective items to vendor for reworking process. Because of this policy, end customers will only obtain nondefective items. The analytical optimization is considered to obtain the optimum solution of the model. The main goal of this paper is to reduce the total cost by considering carbon emission during the transportation. A numerical example, graphical representation, and sensitivity analysis are given to illustrate the model.

  9. Greenhouse gas penalty and incentive policies for a joint economic lot size model with industrial and transport emissions

    Directory of Open Access Journals (Sweden)

    Ivan Darma Wangsa

    2017-03-01

    Full Text Available This paper presents a joint economic lot size model for a single manufacturer-a single buyer. The purposed model involves the greenhouse gas emission from industrial and transport sectors. We divide the emission into two types, namely the direct and indirect emissions. In this paper, we consider the Government’s penalty and incentive policies to reduce the emission. We assume that the demand of the buyer is normally distributed and partially backordered. The objective is to minimize joint total cost incurred by a single manufacturer-a single buyer and involves the transportation costs of the freight forwarder. Transportation costs are the function of shipping weight, distance, fuel price and consumption with two transportation modes: truckload and less-than-truckload shipments. Finally, an algorithm procedure is proposed to determine the optimal order quantity, safety factor, actual shipping weight, total emission and frequency of deliveries. Numerical examples and analyses are given to illustrate the results.

  10. Parallel ant colony algorithm and its application in the capacitated lot sizing problem for an agile supply chain

    Institute of Scientific and Technical Information of China (English)

    李树刚; 吴智铭; 庞小红

    2004-01-01

    In order to study the capacitated lot sizing problem for a supply chain of corporate multi-location fac-tories to minimize the total costs of production, inventory and transportation under the system capacity restriction and product due date, while at the same time considering the menu distributed balance, the mathematical pro-gramming models are decomposed and reduced from the 3 levels into 2 levels according to the idea of just-in-time production. In order to overcome the premature convergence of ACA (ant colony algorithms) , the idea of mute operation is adopted in genetic algorithms and a PACA (parallel ant colony algorithms) is proposed forsupply chain optimization. Finally, an illustrative example is given, and a comparison is made with standard BAR ( Branch and Bound) and PACA approach. The result shows that the latter is more effective and promis-ing.

  11. Using genetic algorithm for lot sizing and scheduling problem with arbitrary job volumes and distinct job due date considerations

    Science.gov (United States)

    Wang, Deyun; Grunder, Olivier; EL Moudni, Abdellah

    2014-08-01

    This paper considers an integrated lot sizing and scheduling problem for a production-distribution environment with arbitrary job volumes and distinct due dates considerations. In the problem, jobs are firstly batch processed on a batching machine at production stage and then delivered to a pre-specified customer at the subsequent delivery stage by a capacitated vehicle. Each job is associated with a distinct due date and a distinct volume, and has to be delivered to the customer before its due date, i.e. delay is not allowed. The processing time of a batch is a constant independent of the jobs it contains. In production, a constant set-up time as well as a constant set-up cost is required before the first job of this batch is processed. In delivery, a constant delivery time as well as a constant delivery cost is needed for each round-trip delivery between the factory and the customer. Moreover, it is supposed that a job that arrives at the customer before its due date will incur a customer inventory cost. The objective is to find a coordinated lot sizing and scheduling scheme such that the total cost is minimised while guaranteeing a certain customer service level. A mixed integer formulation is proposed for this problem, and then a genetic algorithm is developed to solve it. To evaluate the performance of the proposed genetic algorithm, a lower bound on the objective value is established. Computational experiments show that the proposed genetic algorithm performs well on randomly generated problem instances.

  12. AN OPTIMIZATION-BASED HEURISTIC FOR A CAPACITATED LOT-SIZING MODEL IN AN AUTOMATED TELLER MACHINES NETWORK

    Directory of Open Access Journals (Sweden)

    Supatchaya Chotayakul

    2013-01-01

    Full Text Available This research studies a cash inventory problem in an ATM Network to satisfy customer’s cash needs over multiple periods with deterministic demand. The objective is to determine the amount of money to place in Automated Teller Machines (ATMs and cash centers for each period over a given time horizon. The algorithms are designed as a multi-echelon inventory problem with single-item capacitated lot-sizing to minimize total costs of running ATM network. In this study, we formulate the problem as a Mixed Integer Program (MIP and develop an approach based on reformulating the model as a shortest path formulation for finding a near-optimal solution of the problem. This reformulation is the same as the traditional model, except the capacity constraints, inventory balance constraints and setup constraints related to the management of the money in ATMs are relaxed. This new formulation gives more variables and constraints, but has a much tighter linear relaxation than the original and is faster to solve for short term planning. Computational results show its effectiveness, especially for large sized problems.

  13. The Synchronized and Integrated Two-Level Lot Sizing and Scheduling Problem: Evaluating the Generalized Mathematical Model

    Directory of Open Access Journals (Sweden)

    Claudio F. M. Toledo

    2015-01-01

    Full Text Available This paper presents the synchronized and integrated two-level lot sizing and scheduling problem (SITLSP. This problem is found in beverage production, foundry, glass industry, and electrofused grains, where the production processes have usually two interdependent levels with sequence-dependent setups in each level. For instance, in the first level of soft drink production, raw materials are stored in tanks flowing to production lines in the second level. The amount and the time the raw materials and products have to be stored and produced should be determined. A synchronization problem occurs because the production in lines and the storage in tanks have to be compatible with each other throughout the time horizon. The SITLSP and its mathematical model are described in detail by this paper. The lack of similar models in the literature has led us to also propose a set of instances for the SITLSP, based on data provided by a soft drink company. Thus, a set of benchmark results for these problem instances are established using an exact method available in an optimization package. Moreover, results for two relaxations proved that the modeling methodology could be useful in real-world applications.

  14. Optimal production lot size and reorder point of a two-stage supply chain while random demand is sensitive with sales teams' initiatives

    Science.gov (United States)

    Sankar Sana, Shib

    2016-01-01

    The paper develops a production-inventory model of a two-stage supply chain consisting of one manufacturer and one retailer to study production lot size/order quantity, reorder point sales teams' initiatives where demand of the end customers is dependent on random variable and sales teams' initiatives simultaneously. The manufacturer produces the order quantity of the retailer at one lot in which the procurement cost per unit quantity follows a realistic convex function of production lot size. In the chain, the cost of sales team's initiatives/promotion efforts and wholesale price of the manufacturer are negotiated at the points such that their optimum profits reached nearer to their target profits. This study suggests to the management of firms to determine the optimal order quantity/production quantity, reorder point and sales teams' initiatives/promotional effort in order to achieve their maximum profits. An analytical method is applied to determine the optimal values of the decision variables. Finally, numerical examples with its graphical presentation and sensitivity analysis of the key parameters are presented to illustrate more insights of the model.

  15. Reexamination of "Combining an alternative multi-delivery policy into economic production lot size problem with partial rework" Using an Alternative Approach

    Directory of Open Access Journals (Sweden)

    Y-S. P. Chiu

    2013-06-01

    Full Text Available A conventional approach for solving an economic production quantity (EPQ model with multi-delivery policy andquality assurance is to use mathematical modeling for deriving the system cost function and to employ differentialcalculus for proving convexity of the cost function before determining the optimal operating policy. This paperpresents a simplified solution procedure to reexamine a specific EPQ model [1] and demonstrates that both, theoptimal manufacturing lot size and the long-run cost function can be derived without derivatives. The proposedapproach may enable practitioners—with little knowledge of calculus—to understand such a real life vendor-buyerintegrated system with ease.

  16. Optimal pricing and lot-sizing for perishable inventory with price and time dependent ramp-type demand

    Science.gov (United States)

    Panda, S.; Saha, S.; Basu, M.

    2013-01-01

    Product perishability is an important aspect of inventory control. To minimise the effect of deterioration, retailers in supermarkets, departmental store managers, etc. always want higher inventory depletion rate. In this article, we propose a dynamic pre- and post-deterioration cumulative discount policy to enhance inventory depletion rate resulting low volume of deterioration cost, holding cost and hence higher profit. It is assumed that demand is a price and time dependent ramp-type function and the product starts to deteriorate after certain amount of time. Unlike the conventional inventory models with pricing strategies, which are restricted to a fixed number of price changes and to a fixed cycle length, we allow the number of price changes before as well as after the start of deterioration and the replenishment cycle length to be the decision variables. Before start of deterioration, discounts on unit selling price are provided cumulatively in successive pricing cycles. After the start of deterioration, discounts on reduced unit selling price are also provided in a cumulative way. A mathematical model is developed and the existence of the optimal solution is verified. A numerical example is presented, which indicates that under the cumulative effect of price discounting, dynamic pricing policy outperforms static pricing strategy. Sensitivity analysis of the model is carried out.

  17. Size Matters a Lot: Drought-Affected Italian Oaks Are Smaller and Show Lower Growth Prior to Tree Death

    Science.gov (United States)

    Colangelo, Michele; Camarero, Jesús J.; Borghetti, Marco; Gazol, Antonio; Gentilesca, Tiziana; Ripullone, Francesco

    2017-01-01

    Hydraulic theory suggests that tall trees are at greater risk of drought-triggered death caused by hydraulic failure than small trees. In addition the drop in growth, observed in several tree species prior to death, is often interpreted as an early-warning signal of impending death. We test these hypotheses by comparing size, growth, and wood-anatomy patterns of living and now-dead trees in two Italian oak forests showing recent mortality episodes. The mortality probability of trees is modeled as a function of recent growth and tree size. Drift-diffusion-jump (DDJ) metrics are used to detect early-warning signals. We found that the tallest trees of the anisohydric Italian oak better survived drought contrary to what was predicted by the theory. Dead trees were characterized by a lower height and radial-growth trend than living trees in both study sites. The growth reduction of now-dead trees started about 10 years prior to their death and after two severe spring droughts during the early 2000s. This critical transition in growth was detected by DDJ metrics in the most affected site. Dead trees were also more sensitive to drought stress in this site indicating different susceptibility to water shortage between trees. Dead trees did not form earlywood vessels with smaller lumen diameter than surviving trees but tended to form wider latewood vessels with a higher percentage of vessel area. Since living and dead trees showed similar competition we did not expect that moderate thinning and a reduction in tree density would increase the short-term survival probability of trees. PMID:28270816

  18. Research on product size and grinding dynamics of vibration mills

    Institute of Scientific and Technical Information of China (English)

    YIN Zhong-jun; HAN Tian; CHEN Bing; ZHANG Wen-zhong

    2007-01-01

    In order to improve vibration mills grinding effect and increase productive efficiency, prime factors of vibration mills were gained much attention. The purpose of this study is to reveal product size distribution and grinding dynamics of vibration mills by orthogonal experi-ments. The metallurgical refractory materials were used as research object. In order to explore the relationships between grinding effect and primary factors, lots of milling experiments were carried out. Based on the results, the conclusions can be summarized: as time runs, the size distri-bution shows exponential trend, and range becomes more and more narrow. Also the quantitative analysis result between grinding effect and primary factors was obtained by non-linear regres-sion: high frequency, high amplitude and low fill ratio can increase grinding speed.

  19. Genome Size Dynamics and Evolution in Monocots

    Directory of Open Access Journals (Sweden)

    Ilia J. Leitch

    2010-01-01

    Full Text Available Monocot genomic diversity includes striking variation at many levels. This paper compares various genomic characters (e.g., range of chromosome numbers and ploidy levels, occurrence of endopolyploidy, GC content, chromosome packaging and organization, genome size between monocots and the remaining angiosperms to discern just how distinctive monocot genomes are. One of the most notable features of monocots is their wide range and diversity of genome sizes, including the species with the largest genome so far reported in plants. This genomic character is analysed in greater detail, within a phylogenetic context. By surveying available genome size and chromosome data it is apparent that different monocot orders follow distinctive modes of genome size and chromosome evolution. Further insights into genome size-evolution and dynamics were obtained using statistical modelling approaches to reconstruct the ancestral genome size at key nodes across the monocot phylogenetic tree. Such approaches reveal that while the ancestral genome size of all monocots was small (1C=1.9 pg, there have been several major increases and decreases during monocot evolution. In addition, notable increases in the rates of genome size-evolution were found in Asparagales and Poales compared with other monocot lineages.

  20. 基于遗传算法的柔性作业车间柔性分批调度问题研究%Genetic Algorithm Based Flexible Job-shop Scheduling and Flexible Size-lot Splitting

    Institute of Scientific and Technical Information of China (English)

    周超; 胡燕海; 李建辉

    2015-01-01

    针对柔性作业车间柔性分批调度问题的复杂性,采用遗传算法进行求解,在引入柔性分批方法后,并提出了染色体的两级编码方法,设计了2种交叉和变异操作方法,以防止操作中非法解的产生,提高求解效率。该算法不仅解决批量分批,而且也解决子批排序和选择加工路线的问题。对比整批调度和柔性分批调度的 Makespan 后,仿真结果表明,柔性分批调度可缩短生产周期,验证了采用新算法的可行性和有效性。%In this paper, genetic algorithm is employed to solve the complex problems in flexible job-shop scheduling and size-lot splitting. A two-stage encoding method of chromosomes is presented and two kinds of crossover and mutation methods are designed to prevent the incorrect solutions in the manipulation. The algorithm not only solves the problem with lot splitting, but also the problem of sorting and selection of flexible size-lot splitting processing route. Based on the Makespan comparison of entire batch scheduling and flexible size-lot splitting, it is found that the production cycle with flexible size-lot splitting can be shortened using the proposed method, with which the feasibility and effectiveness of the proposed method are hence verified.

  1. Cluster dynamics largely shapes protoplanetary disc sizes

    CERN Document Server

    Vincke, Kirsten

    2016-01-01

    It is still on open question to what degree the cluster environment influences the sizes of protoplanetary discs surrounding young stars. Particularly so for the short-lived clusters typical for the solar neighbourhood in which the stellar density and therefore the influence of the cluster environment changes considerably over the first 10 Myr. In previous studies often the effect of the gas on the cluster dynamics has been neglected, this is remedied here. Using the code NBody6++ we study the stellar dynamics in different developmental phases - embedded, expulsion, expansion - including the gas and quantify the effect of fly-bys on the disc size. We concentrate on massive clusters ($M_{\\text{cl}} \\geq 10^3 - 6 \\cdot 10^4 M_{\\text{Sun}}$), which are representative for clusters like the Orion Nebula Cluster (ONC) or NGC 6611. We find that not only the stellar density but also the duration of the embedded phase matters. The densest clusters react fastest to the gas expulsion and drop quickly in density, here 98...

  2. MODEL PENENTUAN UKURAN LOT PRODUKSI DENGAN POLA PERMINTAAN BERFLUKTUASI

    Directory of Open Access Journals (Sweden)

    Docki Saraswati

    2009-01-01

    Full Text Available The purpose of this paper is to examine the impact of varying demand on the production lot size and the schedule of delivery in the integrated inventory system. This system is consisted of a single manufacturer as the supplier and a single buyer. Mostly, the problems on the economic lot size model are assumed that demand is continuous with time. Actually, demand occurs are varying in time rather than continuously over the planning time horizon. In this case, the buyer has decided the amount of order for each period is varied, because of the changing market environment. The integrated inventory system model between a supplier and a buyer are developed and implemented under the condition with varied demand. Forward dynamic programming is implemented for searching the solution. The objective is to minimize the total cost, associated with a single product for a deterministic varying demand. Two conditions are examined here, i.e., the integrated model with uncapacitated and capacitated production system. The difference between these two models is in the constraints formulation. The capacity constraints will give higher total cost, especially if the setup cost higher than the holding cost. A numerical example is presented to illustrate the implementation of the solution algorithm. Abstract in Bahasa Indonesia: Pada makalah ini diteliti pengaruh permintaan yang berfluktuasi terhadap penentuan ukuran lot produksi dan jadwal pengiriman pada sistem persediaan terintegrasi, dengan total ongkos persediaan melibatkan sistem persediaan pemanufaktur dan pembeli secara bersama. Sistem terdiri atas pemanufaktur tunggal dan pembeli tunggal untuk pemesanan satu jenis produk.Umumnya permasalahan penentuan ukuran lot produksi memiliki asumsi bahwa permintaan bersifat kontinu terhadap waktu. Penentuan ukuran lot pada model integrasi sistem persediaan antara pemanufaktur dan pembeli dengan kondisi permintaan berfluktuatif bertujuan meminimasi total ongkos. Pencarian

  3. Adaptive Dynamics of Regulatory Networks: Size Matters

    Directory of Open Access Journals (Sweden)

    2009-03-01

    Full Text Available To accomplish adaptability, all living organisms are constructed of regulatory networks on different levels which are capable to differentially respond to a variety of environmental inputs. Structure of regulatory networks determines their phenotypical plasticity, that is, the degree of detail and appropriateness of regulatory replies to environmental or developmental challenges. This regulatory network structure is encoded within the genotype. Our conceptual simulation study investigates how network structure constrains the evolution of networks and their adaptive abilities. The focus is on the structural parameter network size. We show that small regulatory networks adapt fast, but not as good as larger networks in the longer perspective. Selection leads to an optimal network size dependent on heterogeneity of the environment and time pressure of adaptation. Optimal mutation rates are higher for smaller networks. We put special emphasis on discussing our simulation results on the background of functional observations from experimental and evolutionary biology.

  4. Adaptive Dynamics of Regulatory Networks: Size Matters

    Directory of Open Access Journals (Sweden)

    Martinetz Thomas

    2009-01-01

    Full Text Available To accomplish adaptability, all living organisms are constructed of regulatory networks on different levels which are capable to differentially respond to a variety of environmental inputs. Structure of regulatory networks determines their phenotypical plasticity, that is, the degree of detail and appropriateness of regulatory replies to environmental or developmental challenges. This regulatory network structure is encoded within the genotype. Our conceptual simulation study investigates how network structure constrains the evolution of networks and their adaptive abilities. The focus is on the structural parameter network size. We show that small regulatory networks adapt fast, but not as good as larger networks in the longer perspective. Selection leads to an optimal network size dependent on heterogeneity of the environment and time pressure of adaptation. Optimal mutation rates are higher for smaller networks. We put special emphasis on discussing our simulation results on the background of functional observations from experimental and evolutionary biology.

  5. Dynamic finite-size scaling at first-order transitions

    Science.gov (United States)

    Pelissetto, Andrea; Vicari, Ettore

    2017-07-01

    We investigate the dynamic behavior of finite-size systems close to a first-order transition (FOT). We develop a dynamic finite-size scaling (DFSS) theory for the dynamic behavior in the coexistence region where different phases coexist. This is characterized by an exponentially large time scale related to the tunneling between the two phases. We show that, when considering time scales of the order of the tunneling time, the dynamic behavior can be described by a two-state coarse-grained dynamics. This allows us to obtain exact predictions for the dynamical scaling functions. To test the general DFSS theory at FOTs, we consider the two-dimensional Ising model in the low-temperature phase, where the external magnetic field drives a FOT, and the 20-state Potts model, which undergoes a thermal FOT. Numerical results for a purely relaxational dynamics fully confirm the general theory.

  6. Population dynamic theory of size-dependent cannibalism

    NARCIS (Netherlands)

    Claessen, D.; de Roos, A.M.; Persson, L.

    2004-01-01

    Cannibalism is characterized by four aspects: killing victims, gaining energy from victims, size-dependent interactions and intraspecific competition. In this review of mathematical models of cannibalistic populations, we relate the predicted population dynamic consequences of cannibalism to its fou

  7. Population dynamic theory of size-dependent cannibalism

    NARCIS (Netherlands)

    Claessen, D.; de Roos, A.M.; Persson, L.

    2004-01-01

    Cannibalism is characterized by four aspects: killing victims, gaining energy from victims, size-dependent interactions and intraspecific competition. In this review of mathematical models of cannibalistic populations, we relate the predicted population dynamic consequences of cannibalism to its fou

  8. Evolutionary dynamics with fluctuating population sizes and strong mutualism

    Science.gov (United States)

    Chotibut, Thiparat; Nelson, David R.

    2015-08-01

    Game theory ideas provide a useful framework for studying evolutionary dynamics in a well-mixed environment. This approach, however, typically enforces a strictly fixed overall population size, deemphasizing natural growth processes. We study a competitive Lotka-Volterra model, with number fluctuations, that accounts for natural population growth and encompasses interaction scenarios typical of evolutionary games. We show that, in an appropriate limit, the model describes standard evolutionary games with both genetic drift and overall population size fluctuations. However, there are also regimes where a varying population size can strongly influence the evolutionary dynamics. We focus on the strong mutualism scenario and demonstrate that standard evolutionary game theory fails to describe our simulation results. We then analytically and numerically determine fixation probabilities as well as mean fixation times using matched asymptotic expansions, taking into account the population size degree of freedom. These results elucidate the interplay between population dynamics and evolutionary dynamics in well-mixed systems.

  9. Woman's lot in India.

    Science.gov (United States)

    Goyal, S K

    1980-01-26

    I read Dr. Rao's article on attitudes to women and nutrition programmes in India (Dec. 22/29, p. 1357) with considerable interest. In India parents have to save a lot of money to be able to give a dowry when a daughter marries. In addition they are expected to spend considerable sums when their daughters' children are born and when the grandchildren in turn marry. The task of looking after elderly parents--and of discharging their responsibilities if they themselves are unable to do so--falls upon the sons. In India daughters rarely help out their parents in this way, and the parents will not usually agree to accept help from daughters if they have a son who is prepared to discharge the sacred duty of helping parents in time of need. Once she marries, a daughter's obligations to her parents cease while their obligations to her extend even further to include her husband, children, and in-laws. No wonder the birth of a girl is rarely a cause of celebration in India. The main cause for the plight of women in India is poverty. In most Indian families, the woman of the house will consume less than anyone of nutritious items such as milk, cheese, meat, fish, and butter. Whenever the family's meagre resources are shared out, whether for food, for education, for medical care, it is the males who are given preference. This unequal distribution takes place with the full approval of the woman of the house. Food is normally allocated by the woman, and when food is scarce they tend to favour sons over daughters. Readers in the West may feel that women get the worst possible deal in India. However, although parents do not normally spend as much on the education of their daughters as they do on their sons, in the long run daughters very often get more than their fair share of the family's fortunes because of the dowry system and other social customs.

  10. Summary of mathematical models and algorithms of lot-sizing problem in discrete manufacturing enterprises%离散制造业中生产批量计划问题的模型与算法

    Institute of Scientific and Technical Information of China (English)

    韩毅

    2011-01-01

    制造业是衡量—个国家和地区的综合经济实力和发展水平的重要标准,是民生之本和产业主体.制造业的重要组成成分之一是离散制造业,其中的重要问题是生产批量计划问题(Lot-sizing Problem,LP).生产批量计划问题是企业生产过程中的重要决策问题,与运筹学、管理科学和工业工程等领域联系紧密.迄今为止,国内外学者对该问题的研究历史已超过50年.在参考国内外相关文献的基础上,对生产批量计划问题的模型和求解算法作了系统、全面的总结,指出了将来可以进一步研究的重点方向.%Manufacturing Industry (MI) is an important meteyard for evaluating the synchronized economic standing and development level.It is also the root of people's well-beings and the main body of production enterprises.Discrete Manufacturing Industry(DMI) is one of the main components of MI,the most significant problem among which is Lot-sizing Problem (LP).In the production scheduling systems,LP is a crucial decisive problem.LP keeps close relationship with Operations Research (OR), management science, industry engineering and etc.So far,the history of researchs on LP from domestic and foreign scholars has beyond 50 years.This paper surveys some studies of LP and introduces the mathematical models and algorithms in detail.Furthermore,the potential directions for further researches and applications are presented.

  11. Enhanced oxidation resistance of active nanostructures via dynamic size effect

    Science.gov (United States)

    Liu, Yun; Yang, Fan; Zhang, Yi; Xiao, Jianping; Yu, Liang; Liu, Qingfei; Ning, Yanxiao; Zhou, Zhiwen; Chen, Hao; Huang, Wugen; Liu, Ping; Bao, Xinhe

    2017-02-01

    A major challenge limiting the practical applications of nanomaterials is that the activities of nanostructures (NSs) increase with reduced size, often sacrificing their stability in the chemical environment. Under oxidative conditions, NSs with smaller sizes and higher defect densities are commonly expected to oxidize more easily, since high-concentration defects can facilitate oxidation by enhancing the reactivity with O2 and providing a fast channel for oxygen incorporation. Here, using FeO NSs as an example, we show to the contrary, that reducing the size of active NSs can drastically increase their oxidation resistance. A maximum oxidation resistance is found for FeO NSs with dimensions below 3.2 nm. Rather than being determined by the structure or electronic properties of active sites, the enhanced oxidation resistance originates from the size-dependent structural dynamics of FeO NSs in O2. We find this dynamic size effect to govern the chemical properties of active NSs.

  12. Investigation of Lot Sizing Problem in Supply-demand Cooperation in Supply Chain System%供应链体系构建中供需双方合作批量问题探究

    Institute of Scientific and Technical Information of China (English)

    靳添婷; 王丽莉

    2013-01-01

    伴随着社会经济的不断发展和买方市场的初步形成,以生产与产品为中心的管理模式早已满足不了激烈市场竞争的需求,以顾客为中心的供应链管理模式应运而生,而在供应链管理模式中最基本和重要的内容在于供需研究,对供应链体系构建中供需双方合作批量问题进行探讨,可以进一步优化供应链,实现供需双方共赢的目的.%Along with the development of the social economy and the preliminary forming of the buyer's market, the current supply chain mode centered on product and production can no longer meet the demand of the fierce market competition, which resultantly gives rise to the supply chain mode centered on customer. In this paper, we argued that the most basic and important content of a supply chain management mode was the study on supply and demand and the relationship between the two and then examined the lot sizing in the cooperation of the supplying and demanding parties in the supply chain system, which hopefully would further optimize the supply chain and realize win-win for both parties.

  13. Life cycle size dynamics in Didymosphenia geminata (Bacillariophyceae).

    Science.gov (United States)

    Bishop, Ian W; Spaulding, Sarah A

    2017-06-01

    Didymosphenia geminata has received a great deal of attention in the last 25 years, and considerable effort has gone into determining the origin, ecological impact, and economic consequences of its invasive behavior. While environmental conditions are a controlling influence in distribution, the extreme success of the species may be tied to its basic biology and life history. Little is known, however, about population dynamics, size restoration and reproduction of D. geminata. The objective of this study was to determine the temporal patterns in cell size frequency, size restoration strategy, and synchronization of life cycles between populations in close proximity. We implemented FlowCam technology to measure the length of more than 100,000 D. geminata cells from two sites in South Boulder Creek, Colorado over 1 year. We applied finite mixture modeling to uncover temporal patterns in size distribution. Our results show that collections of D. geminata exhibited a complex, multimodal size distribution, almost always containing four overlapping age cohorts. We failed to observe direct visual evidence of the sexual phase. Multiple abrupt and directional shifts in size distribution, however, were documented providing conclusive evidence of cell size restoration. Lastly, nodules in close proximity were asynchronous with respect to size frequency profiles and size diminution, highlighting the relevance of spatial heterogeneity in in situ diatom size dynamics. This study is the first to document the complexity of diatom cell size distribution in a lotic system, size restoration in D. geminata, and the variability in rates of size reduction at microhabitat spatial scales. © 2017 Phycological Society of America.

  14. Dynamic properties of epidemic spreading on finite size complex networks

    Institute of Scientific and Technical Information of China (English)

    Li Ying; Liu Yang; Shan Xiu-Ming; Ren Yong; Jiao Jian; Qiu Ben

    2005-01-01

    The Internet presents a complex topological structure, on which computer viruses can easily spread. By using theoretical analysis and computer simulation methods, the dynamic process of disease spreading on finite size networks with complex topological structure is investigated. On the finite size networks, the spreading process of SIS (susceptibleinfected-susceptible) model is a finite Markov chain with an absorbing state. Two parameters, the survival probability and the conditional infecting probability, are introduced to describe the dynamic properties of disease spreading on finite size networks. Our results can help understanding computer virus epidemics and other spreading phenomena on communication and social networks. Also, knowledge about the dynamic character of virus spreading is helpful for adopting immunity policy.

  15. Paleowattmeters: A scaling relation for dynamically recrystallized grain size

    Science.gov (United States)

    Austin, Nicholas J.; Evans, Brian

    2007-04-01

    During dislocation creep, mineral grains often evolve to a stable size, dictated by the deformation conditions. We suggest that grain-size evolution during deformation is determined by the rate of mechanical work. Provided that other elements of microstructure have achieved steady state and that the dissipation rate is roughly constant, then changes in internal energy will be proportional to changes in grain-boundary area. If normal grain-growth and dynamic grain-size reduction occur simultaneously, then the steady-state grain size is determined by the balance of those rates. A scaling model using these assumptions and published grain-growth and mechanical relations matches stress grain-size relations for quartz and olivine rocks with no fitting. For marbles, the model also explains scatter not rationalized by assuming that recrystallized grain size is a function of stress alone. When extrapolated to conditions typical for natural mylonites, the model is consistent with field constraints on stresses and strain rates.

  16. Estimating spatio-temporal dynamics of size-structured populations

    DEFF Research Database (Denmark)

    Kristensen, Kasper; Thygesen, Uffe Høgsbro; Andersen, Ken Haste

    2014-01-01

    Spatial distributions of structured populations are usually estimated by fitting abundance surfaces for each stage and at each point of time separately, ignoring correlations that emerge from growth of individuals. Here, we present a statistical model that combines spatio-temporal correlations...... with simple stock dynamics, to estimate simultaneously how size distributions and spatial distributions develop in time. We demonstrate the method for a cod population sampled by trawl surveys. Particular attention is paid to correlation between size classes within each trawl haul due to clustering...... of individuals with similar size. The model estimates growth, mortality and reproduction, after which any aspect of size-structure, spatio-temporal population dynamics, as well as the sampling process can be probed. This is illustrated by two applications: 1) tracking the spatial movements of a single cohort...

  17. Finite size effects in the dynamics of opinion formation

    CERN Document Server

    Toral, R; Tessone, Claudio J.; Toral, Raul

    2006-01-01

    For some models of relevance in the social sciences we review some examples in which system size plays an important role in the final outcome of the dynamics. We discuss the conditions under which changes of behavior can appear only when the number of agents in the model takes a finite value. Those changes of behavior can be related to the apparent phase transitions that appear in some physical models. We show examples in the Galam's model of opinion transmission and the Axelrod's model of culture formation stressing the role that the network of interactions has on the main results of both models. Finally, we present the phenomenon of system-size stochastic resonance by which a forcing signal (identified as an advertising agent) is optimally amplified by a population of the right (intermediate) size. Our work stresses the role that the system size has in the dynamics of social systems and the inappropriateness of taking the thermodynamic limit for these systems.

  18. Supplemental Environmental Baseline Survey for Proposed Land Use Permit Modification for Expansion of the Dynamic Explosive Test Site (DETS) 9940 Main Complex Parking Lot

    Energy Technology Data Exchange (ETDEWEB)

    Peek, Dennis W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-10-01

    The “subject property” is comprised of a parcel of land within the Kirtland Military Reservation, Bernalillo County, New Mexico, as shown on the map in Appendix B of this document. The land requirement for the parking lot addition to the 9940 Main Complex is approximately 2.7 acres. The scope of this Supplemental Environmental Baseline Survey (SEBS) is for the parking lot addition land transfer only. For details on the original 9940 Main Complex see Environmental Baseline Survey, Land Use Permit Request for the 9940 Complex PERM/0-KI-00-0001, August 21, 2003, and for details on the 9940 Complex Expansion see Environmental Baseline Survey, Proposed Land Use Permit Expansion for 9940 DETS Complex, June 24, 2009. The 2.7-acre parcel of land for the new parking lot, which is the subject of this EBS (also referred to as the “subject property”), is adjacent to the southwest boundary of the original 12.3- acre 9940 Main Complex. No testing is known to have taken place on the subject property site. The only activity known to have taken place was the burial of overhead utility lines in 2014. Adjacent to the subject property, the 9940 Main Complex was originally a 12.3-acre site used by the Department of Energy (DOE) under a land use permit from the United States Air Force (USAF). Historical use of the site, dating from 1964, included arming, fusing, and firing of explosives and testing of explosives systems components. In the late 1970s and early 1980s experiments at the 9940 Main Complex shifted toward reactor safety issues. From 1983 to 1988, fuel coolant interaction (FCI) experiments were conducted, as were experiments with conventional high explosives (HE). Today, the land is used for training of the Nuclear Emergency Response community and for research on energetic materials. In 2009, the original complex was expanded to include four additional 20-acre areas: 9940 Training South, 9940 Training East, T-Range 6, and Training West Landing Zone. The proposed use of

  19. Size-Dependent Melting Behaviour of Nanometre-Sized Pb Particles Studied by Dynamic Mechanical Analysis

    Institute of Scientific and Technical Information of China (English)

    CHEN Xiao-Min; FEI Guang-Tao; CUI Ping

    2006-01-01

    Nanometre-sized (hereafter nano-)Pb particles embedded in an Al matrix are prepared by ball milling.It is found that the size of nano-Pb particles was decreased with increasing milling time.The melting behaviour of nano-Pb particles embedded in the Al matrix is studied by means of dynamic mechanical analysis,and a single internal friction peak in the vicinity of Pb melting temperature is observed.The onset temperature of the peak moves to lower temperature with the decrease of particles size and the internal friction peak height is increased,which indicates a size-dependent melting behaviour of nano-Pb particles.It is suggested that the size-dependent melting behaviour is associated with surface melting.

  20. Droplet sizes, dynamics and deposition in vertical annular flow

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, J C.B.; Dukler, A E

    1985-10-01

    The role of droplets in vertical upwards annular flow is investigated, focusing on the droplet size distributions, dynamics, and deposition phenomena. An experimental program was performed based on a new laser optical technique developed in these laboratories and implemented here for annular flow. This permitted the simultaneous measurement of droplet size, axial and radial velocity. The dependence of droplet size distributions on flow conditions is analyzed. The Upper-Log Normal function proves to be a good model for the size distribution. The mechanism controlling the maximum stable drop size was found to result from the interaction of the pressure fluctuations of the turbulent flow of the gas core with the droplet. The average axial droplet velocity showed a weak dependence on gas rates. This can be explained once the droplet size distribution and droplet size-velocity relationship are analyzed simultaneously. The surprising result from the droplet conditional analysis is that larger droplet travel faster than smaller ones. This dependence cannot be explained if the drag curves used do not take into account the high levels of turbulence present in the gas core in annular flow. If these are considered, then interesting new situations of multiplicity and stability of droplet terminal velocities are encountered. Also, the observed size-velocity relationship can be explained. A droplet deposition is formulated based on the particle inertia control. This permitted the calculation of rates of drop deposition directly from the droplet size and velocities data.

  1. Enhanced oxidation resistance of active nanostructures via dynamic size effect

    Science.gov (United States)

    Liu, Yun; Yang, Fan; Zhang, Yi; Xiao, Jianping; Yu, Liang; Liu, Qingfei; Ning, Yanxiao; Zhou, Zhiwen; Chen, Hao; Huang, Wugen; Liu, Ping; Bao, Xinhe

    2017-01-01

    A major challenge limiting the practical applications of nanomaterials is that the activities of nanostructures (NSs) increase with reduced size, often sacrificing their stability in the chemical environment. Under oxidative conditions, NSs with smaller sizes and higher defect densities are commonly expected to oxidize more easily, since high-concentration defects can facilitate oxidation by enhancing the reactivity with O2 and providing a fast channel for oxygen incorporation. Here, using FeO NSs as an example, we show to the contrary, that reducing the size of active NSs can drastically increase their oxidation resistance. A maximum oxidation resistance is found for FeO NSs with dimensions below 3.2 nm. Rather than being determined by the structure or electronic properties of active sites, the enhanced oxidation resistance originates from the size-dependent structural dynamics of FeO NSs in O2. We find this dynamic size effect to govern the chemical properties of active NSs. PMID:28223687

  2. Size-Dependent Dynamic Behavior of a Microcantilever Plate

    Directory of Open Access Journals (Sweden)

    Xiaoming Wang

    2012-01-01

    Full Text Available Material length scale considerably affects the mechanical properties of microcantilever components. Recently, cantilever-plate-like structures have been commonly used, whereas the lack of studies on their size effects constrains the design, testing, and application of these structures. We have studied the size-dependent dynamic behavior of a cantilever plate based on a modified couple stress theory and the differential quadrature method in this note. The numerical solutions of microcantilever plate equation involving the size effect have been presented. We have also analyzed the bending and vibration of the microcantilever plates considering the size effect and discussed the dependence of the size effect on their geometric dimensions. The results have shown that (1 the mechanical characteristics of the cantilever plate show obvious size effects; as a result, the bending deflection of a microcantilever plate reduces whereas the natural frequency increases effectively and (2 for the plates with the same material, the size effect becomes more obvious when the plates are thinner.

  3. The comparisons of lot sizes and costs based on the different bodies responsible for supply -hub operations%不同Supply—hub营运主体下的批量与成本比较研究

    Institute of Scientific and Technical Information of China (English)

    桂华明; 马士华

    2012-01-01

    The supply pattern based on supply -hub under the Just -In -Time (JIT) environment is considered, and the average cost function of manufacturer, supply - huh, and supplier is established. Moreover, the production and order lot - size models of the supply - hub operation and cost, which manufacturer and supplier are responsible for, respectively, are proposed. The results show that under the condition that supply - hub is appropriate,it is more favorable to the supplier than to the manufacturer when the supplier is responsible for supply - hub operation and cost comparing with the manufacturer is responsible for, but the total cost of the supply chain is reduced. It is able to reduce the costs of the manufacturer and the supplier on certain level through negotiations and interest transfer, therefore entire supply chain is achieved Pareto optimization; Moreover, with the distance between the supplier and supply - hub is the further, it is more favorable to the supply chain when the supplier is responsible for supply - hub operation and cost rather than the manufacturer is responsible for that.%本文考虑了JIT环境下基于Supply—hub的供货模式,建立了制造商、Supply—hub和供应商的平均成本函数,并提出了分别由制造商和供应商负责Supply—hub营运及成本的生产与订货批量模型。结果表明,在Supply—hub适用的条件下,相比由制造商负责,供应商负责Supply—hub的运营及成本时,对供应商有利而不利于制造商,但整个供应链的总成本减少,通过供应商与制造商之间的协商和利益转移,可以使制造商和供应商的成本都有所减少,从而实现整个供应链的Pareto优化,此外,供应商距离Supply—hub越远,相比制造商负责,由供应商负责Supply—hub的营运及成本对整个供应链更有利。

  4. Remanufacturing lot sizing production planning considering product differentiation in multi-uncertain environment%多重不确定环境下考虑产品差异的再制造批量生产计划

    Institute of Scientific and Technical Information of China (English)

    景熠; 王旭; 李文川; 邓蕾

    2012-01-01

    To solve manufacturing and remanufacturing lot sizing planning problems under the situation of hybrid production in multi-uncertain environment, a mixed integer programming model with constraints of inventory and production capacity was established. In this model, the discrete scenario set of know probability was used to describe returned products quantity and product demand's uncertainty, to describe the uncertainty of remanufacturing cost based on interval analysis, and to describe the uncertainty of remanufacturing rate with stochastic chance constrained programming. Satisfying demand ratio, operation cost and remanufacturing product rate were used as oper ation objects. Meanwhile, product differentiation was considered, and the strategy of one-way substitution was proposed to improve the flexibility of production planning. Adaptive mechanism was introduced in double chromosomes genetic algorithm to design solution for simulation example. The results showed the effectiveness and validity of proposed model.%针对多重不确定环境下制造/再制造混合生产场景中的批量计划问题,建立了库存和生产能力受限的混合整数规划模型。该模型分别采用已知概率的离散情景集合描述收回品数量和产品需求的不确定性,区间分析描述再制造成本的不确定性,以及随机机会约束描述再制造率的不确定性,并以需求满足率、运作成本和再制造产品率为运作目标,同时考虑再制造产品的差异,以单向替代策略增强生产计划的柔性。最后,将自适应机制引入双倍体遗传算法,设计了相应的求解过程,并对仿真算例进行了求解。计算结果表明,该计划模型和求解算法具有一定的有效性和实用性。

  5. Femtosecond Excited State Dynamics of Size Selected Neutral Molecular Clusters.

    Science.gov (United States)

    Montero, Raúl; León, Iker; Fernández, José A; Longarte, Asier

    2016-07-21

    The work describes a novel experimental approach to track the relaxation dynamics of an electronically excited distribution of neutral molecular clusters formed in a supersonic expansion, by pump-probe femtosecond ionization. The introduced method overcomes fragmentation issues and makes possible to retrieve the dynamical signature of a particular cluster from each mass channel, by associating it to an IR transition of the targeted structure. We have applied the technique to study the nonadiabatic relaxation of pyrrole homoclusters. The results obtained exciting at 243 nm, near the origin of the bare pyrrole electronic absorption, allow us to identify the dynamical signature of the dimer (Py)2, which exhibits a distinctive lifetime of τ1 ∼ 270 fs, considerably longer than the decays recorded for the monomer and bigger size clusters (Py)n>2. A possible relationship between the measured lifetime and the clusters geometries is tentatively discussed.

  6. Size effects in molecular dynamics thermal conductivity predictions

    Science.gov (United States)

    Sellan, D. P.; Landry, E. S.; Turney, J. E.; McGaughey, A. J. H.; Amon, C. H.

    2010-06-01

    We predict the bulk thermal conductivity of Lennard-Jones argon and Stillinger-Weber silicon using the Green-Kubo (GK) and direct methods in classical molecular dynamics simulations. While system-size-independent thermal conductivities can be obtained with less than 1000 atoms for both materials using the GK method, the linear extrapolation procedure [Schelling , Phys. Rev. B 65, 144306 (2002)] must be applied to direct method results for multiple system sizes. We find that applying the linear extrapolation procedure in a manner consistent with previous researchers can lead to an underprediction of the GK thermal conductivity (e.g., by a factor of 2.5 for Stillinger-Weber silicon at a temperature of 500 K). To understand this discrepancy, we perform lattice dynamics calculations to predict phonon properties and from these, length-dependent thermal conductivities. From these results, we find that the linear extrapolation procedure is only accurate when the minimum system size used in the direct method simulations is comparable to the largest mean-free paths of the phonons that dominate the thermal transport. This condition has not typically been satisfied in previous works. To aid in future studies, we present a simple metric for determining if the system sizes used in direct method simulations are sufficiently large so that the linear extrapolation procedure can accurately predict the bulk thermal conductivity.

  7. Dynamic Range Size Analysis of Territorial Animals: An Optimality Approach.

    Science.gov (United States)

    Tao, Yun; Börger, Luca; Hastings, Alan

    2016-10-01

    Home range sizes of territorial animals are often observed to vary periodically in response to seasonal changes in foraging opportunities. Here we develop the first mechanistic model focused on the temporal dynamics of home range expansion and contraction in territorial animals. We demonstrate how simple movement principles can lead to a rich suite of range size dynamics, by balancing foraging activity with defensive requirements and incorporating optimal behavioral rules into mechanistic home range analysis. Our heuristic model predicts three general temporal patterns that have been observed in empirical studies across multiple taxa. First, a positive correlation between age and territory quality promotes shrinking home ranges over an individual's lifetime, with maximal range size variability shortly before the adult stage. Second, poor sensory information, low population density, and large resource heterogeneity may all independently facilitate range size instability. Finally, aggregation behavior toward forage-rich areas helps produce divergent home range responses between individuals from different age classes. This model has broad applications for addressing important unknowns in animal space use, with potential applications also in conservation and health management strategies.

  8. Remnant lipoprotein size distribution profiling via dynamic light scattering analysis.

    Science.gov (United States)

    Chandra, Richa; Mellis, Birgit; Garza, Kyana; Hameed, Samee A; Jurica, James M; Hernandez, Ana V; Nguyen, Mia N; Mittal, Chandra K

    2016-11-01

    Remnant lipoproteins (RLP) are a metabolically derived subpopulation of triglyceride-rich lipoproteins (TRL) in human blood that are involved in the metabolism of dietary fats or triglycerides. RLP, the smaller and denser variants of TRL particles, are strongly correlated with cardiovascular disease (CVD) and were listed as an emerging atherogenic risk factor by the AHA in 2001. Varying analytical techniques used in clinical studies in the size determination of RLP contribute to conflicting hypotheses in regard to whether larger or smaller RLP particles contribute to CVD progression, though multiple pathways may exist. We demonstrated a unique combinatorial bioanalytical approach involving the preparative immunoseparation of RLP, and dynamic light scattering for size distribution analysis. This is a new facile and robust methodology for the size distribution analysis of RLP that in conjunction with clinical studies may reveal the mechanisms by which RLP cause CVD progression. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Effects of grain size evolution on mantle dynamics

    Science.gov (United States)

    Schulz, Falko; Tosi, Nicola; Plesa, Ana-Catalina; Breuer, Doris

    2016-04-01

    The rheology of planetary mantle materials is strongly dependent on temperature, pressure, strain-rate, and grain size. In particular, the rheology of olivine, the most abundant mineral of the Earth's upper mantle, has been extensively studied in the laboratory (e.g., Karato and Wu, 1993; Hirth and Kohlstedt, 2003). Two main mechanisms control olivine's deformation: dislocation and diffusion creep. While the former implies a power-law dependence of the viscosity on the strain-rate that leads to a non-Newtonian behaviour, the latter is sensitively dependent on the grain size. The dynamics of planetary interiors is locally controlled by the deformation mechanism that delivers the lowest viscosity. Models of the dynamics and evolution of planetary mantles should thus be capable to self-consistently distinguish which of the two mechanisms dominates at given conditions of temperature, pressure, strain-rate and grain size. As the grain size can affect the viscosity associated with diffusion creep by several orders of magnitude, it can strongly influence the dominant deformation mechanism. The vast majority of numerical, global-scale models of mantle convection, however, are based on the use of a linear diffusion-creep rheology with constant grain-size. Nevertheless, in recent studies, a new equation has been proposed to properly model the time-dependent evolution of the grain size (Austin and Evens, 2007; Rozel et al., 2010). We implemented this equation in our mantle convection code Gaia (Hüttig et al., 2013). In the framework of simple models of stagnant lid convection, we compared simulations based on the fully time-dependent equation of grain-size evolution with simulations based on its steady-state version. In addition, we tested a number of different parameters in order to identify those that affects the grain size to the first order and, in turn, control the conditions at which mantle deformation is dominated by diffusion or dislocation creep. References Austin

  10. Population dynamic theory of size-dependent cannibalism.

    Science.gov (United States)

    Claessen, David; de Roos, André M.; Persson, Lennart

    2004-01-01

    Cannibalism is characterized by four aspects: killing victims, gaining energy from victims, size-dependent interactions and intraspecific competition. In this review of mathematical models of cannibalistic populations, we relate the predicted population dynamic consequences of cannibalism to its four defining aspects. We distinguish five classes of effects of cannibalism: (i) regulation of population size; (ii) destabilization resulting in population cycles or chaos; (iii) stabilization by damping population cycles caused by other interactions; (iv) bistability such that, depending on the initial conditions, the population converges to one of two possible stable states; and (v) modification of the population size structure. The same effects of cannibalism may be caused by different combinations of aspects of cannibalism. By contrast, the same combination of aspects may lead to different effects. For particular cannibalistic species, the consequences of cannibalism will depend on the presence and details of the four defining aspects. Empirical evidence for the emerged theory of cannibalism is discussed briefly. The implications of the described dynamic effects of cannibalism are discussed in the context of community structure, making a comparison with the community effects of intraguild predation. PMID:15101690

  11. Estudo do efeito de programas de melhoria contínua em variáveis do chão de fábrica na relação entre tamanho de lote de produção e lead time: lead time relationship Study of the effect of continuous improvement programs on lot size

    Directory of Open Access Journals (Sweden)

    Moacir Godinho Filho

    2010-01-01

    variables on the shop floor, aiming to increase the manager’s intuition about manufacturing dynamics. One of these is the relationship between lot size and average lead time, which is studied in this paper. Although this general relationship is widely recognized, only a selected number of authors address this relationship in a practical manner. This paper presenta and compares the effect of six continuous improvement programs (arrival variability, process variability, quality (defect rate, time to failure, repair time, and set up time on lot size × lead time relationship in a multi-product, single-machine environment, by means of a combination of System Dynamics (FORRESTER, 1962 and Factory Physics (HOPP and SPEARMAN, 2008 approaches. Two sets of experiments are performed in this paper: a A large (50% improvement in each parameter separately, as might be obtained by a significant one-time investment; b a small improvement in all parameters simultaneously. The results showed: (a the positive effect of continuous improvement in shop floor variables on lead time ; (b the importance of knowing the lot size × lead time curve and the effect of set up reduction programs before beginning with lot size reduction program; (c that investing in small improvements in several variables is preferable regarding lead time than investing in a large improvement in just one variable; (d some insights about modern manufacturing management paradigms such as: Lean Manufacturing and Quick Response Manufacturing.

  12. Finite-size scaling approach to dynamic storage allocation problem

    Science.gov (United States)

    Seyed-allaei, Hamed

    2003-09-01

    It is demonstrated how dynamic storage allocation algorithms can be analyzed in terms of finite-size scaling. The method is illustrated in the three simple cases of the first-fit, next-fit and best-fit algorithms, and the system works at full capacity. The analysis is done from two different points of view-running speed and employed memory. In both cases, and for all algorithms, it is shown that a simple scaling function exists and the relevant exponents are calculated. The method can be applied on similar problems as well.

  13. Lot Sizes Coordination among a Manufacturer and Two Suppliers Based on Supply-Hub%基于Supply-hub的2个供应商单制造商批量协调问题研究

    Institute of Scientific and Technical Information of China (English)

    桂华明; 马士华; 关旭; 张林兰

    2012-01-01

    Considering an assembly-type supply chain consisting of two suppliers and a manufacturer, the cost functions of them are established. Moreover, the production and order quantity models are proposed respectively by the manufacturer and two suppliers responsible for the supply-hub's operation and costs. The results show that when the manufacturer is responsible for the supply-hub's operation, the farther the suppliers are from the supply-hub, the greater the manufacturer's production quantity is, and the replenishing lot-sizes of parts to the supply-hub are greater compared to the manufacturer being responsible for the supply-hub's operation. When two suppliers are responsible for the supply-hub's operation, the production quantities of the manufacturer and suppliers do not vary with the distance between suppliers and supply-hub. Moreover, in the conditions for using supply-hub model, compared to the manufacturer, the suppliers are responsible for supply-hub operation and costs, which may make the whole supply chain to achieve Pareto optimization since the manufacturer and suppliers can obtain a win-win solution.%考虑一个由2个供应商和单制造商组成的装配型供应链,分析并建立了制造商、Supply-hub和2个供应商的平均成本函数,提出了分别由制造商和2个供应商负责Supply-hub营运及成本时的生产与订货批量模型.研究结果表明:当由制造商负责时,供应商距离Supply-hub越远,制造商的生产批量越大,且Supply-hub中的零部件补货批量相比供应商负责时更大;当由供应商负责时,制造商的生产批量不随供应商的远近而变化,供应商的零部件生产批量也不变.此外,在适用Supply-hub的条件下,相比由制造商负责,由2个供应商负责Supply-hub的运营并分担其成本时,整个供应链的总成本更低,2个供应商与制造商之间可以通过合理分配使2个供应商与制造商的营运成本均有所降低,从而实现整个供应链系统的Pareto优化.

  14. Evaluation of the CLSI EP26-A protocol for detection of reagent lot-to-lot differences.

    Science.gov (United States)

    Katzman, Brooke M; Ness, Karl M; Algeciras-Schimnich, Alicia

    2017-09-01

    Verification of new reagent lots is a required laboratory task. The Clinical and Laboratory Standards Institute (CLSI) EP26-A guideline provides a lot-to-lot verification protocol to detect significant changes in test performance. The aim of this study was to compare the performance of EP26-A with our laboratory reagent lot verification protocol. Prospective evaluations for two reagent lots each for thyroid stimulating hormone (TSH), thyroglobulin (Tg), thyroxine (T4), triiodothyronine (T3), free triiodothyronine (fT3), and thyroid peroxidase antibody (TPOAb) were performed. The laboratory's lot verification process included evaluation of 20 patient samples with the current and new lots and acceptability based on a predefined criteria. For EP26-A, method imprecision data and critical differences based on previously defined lot-to-lot consistency goals were used to define sample size requirements and rejection limits. EP26-A required the following number of samples: 23 for TSH, 17 for Tg, 33 for T4, 31 for T3, 48 for fT3, and 1 for TPOAb. Our current protocol and EP26-A were in agreement in 9 of the 12 (75%) paired verifications. Of the 3 discrepant verifications, Tg and TSH reagent lots were rejected by EP26-A due to significant differences at medical decision points; whereas TPOAb was rejected by the current laboratory protocol. The EP26-A protocol arrived at the same conclusions as our protocol in 75% of the evaluations and required more samples for 4 of the 6 analytes tested. Challenges associated with determining rejection limits and the need for increased sample sizes may be critical factors that limit the utility of EP26-A. Copyright © 2017 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

  15. Metastable structures and size effects in small group dynamics.

    Science.gov (United States)

    Lauro Grotto, Rosapia; Guazzini, Andrea; Bagnoli, Franco

    2014-01-01

    In his seminal works on group dynamics Bion defined a specific therapeutic setting allowing psychoanalytic observations on group phenomena. In describing the setting he proposed that the group was where his voice arrived. This physical limit was later made operative by assuming that the natural dimension of a therapeutic group is around 12 people. Bion introduced a theory of the group aspects of the mind in which proto-mental individual states spontaneously evolve into shared psychological states that are characterized by a series of features: (1) they emerge as a consequence of the natural tendency of (both conscious and unconscious) emotions to combine into structured group patterns; (2) they have a certain degree of stability in time; (3) they tend to alternate so that the dissolution of one is rapidly followed by the emergence of another; (4) they can be described in qualitative terms according to the nature of the emotional mix that dominates the state, in structural terms by a kind of typical "leadership" pattern, and in "cognitive" terms by a set of implicit expectations that are helpful in explaining the group behavior (i.e., the group behaves "as if" it was assuming that). Here we adopt a formal approach derived from Socio-physics in order to explore some of the structural and dynamic properties of this small group dynamics. We will described data from an analytic DS model simulating small group interactions of agents endowed with a very simplified emotional and cognitive dynamic in order to assess the following main points: (1) are metastable collective states allowed to emerge in the model and if so, under which conditions in the parameter space? (2) can these states be differentiated in structural terms? (3) to what extent are the emergent dynamic features of the systems dependent of the system size? We will finally discuss possible future applications of the quantitative descriptions of the interaction structure in the small group clinical setting.

  16. Metastable structures and size effects in small group dynamics

    Directory of Open Access Journals (Sweden)

    Rosapia eLauro Grotto

    2014-07-01

    Full Text Available In his seminal works on group dynamics Bion defined a specific therapeutic setting allowing psychoanalytic observations on group phenomena. In describing the setting he proposed that the group was where his voice arrived. This physical limit was later made operative by assuming that the natural dimension of a therapeutic group is around 12 people. Bion introduced a theory of the group aspects of the mind in which proto-mental individual states spontaneously evolve into shared psychological states that are characterized by a series of features: 1 they emerge as a consequence of the natural tendency of (both conscious and unconscious emotions to combine into structured group patterns; 2 they have a certain degree of stability in time; 3 they tend to alternate so that the dissolution of one is rapidly followed by the emergence of another; 4 they can be described in qualitative terms according to the nature of the emotional mix that dominates the state, in structural terms by a kind of typical 'leadership’ pattern, and in 'cognitive’ terms by a set of implicit expectations that are helpful in explaining the group behavior (i.e. the group behaves 'as if’ it was assuming that…. Here we adopt a formal approach derived from Socio-physics in order to explore some of the structural and dynamic properties of this small group dynamics. We will described data from an analytic DS model simulating small group interactions of agents endowed with a very simplified emotional and cognitive dynamic in order to assess the following main points: 1 are metastable collective states allowed to emerge in the model and if so, under which conditions in the parameter space? 3 can these states be differentiated in structural terms? 3 to what extent are the emergent dynamic features of the systems dependent of the system size? We will finally discuss possible future applications of the quantitative descriptions of the interaction structure in the small group clinical

  17. Molecular dynamics-based refinement of nanodiamond size measurements obtained with dynamic light scattering

    CERN Document Server

    Koniakhin, S V; Terterov, I N; Shvidchenko, A V; Eidelman, E D; Dubina, M V

    2016-01-01

    The determination of particle size by dynamic light scattering uses the Stokes-Einstein relation, which can break down for nanoscale objects. Here we employ a molecular dynamics simulation of fully solvated 1-5 nm carbon nanoparticles for the refinement of the experimental data obtained for nanodiamonds in water by using dynamic light scattering. We performed molecular dynamics simulations in differently sized boxes and calculated nanoparticles diffusion coefficients using the velocity autocorrelation function and mean-square displacement. We found that the predictions of the Stokes-Einstein relation are accurate for nanoparticles larger than 3 nm while for smaller nanoparticles the diffusion coefficient should be corrected and different boundary conditions should be taken into account.

  18. Brain dynamics of meal size selection in humans.

    Science.gov (United States)

    Toepel, Ulrike; Bielser, Marie-Laure; Forde, Ciaran; Martin, Nathalie; Voirin, Alexandre; le Coutre, Johannes; Murray, Micah M; Hudry, Julie

    2015-06-01

    Although neuroimaging research has evidenced specific responses to visual food stimuli based on their nutritional quality (e.g., energy density, fat content), brain processes underlying portion size selection remain largely unexplored. We identified spatio-temporal brain dynamics in response to meal images varying in portion size during a task of ideal portion selection for prospective lunch intake and expected satiety. Brain responses to meal portions judged by the participants as 'too small', 'ideal' and 'too big' were measured by means of electro-encephalographic (EEG) recordings in 21 normal-weight women. During an early stage of meal viewing (105-145 ms), data showed an incremental increase of the head-surface global electric field strength (quantified via global field power; GFP) as portion judgments ranged from 'too small' to 'too big'. Estimations of neural source activity revealed that brain regions underlying this effect were located in the insula, middle frontal gyrus and middle temporal gyrus, and are similar to those reported in previous studies investigating responses to changes in food nutritional content. In contrast, during a later stage (230-270 ms), GFP was maximal for the 'ideal' relative to the 'non-ideal' portion sizes. Greater neural source activity to 'ideal' vs. 'non-ideal' portion sizes was observed in the inferior parietal lobule, superior temporal gyrus and mid-posterior cingulate gyrus. Collectively, our results provide evidence that several brain regions involved in attention and adaptive behavior track 'ideal' meal portion sizes as early as 230 ms during visual encounter. That is, responses do not show an increase paralleling the amount of food viewed (and, in extension, the amount of reward), but are shaped by regulatory mechanisms.

  19. Local Dynamics and Global Size Coupling during Magnetic Reconnection

    Science.gov (United States)

    Jacobson, C. M.; Breslau, J. A.; Jardin, S. C.; Ji, H.

    2008-11-01

    Magnetic reconnection is an important physical process not only in small systems such as laboratory plasmas, but also in large systems such as solar flares. The reconnection rate increases with resistivity η and decreases with the current sheet length L. Recent experimental results suggest that these parameters are not independent, but anti-correlate such that ηL is kept roughly constant; thus the reconnection rate is a function of both local dynamics and global size [1]. In order to verify these results and further extend the system size, a numerical MHD model [2] is used. This code allows simulation of either two-fluid or single-fluid resistive MHD reconnection of colliding flux tubes on a 2D grid. The resistivity and system size are systematically varied, and scalings of the ion skin depth, collisionality, and reconnection rate due to these quantities are presented. Results are compared to experimental data, and findings are projected to solar flare scales. [1] A. Kuritsyn et al. Geophys. Res. Lett. 34, L16106 (2007) [2] J. A. Breslau and S. C. Jardin, Comput. Phys. Commun. 151, 8 (2003)

  20. Ultrafast image-based dynamic light scattering for nanoparticle sizing

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Wu; Zhang, Jie; Liu, Lili; Cai, Xiaoshu, E-mail: usst-caixs@163.com [Institute of Particle and Two-Phase Flow Measurement, Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering, University of Shanghai for Science and Technology, 516 Jungong Road, Shanghai 200093 (China)

    2015-11-15

    An ultrafast sizing method for nanoparticles is proposed, called as UIDLS (Ultrafast Image-based Dynamic Light Scattering). This method makes use of the intensity fluctuation of scattered light from nanoparticles in Brownian motion, which is similar to the conventional DLS method. The difference in the experimental system is that the scattered light by nanoparticles is received by an image sensor instead of a photomultiplier tube. A novel data processing algorithm is proposed to directly get correlation coefficient between two images at a certain time interval (from microseconds to milliseconds) by employing a two-dimensional image correlation algorithm. This coefficient has been proved to be a monotonic function of the particle diameter. Samples of standard latex particles (79/100/352/482/948 nm) were measured for validation of the proposed method. The measurement accuracy of higher than 90% was found with standard deviations less than 3%. A sample of nanosilver particle with nominal size of 20 ± 2 nm and a sample of polymethyl methacrylate emulsion with unknown size were also tested using UIDLS method. The measured results were 23.2 ± 3.0 nm and 246.1 ± 6.3 nm, respectively, which is substantially consistent with the transmission electron microscope results. Since the time for acquisition of two successive images has been reduced to less than 1 ms and the data processing time in about 10 ms, the total measuring time can be dramatically reduced from hundreds seconds to tens of milliseconds, which provides the potential for real-time and in situ nanoparticle sizing.

  1. Size Matters!. Birth Size and a Size-Independent Stochastic Term Determine Asexual Reproduction Dynamics in Freshwater Planarians

    Science.gov (United States)

    Thomas, Michael A.; Quinodoz, Sofia; Schötz, Eva-Maria

    2012-09-01

    Asexual reproduction by division in higher organisms is rare, because a prerequisite is the ability to regenerate an entire organism from a piece of the original body. Freshwater planarians are one of the few animals that can reproduce this way, but little is known about the regulation of their reproduction cycles or strategies. We have previously shown that a planarian's reproduction strategy is randomized to include fragmentations, producing multiple offspring, as well as binary fissions, and can be partially explained by a maximum relative entropy principle. In this study we attempt to decompose the factors controlling their reproduction cycle. Based on recent studies on the cell cycle of budding yeast, which suggest that molecular noise in gene expression and cell size at birth together control cell cycle variability, we investigated whether the variability in planarian reproduction waiting times could be similarly regulated. We find that such a model can indeed explain the observed distribution of waiting times between birth and next reproductive event, suggesting that birth size and a stochastic noise term govern the reproduction dynamics of asexual planarians.

  2. 基于决策权分配的供应链批量模型比较研究%Comparative Study of Supply Chain Lot-sizing Models Based on Decision Rights Assignment

    Institute of Scientific and Technical Information of China (English)

    李富昌; 王勇; 张宗益

    2011-01-01

    Current literature primarily emphasizes coordination issues, but underestimates the importance of integration between retailers. This paper develops a retailer-led decentralized optimization model and a centralized decision-making model for supply chain operations by taking into consideration of sales price discount and transport capacity flexibility. We study delivery frequency and lot size, and analyze how a firm's decision rights can affect the performance of individual firms and the entire supply chain. Large retailers have the economies of-scale advantage when negotiating directly with suppliers. Hence,these retailers can not only have great price discount, but also largely reduced transportation cost. We defined the relationships between megs retailers and their suppliers as the “retailer-lsd decentralized optimization model” because megs retailers can influence the decision of suppliers. A retailer-led decentralized optimization model can inevitably create deviations between optimization of individual retailers and the entire supply chain. In order to solve “anti-beck-effective" phenomenon between retailer and supplier, we developed a centralized decision-making model for the entire supply chain and studied transportation integration problems of homogeneous retailers. In the first part of this paper, we described model assumptions and analyzed the cost structures of retailer and supplier. In the second part, we used the cost-benefit function to develop a retailer-led model of decentralized optimization ( Model 1 ), a centralized decision-making model for the entire supply chain (Model 2 ) and a centralized decision-making model integrating homogeneous retailers (Model 3 ). The retailer-led decentralized optimization model assumes that retailers occupy the dominant position and are responsible for handling logistics and distribution. However, the model can create supply chain inefficiency. The centralized decisionmaking model is to overcome the weakness

  3. 7 CFR 29.35 - Lot seal.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Lot seal. 29.35 Section 29.35 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... INSPECTION Regulations Definitions § 29.35 Lot seal. A seal approved by the Director for sealing lots...

  4. Finite-size effects on the lattice dynamics in spin crossover nanomaterials. II. Molecular dynamics simulations

    Science.gov (United States)

    Mikolasek, Mirko; Nicolazzi, William; Terki, Férial; Molnár, Gábor; Bousseksou, Azzedine

    2017-07-01

    In the first part of this work, an experimental study of the lattice dynamics of spin crossover nanoparticles was performed using the nuclear inelastic scattering (NIS). A size dependence of low energy phonon modes appears under 10 nm, but its origin is not well understood. In this paper, we investigate the phonon confinement effects in the framework of molecular dynamics simulations by modeling three-dimensional nanoparticles considering a cubic lattice with an octahedral pattern. The vibrational density of states is computed and compared to the experiment. The simulations allow one to highlight both the role of the phonon quantification and the role of the size and shape distributions of particles on the extracted parameters leading to a better understanding of the experimental results.

  5. Dynamic Simulation of EAF on RTDS for Compensation Sizing

    Science.gov (United States)

    Meera, K. S.

    2017-02-01

    Large sized electric arc furnaces (EAF) causes power quality problems such as flicker, harmonics etc. due to their unbalanced and non-linear behavior characteristics. The rapid swings in real and reactive power of such non-linear loads causes fast repetitive voltage variations with appreciable voltage distortion caused by harmonics and unbalance. Some form of reactive compensation is usually adopted to limit the disturbances caused by EAF in electric power system, in particular the flicker. This paper highlights the results of a case study, where the arc furnace is modelled using statistical dynamic model of the furnace using real time digital simulator which allows more real time simulations tests to be conducted in a shorter time and also provides a more detailed power system representation for the tests. The investigation of the simulation study results showed that static VAR compensators can be successfully used for reduction of flicker levels, compensation of reactive power and for the regulation of voltage levels in the EAF plant under study.

  6. 供应链中商业信用与订货批量协调决策%Collaborative Decision-making on Commercial Credit and Lot-sizing in Supply Chain

    Institute of Scientific and Technical Information of China (English)

    窦亚芹; 吴文杰; 储俊

    2014-01-01

    Commercial credit, economic quantity, revenue sharing, supply chain management. Based on different commercial credit strategy assumes provided by supplier, this paper study joint lot decision problem in two-level supply chain consist of a single supplier and a single retailer. On the basis of analysis of existing literature and sort, we think length of the commercial credit as decision variables and consider the circumstances that suppliers may enlarge procurement as an integer multiple by order quantity of retailers in each cycle. Thus, we construct optimal lot decision model under different strategies of suppliers and integrated cost model of supply chain. In addition, we provide income distribution program about cost savings in supply chain. The results show that order quantities of retailers will be higher and the overall cost of the supply chain will be lower when suppliers provide incentives of commercial credit, compared with the case that suppliers don't provide incentives of commercial credit. Finally, some numerical examples are used to illustrate the results obtained in this paper.%文章基于供应商提供的不同商业信用策略假设,研究了由单一供应商和单一零售商构成的二级供应链中的联合批量决策问题。文章在对现有文献进行分析和梳理的基础上,将商业信用期长度作为决策变量,并考虑每循环周期供应商可能按照零售商订货量的整数倍放大采购的情形,构建出供应商不同商业信用策略下供应商和零售商的最优批量决策模型和供应链综合成本决策模型,并给出了供应链成本节约的收益分配方案。结果表明,与不提供商业信用激励相比,供应商提供商业信用激励时零售商的订购批量会更高,供应链的综合成本也更低。考虑到供应链联合决策中可能出现的收益不均衡问题,文章提出针对供应链协同带来的成本节约,按供应商与零售商投入存货成

  7. Plant Size and Competitive Dynamics along Nutrient Gradients.

    Science.gov (United States)

    Goldberg, Deborah E; Martina, Jason P; Elgersma, Kenneth J; Currie, William S

    2017-08-01

    Resource competition theory in plants has focused largely on resource acquisition traits that are independent of size, such as traits of individual leaves or roots or proportional allocation to different functions. However, plants also differ in maximum potential size, which could outweigh differences in module-level traits. We used a community ecosystem model called mondrian to investigate whether larger size inevitably increases competitive ability and how size interacts with nitrogen supply. Contrary to the conventional wisdom that bigger is better, we found that invader success and competitive ability are unimodal functions of maximum potential size, such that plants that are too large (or too small) are disproportionately suppressed by competition. Optimal size increases with nitrogen supply, even when plants compete for nitrogen only in a size-symmetric manner, although adding size-asymmetric competition for light does substantially increase the advantage of larger size at high nitrogen. These complex interactions of plant size and nitrogen supply lead to strong nonlinearities such that small differences in nitrogen can result in large differences in plant invasion success and the influence of competition along productivity gradients.

  8. Measurement of Dynamic Viscoelasticity of Full-Size Wood Composite Panels Using a Vibration Testing Method

    Science.gov (United States)

    Cheng Guan; Houjiang Zhang; John F. Hunt; Lujing Zhou; Dan Feng

    2016-01-01

    The dynamic viscoelasticity of full-size wood composite panels (WCPs) under the free-free vibrational state were determined by a vibration testing method. Vibration detection tests were performed on 194 pieces of three types of full-size WCPs (particleboard, medium density fiberboard, and plywood (PW)). The dynamic viscoelasticity from smaller specimens cut from the...

  9. 7 CFR 29.6025 - Lot.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Lot. 29.6025 Section 29.6025 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... INSPECTION Standards Definitions § 29.6025 Lot. A pile, basket, bulk, package, or other definite unit....

  10. 7 CFR 29.31 - Lot.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Lot. 29.31 Section 29.31 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... INSPECTION Regulations Definitions § 29.31 Lot. A pile, basket, bulk, package, or other definite unit....

  11. Dynamics of genome size evolution in birds and mammals

    Science.gov (United States)

    Feschotte, Cédric

    2017-01-01

    Genome size in mammals and birds shows remarkably little interspecific variation compared with other taxa. However, genome sequencing has revealed that many mammal and bird lineages have experienced differential rates of transposable element (TE) accumulation, which would be predicted to cause substantial variation in genome size between species. Thus, we hypothesize that there has been covariation between the amount of DNA gained by transposition and lost by deletion during mammal and avian evolution, resulting in genome size equilibrium. To test this model, we develop computational methods to quantify the amount of DNA gained by TE expansion and lost by deletion over the last 100 My in the lineages of 10 species of eutherian mammals and 24 species of birds. The results reveal extensive variation in the amount of DNA gained via lineage-specific transposition, but that DNA loss counteracted this expansion to various extents across lineages. Our analysis of the rate and size spectrum of deletion events implies that DNA removal in both mammals and birds has proceeded mostly through large segmental deletions (>10 kb). These findings support a unified “accordion” model of genome size evolution in eukaryotes whereby DNA loss counteracting TE expansion is a major determinant of genome size. Furthermore, we propose that extensive DNA loss, and not necessarily a dearth of TE activity, has been the primary force maintaining the greater genomic compaction of flying birds and bats relative to their flightless relatives. PMID:28179571

  12. Relationship between dynamic recrystallization, grain size distribution and rheology

    NARCIS (Netherlands)

    Heege, Johannes Hendrik ter

    2002-01-01

    The solid state flow behavior (rheology) of materials constituting the Earth’s mantle and crust is of key importance in controlling the dynamics of large scale geodynamic processes, such as mantle convection, subduction, mountain building and basin formation. Flow laws that are calibrated using

  13. Relationship between dynamic recrystallization, grain size distribution and rheology

    NARCIS (Netherlands)

    Heege, Johannes Hendrik ter

    2002-01-01

    The solid state flow behavior (rheology) of materials constituting the Earth’s mantle and crust is of key importance in controlling the dynamics of large scale geodynamic processes, such as mantle convection, subduction, mountain building and basin formation. Flow laws that are calibrated using l

  14. Metastable structures and size effects in small group dynamics

    OpenAIRE

    2014-01-01

    In his seminal works on group dynamics Bion defined a specific therapeutic setting allowing psychoanalytic observations on group phenomena. In describing the setting he proposed that the group was where his voice arrived. This physical limit was later made operative by assuming that the natural dimension of a therapeutic group is around 12 people. Bion introduced a theory of the group aspects of the mind in which proto-mental individual states spontaneously evolve into shared psychological s...

  15. Metastable structures and size effects in small group dynamics

    OpenAIRE

    2014-01-01

    In his seminal works on group dynamics Bion defined a specific therapeutic setting allowing psychoanalytic observations on group phenomena. In describing the setting he proposed that the group was where his voice arrived. This physical limit was later made operative by assuming that the natural dimension of a therapeutic group is around 12 people. Bion introduced a theory of the group aspects of the mind in which proto-mental individual states spontaneously evolve into shared psychological st...

  16. Effect of Porosity and Cell Size on the Dynamic Compressive Properties of Aluminum Alloy Foams

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The dynamic mechanical properties of open-cell aluminum alloy foams with different relative densities and cell sizeshave been investigated by compressive tests. The strain rates varied from 700 s-1 to 2600 s-1. The experimentalresults showed that the dynamic compressive stress-strain curves exhibited a typical three-stage behavior: elastic,plateau and densification. The dynamic compressive strength of foams is affected not only by the relative densitybut also by the strain rate and cell size. Aluminum alloy foams with higher relative density or smaller cell size aremore sensitive to the strain rate than foams with lower relative density or larger cell size.

  17. 46 CFR 160.026-6 - Sampling, inspection, and tests of production lots.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 6 2010-10-01 2010-10-01 false Sampling, inspection, and tests of production lots. 160... Hermetically Sealed Containers), for Merchant Vessels § 160.026-6 Sampling, inspection, and tests of production... 160.026-6(d1)—Sampling for Laboratory Tests Lot size Number of sets of samples to be selected...

  18. ANALYSIS OF HARRELL MONOSODIUM TITANATE LOT 46000908120

    Energy Technology Data Exchange (ETDEWEB)

    Taylor-Pashow, K.

    2014-04-09

    Monosodium titanate (MST) for use in the Actinide Removal Process (ARP) must be qualified and verified in advance. A single qualification sample for each batch of material is sent to SRNL for analysis, as well as a statistical sampling of verification samples. The original Harrell Industries Lot #46000908120 qualification and 16 verification samples received in October 2012 failed to meet the specification for weight percent solids. All of the pails sampled and tested contained less than 15 wt % MST solids. The lot was returned to the vendor, and in February 2014 a new qualification sample and set of 16 verification samples were received from this lot. The new lot met each of the selected specification requirements that were tested and, consequently, the material is acceptable for use in the ARP process.

  19. ANALYSIS OF HARRELL MONOSODIUM TITANATE LOT 46000824120

    Energy Technology Data Exchange (ETDEWEB)

    Taylor-Pashow, K.

    2014-04-09

    Monosodium titanate (MST) for use in the Actinide Removal Process (ARP) must be qualified and verified in advance. A single qualification sample for each batch of material is sent to SRNL for analysis, as well as a statistical sampling of verification samples. The original Harrell Industries Lot #46000824120 qualification and 16 verification samples received in September 2012 failed to meet the specification for weight percent solids. All of the pails sampled and tested contained less than 15 wt % MST solids. The lot was returned to the vendor, and in February 2014 a new qualification sample and set of 14 verification samples were received from this lot. The new lot met each of the selected specification requirements that were tested and, consequently, the material is acceptable for use in the ARP process.

  20. Dynamics of finite size neutrally buoyant particles in isotropic turbulence

    Energy Technology Data Exchange (ETDEWEB)

    Elhimer, M; Jean, A; Praud, O; Bazile, R; Marchal, M; Couteau, G, E-mail: elhimer@imft.fr [Universite de Toulouse, INPT, UPS, IMFT - Institut de Mecanique des Fluides de Toulouse, Allee Camille Soula, F-31400 Toulouse (France); CNRS, IMFT, F-31400 Toulouse (France)

    2011-12-22

    The dynamics of neutrally buoyant particles suspended in a turbulent flow is investigated experimentally, with particles having diameters larger than the Kolmogorov length scale. To that purpose, a turbulence generator have been constructed and the resulting flow characterized. The fluid was then seeded with polystyrene particles of diameter about 1 mm and their velocity measured separately and simultaneously with the surrounding fluid. Comparison of the velocities statistics between the two phases shows no appreciable discrepancy. However, simultaneous velocity measurement shows that particles may move in different direction from the underlying flow.

  1. Experimental Method for Microbubbles Dynamics Monitoring and Radius Sizing

    Science.gov (United States)

    Fouan, Damien; Achaoui, Younes; Payan, Cedric; Mensah, Serge

    Rationale and aim: Within the context of divers' decompression illness prevention, ultrasonic detection and sizing of circulating microbubbles in blood is of great interest. In order to be representative of the divers gas tension level (supersaturation) and thus, to optimize decompression stages, the measurements (made in the right ventricle region) should be performed during a short period of time (ventricle filling <20 ms), efficient to detect a broad range of bubbles' radii population (radius from 20 to 200 _m) and harmless (Mechanical Index MI<0.3).

  2. The size, shape, and dynamics of cellular blebs

    CERN Document Server

    Lim, Fong Yin; Mahadevan, L

    2015-01-01

    A cellular bleb grows when a portion of the cell membrane detaches from the underlying cortex under the influence of a cytoplasmic pressure. We develop a quantitative model for the growth and dynamics of these objects in a simple two-dimensional setting. In particular, we first find the minimum cytoplasmic pressure and minimum unsupported membrane length for a stationary bleb to nucleate and grow as a function of the membrane-cortex adhesion. We next show how a bleb may travel around the periphery of the cell when the cytoplasmic pressure varies in space and time in a prescribed way and find that the traveling speed is governed by the speed of the pressure change induced by local cortical contraction while the shape of the traveling bleb is governed by the speed of cortical healing. Finally, we relax the assumption that the pressure change is prescribed and couple it hydrodynamically to the cortical contraction and membrane deformation. By quantifying the phase space of bleb formation and dynamics, our framew...

  3. The effect of grain size on dynamic tensile extrusion behaviour

    Directory of Open Access Journals (Sweden)

    Park Leeju

    2015-01-01

    Full Text Available Dynamic tensile extrusion (DTE tests were conducted on coarse grained and ultrafine grained (UFG OFHC Cu, Interstitial free (IF Steel, and pure Ta. Equal channel angular pressing (ECAP of 16passes with Bc for Cu, IF Steel and 4 passes for Ta was employed to fabricated UFG materials. DTE tests were carried out by launching the sphere samples (Dia. 7.62 mm to the conical extrusion die at a speed of ∼500 m/sec. The fragmentation behavior of the soft-recovered fragments were examined and compared with each other. The DTE fragmentation behavior of CG and UFG was numerically simulated by the LS-DYNA FEM code.

  4. Finite size effect on dynamical entanglement entropy: CFT and holography

    CERN Document Server

    Mandal, Gautam; Ugajin, Tomonori

    2016-01-01

    Time-dependent entanglement entropy (EE) is computed for a single interval in two-dimensional conformal theories from a quenched initial state in the presence of spatial boundaries. The EE is found to be periodic in time with periodicity equal to the system size $L$. For large enough $L$, the EE shows a rise to a thermal value (characterized by a temperature $1/\\beta$ determined by the initial state), followed by periodic returns to the original value. This works irrespective of whether the conformal field theory (CFT) is rational or irrational. For conformal field theories with a holographic dual, the large $c$ limit plays an essential role in ensuring that the EE computed from the CFT is universal (independent of the details of the CFT and of boundary conditions) and is exactly matched by the holographic EE. The dual geometry is computed and it interpolates between a BTZ black hole at large $L$ and global AdS at large $\\beta$.

  5. Source Authentication for Code Dissemination Supporting Dynamic Packet Size in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Daehee Kim

    2016-07-01

    Full Text Available Code dissemination in wireless sensor networks (WSNs is a procedure for distributing a new code image over the air in order to update programs. Due to the fact that WSNs are mostly deployed in unattended and hostile environments, secure code dissemination ensuring authenticity and integrity is essential. Recent works on dynamic packet size control in WSNs allow enhancing the energy efficiency of code dissemination by dynamically changing the packet size on the basis of link quality. However, the authentication tokens attached by the base station become useless in the next hop where the packet size can vary according to the link quality of the next hop. In this paper, we propose three source authentication schemes for code dissemination supporting dynamic packet size. Compared to traditional source authentication schemes such as μTESLA and digital signatures, our schemes provide secure source authentication under the environment, where the packet size changes in each hop, with smaller energy consumption.

  6. Optimal pricing and lot sizing vendor managed inventory

    Directory of Open Access Journals (Sweden)

    Mohsen Ziaee

    2010-07-01

    Full Text Available Vendor Managed Inventory (VMI is one of the effective techniques for managing theinventory in supply chain. VMI models have been proven to reduce the cost of inventorycompared with traditional economic order quantity method under some conditions such asconstant demand and production expenditure. However, the modeling of the VMI problem hasnever been studied under some realistic assumptions such as price dependent demand. In thispaper, three problem formulations are proposed. In the first problem formulation, we study aVMI problem with one buyer and one supplier when demand is considered to be a function ofprice and price elasticity to demand, and production cost is also a function of demand. Theproposed model is formulated and solved in a form of geometric programming. For the secondand the third models, we consider VMI problem with two buyers and two suppliers assumingthat each buyer centre is relatively close to the other buyer centre. Each supplier has only oneproduct which is different from the product of the other supplier. Two suppliers cooperate incustomer relationship management and two buyers cooperate in supplier relationshipmanagement as well, so the suppliers send the orders of two buyers by one vehicle,simultaneously. For the third model, an additional assumption which is practically applicableand reasonable is considered. For all the proposed models, the optimal solution is comparedwith the traditional one. We demonstrate the implementation of our proposed models usingsome numerical examples.

  7. Measurement of Size-dependent Dynamic Shape Factors of Quartz Particles in Two Flow Regimes

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, Jennifer M.; Bell, David M.; Imre, D.; Kleiber, Paul; Grassian, Vicki H.; Zelenyuk, Alla

    2016-08-02

    Understanding and modeling the behavior of quartz dust particles, commonly found in the atmosphere, requires knowledge of many relevant particles properties, including particle shape. This study uses a single particle mass spectrometer, a differential mobility analyzer, and an aerosol particle mass analyzer to measure quartz aerosol particles mobility, aerodynamic, and volume equivalent diameters, mass, composition, effective density, and dynamic shape factor as a function of particle size, in both the free molecular and transition flow regimes. The results clearly demonstrate that dynamic shape factors can vary significantly as a function of particle size. For the quartz samples studied here, the dynamic shape factors increase with size, indicating that larger particles are significantly more aspherical than smaller particles. In addition, dynamic shape factors measured in the free-molecular (χv) and transition (χt) flow regimes can be significantly different, and these differences vary with the size of the quartz particles. For quartz, χv of small (d < 200 nm) particles is 1.25, while χv of larger particles (d ~ 440 nm) is 1.6, with a continuously increasing trend with particle size. In contrast χt, of small particles starts at 1.1 increasing slowly to 1.34 for 550 nm diameter particles. The multidimensional particle characterization approach used here goes beyond determination of average properties for each size, to provide additional information about how the particle dynamic shape factor may vary even for particles with the same mass and volume equivalent diameter.

  8. Size and Geometry Effects on the Mechanical Properties of Carrara Marble Under Dynamic Loadings

    Science.gov (United States)

    Zou, Chunjiang; Wong, Louis Ngai Yuen

    2016-05-01

    The effects of specimen size and geometry on the dynamic mechanical properties of Carrara marble including compressive strength, failure strain and elastic modulus are investigated in this research. Four different groups of specimens of different sizes and cross-sectional geometries are loaded under a wide range of strain rates by the split Hopkinson pressure bar setup. The experimental results indicate that all these mechanical properties are significantly influenced by the specimen size and geometry to different extent, hence highlighting the importance of taking into account of the specimen size and geometry in dynamic tests on rock materials. In addition, the transmission coefficient and the determination of strain rate under dynamic tests are discussed in detail.

  9. Characteristics of particle size distribution and pollutants content of sediments in parking lots runoff in the coastal area of Korea%韩国西海岸地区停车场径流携带沉积物的粒径分布及污染特征研究

    Institute of Scientific and Technical Information of China (English)

    于海霞; 于江华; 徐礼强; 金永喆

    2013-01-01

    为了解沿海地区城市停车场内径流携带沉积物的粒径分布及污染特征,于2011年4-6月在韩国西海岸12个不同停车场采集了沉积物样品,分别分析了其粒径分布和各粒径中污染物质的含量.结果表明,不同采样点的废弃物形态差异较大,主要表现在较大的植物茎叶、烟蒂及动物粪便等废弃物和含水率等方面.不同采样点的颗粒物粒径大小不同,其颗粒物的均一性也有所差异.总体来讲,106~500μm之间的颗粒物是径流携带沉积物的主要组成部分,其平均质量分数占总体(< 2360 μm)颗粒物的59.9%.对不同粒径中污染物质的含量分析得出,颗粒物中污染物质的含量随粒径增大而减小.其中,< 106 μm的颗粒物中总氮、总磷、COD和挥发性物质的质量分别占各污染物总量的18.9%、17.8%、20.41%和18.9%,而该部分颗粒物本身的平均质量分数只有3.9%.可见<106 μm的颗粒物处于高度污染状态.因此,在城市停车场面源污染管理中,应该对该部分高度污染的颗粒物给以足够的重视.对于不同污染特征的颗粒物应该采用不同的去除方法.%Road-deposit sediment samples were collected from twelve parking lots in the urban coastal area of Korea during April-June of 2004. The particle size distribution and concentrations of pollutants including total nitrogen, total phosphorus, chemical oxygen demand and volatile solids were analyzed. The sediments collected from different parking lots were distinct from each other and typically included contents of branches, cigarette-ends, animal wastes and water constituents. The particle size distribution and uniformity also differed from site to site. Particles in the range of 106 -500 μm contributed to a large portion of the sediments with a mass fraction of 59. 9% . Compared with larger particles, the smaller particles were determined as highly polluted. Around 18.9% of total nitrogen, 17.8% of total

  10. A Study of Joint Lot Size Model for Product Manufacturing and Material Ordering in the Supply Chain with Supply-Hub%嵌入Supply—hub的供应链联合生产与订货批量模型研究

    Institute of Scientific and Technical Information of China (English)

    桂华明

    2012-01-01

    Considering the supply pattern based on supply-hub under the Just-in-Time environment, the cost functions of manufacturer, supply-hub and supplier are established. Two supply chain lot size models for product manufacturing and material ordering are proposed under different decision modes: one is proposed under decentralized model based on Stackelberg model, the other is proposed under centralized model of the integrated supply chain. The results show that the manufacturer's production lot size changes disorderly under decentralized model, but it increases along with the increase of the distance between supplier and supply-hub under centralized model. Compared to decentralized model, the total cost of manufacturer increases but the total cost of both suppher and the whole supply chain decreases under centralized model. Through appropriately reducing material transfer price, the whole supply chain may achieve Pareto optimization since the manufacturer and supplier can obtain a win-win solution, and the farther distance between supplier and supply-hub, the more benefit the whole supply chain can get by coordination.%考虑JIT环境下基于Supply—hub的供货模式,建立了制造商、Supply—hub和供应商的平均成本函数.提出了供应链分散决策和集中决策情形下的制造商和供应商的生产与订货批量模型。结果表明,制造商的生产批量在供应链分散决策时变化无规律。而在供应链集中决策时随着供应商与Supply—hub之间距离的增加而增加:相比分散决策.供应链集中决策时制造商的成本增加而供应商的成本减少.而整个供应链的总成本减少,供应商可以通过转移支付让制造商和供应商均受益.从而实现整个供应链的帕累托优化.随着供应商与Supply—hub之间的距离增加,协调能够让供应链得到更多的收益。

  11. 7 CFR 989.104 - Lot.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Lot. 989.104 Section 989.104 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and... means: (1) For in-line inspection (i.e., where samples are drawn from a flow of raisins prior to...

  12. INCREASING RETURNS TO SCALE, DYNAMICS OF INDUSTRIAL STRUCTURE AND SIZE DISTRIBUTION OF FIRMS

    Institute of Scientific and Technical Information of China (English)

    Ying FAN; Menghui LI; Zengru DI

    2006-01-01

    A multi-agent model is presented to discuss the market dynamics and the size distribution of firms.The model emphasizes the effects of increasing returns to scale and gives the description of the born and death of adaptive producers. The evolution of market structure and its behavior under the technological shocks are investigated. Its dynamical results are in good agreement with some empirical "stylized facts" of industrial evolution. With the diversity of demand and adaptive growth strategies of firms, the firm size in the generalized model obeys the power-law distribution. Three factors mainly determine the competitive dynamics and the skewed size distributions of firms: 1. Self-reinforcing mechanism; 2. Adaptive firm growing strategies; 3. Demand diversity or widespread heterogeneity in the technological capabilities of firms.

  13. COAP BASED ACUTE PARKING LOT MONITORING SYSTEM USING SENSOR NETWORKS

    Directory of Open Access Journals (Sweden)

    R. Aarthi

    2014-06-01

    Full Text Available Vehicle parking is the act of temporarily maneuvering a vehicle in to a certain location. To deal with parking monitoring system issue such as traffic, this paper proposes a vision of improvements in monitoring the vehicles in parking lots based on sensor networks. Most of the existing paper deals with that of the automated parking which is of cluster based and each has its own overheads like high power, less energy efficiency, incompatible size of lots, space. The novel idea in this work is usage of CoAP (Constrained Application Protocol which is recently created by IETF (draft-ietf-core-coap-18, June 28, 2013, CoRE group to develop RESTful application layer protocol for communications within embedded wireless networks. This paper deals with the enhanced CoAP protocol using multi hop flat topology, which makes the acuters feel soothe towards parking vehicles. We aim to minimize the time consumed for finding free parking lot as well as increase the energy efficiency

  14. Aggregate size and structure determination of nanomaterials in physiological media: importance of dynamic evolution

    Science.gov (United States)

    Afrooz, A. R. M. Nabiul; Hussain, Saber M.; Saleh, Navid B.

    2014-12-01

    Most in vitro nanotoxicological assays are performed after 24 h exposure. However, in determining size and shape effect of nanoparticles in toxicity assays, initial characterization data are generally used to describe experimental outcome. The dynamic size and structure of aggregates are typically ignored in these studies. This brief communication reports dynamic evolution of aggregation characteristics of gold nanoparticles. The study finds that gradual increase in aggregate size of gold nanospheres (AuNS) occurs up to 6 h duration; beyond this time period, the aggregation process deviates from gradual to a more abrupt behavior as large networks are formed. Results of the study also show that aggregated clusters possess unique structural conformation depending on nominal diameter of the nanoparticles. The differences in fractal dimensions of the AuNS samples likely occurred due to geometric differences, causing larger packing propensities for smaller sized particles. Both such observations can have profound influence on dosimetry for in vitro nanotoxicity analyses.

  15. Development of an Autonomous Flight Control System for Small Size Unmanned Helicopter Based on Dynamical Model

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    It is devoted to the development of an autonomous flight control system for small size unmanned helicopter based on dynamical model. At first, the mathematical model of a small size helicopter is described. After that simple but effective MTCV control algorithm was proposed. The whole flight control algorithm is composed of two parts:orientation controller based on the model for rotation dynamics and a robust position controller for a double integrator. The MTCV block is also used to achieve translation velocity control. To demonstrate the performance of the presented algorithm, simulation results and results achieved in real flight experiments were presented.

  16. Dynamic Dipole-Dipole Interactions between Excitons in Quantum Dots of Different Sizes

    DEFF Research Database (Denmark)

    Matsueda, Hideaki; Leosson, Kristjan; Xu, Zhangcheng

    2005-01-01

    Micro-photoluminescence spectra of GaAs/AlGaAs coupled quantum dots (QDs) are given, and proposed to be analyzed by our resonance dynamic dipole-dipole interaction (RDDDI) model, based on parity inheritance and exchange of virtual photons among QDs of different sizes.......Micro-photoluminescence spectra of GaAs/AlGaAs coupled quantum dots (QDs) are given, and proposed to be analyzed by our resonance dynamic dipole-dipole interaction (RDDDI) model, based on parity inheritance and exchange of virtual photons among QDs of different sizes....

  17. Dynamic Dipole-Dipole Interactions between Excitons in Quantum Dots of Different Sizes

    DEFF Research Database (Denmark)

    Matsueda, Hideaki; Leosson, Kristjan; Xu, Zhangcheng;

    2005-01-01

    Micro-photoluminescence spectra of GaAs/AlGaAs coupled quantum dots (QDs) are given, and proposed to be analyzed by our resonance dynamic dipole-dipole interaction (RDDDI) model, based on parity inheritance and exchange of virtual photons among QDs of different sizes.......Micro-photoluminescence spectra of GaAs/AlGaAs coupled quantum dots (QDs) are given, and proposed to be analyzed by our resonance dynamic dipole-dipole interaction (RDDDI) model, based on parity inheritance and exchange of virtual photons among QDs of different sizes....

  18. A thermo dynamical model for the shape and size effect on melting of boron carbide nanoparticles.

    Science.gov (United States)

    Antoniammal, Paneerselvam; Arivuoli, Dakshanamoorthy

    2012-02-01

    The size and shape dependence of the melting temperature of Boron Carbide (B4C) nanoparticles has been investigated with a numerical thermo dynamical approach. The problem considered in this paper is the inward melting of nanoparticles with spherical and cylindrical geometry. The cylindrical Boron Carbide (B4C) nanoparticles, whose melting point has been reported to decrease with decreasing particle radius, become larger than spherical shaped nanoparticle. Comparative investigation of the size dependence of the melting temperature with respect to the two shapes is also been done. The melting temperature obtained in the present study is approximately a dealing function of radius, in a good agreement with prediction of thermo dynamical model.

  19. Sizing of the Series Dynamic Breaking Resistor in a Doubly Fed Induction Generator Wind Turbine

    DEFF Research Database (Denmark)

    Soliman, Hammam; Wang, Huai; Zhou, Dao

    2014-01-01

    This paper investigates the effect of Series Dynamic Breaking Resistor (SDBR) sizing on a Doubly Fed Induction Generator (DFIG) based wind power conversion system. The boundary of the SDBR value is firstly derived by taking into account the controllability of the rotor side converter and the maxi......This paper investigates the effect of Series Dynamic Breaking Resistor (SDBR) sizing on a Doubly Fed Induction Generator (DFIG) based wind power conversion system. The boundary of the SDBR value is firstly derived by taking into account the controllability of the rotor side converter...

  20. ATX-2, the C. elegans Ortholog of Human Ataxin-2, Regulates Centrosome Size and Microtubule Dynamics.

    Directory of Open Access Journals (Sweden)

    Michael D Stubenvoll

    2016-09-01

    Full Text Available Centrosomes are critical sites for orchestrating microtubule dynamics, and exhibit dynamic changes in size during the cell cycle. As cells progress to mitosis, centrosomes recruit more microtubules (MT to form mitotic bipolar spindles that ensure proper chromosome segregation. We report a new role for ATX-2, a C. elegans ortholog of Human Ataxin-2, in regulating centrosome size and MT dynamics. ATX-2, an RNA-binding protein, forms a complex with SZY-20 in an RNA-independent fashion. Depleting ATX-2 results in embryonic lethality and cytokinesis failure, and restores centrosome duplication to zyg-1 mutants. In this pathway, SZY-20 promotes ATX-2 abundance, which inversely correlates with centrosome size. Centrosomes depleted of ATX-2 exhibit elevated levels of centrosome factors (ZYG-1, SPD-5, γ-Tubulin, increasing MT nucleating activity but impeding MT growth. We show that ATX-2 influences MT behavior through γ-Tubulin at the centrosome. Our data suggest that RNA-binding proteins play an active role in controlling MT dynamics and provide insight into the control of proper centrosome size and MT dynamics.

  1. Finite-size scaling study of dynamic critical phenomena in a vapor-liquid transition

    Science.gov (United States)

    Midya, Jiarul; Das, Subir K.

    2017-01-01

    Via a combination of molecular dynamics (MD) simulations and finite-size scaling (FSS) analysis, we study dynamic critical phenomena for the vapor-liquid transition in a three dimensional Lennard-Jones system. The phase behavior of the model has been obtained via the Monte Carlo simulations. The transport properties, viz., the bulk viscosity and the thermal conductivity, are calculated via the Green-Kubo relations, by taking inputs from the MD simulations in the microcanonical ensemble. The critical singularities of these quantities are estimated via the FSS method. The results thus obtained are in nice agreement with the predictions of the dynamic renormalization group and mode-coupling theories.

  2. Manufacturing lot affects polyethylene tibial insert volume, thickness, and surface geometry.

    Science.gov (United States)

    Teeter, Matthew G; Milner, Jaques S; MacDonald, Steven J; Naudie, Douglas D R

    2013-08-01

    To perform wear measurements on retrieved joint replacement implants, a reference geometry of the implant's original state is required. Since implants are rarely individually scanned before implantation, a different, new implant of the same kind and size is frequently used. However, due to manufacturing variability, errors may be introduced into these measurements, as the dimensions between the retrieved and reference components may not be exactly the same. The hypothesis of this study was that new polyethylene tibial inserts from different manufacturing lots would demonstrate greater variability than those from the same lot. In total, 12 new tibial inserts of the same model and size were obtained, 5 from the same lot and the remainder from different lots. The geometry of each tibial insert was obtained using microcomputed tomography. Measurements of tibial insert volume, thickness, and three-dimensional surface deviations were obtained and compared between tibial inserts from the same and different manufacturing lots. Greater variability was found for the tibial inserts from different manufacturing lots for all types of measurements, including a fourfold difference in volume variability (p manufacturing lots for use as the reference geometry.

  3. Glassy dynamics of model colloidal polymers: The effect of "monomer" size

    Science.gov (United States)

    Li, Jian; Zhang, Bo-kai; Li, Hui-shu; Chen, Kang; Tian, Wen-de; Tong, Pei-qing

    2016-05-01

    In recent years, attempts have been made to assemble colloidal particles into chains, which are termed "colloidal polymers." An apparent difference between molecular and colloidal polymers is the "monomer" size. Here, we propose a model to represent the variation from molecular polymer to colloidal polymer and study the quantitative differences in their glassy dynamics. For chains, two incompatible local length scales, i.e., monomer size and bond length, are manifested in the radial distribution function and intramolecular correlation function. The mean square displacement of monomers exhibits Rouse-like sub-diffusion at intermediate time/length scale and the corresponding exponent depends on the volume fraction and the monomer size. We find that the threshold volume fraction at which the caging regime emerges can be used as a rescaling unit so that the data of localization length versus volume fraction for different monomer sizes can gather close to an exponential curve. The increase of monomer size effectively increases the hardness of monomers and thus makes the colloidal polymers vitrify at lower volume fraction. Static and dynamic equivalences between colloidal polymers of different monomer sizes have been discussed. In the case of having the same peak time of the non-Gaussian parameter, the motion of monomers of larger size is much less non-Gaussian. The mode-coupling critical exponents for colloidal polymers are in agreement with that of flexible bead-spring chains.

  4. The Dynamics of Small-Sized Ensembles of the Phase-Locked Loops with Unidirectional Couplings

    Science.gov (United States)

    Aleshin, K. N.; V. Matrosov, V.; Shalfeev, V. D.

    2016-06-01

    We study collective dynamics of a small-sized chain of the unidirectionally coupled phase-locked loop. The conditions for the synchronous-regime existence are found, the asynchronous selfoscillation regimes and the transitions among them are studied, and the property of inheriting the structure of the parameter space of the chain when a new element is added to it is established.

  5. Dynamic dipole-dipole interactions between excitons in quantum dots of different sizes

    DEFF Research Database (Denmark)

    Matsueda, Hideaki; Leosson, Kristjan; Xu, Zhangcheng;

    2004-01-01

    A model of the resonance dynamic dipole-dipole interaction between excitons confined in quantum dots (QDs) of different sizes at close enough distance is given in terms of parity inheritance and exchange of virtual photons. Microphotoluminescence spectra of GaAs-AlGaAs coupled QDs are proposed to...

  6. Brain Dynamics of Word Familiarization in 20-Month-Olds: Effects of Productive Vocabulary Size

    Science.gov (United States)

    Torkildsen, Janne von Koss; Hansen, Hanna Friis; Svangstu, Janne Mari; Smith, Lars; Simonsen, Hanne Gram; Moen, Inger; Lindgren, Magnus

    2009-01-01

    The present study investigated the brain mechanisms involved during young children's receptive familiarization with new words, and whether the dynamics of these mechanisms are related to the child's productive vocabulary size. To this end, we recorded event-related potentials (ERPs) from 20-month-old children in a pseudoword repetition task.…

  7. Required sample size for monitoring stand dynamics in strict forest reserves: a case study

    Science.gov (United States)

    Diego Van Den Meersschaut; Bart De Cuyper; Kris Vandekerkhove; Noel Lust

    2000-01-01

    Stand dynamics in European strict forest reserves are commonly monitored using inventory densities of 5 to 15 percent of the total surface. The assumption that these densities guarantee a representative image of certain parameters is critically analyzed in a case study for the parameters basal area and stem number. The required sample sizes for different accuracy and...

  8. Experimental investigation of dynamic effects in capillary pressure: Grain size dependency and upscaling

    Science.gov (United States)

    Camps-Roach, Geremy; O'Carroll, Denis M.; Newson, Timothy A.; Sakaki, Toshihiro; Illangasekare, Tissa H.

    2010-08-01

    The macroscopic flow equations used to predict two-phase flow typically utilizes a capillary pressure-saturation relationship determined under equilibrium conditions. Theoretical reasoning, experimental evidence, and numerical modeling results have indicated that when one fluid phase replaces another fluid, this relationship may not be unique but may depend on the rate at which the phase saturations change in response to changes in phase pressures. This nonuniqueness likely depends on a variety of factors including soil-fluid properties and possibly physical scale. To quantify this dependency experimentally, direct measurements of equilibrium and dynamic capillary pressure-saturation relationships were developed for two Ottawa sands with different grain sizes using a 20 cm long column. A number of replicate air-water experiments were conducted to facilitate statistical comparison of capillary pressure-saturation relationships. Water and air pressures and phase saturations were measured at three different vertical locations in the sand column under different desaturation rates (1) to measure local capillary pressure-saturation relationships (static and dynamic); (2) to quantify the dynamic coefficient τ, a measure of the magnitude of observed dynamic effects, as a function of water saturation for different grain sizes and desaturation rates; (3) to investigate the importance of grain size on measured dynamic effects; and (4) to assess the importance of sample scale on the magnitude of dynamic effects in capillary pressure. A comparison of the static and dynamic Pc-Sw relationships showed that at a given water saturation, capillary pressure measured under transient water drainage conditions is statistically larger than capillary pressure measured under equilibrium or static conditions, consistent with thermodynamic theory. The dynamic coefficient τ, used in the expression relating the static and dynamic capillary pressures to the desaturation rate was dependant on

  9. Structural and dynamical properties of ionic liquids: the influence of ion size disparity.

    Science.gov (United States)

    Spohr, H V; Patey, G N

    2008-08-14

    The influence of ion size disparity on structural and dynamical properties of ionic liquids is systematically investigated employing molecular dynamics simulations. Ion size ratios are varied over a realistic range (from 1:1 to 5:1) while holding other important molecular and system parameters fixed. In this way we isolate and identify effects that stem from size disparity alone. In strongly size disparate systems the larger species (cations in our model) tend to dominate the structure; the anion-anion distribution is largely determined by anion-cation correlations. The diffusion coefficients of both species increase, and the shear viscosity decreases with increasing size disparity. The influence of size disparity is strongest up to a size ratio of 3:1, then decreases, and by 5:1 both the diffusion coefficients and viscosity appear to be approaching limiting values. The conventional Stokes-Einstein expression for diffusion coefficients holds reasonably well for the cations but fails for the smaller anions as size disparity increases likely due to the neglect of strong anion-cation correlations. The electrical conductivity is not a simple monotonic function of size disparity; it first increases up to size ratios of 2:1, remains nearly constant until 3:1, then decreases such that the conductivities of the 1:1 and 5:1 systems are similar. This behavior is traced to the competing influences of ion diffusion (enhancing) and ion densities (reducing) on conductivities at constant packing fraction. The temperature dependence of the transport properties is examined for the 1:1 and 3:1 systems. In accord with experiment, the temperature dependence of all transport properties is well represented by the Vogel-Fulcher-Tammann equation. The dependence of the diffusion coefficients on the temperature/viscosity ratio is well described by the fractional Stokes-Einstein relation D proportional to (T/eta)(beta) with beta approximately = 0.8, consistent with the exponent observed for

  10. Statistical validation of reagent lot change in the clinical chemistry laboratory can confer insights on good clinical laboratory practice.

    Science.gov (United States)

    Cho, Min-Chul; Kim, So Young; Jeong, Tae-Dong; Lee, Woochang; Chun, Sail; Min, Won-Ki

    2014-11-01

    Verification of new lot reagent's suitability is necessary to ensure that results for patients' samples are consistent before and after reagent lot changes. A typical procedure is to measure results of some patients' samples along with quality control (QC) materials. In this study, the results of patients' samples and QC materials in reagent lot changes were analysed. In addition, the opinion regarding QC target range adjustment along with reagent lot changes was proposed. Patients' sample and QC material results of 360 reagent lot change events involving 61 analytes and eight instrument platforms were analysed. The between-lot differences for the patients' samples (ΔP) and the QC materials (ΔQC) were tested by Mann-Whitney U tests. The size of the between-lot differences in the QC data was calculated as multiples of standard deviation (SD). The ΔP and ΔQC values only differed significantly in 7.8% of the reagent lot change events. This frequency was not affected by the assay principle or the QC material source. One SD was proposed for the cutoff for maintaining pre-existing target range after reagent lot change. While non-commutable QC material results were infrequent in the present study, our data confirmed that QC materials have limited usefulness when assessing new reagent lots. Also a 1 SD standard for establishing a new QC target range after reagent lot change event was proposed.

  11. Simulation of Particle Size Effect on Dynamic Properties and Fracture of PTFE-W-Al Composites

    Science.gov (United States)

    Herbold, E. B.; Cai, J.; Benson, D. J.; Nesterenko, V. F.

    2007-12-01

    Recent investigations of the dynamic compressive strength of cold isostatically pressed composites of polytetrafluoroethylene (PTFE), tungsten (W) and aluminum (Al) powders show significant differences depending on the size of metallic particles. The addition of W increases the density and changes the overall strength of the sample depending on the size of W particles. To investigate relatively large deformations, multi-material Eulerian and arbitrary Lagrangian-Eulerian methods, which have the ability to efficiently handle the formation of free surfaces, were used. The calculations indicate that the increased sample strength with fine metallic particles is due to the dynamic formation of force chains. This phenomenon occurs for samples with a higher porosity of the PTFE matrix compared to samples with larger particle size of W and a higher density PTFE matrix.

  12. Sizing of the Series Dynamic Breaking Resistor in a Doubly Fed Induction Generator Wind Turbine

    DEFF Research Database (Denmark)

    Soliman, Hammam; Wang, Huai; Zhou, Dao

    2014-01-01

    This paper investigates the effect of Series Dynamic Breaking Resistor (SDBR) sizing on a Doubly Fed Induction Generator (DFIG) based wind power conversion system. The boundary of the SDBR value is firstly derived by taking into account the controllability of the rotor side converter and the maxi......This paper investigates the effect of Series Dynamic Breaking Resistor (SDBR) sizing on a Doubly Fed Induction Generator (DFIG) based wind power conversion system. The boundary of the SDBR value is firstly derived by taking into account the controllability of the rotor side converter...... and the maximum allowable voltage of the stator. Then the impact of the SDBR value on the rotor current, stator voltage, DC-link voltage, reactive power capability and introduced power loss during voltage sag operation is evaluated by simulation. The presented study enables a trade-off sizing of the SDBR among...

  13. The effect of food portion sizes on the obesity prevention using system dynamics modelling

    Science.gov (United States)

    Abidin, Norhaslinda Zainal; Zulkepli, Jafri Hj; Zaibidi, Nerda Zura

    2014-09-01

    The rise in income and population growth have increased the demand for food and induced changes in food habits, food purchasing and consumption patterns in Malaysia. With this transition, one of the plausible causes of weight gain and obesity is the frequent consumption of outside food which is synonymous with bigger portion size. Therefore, the aim of this paper is to develop a system dynamics model to analyse the effect of reducing food portion size on weight and obesity prevention. This study combines the different strands of knowledge comprise of nutrition, physical activity and body metabolism. These elements are synthesized into a system dynamics model called SIMULObese. Findings from this study suggested that changes in eating behavior should not emphasize only on limiting the food portion size consumption. The efforts should also consider other eating events such as controlling the meal frequency and limiting intake of high-calorie food in developing guidelines to prevent obesity.

  14. 基于改进蚁群算法的一类运输能力约束的生产-运输批量问题求解%An Improved Ant Colony Algorithm for Solving Production Transportation Lot-Sizing Problem

    Institute of Scientific and Technical Information of China (English)

    李英俊; 陈志祥

    2012-01-01

    针对生产与运输两个过程的联合决策,通过分析一类生产-运输批量优化问题,建立的混合0-1整数规划模型整合了多产品多阶段能力约束批量生产和产品运输.其中运输成本由运输工具使用数量决定,当企业内部运输能力不能满足运输需求时可将运输外包,但需支付更高的运输成本.根据此问题的特点,构造改进蚁群算法求解,令其信息素和启发信息都存在0和1两种状态下的不同取值,通过转移概率确定0-1生产准备矩阵,进一步得到生产矩阵和运输计划.仿真实验结果表明在生产批量决策的同时考虑运输,可以减少运输成本,令总费用最小,通过将实验结果与其他优化算法比较,所构造的蚁群算法寻优概率是100%,平均进化10代,平均耗时小于l s,稳定性和求解效率均高于其他算法,是求解这类问题一种有效与适用的算法.%Aiming at the implementation of joint decision of production and transportation, production-transportation lot-sizing problem is discussed, which is a multi-item-and-multi-period capacitated lot-sizing and transportation problem. This problem is then formulated as a 0-1 mixed integer programming problem. In this model, the transportation cost is decided by the numbers of containers. However, if demands ex-ceed the transportation capacity, it can be outsourced, but with higher freight rate. After analyzing the properties of the model, an improved ant colony algorithm (ANT) is proposed. By this algorithm, different value of pheromone and heuristic information is set as 0-state or 1 -state. Then, the 0-1 setup matrix, production matrix, and transportation plan can be obtained accordingly. A numerical example shows that integrated production and transportation can effectively reduce the procurement cost and further reduce the total cost. Comparison with other methods shows that the searching optimization probability of the proposed ANT is 100% , the average

  15. Molecular dynamics simulations of nanodroplet spreading on solid surfaces, effect of droplet size

    Energy Technology Data Exchange (ETDEWEB)

    Sedighi, Nahid; Aggarwal, Suresh K [Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, IL (United States); Murad, Sohail [Department of Chemical Engineering, University of Illinois at Chicago, Chicago, IL (United States)], E-mail: ska@uic.edu

    2010-06-15

    Molecular dynamics simulations were performed to study the spreading characteristics of nano-sized droplets on solid surfaces. The spreading behavior was analyzed in terms of the temporal evolution of the dynamic contact angle and spreading diameter for wettable, partially wettable and non-wettable surfaces. The computational model was validated through qualitative comparison with the measurements of Bayer and Megaridis, and through comparison with existing correlations. The comparison based on the ratio of relevant time scales indicated that for the conditions investigated, the spreading dynamics is governed by inertial and surface forces, with negligible influence of viscous forces. In addition, the simulation results indicated that the dynamic contact angle and spreading diameter, as well as the advancing and receding time periods, exhibit strong dependence on droplet size. These results were further analyzed to obtain correlations for the effect of droplet size on these spreading parameters. The correlations indicated that the normalized spreading diameter and contact angle scale with drop diameter as D{sub m} /D{sub 0} {approx}D{sub 0}{sup 0.5} and {theta}{sub R} {approx}D{sub 0}{sup 0.5}, while the advancing and receding time periods scale as t{approx}D{sub 0}{sup 2/3}. Global kinetic energy and surface energy considerations were used to provide a physical basis for these correlations. The correlations were also found to be generally consistent with the experimentally observed spreading behavior of macroscopic droplets.

  16. Molecular dynamics simulations of nanodroplet spreading on solid surfaces, effect of droplet size

    Science.gov (United States)

    Sedighi, Nahid; Murad, Sohail; Aggarwal, Suresh K.

    2010-06-01

    Molecular dynamics simulations were performed to study the spreading characteristics of nano-sized droplets on solid surfaces. The spreading behavior was analyzed in terms of the temporal evolution of the dynamic contact angle and spreading diameter for wettable, partially wettable and non-wettable surfaces. The computational model was validated through qualitative comparison with the measurements of Bayer and Megaridis, and through comparison with existing correlations. The comparison based on the ratio of relevant time scales indicated that for the conditions investigated, the spreading dynamics is governed by inertial and surface forces, with negligible influence of viscous forces. In addition, the simulation results indicated that the dynamic contact angle and spreading diameter, as well as the advancing and receding time periods, exhibit strong dependence on droplet size. These results were further analyzed to obtain correlations for the effect of droplet size on these spreading parameters. The correlations indicated that the normalized spreading diameter and contact angle scale with drop diameter as Dm /D0 ~D00.5 and θR ~D00.5, while the advancing and receding time periods scale as t~D02/3. Global kinetic energy and surface energy considerations were used to provide a physical basis for these correlations. The correlations were also found to be generally consistent with the experimentally observed spreading behavior of macroscopic droplets.

  17. A Hill Cipher Modification Based on Eigenvalues Extension with Dynamic Key Size HCM-EXDKS

    Directory of Open Access Journals (Sweden)

    Ahmed Y. Mahmoud

    2014-04-01

    Full Text Available All the proposed Hill cipher modifications have been restricted to the use of dynamic keys only. In this paper, we propose an extension of Hill cipher modification based on eigenvalues HCM-EE, called HCM-EXDKS. The proposed extension generating dynamic encryption key matrix by exponentiation that is made efficiently with the help of eigenvalues, HCM-EXDKS introduces a new class of dynamic keys together with dynamically changing key size. Security of HCM-EXDKS is provided by the use of a large number of dynamic keys with variable size. The proposed extension is more effective in the encryption quality of RGB images than HCM-EE and Hill cipher-known modifications in the case of images with large single colour areas and slightly more effective otherwise. HCM-EXDKS almost has the same encryption time as HCM-EE, and HCM-HMAC. HCM-EXDKS is two times faster than HCM-H, having the best encryption quality among Hill cipher modifications compared versus HCM-EXDKS.

  18. Excited-state dynamics of size-dependent colloidal TiO2-Au nanocomposites

    Science.gov (United States)

    Karam, Tony E.; Khoury, Rami A.; Haber, Louis H.

    2016-03-01

    The ultrafast excited-state dynamics of size-dependent TiO2-Au nanocomposites synthesized by reducing gold nanoclusters to the surface of colloidal TiO2 nanoparticles are studied using pump-probe transient absorption spectroscopy with 400 nm excitation pulses. The results show that the relaxation processes of the plasmon depletion band, which are described by electron-phonon and phonon-phonon scattering lifetimes, are independent of the gold nanocluster shell size surrounding the TiO2 nanoparticle core. The dynamics corresponding to interfacial electron transfer between the gold nanoclusters and the TiO2 bandgap are observed to spectrally overlap with the gold interband transition signal, and the electron transfer lifetimes are shown to significantly decrease as the nanocluster shell size increases. Additionally, size-dependent periodic oscillations are observed and are attributed to acoustic phonons of a porous shell composed of aggregated gold nanoclusters around the TiO2 core, with frequencies that decrease and damping times that remain constant as the nanocluster shell size increases. These results are important for the development of improved catalytic nanomaterial applications.

  19. Study of system- size effects in multi- fragmentation using Quantum Molecular Dynamics model

    CERN Document Server

    Singh, J; Aichelin, Jörg; Singh, Jaivir; Puri, Rajeev K.

    2001-01-01

    We report, for the first time, the dependence of the multiplicity of different fragments on the system size employing a quantum molecular dynamics model. This dependence is extracted from the simulations of symmetric collisions of Ca+Ca, Ni+Ni, Nb+Nb, Xe+Xe, Er+Er, Au+Au and U+U at incident energies between 50 A MeV and 1 A GeV. We find that the multiplicity of different fragments scales with the size of the system which can be parameterized by a simple power law.

  20. Size Effect of Lattice Thermal Conductivity Across Nanoscale Thin Films by Molecular Dynamics Simulations

    Institute of Scientific and Technical Information of China (English)

    FENG Xiao-Li; LI Zhi-Xin; GUO Zeng-Yuan

    2001-01-01

    Thermal conductivity in the normal direction of ultra-thin dielectric films is predicted by molecular dynamics calculations for argon crystal. For film thicknesses of about 2-10nm within which real measurements cannot yet be implemented, the size dependence of lattice thermal conductivity is captured and a remarkable thermal conductivity drop is found as compared with bulk experimental data. This size effect demonstrates that phonon-boundary scattering in thin films may also be very significant at high temperatures even above the Debye temperature. The influence of different potential models is examined according to the comparison between results from the Lennard-Jones potential and a soft-sphere potential.

  1. Influence of protein crowder size on hydration structure and dynamics in macromolecular crowding

    Science.gov (United States)

    Wang, Po-hung; Yu, Isseki; Feig, Michael; Sugita, Yuji

    2017-03-01

    We investigate the effects of protein crowder sizes on hydration structure and dynamics in macromolecular crowded systems by all-atom MD simulations. The crowded systems consisting of only small proteins showed larger total surface areas than those of large proteins at the same volume fractions. As a result, more water molecules were trapped within the hydration shells, slowing down water diffusion. The simulation results suggest that the protein crowder size is another factor to determine the effect of macromolecular crowding and to explain the experimental kinetic data of proteins and DNAs in the presence of crowding agents.

  2. Investigation of particles size effects in Dissipative Particle Dynamics (DPD) modelling of colloidal suspensions

    Science.gov (United States)

    Mai-Duy, N.; Phan-Thien, N.; Khoo, B. C.

    2015-04-01

    In the Dissipative Particle Dynamics (DPD) simulation of suspension, the fluid (solvent) and colloidal particles are replaced by a set of DPD particles and therefore their relative sizes (as measured by their exclusion zones) can affect the maximal packing fraction of the colloidal particles. In this study, we investigate roles of the conservative, dissipative and random forces in this relative size ratio (colloidal/solvent). We propose a mechanism of adjusting the DPD parameters to properly model the solvent phase (the solvent here is supposed to have the same isothermal compressibility to that of water).

  3. Communication: Kirkwood-Buff integrals in the thermodynamic limit from small-sized molecular dynamics simulations

    Science.gov (United States)

    Cortes-Huerto, R.; Kremer, K.; Potestio, R.

    2016-10-01

    We present an accurate and efficient method to obtain Kirkwood-Buff (KB) integrals in the thermodynamic limit from small-sized molecular dynamics simulations. By introducing finite size effects into integral equations of statistical mechanics, we derive an analytical expression connecting the KB integrals of the bulk system with the fluctuations of the number of molecules in the corresponding closed system. We validate the method by calculating the activity coefficients of aqueous urea mixtures and the KB integrals of Lennard-Jones fluids. Moreover, our results demonstrate how to identify simulation conditions under which computer simulations reach the thermodynamic limit.

  4. Hybrid Discrete Differential Evolution Algorithm for Lot Splitting with Capacity Constraints in Flexible Job Scheduling

    Directory of Open Access Journals (Sweden)

    Xinli Xu

    2013-01-01

    Full Text Available A two-level batch chromosome coding scheme is proposed to solve the lot splitting problem with equipment capacity constraints in flexible job shop scheduling, which includes a lot splitting chromosome and a lot scheduling chromosome. To balance global search and local exploration of the differential evolution algorithm, a hybrid discrete differential evolution algorithm (HDDE is presented, in which the local strategy with dynamic random searching based on the critical path and a random mutation operator is developed. The performance of HDDE was experimented with 14 benchmark problems and the practical dye vat scheduling problem. The simulation results showed that the proposed algorithm has the strong global search capability and can effectively solve the practical lot splitting problems with equipment capacity constraints.

  5. Spawning Dynamics and Size Related Trends in Reproductive Parameters of Southern Bluefin Tuna, Thunnus maccoyii.

    Directory of Open Access Journals (Sweden)

    Jessica H Farley

    Full Text Available Knowledge of spawning behaviour and fecundity of fish is important for estimating the reproductive potential of a stock and for constructing appropriate statistical models for assessing sustainable catch levels. Estimates of length-based reproductive parameters are particularly important for determining potential annual fecundity as a function of fish size, but they are often difficult to estimate reliably. Here we provide new information on the reproductive dynamics of southern bluefin tuna (SBT Thunnus maccoyii through the analysis of fish size and ovary histology collected on the spawning ground in 1993-1995 and 1999-2002. These are used to refine previous parameter estimates of spawning dynamics and investigate size related trends in these parameters. Our results suggest that the small SBT tend to arrive on the spawning ground slightly later and depart earlier in the spawning season relative to large fish. All females were mature and the majority were classed as spawning capable (actively spawning or non-spawning with a very small proportion classed as regressing. The fraction of females spawning per day decreased with fish size, but once females start a spawning episode, they spawned daily irrespective of size. Mean batch fecundity was estimated directly at 6.5 million oocytes. Analysis of ovary histology and ovary weight data indicated that relative batch fecundity, and the duration of spawning and non-spawning episodes, increased with fish size. These reproductive parameter estimates could be used with estimates of residency time on the spawning ground as a function of fish size (if known and demographic data for the spawning population to provide a time series of relative annual fecundity for SBT.

  6. Chaotic dynamics of size dependent Timoshenko beams with functionally graded properties along their thickness

    Science.gov (United States)

    Awrejcewicz, J.; Krysko, A. V.; Pavlov, S. P.; Zhigalov, M. V.; Krysko, V. A.

    2017-09-01

    Chaotic dynamics of microbeams made of functionally graded materials (FGMs) is investigated in this paper based on the modified couple stress theory and von Kármán geometric nonlinearity. We assume that the beam properties are graded along the thickness direction. The influence of size-dependent and functionally graded coefficients on the vibration characteristics, scenarios of transition from regular to chaotic vibrations as well as a series of static problems with an emphasis put on the load-deflection behavior are studied. Our theoretical/numerical analysis is supported by methods of nonlinear dynamics and the qualitative theory of differential equations supplemented by Fourier and wavelet spectra, phase portraits, and Lyapunov exponents spectra estimated by different algorithms, including Wolf's, Rosenstein's, Kantz's, and neural networks. We have also detected and numerically validated a general scenario governing transition into chaotic vibrations, which follows the classical Ruelle-Takens-Newhouse scenario for the considered values of the size-dependent and grading parameters.

  7. Node dynamics and cusps size distribution at the border of liquid sheets

    Science.gov (United States)

    Villermaux, E.; Almarcha, C.

    2016-08-01

    We study the intrinsic dynamics of cusps, or indentations, moving along a liquid sheet border, and characterize their ensemble statistics. Gordillo and collaborators [J. Fluid Mech. 754, R1 (2014), 10.1017/jfm.2014.397] have shown that the symmetrical stationary cusp is the only structure accommodating for both mass and momentum conservation at a steadily receding liquid sheet rim. Cusps are also known to typically move along a sheet border, to present an asymmetry, and to be distributed in size around a mean. We show here why a heterogeneous assembly of cusps traveling along the sheet rim occurs spontaneously, why big and small cusps coexist at the same time, and, more precisely, we establish a specific link between the microscopic dynamics directing their motion, and the ensemble averaged distribution of their sizes.

  8. Dynamics of Dissolved Organic Matter and Microbes in Seawater through Sub-Micron Particle Size Analyses

    Digital Repository Service at National Institute of Oceanography (India)

    Goes, J.I.; Balch, W.M.; Vaughn, J.M.; Gomes, H.R.

    , 1997). In view of the above, understanding the processes regulating the dynamics and distribution of DOM in seawater, assumes tremendous importance for global biogeochemistry and climate change studies. Phytoplankton are the primary source of oceanic.... The exact relationship between the lift force and the channel flow velocity is not well- characterized and calibrations with standard monodispersed particles (>1?m) are necessary to calibrate an FFFF fractogram into a size distribution plot. The FFFF...

  9. Structure, compressibility factor, and dynamics of highly size-asymmetric binary hard-disk liquids.

    Science.gov (United States)

    Xu, Wen-Sheng; Sun, Zhao-Yan; An, Li-Jia

    2012-09-14

    By using event-driven molecular dynamics simulation, we investigate effects of varying the area fraction of the smaller component on structure, compressibility factor, and dynamics of the highly size-asymmetric binary hard-disk liquids. We find that the static pair correlations of the large disks are only weakly perturbed by adding small disks. The higher-order static correlations of the large disks, by contrast, can be strongly affected. Accordingly, the static correlation length deduced from the bond-orientation correlation functions first decreases significantly and then tends to reach a plateau as the area fraction of the small disks increases. The compressibility factor of the system first decreases and then increases upon increasing the area fraction of the small disks and separating different contributions to it allows to rationalize this non-monotonic phenomenon. Furthermore, adding small disks can influence dynamics of the system in quantitative and qualitative ways. For the large disks, the structural relaxation time increases monotonically with increasing the area fraction of the small disks at low and moderate area fractions of the large disks. In particular, "reentrant" behavior appears at sufficiently high area fractions of the large disks, strongly resembling the reentrant glass transition in short-ranged attractive colloids and the inverted glass transition in binary hard spheres with large size disparity. By tuning the area fraction of the small disks, relaxation process for the small disks shows concave-to-convex crossover and logarithmic decay behavior, as found in other binary mixtures with large size disparity. Moreover, diffusion of both species is suppressed by adding small disks. Long-time diffusion for the small disks shows power-law-like behavior at sufficiently high area fractions of the small disks, which implies precursors of a glass transition for the large disks and a localization transition for the small disks. Therefore, our results

  10. Scale-invariant neuronal avalanche dynamics and the cut-off in size distributions.

    Directory of Open Access Journals (Sweden)

    Shan Yu

    Full Text Available Identification of cortical dynamics strongly benefits from the simultaneous recording of as many neurons as possible. Yet current technologies provide only incomplete access to the mammalian cortex from which adequate conclusions about dynamics need to be derived. Here, we identify constraints introduced by sub-sampling with a limited number of electrodes, i.e. spatial 'windowing', for well-characterized critical dynamics-neuronal avalanches. The local field potential (LFP was recorded from premotor and prefrontal cortices in two awake macaque monkeys during rest using chronically implanted 96-microelectrode arrays. Negative deflections in the LFP (nLFP were identified on the full as well as compact sub-regions of the array quantified by the number of electrodes N (10-95, i.e., the window size. Spatiotemporal nLFP clusters organized as neuronal avalanches, i.e., the probability in cluster size, p(s, invariably followed a power law with exponent -1.5 up to N, beyond which p(s declined more steeply producing a 'cut-off' that varied with N and the LFP filter parameters. Clusters of size s≤N consisted mainly of nLFPs from unique, non-repeated cortical sites, emerged from local propagation between nearby sites, and carried spatial information about cluster organization. In contrast, clusters of size s>N were dominated by repeated site activations and carried little spatial information, reflecting greatly distorted sampling conditions. Our findings were confirmed in a neuron-electrode network model. Thus, avalanche analysis needs to be constrained to the size of the observation window to reveal the underlying scale-invariant organization produced by locally unfolding, predominantly feed-forward neuronal cascades.

  11. The effect of EIF dynamics on the cryopreservation process of a size distributed cell population.

    Science.gov (United States)

    Fadda, S; Briesen, H; Cincotti, A

    2011-06-01

    Typical mathematical modeling of cryopreservation of cell suspensions assumes a thermodynamic equilibrium between the ice and liquid water in the extracellular solution. This work investigates the validity of this assumption by introducing a population balance approach for dynamic extracellular ice formation (EIF) in the absence of any cryo-protectant agent (CPA). The population balance model reflects nucleation and diffusion-limited growth in the suspending solution whose driving forces are evaluated in the relevant phase diagram. This population balance description of the extracellular compartment has been coupled to a model recently proposed in the literature [Fadda et al., AIChE Journal, 56, 2173-2185, (2010)], which is capable of quantitatively describing and predicting internal ice formation (IIF) inside the cells. The cells are characterized by a size distribution (i.e. through another population balance), thus overcoming the classic view of a population of identically sized cells. From the comparison of the system behavior in terms of the dynamics of the cell size distribution it can be concluded that the assumption of a thermodynamic equilibrium in the extracellular compartment is not always justified. Depending on the cooling rate, the dynamics of EIF needs to be considered. Copyright © 2011 Elsevier Inc. All rights reserved.

  12. How reliable are Finite-Size Lyapunov Exponents for the assessment of ocean dynamics?

    CERN Document Server

    Hernández-Carrasco, Ismael; López, Cristóbal; Turiel, Antonio

    2010-01-01

    Much of atmospheric and oceanic transport is associated with coherent structures. Lagrangian methods are emerging as optimal tools for their identification and analysis. An important Lagrangian technique which is starting to be widely used in oceanography is that of Finite-Size Lyapunov Exponents (FSLEs). Despite this growing relevance there are still many open questions concerning the reliability of the FSLEs in order to analyse the ocean dynamics. In particular, it is still unclear how robust they are when confronted with real data. In this paper we analyze the effect on this Lagrangian technique of the two most important effects when facing real data, namely noise and dynamics of unsolved scales. Our results, using as a benchmarch data from a primitive numerical model of the Mediterranean Sea, show that even when some dynamics is missed the FSLEs results still give an accurate picture of the oceanic transport properties.

  13. Fragment size distribution statistics in dynamic fragmentation of laser shock-loaded tin

    Directory of Open Access Journals (Sweden)

    Weihua He

    2017-06-01

    Full Text Available This work investigates the geometric statistics method to characterize the size distribution of tin fragments produced in the laser shock-loaded dynamic fragmentation process. In the shock experiments, the ejection of the tin sample with etched V-shape groove in the free surface are collected by the soft recovery technique. Subsequently, the produced fragments are automatically detected with the fine post-shot analysis techniques including the X-ray micro-tomography and the improved watershed method. To characterize the size distributions of the fragments, a theoretical random geometric statistics model based on Poisson mixtures is derived for dynamic heterogeneous fragmentation problem, which reveals linear combinational exponential distribution. The experimental data related to fragment size distributions of the laser shock-loaded tin sample are examined with the proposed theoretical model, and its fitting performance is compared with that of other state-of-the-art fragment size distribution models. The comparison results prove that our proposed model can provide far more reasonable fitting result for the laser shock-loaded tin.

  14. The Importance of Grain Size to Mantle Dynamics and Seismological Observations: A Multidisciplinary Approach

    Science.gov (United States)

    Gassmöller, Rene; Dannberg, Juliane; Eilon, Zach; Moulik, Pritwiraj; Myhill, Robert; Faul, Ulrich

    2016-04-01

    Dynamic models of Earth's convecting mantle usually implement flow laws with constant grain size, stress-independent viscosity and a limited treatment of variations associated with changes in mineral assemblage. These simplifications greatly reduce computational requirements but preclude effects such as shear localisation and transient changes in rheology associated with phase transitions, which have the potential to fundamentally change flow patterns in the mantle. Here we use the finite-element code ASPECT [Bangerth et al., 2013] to model grain size evolution and the interplay between grain size, stress and strain rate in the convecting mantle. We include the simultaneous and competing effects of dynamic recrystallisation resulting from work done by dislocation creep, grain growth in multiphase assemblages and recrystallisation at phase transitions. Grain size variations also affect seismic properties of mantle materials. We apply published formalisms [Jackson & Faul, 2010; McCarthy et al., 2011; Takei et al., 2014] to relate intrinsic variables (P, T, and grain size) from our numerical models to seismic velocity (Vs) and attenuation (Q). We investigate these formalisms for consistency with seismic observations at conditions beyond the range of the experiments upon which they are based; this requires constraining the range of pre-factors and activation volumes relevant for the lower mantle. Our calculations use thermodynamically self-consistent anharmonic elastic moduli determined for the mineral assemblages in the mantle using HeFESTo [Stixrude and Lithgow-Bertelloni, 2013]. We investigate the effect of realistically heterogeneous grain sizes by computing synthetic seismological data; these highlight the frequency-dependent sensitivity of seismic waves to grain size, which is important when interpreting Vs and Q observations in terms of mineral assemblage and temperature. Our models show that grain size evolution can lead to lateral viscosity variations of six

  15. Chaotic dynamics of the size-dependent non-linear micro-beam model

    Science.gov (United States)

    Krysko, A. V.; Awrejcewicz, J.; Pavlov, S. P.; Zhigalov, M. V.; Krysko, V. A.

    2017-09-01

    In this work, a size-dependent model of a Sheremetev-Pelekh-Reddy-Levinson micro-beam is proposed and validated using the couple stress theory, taking into account large deformations. The applied Hamilton's principle yields the governing PDEs and boundary conditions. A comparison of statics and dynamics of beams with and without size-dependent components is carried out. It is shown that the proposed model results in significant, both qualitative and quantitative, changes in the nature of beam deformations, in comparison to the so far employed standard models. A novel scenario of transition from regular to chaotic vibrations of the size-dependent Sheremetev-Pelekh model, following the Pomeau-Manneville route to chaos, is also detected and illustrated, among others.

  16. Structural, Dynamical, and Electronic Transport Properties of Modified DNA Duplexes Containing Size-Expanded Nucleobases

    Energy Technology Data Exchange (ETDEWEB)

    Fuentes-Cabrera, Miguel A [ORNL; Orozco, Modesto [Institut de Recerca Biomedica, Parc Cientific de Barcelona, Barcelona, Spain; Luque, Javier [Universitat de Barcelona; Sumpter, Bobby G [ORNL; Blas, Jose [Universidad de Castilla-La Mancha; Ordejon, Pablo J [ORNL; Huertas, Oscar [Universitat de Barcelona; Tabares, Carolina [Universitat de Barcelona

    2011-01-01

    Among the distinct strategies proposed to expand the genetic alphabet, sizeexpanded nucleobases are promising for the development of modified DNA duplexes with improved biotechnological properties. In particular, duplexes built up by replacing canonical bases with the corresponding benzo-fused counterparts could be valuable as molecular nanowires. In this context, this study reports the results of classical molecular dynamics simulations carried out to examine the structural and dynamical features of size-expanded DNAs, including both hybrid duplexes containing mixed pairs of natural and benzo-fused bases (xDNA) and pure size-expanded (xxDNA) duplexes. Furthermore, the electronic structure of both natural and size-expanded duplexes is examined by means of density functional computations. The results confirm that the structural and flexibility properties of the canonical DNA are globally little affected by the presence of benzo-fused bases. Themost relevant differences are found in the enhanced size of the grooves, and the reduction in the twist. However, the analysis also reveals subtle structural effects related to the nature and sequence of benzo-fused bases in the duplex. On the other hand, electronic structure calculations performed for xxDNAs confirm the reduction in the HOMOLUMO gap predicted from the analysis of the natural bases and their size-expanded counterparts, which suggests that pure size-expanded DNAs can be good conductors. A more complex situation is found for xDNAs, where fluctuations in the electrostatic interaction between base pairs exerts a decisive influence on the modulation of the energy gap.

  17. Seed vigour and seed lot quality

    Directory of Open Access Journals (Sweden)

    Lekić Slavoljub S.

    2001-01-01

    Full Text Available This paper discusses seed vigour as the most important seed characteristic the seed lot quality depends on. In Serbian, the terms such as vigor, viability and germ inability are used in various ways, depending on the author, which leaves room to possible misunderstanding in interpretation of research results and misuse of expert terminology. The modest lexical fund, compared to that of the English language, for instance, greatly contributes to the problem, and so does the absence of terminological standardization. Since the current technology and research level in seed science and technology requires appropriate terminology, this article offers an outline of basic seed traits related expert terminology as a foundation of future seed research and technology development. .

  18. A socio-hydrologic model of coupled water-agriculture dynamics with emphasis on farm size.

    Science.gov (United States)

    Brugger, D. R.; Maneta, M. P.

    2015-12-01

    Agricultural land cover dynamics in the U.S. are dominated by two trends: 1) total agricultural land is decreasing and 2) average farm size is increasing. These trends have important implications for the future of water resources because 1) growing more food on less land is due in large part to increased groundwater withdrawal and 2) larger farms can better afford both more efficient irrigation and more groundwater access. However, these large-scale trends are due to individual farm operators responding to many factors including climate, economics, and policy. It is therefore difficult to incorporate the trends into watershed-scale hydrologic models. Traditional scenario-based approaches are valuable for many applications, but there is typically no feedback between the hydrologic model and the agricultural dynamics and so limited insight is gained into the how agriculture co-evolves with water resources. We present a socio-hydrologic model that couples simplified hydrologic and agricultural economic dynamics, accounting for many factors that depend on farm size such as irrigation efficiency and returns to scale. We introduce an "economic memory" (EM) state variable that is driven by agricultural revenue and affects whether farms are sold when land market values exceed expected returns from agriculture. The model uses a Generalized Mixture Model of Gaussians to approximate the distribution of farm sizes in a study area, effectively lumping farms into "small," "medium," and "large" groups that have independent parameterizations. We apply the model in a semi-arid watershed in the upper Columbia River Basin, calibrating to data on streamflow, total agricultural land cover, and farm size distribution. The model is used to investigate the sensitivity of the coupled system to various hydrologic and economic scenarios such as increasing market value of land, reduced surface water availability, and increased irrigation efficiency in small farms.

  19. Molecular Dynamics Study for Channel Size Dependence of Shear Stress Between Droplet and Wall.

    Science.gov (United States)

    Fukushima, Akinori; Mima, Toshiki; Kinefuchi, Ikuya; Tokumasu, Takashi

    2015-04-01

    In this study, the channel size dependence of the shear stress between water droplets and solid walls in nm-order channel was analyzed. We considered a several different-sized and highly hydrophobic channel whose macroscopic contact angle was about 150 degrees. We have evaluated the shear stress and the normal pressure by molecular dynamics simulation. Analyzing shear stress and normal pressure based on the macroscopic model, we have discussed the difference between the macroscopic model based on hydrodynamics and the microscopic model. As a result, in the high hydrophobic case, it became clear that the shear stress depends on the channel size due to the large Laplace pressure. Furthermore, in the case that the channel size was less than 50 A, the normal pressure by the molecular simulation didn't agree with the expected value from the Young-Laplace equation. From this study it was clear that molecular simulation is needed when the channel size is less than 40 A.

  20. Effect of meal size on the specific dynamic action of the juvenile snakehead (Channa argus).

    Science.gov (United States)

    Wang, Qianqian; Wang, Wen; Huang, Qingda; Zhang, Yurong; Luo, Yiping

    2012-04-01

    The effect of meal size on the specific dynamic action (SDA) of the juvenile snakehead (Channa argus) was assessed at 25 °C. The fish were fed with test diets at meal sizes of 0.5, 1, 2, 3, 4, and 5% body mass and the postprandial oxygen consumption rate was determined at 1-h intervals until it returned to the pre-prandial level. The peak metabolic rate increased from 237.4 to 283.2 mg O(2) kg(-1) h(-1) as the relative meal size increased from 0.5% to 3% and leveled off at 4% and 5%. Factorial metabolic scope increased from 1.53 to 1.99 and SDA duration increased from 11.7 to 32.3h as the relative meal size increased from 0.5% to 5%. The relationship between SDA duration (D) and relative meal size (M) was described as: D=4.28 M+10.62 (r(2)=0.752, Psnakehead may adopt different feeding strategies when taking in different amounts of food.

  1. Size-dependent mechanical behavior of nanoscale polymer particles through coarse-grained molecular dynamics simulation.

    Science.gov (United States)

    Zhao, Junhua; Nagao, Shijo; Odegard, Gregory M; Zhang, Zhiliang; Kristiansen, Helge; He, Jianying

    2013-12-21

    Anisotropic conductive adhesives (ACAs) are promising materials used for producing ultra-thin liquid-crystal displays. Because the mechanical response of polymer particles can have a significant impact in the performance of ACAs, understanding of this apparent size effect is of fundamental importance in the electronics industry. The objective of this research is to use a coarse-grained molecular dynamics model to verify and gain physical insight into the observed size dependence effect in polymer particles. In agreement with experimental studies, the results of this study clearly indicate that there is a strong size effect in spherical polymer particles with diameters approaching the nanometer length scale. The results of the simulations also clearly indicate that the source for the increases in modulus is the increase in relative surface energy for decreasing particle sizes. Finally, the actual contact conditions at the surface of the polymer nanoparticles are shown to be similar to those predicted using Hertz and perfectly plastic contact theory. As ACA thicknesses are reduced in response to reductions in polymer particle size, it is expected that the overall compressive stiffness of the ACA will increase, thus influencing the manufacturing process.

  2. Dissipative particle dynamics study of relationship between wall thickness and size in polymer vesicles

    Science.gov (United States)

    Xiao, Mengying; Wang, Rong; Xie, Daiqian

    2012-02-01

    Vesicles and membrane properties have long been thought to be essential for reproducing the natural environment of living cells. By using dissipative particle dynamics method, we have studied the relationship between wall thickness and size of vesicles obtained from A1BnA1 block copolymers, where block A is hydrophilic and block B is hydrophobic. Our findings suggest that, the wall thickness is sensitive to the size of vesicles at a low block length ratio of B/A, but insensitive to the size at a large ratio. It shows both weak and strong effects with a crossover point in between. These behaviors are consistent with the experimental results of Eisenberg and co-workers. Besides, an additional crossover point also has been observed. With the B/A ratio increases, the relationship goes from strong to weak behavior, and this transformation first appears to affect the outer area for large sized vesicles, and then to the inner area for small sized vesicles. These results may also be useful in delivery applications through controlling the hydrophobic membrane and the hydrophilic coronas.

  3. Colorectal carcinoma evaluated by incremental dynamic CT; Comparison of CT density, histology, and tumor size

    Energy Technology Data Exchange (ETDEWEB)

    Furukawa, Hiroyoshi; Hara, Tsuyoshi; Taniguchi, Tetsushi (Shimizu Kosei Hospital, Shizuoka (Japan))

    1992-06-01

    Evaluation of incremental dynamic CT scan and histologic findings were compared in order to clarify the cause of the differences in colorectal carcinoma as observed on CT after administration of contrast medium. In 48 cases demonstrated on postcontrast dynamic CT scan, the CT density of the tumor was homogeneous (Type 1) in 26 (54.2%) cases and heterogeneous (Type 2) in 22 (45.8%) cases. Well differentiated adenocarcinoma was seen as Type 1 in 11 of 13 (84.6%) cases while moderately differentiated adenocarcinoma was of Type 1 in 15 of 29 (51.7%) cases. Poorly differentiated and mucinous adenocarcinoma were detected as Type 2 in all cases. A comparison of CT types and tumor size showed that as tumor size increased, the number of Type 1 cases decreased while Type 2 cases increased. Histologically, high density areas consisted mainly of well-developed tubular, branching glands of adenocarcinoma, while low density areas were composed of fibrous or mucinous stroma or necrosis. Dynamic CT scans for colorectal cancer are useful not only for preoperative staging but also for tissue characterization. (author).

  4. Coarsening dynamics in condensing zero-range processes and size-biased birth death chains

    Science.gov (United States)

    Jatuviriyapornchai, Watthanan; Grosskinsky, Stefan

    2016-05-01

    Zero-range processes with decreasing jump rates are well known to exhibit a condensation transition under certain conditions on the jump rates, and the dynamics of this transition continues to be a subject of current research interest. Starting from homogeneous initial conditions, the time evolution of the condensed phase exhibits an interesting coarsening phenomenon of mass transport between cluster sites characterized by a power law. We revisit the approach in Godrèche (2003 J. Phys. A: Math. Gen. 36 6313) to derive effective single site dynamics which form a nonlinear birth death chain describing the coarsening behavior. We extend these results to a larger class of parameter values, and introduce a size-biased version of the single site process, which provides an effective tool to analyze the dynamics of the condensed phase without finite size effects and is the main novelty of this paper. Our results are based on a few heuristic assumptions and exact computations, and are corroborated by detailed simulation data.

  5. Quantifying the size-resolved dynamics of indoor bioaerosol transport and control.

    Science.gov (United States)

    Kunkel, S A; Azimi, P; Zhao, H; Stark, B C; Stephens, B

    2017-09-01

    Understanding the bioaerosol dynamics of droplets and droplet nuclei emitted during respiratory activities is important for understanding how infectious diseases are transmitted and potentially controlled. To this end, we conducted experiments to quantify the size-resolved dynamics of indoor bioaerosol transport and control in an unoccupied apartment unit operating under four different HVAC particle filtration conditions. Two model organisms (Escherichia coli K12 and bacteriophage T4) were aerosolized under alternating low and high flow rates to roughly represent constant breathing and periodic coughing. Size-resolved aerosol sampling and settle plate swabbing were conducted in multiple locations. Samples were analyzed by DNA extraction and quantitative polymerase chain reaction (qPCR). DNA from both organisms was detected during all test conditions in all air samples up to 7 m away from the source, but decreased in magnitude with the distance from the source. A greater fraction of T4 DNA was recovered from the aerosol size fractions smaller than 1 μm than E. coli K12 at all air sampling locations. Higher efficiency HVAC filtration also reduced the amount of DNA recovered in air samples and on settle plates located 3-7 m from the source. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  6. Powder Lot Variations: A Case Study with Varget - Hodgdon Extreme

    CERN Document Server

    Courtney, Elya

    2015-01-01

    Small arms propellant distributor Hodgdon claims that rifle powders in its Extreme line have small velocity variations with both temperature changes and lot number. This paper reports on the variations in average velocity of four different lots of Hodgdon Extreme Varget tested in two .223 Remington loads. Compared to the lot with the slowest average velocity, the other three lots of powder had higher average velocities ranging from 23.4 ft/s faster up to 45.6 ft/s faster with a 69 grain Nosler Custom Competition bullet and from 7.9 ft/s faster to 15.3 ft/s with the 53 grain Hornady VMAX. The mean velocity differences between lots are slightly correlated between the two loads with a correlation coefficient of 0.54. This correlation suggests that factors other than lot to lot variations contribute significantly to the measured velocity variations. Unlike the much larger lot to lot variations that were reported previously for H4831, lot to lot variations in velocity for Varget seem consistent with Hodgdon's mark...

  7. A study of dynamic finite size scaling behavior of the scaling functions—calculation of dynamic critical index of Wolff algorithm

    Science.gov (United States)

    Gündüç, Semra; Dilaver, Mehmet; Aydın, Meral; Gündüç, Yiğit

    2005-02-01

    In this work we have studied the dynamic scaling behavior of two scaling functions and we have shown that scaling functions obey the dynamic finite size scaling rules. Dynamic finite size scaling of scaling functions opens possibilities for a wide range of applications. As an application we have calculated the dynamic critical exponent (z) of Wolff's cluster algorithm for 2-, 3- and 4-dimensional Ising models. Configurations with vanishing initial magnetization are chosen in order to avoid complications due to initial magnetization. The observed dynamic finite size scaling behavior during early stages of the Monte Carlo simulation yields z for Wolff's cluster algorithm for 2-, 3- and 4-dimensional Ising models with vanishing values which are consistent with the values obtained from the autocorrelations. Especially, the vanishing dynamic critical exponent we obtained for d=3 implies that the Wolff algorithm is more efficient in eliminating critical slowing down in Monte Carlo simulations than previously reported.

  8. Micrometer-sized water droplet impingement dynamics and evaporation on a flat dry surface.

    Science.gov (United States)

    Briones, Alejandro M; Ervin, Jamie S; Putnam, Shawn A; Byrd, Larry W; Gschwender, Lois

    2010-08-17

    A comprehensive numerical and experimental investigation on micrometer-sized water droplet impact dynamics and evaporation on an unheated, flat, dry surface is conducted from the standpoint of spray-cooling technology. The axisymmetric time-dependent governing equations of continuity, momentum, energy, and species are solved. Surface tension, wall adhesion effect, gravitational body force, contact line dynamics, and evaporation are accounted for in the governing equations. The explicit volume of fluid (VOF) model with dynamic meshing and variable-time stepping in serial and parallel processors is used to capture the time-dependent liquid-gas interface motion throughout the computational domain. The numerical model includes temperature- and species-dependent thermodynamic and transport properties. The contact line dynamics and the evaporation rate are predicted using Blake's and Schrage's molecular kinetic models, respectively. An extensive grid independence study was conducted. Droplet impingement and evaporation data are acquired with a standard dispensing/imaging system and high-speed photography. The numerical results are compared with measurements reported in the literature for millimeter-size droplets and with current microdroplet experiments in terms of instantaneous droplet shape and temporal spread (R/D(0) or R/R(E)), flatness ratio (H/D(0)), and height (H/H(E)) profiles, as well as temporal volume (inverted A) profile. The Weber numbers (We) for impinging droplets vary from 1.4 to 35.2 at nearly constant Ohnesorge number (Oh) of approximately 0.025-0.029. Both numerical and experimental results show that there is air bubble entrapment due to impingement. Numerical results indicate that Blake's formulation provides better results than the static (SCA) and dynamic contact angle (DCA) approach in terms of temporal evolution of R/D(0) and H/D(0) (especially at the initial stages of spreading) and equilibrium flatness ratio (H(E)/D(0)). Blake's contact line

  9. Size dependency and potential field influence on deriving mechanical properties of carbon nanotubes using molecular dynamics

    Directory of Open Access Journals (Sweden)

    K.G.S. Dilrukshi

    2015-07-01

    Full Text Available A thorough understanding on the mechanical properties of carbon nanotube (CNT is essential in extending the advanced applications of CNT based systems. However, conducting experiments to estimate mechanical properties at this scale is extremely challenging. Therefore, development of mechanistic models to estimate the mechanical properties of CNTs along with the integration of existing continuum mechanics concepts is critically important. This paper presents a comprehensive molecular dynamics simulation study on the size dependency and potential function influence of mechanical properties of CNT. Commonly used reactive bond order (REBO and adaptive intermolecular reactive bond order (AIREBO potential functions were considered in this regard. Young’s modulus and shear modulus of CNTs are derived by integrating classical continuum mechanics concepts with molecular dynamics simulations. The results indicate that the potential function has a significant influence on the estimated mechanical properties of CNTs, and the influence of potential field is much higher when studying the torsional behaviour of CNTs than the tensile behaviour.

  10. Neutral dynamics with environmental noise: Age-size statistics and species lifetimes

    Science.gov (United States)

    Kessler, David; Suweis, Samir; Formentin, Marco; Shnerb, Nadav M.

    2015-08-01

    Neutral dynamics, where taxa are assumed to be demographically equivalent and their abundance is governed solely by the stochasticity of the underlying birth-death process, has proved itself as an important minimal model that accounts for many empirical datasets in genetics and ecology. However, the restriction of the model to demographic [O (√{N }) ] noise yields relatively slow dynamics that appears to be in conflict with both short-term and long-term characteristics of the observed systems. Here we analyze two of these problems—age-size relationships and species extinction time—in the framework of a neutral theory with both demographic and environmental stochasticity. It turns out that environmentally induced variations of the demographic rates control the long-term dynamics and modify dramatically the predictions of the neutral theory with demographic noise only, yielding much better agreement with empirical data. We consider two prototypes of "zero mean" environmental noise, one which is balanced with regard to the arithmetic abundance, another balanced in the logarithmic (fitness) space, study their species lifetime statistics, and discuss their relevance to realistic models of community dynamics.

  11. Nonlinear dynamics of a vapor bubble expanding in a superheated region of finite size

    Science.gov (United States)

    Annenkova, E. A.; Kreider, W.; Sapozhnikov, O. A.

    2015-10-01

    Growth of a vapor bubble in a superheated liquid is studied theoretically. Contrary to the typical situation of boiling, when bubbles grow in a uniformly heated liquid, here the superheated region is considered in the form of a millimeter-sized spherical hot spot. An initial micron-sized bubble is positioned at the hot spot center and a theoretical model is developed that is capable of studying bubble growth caused by vapor pressure inside the bubble and corresponding hydrodynamic and thermal processes in the surrounding liquid. Such a situation is relevant to the dynamics of vapor cavities that are created in soft biological tissue in the focal region of a high-intensity focused ultrasound beam with a shocked pressure waveform. Such beams are used in the recently proposed treatment called boiling histotripsy. Knowing the typical behavior of vapor cavities during boiling histotripsy could help to optimize the therapeutic procedure.

  12. Nonlinear dynamics of a vapor bubble expanding in a superheated region of finite size

    Energy Technology Data Exchange (ETDEWEB)

    Annenkova, E. A., E-mail: a-a-annenkova@yandex.ru [Physics Faculty, Moscow State University, Leninskie Gory, 119991 Moscow (Russian Federation); Kreider, W. [Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, 1013 NE 40th St., Seattle, WA 98105 (United States); Sapozhnikov, O. A. [Physics Faculty, Moscow State University, Leninskie Gory, 119991 Moscow (Russian Federation); Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, 1013 NE 40th St., Seattle, WA 98105 (United States)

    2015-10-28

    Growth of a vapor bubble in a superheated liquid is studied theoretically. Contrary to the typical situation of boiling, when bubbles grow in a uniformly heated liquid, here the superheated region is considered in the form of a millimeter-sized spherical hot spot. An initial micron-sized bubble is positioned at the hot spot center and a theoretical model is developed that is capable of studying bubble growth caused by vapor pressure inside the bubble and corresponding hydrodynamic and thermal processes in the surrounding liquid. Such a situation is relevant to the dynamics of vapor cavities that are created in soft biological tissue in the focal region of a high-intensity focused ultrasound beam with a shocked pressure waveform. Such beams are used in the recently proposed treatment called boiling histotripsy. Knowing the typical behavior of vapor cavities during boiling histotripsy could help to optimize the therapeutic procedure.

  13. System Dynamics Modeling for Determining Optimal Ship Sizes and Types in Coastal Liner Services

    Directory of Open Access Journals (Sweden)

    Sung-il Park

    2014-04-01

    Full Text Available The problem of determining the required ship investment for deployment is an ongoing problem faced by governments and ship operators. The nature of ship investment is capital-intensive and the return on investment is often take long time. This paper attempts to establish system dynamics modeling (SDM to simulate and solve this problem in order to help ship operators make effective strategic decisions. A case study of coastal liner services between Incheon and Baengnyeong Island in South Korea was performed. Using scenario analysis, the possible ship sizes (small: 350 tons; large: 2,500 tons and types (new or used were considered by comparing potential revenue with costs. The results indicated that putting a used large-sized ship into operation would accommodate the increasing passenger and cargo volumes, and improve customer services.

  14. Melting Properties of Medium-Sized Silicon Nanoclusters: A Molecular Dynamics Study

    Science.gov (United States)

    Li, Haipeng; Xu, Runfeng; Bi, Zetong; Shen, Xiaopeng; Han, Kui

    2017-07-01

    The structures and melting properties of the medium-sized silicon nanoclusters have been comparatively studied using the molecular dynamics method. Structural and thermodynamic parameters are used to characterize the melting properties of the clusters. The size dependence of the melting temperature of silicon nanoclusters is determined using the computation results. Different from the homogeneous melting of bulk silicon, melting of silicon nanoparticles proceeds over a finite temperature range due to surface effects, which shows the heterogeneous melting of nanoclusters. We found that the melting starts at the cluster surface and progressively shifts into the core region. This study provides a fundamental perspective on the melting behaviors of semiconductor silicon nanoclusters at the atomistic level.

  15. Dynamic light scattering study of peanut agglutinin: Size, shape and urea denaturation

    Indian Academy of Sciences (India)

    Sagarika Dev; Avadhesha Surolia

    2006-12-01

    Peanut agglutinin (PNA) is a homotetrameric protein with a unique open quaternary structure. PNA shows non-two state profile in chaotrope induced denaturation. It passes through a monomeric molten globule like state before complete denaturation (Reddy et al 1999). This denaturation profile is associated with the change in hydrodynamic radius of the native protein. Though the molten globule-like state is monomeric in nature it expands in size due to partial denaturation. The size and shape of the native PNA as well as the change in hydrodynamic radius of the protein during denaturation has been studied by dynamic light scattering (DLS). The generation of two species is evident from the profile of hydrodynamic radii. This study also reveals the extent of compactness of the intermediate state.

  16. A lot to look forward to

    CERN Multimedia

    2013-01-01

    CERN moves from momentous year to momentous year, and although 2013 will be very different for us than 2012, there is still a lot to look forward to. As I write, the proton-lead run is just getting under way, giving the LHC experiments a new kind of data to investigate. But the run will be short, and our main activity this year will be the start of the LHC’s first long shutdown.   This is the first year I can remember in which all of CERN’s accelerators will be off. The reason is that there is much to be done: the older machines need maintenance, and the LHC has to be prepared for higher energy running. That involves opening up the interconnections between each of the machine’s 1,695 main magnet cryostats, consolidating all of the 10,170 splices carrying current to the main dipole and quadrupole windings, and a range of other work to improve the machine. The CERN accelerator complex will start to come back to life in 2014, and it’s fair to say that when...

  17. Effects of Atomistic Domain Size on Hybrid Lattice Boltzmann-Molecular Dynamics Simulations of Dense Fluids

    Science.gov (United States)

    Dupuis, A.; Koumoutsakos, P.

    We present a convergence study for a hybrid Lattice Boltzmann-Molecular Dynamics model for the simulation of dense liquids. Time and length scales are decoupled by using an iterative Schwarz domain decomposition algorithm. The velocity field from the atomistic domain is introduced as forcing terms to the Lattice Boltzmann model of the continuum while the mean field of the continuum imposes mean field conditions for the atomistic domain. In the present paper we investigate the effect of varying the size of the atomistic subdomain in simulations of two dimensional flows of liquid argon past carbon nanotubes and assess the efficiency of the method.

  18. Size-dependent ultrafast structural dynamics inside phospholipid vesicle bilayers measured with 2D IR vibrational echoes

    Science.gov (United States)

    Kel, Oksana; Tamimi, Amr; Fayer, Michael D.

    2014-01-01

    The ultrafast structural dynamics inside the bilayers of dilauroylphosphatidylcholine (DLPC) and dipalmitoylphosphatidylcholine vesicles with 70, 90, and 125 nm diameters were directly measured with 2D IR vibrational echo spectroscopy. The antisymmetric CO stretch of tungsten hexacarbonyl was used as a vibrational probe and provided information on spectral diffusion (structural dynamics) in the alkyl region of the bilayers. Although the CO stretch absorption spectra remain the same, the interior structural dynamics become faster as the size of the vesicles decrease, with the size dependence greater for dipalmitoylphosphatidylcholine than for DLPC. As DLPC vesicles become larger, the interior dynamics approach those of the planar bilayer. PMID:24395796

  19. Assessing gull abundance and food availability in urban parking lots

    Science.gov (United States)

    Clark, Daniel E.; Whitney, Jillian J.; MacKenzie, Kenneth G.; Koenen, Kiana K. G.; DeStefano, Stephen

    2015-01-01

    Feeding birds is a common activity throughout the world; yet, little is known about the extent of feeding gulls in urban areas. We monitored 8 parking lots in central Massachusetts, USA, during the fall and winter of 2011 to 2013 in 4 monitoring sessions to document the number of gulls present, the frequency of human–gull feeding interactions, and the effectiveness of signage and direct interaction in reducing human-provisioned food. Parking lots were divided between “education” and “no-education” lots. In education lots, we erected signs about problems caused when people feed birds and also asked people to stop feeding birds. We did not erect signs or ask people to stop feeding birds at no-education lots. We spent >1,200 hours in parking lots (range = 136 to 200 hours per parking lot), and gulls were counted every 20 minutes. We conducted >4,000 counts, and ring-billed gulls (Lorus delawarensis) accounted for 98% of all gulls. Our educational efforts were minimally effective. There were fewer feedings (P = 0.01) in education lots during one of the monitoring sessions but significantly more gulls (P = 0.008) in education lots during 2 monitoring sessions. While there was a marginal decrease (P = 0.055) in the number of feedings after no-education lots were transformed into education lots, there was no difference in gull numbers in these lots (P = 0.16). Education appears to have some influence in reducing the number of people feeding gulls, but our efforts were not able to reduce the number of human feeders or the amount of food enough to influence the number of gulls using parking lots.

  20. Mesozooplankton size structure in response to environmental conditions in the East China Sea: How much does size spectra theory fit empirical data of a dynamic coastal area?

    Science.gov (United States)

    García-Comas, Carmen; Chang, Chun-Yi; Ye, Lin; Sastri, Akash R.; Lee, Yu-Ching; Gong, Gwo-Ching; Hsieh, Chih-hao

    2014-02-01

    A fundamental ecological trait of marine organisms is body size. Various theoretical models have used the size distribution of plankton communities to explain their trophic structure and functioning. Recent studies indicate that changes associated with global warming, eutrophication, and fisheries might have dramatically shifted the size structure of marine organisms and thus changed ecosystem functioning. Accordingly, size structure has been suggested as a useful indicator for monitoring ecosystem status. Here, we used three size metrics to represent mesozooplankton size structure: the slope of normalized biomass spectra (NB-SS), NB-SS linear fit, and size diversity. We analyzed the relationship between zooplankton size structure and environmental conditions in the very dynamic East China Sea (ECS). We tested four hypotheses predicted by theoretical studies: (1) a coastal-offshore gradient for NB-SS, (2) a negative relationship between temperature and NB-SS steepness, (3) a positive relationship between trophic status (i.e., chlorophyll a and inorganic-nutrient concentrations as a proxy) and NB-SS steepness, and (4) a positive relationship between oligotrophy and NB-SS linearity. Hypotheses 1-3 did not stand up to our analyses of the empirical data, while hypothesis 4 was supported. In the ECS, we found no clear spatial gradient for each of the three size metrics, where (i) size diversity was not correlated to temperature and significantly decreased with chl a and phosphate concentrations, (ii) the NB-SS slope showed no relationship with the environment, and (iii) NB-SS linearity tended to be higher in more oligotrophic offshore waters. Trophic status exerted a stronger effect than temperature on size distribution, but its effect was opposite to model prediction. Our results suggest that population dynamics (i.e., pulses of reproduction due to increased food availability) override metabolic scaling effects on mesozooplankton NB-SS at the mesoscale. In addition

  1. 78 FR 43753 - Inspection and Weighing of Grain in Combined and Single Lots

    Science.gov (United States)

    2013-07-22

    ... the marketing of U.S. grain shipped for export. DATES: Effective September 20, 2013. FOR FURTHER... inspection system that facilitates the marketing of grain in domestic and international markets. The... comments requesting that a maximum single lot size of 1,500 metric tons be adopted. Commenters also...

  2. 7 CFR 52.38 - Sampling plans and procedures for determining lot compliance.

    Science.gov (United States)

    2010-01-01

    ... MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE REGULATIONS AND STANDARDS UNDER THE AGRICULTURAL MARKETING ACT OF 1946 PROCESSED FRUITS AND VEGETABLES, PROCESSED PRODUCTS... sample size, the lot fails the requirement. (c) If in the conduct of on-line in-plant inspection of a...

  3. Dynamic light scattering and atomic force microscopy techniques for size determination of polyurethane nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Giehl Zanetti-Ramos, Betina [Laboratorio de Bioenergetica e Bioquimica de Macromoleculas, Departamento de Ciencias Farmaceuticas (Brazil)], E-mail: betinagzramos@pq.cnpq.br; Beddin Fritzen-Garcia, Mauricia [Laboratorio de Bioenergetica e Bioquimica de Macromoleculas, Departamento de Ciencias Farmaceuticas (Brazil); Schweitzer de Oliveira, Cristian; Avelino Pasa, Andre [Laboratorio de Filmes Finos e Superficie, Departamento de Fisica (Brazil); Soldi, Valdir [Grupo de Estudos em Materiais Polimericos, Departamento de Quimica, Universidade Federal de Santa Catarina, 88040-900, Florianopolis, SC (Brazil); Borsali, Redouane [Centre de Recherche sur les Macromolecules Vegetales CERMAV/CNRS, 38041 - Grenoble (France); Creczynski-Pasa, Tania Beatriz [Laboratorio de Bioenergetica e Bioquimica de Macromoleculas, Departamento de Ciencias Farmaceuticas (Brazil)

    2009-03-01

    Nanoparticles have applications in various industrial fields principally in drug delivery. Nowadays, there are several processes for manufacturing colloidal polymeric systems and methods of preparation as well as of characterization. In this work, Dynamic Light Scattering and Atomic Force Microscopy techniques were used to characterize polyurethane nanoparticles. The nanoparticles were prepared by miniemulsion technique. The lipophilic monomers, isophorone diisocyanate (IPDI) and natural triol, were emulsified in water containing surfactant. In some formulations the poly(ethylene glycol) was used as co-monomer to obtain the hydrophilic and pegylated nanoparticles. Polyurethane nanoparticles observed by atomic force microscopy (AFM) were spherical with diameter around 209 nm for nanoparticles prepared without PEG. From AFM imaging two populations of nanoparticles were observed in the formulation prepared with PEG (218 and 127 nm) while dynamic light scattering (DLS) measurements showed a monodisperse size distribution around 250 nm of diameters for both formulations. The polydispersity index of the formulations and the experimental procedures could influence the particle size determination with these techniques.

  4. Towards Cluster-Assembled Materials of True Monodispersity in Size and Chemical Environment: Synthesis, Dynamics and Activity

    Science.gov (United States)

    2016-10-27

    pathway Status: not yet published Diverse technologies, from catalyst coking to graphene synthesis , entail hydrocarbon dehydrogena- tion and...AFRL-AFOSR-UK-TR-2016-0037 Towards cluster-assembled materials of true monodispersity in size and chemical environment: Synthesis , Dynamics and...Towards cluster-assembled materials of true monodispersity in size and chemical environment: synthesis , dynamics and activity 5a.  CONTRACT NUMBER 5b

  5. Sizing Dynamic Wireless Charging for Light-Duty Electric Vehicles in Roadway Applications

    Energy Technology Data Exchange (ETDEWEB)

    Foote, Andrew P [ORNL; Ozpineci, Burak [ORNL; Chinthavali, Madhu Sudhan [ORNL; Li, Jan-Mou [ORNL

    2016-01-01

    Dynamic wireless charging is a possible cure for the range limitations seen in electric vehicles (EVs) once implemented in highways or city streets. The contribution of this paper is the use of experimental data to show that the expected energy gain from a dynamic wireless power transfer (WPT) system is largely a function of average speed, which allows the power level and number of coils per mile of a dynamic WPT system to be sized for the sustained operation of an EV. First, data from dynamometer testing is used to determine the instantaneous energy requirements of a light-duty EV. Then, experimental data is applied to determine the theoretical energy gained by passing over a coil as a function of velocity and power level. Related simulations are performed to explore possible methods of placing WPT coils within roadways with comparisons to the constant velocity case. Analyses with these cases demonstrate what system ratings are needed to meet the energy requirements of the EV. The simulations are also used to determine onboard energy storage requirements for each driving cycle.

  6. Theoretical lower limits on sizes of ultrafaint dwarf galaxies from dynamical friction

    Science.gov (United States)

    Hernandez, X.

    2016-11-01

    Dwarf spheroidal galaxies (dSphs) are the smallest known stellar systems where under Newtonian interpretations, a significant amount of dark matter is required to explain observed kinematics. In fact, they are, in this sense, the most heavily dark matter-dominated objects known. That, plus the increasingly small sizes of the newly discovered ultrafaint dwarfs, puts these systems in the regime where dynamical friction on individual stars starts to become relevant. We calculate the dynamical friction time-scales for pressure-supported isotropic spherical dark matter-dominated stellar systems, yielding τDF = 0.93(rh/10 pc)2(σ/km s-1) Gyr, where rh is the half-light radius. For a stellar velocity dispersion value of 3 km s-1, as typical for the smallest of the recently detected ultrafaint dwarf spheroidals, dynamical friction time-scales become smaller than the 10 Gyr typical of the stellar ages for these systems, for rh present a comparison with structural parameters of the smallest ultrafaint dwarf spheroidals known, showing that these are already close to the stability limit derived, any future detection of yet smaller such systems would be inconsistent with a particle dark matter hypothesis.

  7. Theoretical lower limits on sizes of ultra faint dwarf galaxies from dynamical friction

    CERN Document Server

    Hernandez, X

    2016-01-01

    Dwarf spheroidal galaxies are the smallest known stellar systems where under Newtonian interpretations, a significant amount of dark matter is required to explain observed kinematics. In fact, they are in this sense the most heavily dark matter dominated objects known. That, plus the increasingly small sizes of the newly discovered ultra faint dwarfs, puts these systems in the regime where dynamical friction on individual stars starts to become relevant. We calculate the dynamical friction timescales for pressure supported isotropic spherical dark matter dominated stellar systems, yielding $\\tau_{DF} =0.93 (r_{h}/10 pc)^{2} (\\sigma/ kms^{-1}) Gyr$. For a stellar velocity dispersion value of $3 km/s$, as typical for the smallest of the recently detected ultra faint dwarf spheroidals, dynamical friction timescales becomes smaller than the $10 Gyr$ typical of the stellar ages for these systems, for half-light radii $r_{h}<19 pc$. Thus, this becomes a theoretical lower limit below which dark matter dominated s...

  8. Size distribution dynamics reveal particle-phase chemistry in organic aerosol formation.

    Science.gov (United States)

    Shiraiwa, Manabu; Yee, Lindsay D; Schilling, Katherine A; Loza, Christine L; Craven, Jill S; Zuend, Andreas; Ziemann, Paul J; Seinfeld, John H

    2013-07-16

    Organic aerosols are ubiquitous in the atmosphere and play a central role in climate, air quality, and public health. The aerosol size distribution is key in determining its optical properties and cloud condensation nucleus activity. The dominant portion of organic aerosol is formed through gas-phase oxidation of volatile organic compounds, so-called secondary organic aerosols (SOAs). Typical experimental measurements of SOA formation include total SOA mass and atomic oxygen-to-carbon ratio. These measurements, alone, are generally insufficient to reveal the extent to which condensed-phase reactions occur in conjunction with the multigeneration gas-phase photooxidation. Combining laboratory chamber experiments and kinetic gas-particle modeling for the dodecane SOA system, here we show that the presence of particle-phase chemistry is reflected in the evolution of the SOA size distribution as well as its mass concentration. Particle-phase reactions are predicted to occur mainly at the particle surface, and the reaction products contribute more than half of the SOA mass. Chamber photooxidation with a midexperiment aldehyde injection confirms that heterogeneous reaction of aldehydes with organic hydroperoxides forming peroxyhemiacetals can lead to a large increase in SOA mass. Although experiments need to be conducted with other SOA precursor hydrocarbons, current results demonstrate coupling between particle-phase chemistry and size distribution dynamics in the formation of SOAs, thereby opening up an avenue for analysis of the SOA formation process.

  9. MetaZipf. A dynamic meta-analysis of city size distributions.

    Science.gov (United States)

    Cottineau, Clémentine

    2017-01-01

    The results from urban scaling in recent years have held the promise of increased efficiency to the societies who could actively control the distribution of their cities' size. However, little evidence exists as to the factors which influence the level of urban unevenness, as expressed by the slope of the rank-size distribution, partly because the diversity of results found in the literature follows the heterogeneity of analysis specifications. In this study, I set up a meta-analysis of Zipf's law which accounts for technical as well as topical factors of variations of Zipf's coefficient. I found 86 studies publishing at least one empirical estimation of this coefficient and recorded their metadata into an open database. I regressed the 1962 corresponding estimates with variables describing the study and the estimation process as well as socio-demographic variables describing the territory under enquiry. A dynamic meta-analysis was also performed to look for factors of evolution of city size unevenness. The results of the most interesting models are presented in the article, whereas all analyses can be reproduced on a dedicated online platform. The results show that on average, 40% of the variation of Zipf's coefficients is due to the technical choices. The main other variables associated with distinct evolutions are linked to the urbanisation process rather than the process of economic development and population growth. Finally, no evidence was found to support the effectiveness of past planning actions in modifying this urban feature.

  10. Experimental investigation of granule size and shape dynamics in twin-screw granulation.

    Science.gov (United States)

    Kumar, Ashish; Vercruysse, Jurgen; Bellandi, Giacomo; Gernaey, Krist V; Vervaet, Chris; Remon, Jean Paul; De Beer, Thomas; Nopens, Ingmar

    2014-11-20

    A twin-screw granulator (TSG), a promising equipment for continuous high shear wet granulation (HSWG), achieves the desired level of mixing by a combination of the appropriate screw configuration and a suitable set of process settings (e.g. feed rate, screw speed, etc.), thus producing a certain granule size and shape distribution (GSSD). However, the primary sizing and shaping mechanism behind the resulting distribution is not well understood due to the opacity of the multiphase system in the granulator. This study experimentally characterised the GSSD dynamics along the TSG barrel length in order to understand the function of individual screw modules and process settings, as well as their interaction. Particle size analysis of granules collected at the outlet of the TSG suggested significant interaction between the process and screw configuration parameters influencing the heterogeneity in the GSSD. By characterising the samples collected along the screw length, a variable influence of the screw modules at different process conditions was observed. At low liquid-to-solid ratio (L/S), the first kneading module seemed to play a significant role in mixing, whereas the second kneading module was found to be more involved in reshaping the granules. At high L/S and high throughput, aggregation mainly took place in the second kneading module changing the GSSD. The results obtained from this study will be further used for the calibration and validation of a mechanistic model and, hence, support future development of a more detailed understanding of the HSWG process in a TSG.

  11. Effect of reaction-step-size noise on the switching dynamics of stochastic populations

    Science.gov (United States)

    Be'er, Shay; Heller-Algazi, Metar; Assaf, Michael

    2016-05-01

    In genetic circuits, when the messenger RNA lifetime is short compared to the cell cycle, proteins are produced in geometrically distributed bursts, which greatly affects the cellular switching dynamics between different metastable phenotypic states. Motivated by this scenario, we study a general problem of switching or escape in stochastic populations, where influx of particles occurs in groups or bursts, sampled from an arbitrary distribution. The fact that the step size of the influx reaction is a priori unknown and, in general, may fluctuate in time with a given correlation time and statistics, introduces an additional nondemographic reaction-step-size noise into the system. Employing the probability-generating function technique in conjunction with Hamiltonian formulation, we are able to map the problem in the leading order onto solving a stationary Hamilton-Jacobi equation. We show that compared to the "usual case" of single-step influx, bursty influx exponentially decreases the population's mean escape time from its long-lived metastable state. In particular, close to bifurcation we find a simple analytical expression for the mean escape time which solely depends on the mean and variance of the burst-size distribution. Our results are demonstrated on several realistic distributions and compare well with numerical Monte Carlo simulations.

  12. Lot sizing and unequal-sized shipment policy for an integrated production-inventory system

    Science.gov (United States)

    Giri, B. C.; Sharma, S.

    2014-05-01

    This article develops a single-manufacturer single-retailer production-inventory model in which the manufacturer delivers the retailer's ordered quantity in unequal shipments. The manufacturer's production process is imperfect and it may produce some defective items during a production run. The retailer performs a screening process immediately after receiving the order from the manufacturer. The expected average total cost of the integrated production-inventory system is derived using renewal theory and a solution procedure is suggested to determine the optimal production and shipment policy. An extensive numerical study based on different sets of parameter values is conducted and the optimal results so obtained are analysed to examine the relative performance of the models under equal and unequal shipment policies.

  13. The use of knowledge-based Genetic Algorithm for starting time optimisation in a lot-bucket MRP

    Science.gov (United States)

    Ridwan, Muhammad; Purnomo, Andi

    2016-01-01

    In production planning, Material Requirement Planning (MRP) is usually developed based on time-bucket system, a period in the MRP is representing the time and usually weekly. MRP has been successfully implemented in Make To Stock (MTS) manufacturing, where production activity must be started before customer demand is received. However, to be implemented successfully in Make To Order (MTO) manufacturing, a modification is required on the conventional MRP in order to make it in line with the real situation. In MTO manufacturing, delivery schedule to the customers is defined strictly and must be fulfilled in order to increase customer satisfaction. On the other hand, company prefers to keep constant number of workers, hence production lot size should be constant as well. Since a bucket in conventional MRP system is representing time and usually weekly, hence, strict delivery schedule could not be accommodated. Fortunately, there is a modified time-bucket MRP system, called as lot-bucket MRP system that proposed by Casimir in 1999. In the lot-bucket MRP system, a bucket is representing a lot, and the lot size is preferably constant. The time to finish every lot could be varying depends on due date of lot. Starting time of a lot must be determined so that every lot has reasonable production time. So far there is no formal method to determine optimum starting time in the lot-bucket MRP system. Trial and error process usually used for it but some time, it causes several lots have very short production time and the lot-bucket MRP would be infeasible to be executed. This paper presents the use of Genetic Algorithm (GA) for optimisation of starting time in a lot-bucket MRP system. Even though GA is well known as powerful searching algorithm, however, improvement is still required in order to increase possibility of GA in finding optimum solution in shorter time. A knowledge-based system has been embedded in the proposed GA as the improvement effort, and it is proven that the

  14. 7 CFR 993.104 - Lot.

    Science.gov (United States)

    2010-01-01

    ... of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and... purposes of §§ 993.50 and 993.150 means: (1) With respect to in-line inspection either (i) the aggregate... not previously inspected in-line, of the same size, in like containers, bearing the same...

  15. Numerical simulation of particle dynamics in an orifice-electrode system. Application to counting and sizing by impedance measurement.

    Science.gov (United States)

    Isèbe, Damien; Nérin, Philippe

    2013-04-01

    This paper describes how to numerically tackle the problem of counting and sizing particles by impedance measurement in an orifice-electrode system. The model allows to simulate the particle dynamics submitted to strong hydrodynamic stresses through a microorifice and to compute the voltage pulses generated by the modification of the inner dielectric medium. This approach gives important information about particles size distribution and allows to quantify the role of trajectory and orientation of particles on the size measurement.

  16. Dynamics of binary-disk interaction. 1: Resonances and disk gap sizes

    Science.gov (United States)

    Artymowicz, Pawel; Lubow, Stephen H.

    1994-01-01

    We investigate the gravitational interaction of a generally eccentric binary star system with circumbinary and circumstellar gaseous disks. The disks are assumed to be coplanar with the binary, geometrically thin, and primarily governed by gas pressure and (turbulent) viscosity but not self-gravity. Both ordinary and eccentric Lindblad resonances are primarily responsible for truncating the disks in binaries with arbitrary eccentricity and nonextreme mass ratio. Starting from a smooth disk configuration, after the gravitational field of the binary truncates the disk on the dynamical timescale, a quasi-equilibrium is achieved, in which the resonant and viscous torques balance each other and any changes in the structure of the disk (e.g., due to global viscous evolution) occur slowly, preserving the average size of the gap. We analytically compute the approximate sizes of disks (or disk gaps) as a function of binary mass ratio and eccentricity in this quasi-equilibrium. Comparing the gap sizes with results of direct simulations using the smoothed particle hydrodynamics (SPH), we obtain a good agreement. As a by-product of the computations, we verify that standard SPH codes can adequately represent the dynamics of disks with moderate viscosity, Reynolds number R approximately 10(exp 3). For typical viscous disk parameters, and with a denoting the binary semimajor axis, the inner edge location of a circumbinary disk varies from 1.8a to 2.6a with binary eccentricity increasing from 0 to 0.25. For eccentricities 0 less than e less than 0.75, the minimum separation between a component star and the circumbinary disk inner edge is greater than a. Our calculations are relevant, among others, to protobinary stars and the recently discovered T Tau pre-main-sequence binaries. We briefly examine the case of a pre-main-sequence spectroscopic binary GW Ori and conclude that circumbinary disk truncation to the size required by one proposed spectroscopic model cannot be due to

  17. Permian-Triassic Osteichthyes (bony fishes): diversity dynamics and body size evolution.

    Science.gov (United States)

    Romano, Carlo; Koot, Martha B; Kogan, Ilja; Brayard, Arnaud; Minikh, Alla V; Brinkmann, Winand; Bucher, Hugo; Kriwet, Jürgen

    2016-02-01

    The Permian and Triassic were key time intervals in the history of life on Earth. Both periods are marked by a series of biotic crises including the most catastrophic of such events, the end-Permian mass extinction, which eventually led to a major turnover from typical Palaeozoic faunas and floras to those that are emblematic for the Mesozoic and Cenozoic. Here we review patterns in Permian-Triassic bony fishes, a group whose evolutionary dynamics are understudied. Based on data from primary literature, we analyse changes in their taxonomic diversity and body size (as a proxy for trophic position) and explore their response to Permian-Triassic events. Diversity and body size are investigated separately for different groups of Osteichthyes (Dipnoi, Actinistia, 'Palaeopterygii', 'Subholostei', Holostei, Teleosteomorpha), within the marine and freshwater realms and on a global scale (total diversity) as well as across palaeolatitudinal belts. Diversity is also measured for different palaeogeographical provinces. Our results suggest a general trend from low osteichthyan diversity in the Permian to higher levels in the Triassic. Diversity dynamics in the Permian are marked by a decline in freshwater taxa during the Cisuralian. An extinction event during the end-Guadalupian crisis is not evident from our data, but 'palaeopterygians' experienced a significant body size increase across the Guadalupian-Lopingian boundary and these fishes upheld their position as large, top predators from the Late Permian to the Late Triassic. Elevated turnover rates are documented at the Permian-Triassic boundary, and two distinct diversification events are noted in the wake of this biotic crisis, a first one during the Early Triassic (dipnoans, actinistians, 'palaeopterygians', 'subholosteans') and a second one during the Middle Triassic ('subholosteans', neopterygians). The origination of new, small taxa predominantly among these groups during the Middle Triassic event caused a

  18. Clusters in Intense XUV pulses: effects of cluster size on expansion dynamics and ionization

    CERN Document Server

    Ackad, Edward; Briggs, Kyle; Ramunno, Lora

    2010-01-01

    We examine the effect of cluster size on the interaction of Ar$_{55}$-Ar$_{2057}$ with intense extreme ultraviolet (XUV) pulses, using a model we developed earlier that includes ionization via collisional excitation as an intermediate step. We find that the dynamics of these irradiated clusters is dominated by collisions. Larger clusters are more highly collisional, produce higher charge states, and do so more rapidly than smaller clusters. Higher charge states produced via collisions are found to reduce the overall photon absorption, since charge states of Ar$^{2+}$ and higher are no longer photo-accessible. We call this mechanism \\textit{collisionally reduced photoabsorption}, and it decreases the effective cluster photoabsorption cross-section by more than 30% for Ar$_{55}$ and 45% Ar$_{2057}$. compared to gas targets with the same number of atoms. An investigation of the shell structure soon after the laser interaction shows an almost uniformly charged core with a modestly charged outer shell which evolve...

  19. Transmission Dynamics and Final Epidemic Size of Ebola Virus Disease Outbreaks with Varying Interventions.

    Science.gov (United States)

    Barbarossa, Maria Vittoria; Dénes, Attila; Kiss, Gábor; Nakata, Yukihiko; Röst, Gergely; Vizi, Zsolt

    2015-01-01

    The 2014 Ebola Virus Disease (EVD) outbreak in West Africa was the largest and longest ever reported since the first identification of this disease. We propose a compartmental model for EVD dynamics, including virus transmission in the community, at hospitals, and at funerals. Using time-dependent parameters, we incorporate the increasing intensity of intervention efforts. Fitting the system to the early phase of the 2014 West Africa Ebola outbreak, we estimate the basic reproduction number as 1.44. We derive a final size relation which allows us to forecast the total number of cases during the outbreak when effective interventions are in place. Our model predictions show that, as long as cases are reported in any country, intervention strategies cannot be dismissed. Since the main driver in the current slowdown of the epidemic is not the depletion of susceptibles, future waves of infection might be possible, if control measures or population behavior are relaxed.

  20. Ground test program for a full-size solar dynamic heat receiver

    Science.gov (United States)

    Sedgwick, L. M.; Kaufmann, K. J.; McLallin, K. L.; Kerslake, T. W.

    Test hardware, facilities, and procedures were developed to conduct ground testing of a full-size, solar dynamic heat receiver in a partially simulated, low earth orbit environment. The heat receiver was designed to supply 102 kW of thermal energy to a helium and xenon gas mixture continuously over a 94 minute orbit, including up to 36 minutes of eclipse. The purpose of the test program was to quantify the receiver thermodynamic performance, its operating temperatures, and thermal response to changes in environmental and power module interface boundary conditions. The heat receiver was tested in a vacuum chamber using liquid nitrogen cold shrouds and an aperture cold plate. Special test equipment was designed to provide the required ranges in interface boundary conditions that typify those expected or required for operation as part of the solar dynamic power module on the Space Station Freedom. The support hardware includes an infrared quartz lamp heater with 30 independently controllable zones and a closed-Brayton cycle engine simulator to circulate and condition the helium-xenon gas mixture. The test article, test support hardware, facilities, and instrumentation developed to conduct the ground test program are all described.

  1. Full-size solar dynamic heat receiver thermal-vacuum tests

    Science.gov (United States)

    Sedgwick, L. M.; Kaufmann, K. J.; McLallin, K. L.; Kerslake, T. W.

    The testing of a full-size, 102 kW, solar dynamic heat receiver utilizing high-temperature thermal energy storage is described. The purpose of the test program was to quantify receiver thermodynamic performance, operating temperatures, and thermal response to changes in environmental and power module interface boundary conditions. The heat receiver was tested in a vacuum chamber with liquid nitrogen cold shrouds and an aperture cold plate to partly simulate a low-Earth-orbit environment. The cavity of the receiver was heated by an infrared quartz lamp heater with 30 independently controllable zones to allow axially and circumferentially varied flux distributions. A closed-Brayton cycle engine simulator conditioned a helium-xenon gas mixture to specific interface conditions to simulate the various operational modes of the solar dynamic power module on the Space Station Freedom. Inlet gas temperature, pressure, and flow rate were independently varied. A total of 58 simulated orbital cycles, each 94 minutes in duration, was completed during the test period.

  2. Performance evaluation of a mouse-sized camera for dynamic studies in small animals

    Science.gov (United States)

    Loudos, George; Majewski, Stan; Wojcik, Randy; Weisenberger, Andrew; Sakellios, Nicolas; Nikita, Konstantina; Uzunoglu, Nikolaos; Bouziotis, Penelope; Varvarigou, Alexandra

    2007-02-01

    A mouse sized camera has been built in terms of collaboration between the presenting institutions. The system is used for the performance of dynamic studies in small animals, in order to evaluate novel radiopharmaceuticals. The active area of the detector is approximately 48×96 mm allowing depiction of the entire mouse in a single view. The system is based on two flat-panel Hamamatsu H8500 position sensitive photomultiplier tubes (PSPMT), a pixellated NaI(Tl) scintillator and a copper-beryllium (CuBe) parallel-hole collimator. In this work, the evaluation results of the system are presented, using phantoms and small animals injected with conventional radiophrmaceuticals. Average resolution was ˜1.6 mm on the collimator surface and increased to ˜4.1 mm in 12 cm distance from the detector. The average energy resolution was measured and found to be ˜15.6% for Tc 99m. Results from imaging thin capillaries demonstrated system's high resolution and sensitivity in activity variations was shown. Initial dynamic studies have been carried out in small animals injected with Tc 99m-DTPA and Tc 99m-MDP. The results show system's ability to perform kinetic imaging in small animals.

  3. Structure and dynamics of nano-sized raft-like domains on the plasma membrane

    Science.gov (United States)

    Herrera, Fernando E.; Pantano, Sergio

    2012-01-01

    Cell membranes are constitutively composed of thousands of different lipidic species, whose specific organization leads to functional heterogeneities. In particular, sphingolipids, cholesterol and some proteins associate among them to form stable nanoscale domains involved in recognition, signaling, membrane trafficking, etc. Atomic-detail information in the nanometer/second scale is still elusive to experimental techniques. In this context, molecular simulations on membrane systems have provided useful insights contributing to bridge this gap. Here we present the results of a series of simulations of biomembranes representing non-raft and raft-like nano-sized domains in order to analyze the particular structural and dynamical properties of these domains. Our results indicate that the smallest (5 nm) raft domains are able to preserve their distinctive structural and dynamical features, such as an increased thickness, higher ordering, lower lateral diffusion, and specific lipid-ion interactions. The insertion of a transmembrane protein helix into non-raft, extended raft-like, and raft-like nanodomain environments result in markedly different protein orientations, highlighting the interplay between the lipid-lipid and lipid-protein interactions.

  4. Effect of Large Finite-Size Wind Farms and Their Wakes on Atmospheric Boundary Layer Dynamics

    Science.gov (United States)

    Wu, Ka Ling; Porté-Agel, Fernando

    2016-04-01

    Through the use of large-eddy simulation, the effect of large finite-size wind farms and their wakes on conventionally-neutral atmospheric boundary layer (ABL) dynamics and power extraction is investigated. Specifically, this study focuses on a wind farm that comprises 25 rows of wind turbines, spanning a distance of 10 km. It is shown that large wind farms have a significant effect on internal boundary layer growth both inside and downwind of the wind farms. If the wind farm is large enough, the internal boundary layer interacts with the thermally-stratified free atmosphere above, leading to a modification of the ABL height and power extraction. In addition, it is shown that large wind farms create extensive wakes, which could have an effect on potential downwind wind farms. Specifically, for the case considered here, a power deficit as large as 8% is found at a distance of 10 km downwind from the wind farm. Furthermore, this study compares the wind farm wake dynamics for cases in which the conventionally neutral ABLs are driven by a unidirectional pressure gradient and Coriolis forces.

  5. Custom sizing of lower limb exoskeleton actuators using gait dynamic modelling of children with cerebral palsy.

    Science.gov (United States)

    Samadi, B; Achiche, S; Parent, A; Ballaz, L; Chouinard, U; Raison, M

    2016-11-01

    The use of exoskeletons as an aid for people with musculoskeletal disorder is the subject to an increasing interest in the research community. These devices are expected to meet the specific needs of users, such as children with cerebral palsy (CP) who are considered a significant population in pediatric rehabilitation. Although these exoskeletons should be designed to ease the movement of people with physical shortcoming, their design is generally based on data obtained from healthy adults, which leads to oversized components that are inadequate to the targeted users. Consequently, the objective of this study is to custom-size the lower limb exoskeleton actuators based on dynamic modeling of the human body for children with CP on the basis of hip, knee, and ankle joint kinematics and dynamics of human body during gait. For this purpose, a multibody modeling of the human body of 3 typically developed children (TD) and 3 children with CP is used. The results show significant differences in gait patterns especially in knee and ankle with respectively 0.39 and -0.33 (Nm/kg) maximum torque differences between TD children and children with CP. This study provides the recommendations to support the design of actuators to normalize the movement of children with CP.

  6. Computational lfuid dynamics simulation of intracranial aneurysms - comparing size and shape

    Institute of Scientific and Technical Information of China (English)

    Zifeng Yang; Hongtao Yu; George P Huang; Ryan Schwieterman; Bryan Ludwig

    2015-01-01

    Objective:To study the hemodynamics of an anatomic internal carotid artery aneurysm derived from a patient-specific model and then manipulate into two phantom morphologies: one growing uniformly by size and the other changing shape unevenly. Methods: The computational model of the saccular, internal carotid artery, aneurysm was constructed from 3D rotational, digitally subtracted, catheter angiography images. Computational fluid dynamics simulations were performed under pulsatile cardiac flow conditions. Velocity vectors, streamlines, pressure, and wall shear stress (WSS) and its variance distributions were quantitatively visualized. Results: The maximum pressure andWSS from the time-averaged distribution on the inside saccular surface of the original case are 415.38 and 17.61 Pa. In contrast, the bi-lobed shape gives rise to higher peak values of pressure (461.00 Pa) andWSS (33.20 Pa) on the saccular dome. Conversely, the evenly enlarged aneurysm actually results in a slightly lower peak pressure (399.58 Pa) and drastically decreasedWSS (9.81 Pa). Conclusions:The current study indicates that the size of the aneurysm should not be the only determining factor for the rupture risk consideration, the irregularity of the aneurysm shape and the corresponding aberrant hemodynamics might be a more important factor to consider for risk assessment.

  7. Molecular dynamics study of the catalyst particle size dependence on carbon nanotube growth

    Science.gov (United States)

    Ding, Feng; Rosén, Arne; Bolton, Kim

    2004-08-01

    The molecular dynamics method, based on an empirical potential energy surface, was used to study the effect of catalyst particle size on the growth mechanism and structure of single-walled carbon nanotubes (SWNTs). The temperature for nanotube nucleation (800-1100 K), which occurs on the surface of the cluster, is similar to that used in catalyst chemical vapor deposition experiments, and the growth mechanism, which is described within the vapor-liquid-solid model, is the same for all cluster sizes studied here (iron clusters containing between 10 and 200 atoms were simulated). Large catalyst particles, which contain at least 20 iron atoms, nucleate SWNTs that have a far better tubular structure than SWNTs nucleated from smaller clusters. In addition, the SWNTs that grow from the larger clusters have diameters that are similar to the cluster diameter, whereas the smaller clusters, which have diameters less than 0.5 nm, nucleate nanotubes that are ≈0.6-0.7 nm in diameter. This is in agreement with the experimental observations that SWNT diameters are similar to the catalyst particle diameter, and that the narrowest free-standing SWNT is 0.6-0.7 nm.

  8. Investigation of the dynamics of nanometer-size dust particles in the inner heliosphere

    Science.gov (United States)

    O'brien, L.

    2015-12-01

    The spatial and size distribution of submicron-sized interplanetary dust particles at 1 AU is highly variable due to the nature of its production and transport through the solar system. Nano-dust particles are thought to be produced by mutual collisions between interplanetary dust particles slowly spiraling toward the Sun and are accelerated outward to high velocities by interaction with the solar wind. The WAVES instruments on the two STEREO spacecraft reported the detection, strong temporal variation, and potentially high flux of these particles [Meyer-Vernet et al., 2009]. Simulations of nano-dust dynamics are performed to gain an understanding of their transport in the inner heliosphere and distribution near 1 AU where they can potentially be detected. Simulations show that the temporal variation in nano-dust detection, as suggested by the STEREO observations, can be described by the dust's interaction with the complex structure of the interplanetary magnetic field (IMF) [Juhasz and Horanyi, 2013]. The dust trajectories and their distribution near Earth's orbit is a function of the initial conditions of both nano-dust particles and the IMF. Le Chat et al. (2015) reported on the correlation between high nano-dust fluxes observed by STEREO and the observed Interplanetary Coronal Mass Ejections (ICMEs). We present the results from simulating nano-dust interaction with ICMEs that are modeled as magnetic clouds, and report that the dust trajectories and, thus, their distribution and velocities at 1 AU are significantly altered.

  9. Dynamics of a Dust Crystal with Two Different Size Dust Species

    CERN Document Server

    Matthews, L S; Hyde, T W

    2005-01-01

    A self-consistent three-dimensional model for a complex (dusty) plasma is used to study the effects of multiple-sized dust grains in a dust crystal. In addition to the interparticle forces, which interact through a Yukawa potential, the model includes the effects of gravity, the variation of the sheath potential above the powered electrode, and a radial confining potential. Simulations studied various ratios of a mix of 6.5- and 8.9-micron monodisperse particles and compared their correlation functions, electric potential energy of the crystal formations, and the dispersion relations for in-plane and out-of-plane dust lattice wave (DLW) modes for two different sheath thicknesses. In the 7 mm sheath, the particles formed two layers in the vertical direction by size, and acted as a two-layer crystal with weak correlation between the layers. In the 3 mm sheath, the particles formed an essentially monolayer crystal; however the crystal dynamics showed some characteristics of a bilayer crystal.

  10. Time bucket length and lot-splitting approach

    NARCIS (Netherlands)

    Riezebos, J

    2004-01-01

    The effect of time bucket length on the choice of a lot-splitting approach is studied. Due to the continuing pressure to reduce throughput times and increase efficiency, managers apply various measures, such as lot splitting and cycle time reduction programmes, that change the length of the time buc

  11. 7 CFR 983.52 - Failed lots/rework procedure.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Failed lots/rework procedure. 983.52 Section 983.52..., ARIZONA, AND NEW MEXICO Regulations § 983.52 Failed lots/rework procedure. (a) Substandard pistachios... committee may establish, with the Secretary's approval, appropriate rework procedures. (b) Failed...

  12. 7 CFR 983.152 - Failed lots/rework procedure.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Failed lots/rework procedure. 983.152 Section 983.152..., ARIZONA, AND NEW MEXICO Rules and Regulations § 983.152 Failed lots/rework procedure. (a) Inshell rework procedure for aflatoxin. If inshell rework is selected as a remedy to meet the aflatoxin regulations of...

  13. 7 CFR 33.7 - Less than carload lot.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Less than carload lot. 33.7 Section 33.7 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... ISSUED UNDER AUTHORITY OF THE EXPORT APPLE ACT Definitions § 33.7 Less than carload lot. Less...

  14. Investigating pyroclast ejection dynamics using shock-tube experiments: temperature, grain size and vent geometry effects.

    Science.gov (United States)

    Cigala, V.; Kueppers, U.; Dingwell, D. B.

    2015-12-01

    Explosive volcanic eruptions eject large quantities of gas and particles into the atmosphere. The portion directly above the vent commonly shows characteristics of underexpanded jets. Understanding the factors that influence the initial pyroclast ejection dynamics is necessary in order to better assess the resulting near- and far-field hazards. Field observations are often insufficient for the characterization of volcanic explosions due to lack of safe access to such environments. Fortunately, their dynamics can be simulated in the laboratory where experiments are performed under controlled conditions. We ejected loose natural particles from a shock-tube while controlling temperature (25˚ and 500˚C), overpressure (15MPa), starting grain size distribution (1-2 mm, 0.5-1 mm and 0.125-0.250 mm), sample-to-vent distance and vent geometry. For each explosion we quantified the velocity of individual particles, the jet spreading angle and the production of fines. Further, we varied the setup to allow for different sample-to-gas ratios and deployed four different vent geometries: 1) cylindrical, 2) funnel with a flaring of 30˚, 3) funnel with a flaring of 15˚ and 4) nozzle. The results showed maximum particle velocities up to 296 m/s, gas spreading angles varying from 21˚ to 37˚ and particle spreading angles from 3˚ to 40˚. Moreover we observed dynamically evolving ejection characteristics and variations in the production of fines during the course of individual experiments. Our experiments mechanistically mimic the process of pyroclast ejection. Thus the capability for constraining the effects of input parameters (fragmentation conditions) and conduit/vent geometry on ballistic pyroclastic plumes has been clearly established. These data obtained in the presence of well-documented conduit and vent conditions, should greatly enhance our ability to numerically model explosive ejecta in nature.

  15. Effect of Cylinder Size on the Modulus of Elasticity and Compressive Strength of Concrete from Static and Dynamic Tests

    Directory of Open Access Journals (Sweden)

    Byung Jae Lee

    2015-01-01

    Full Text Available The primary objective of this study is to investigate the effects of cylinder size (150 by 300 mm and 100 by 200 mm on empirical equations that relate static elastic moduli and compressive strength and static and dynamic elastic moduli of concrete. For the purposes, two sets of one hundred and twenty concrete cylinders, 150 by 300 mm and 100 by 200 mm, were prepared from three different mixtures with target compressive strengths of 30, 35, and 40 MPa. Static and dynamic tests were performed at 4, 7, 14, and 28 days to evaluate compressive strength and static and dynamic moduli of cylinders. The effects of the two different cylinder sizes were investigated through experiments in this study and database collected from the literature. For normal strength concrete (≤40 MPa, the two different cylinder sizes do not result in significant differences in test results including experimental variability, compressive strength, and static and dynamic elastic moduli. However, it was observed that the size effect became substantial in high strength concrete greater than 40 MPa. Therefore, special care is still needed to compare the static and dynamic properties of high strength concrete from the two different cylinder sizes.

  16. La vallée du Lot en Lot-et-Garonne : inventaire topographique

    Directory of Open Access Journals (Sweden)

    Hélène Mousset

    2012-04-01

    Full Text Available La remise en navigation du Lot est à l’origine du projet d’inventaire du patrimoine de la vallée dans sa partie lot-et-garonnaise1. L’ampleur du territoire - 12 cantons riverains2 - et de la perspective historique - du Moyen Age à nos jours - imposaient d’emblée rigueur et objectifs clairs : méthode raisonnée de l’inventaire topographique pour un bilan homogène du patrimoine, fondée sur une enquête systématique du paysage bâti et du mobilier public, sans a priori. Le premier résultat est un catalogue patrimonial sous forme de bases de données3. Mais ce corpus documentaire hétérogène et touffu n’est pas une addition de monographies : il peut et doit être interrogé et exploité comme un ensemble apportant une connaissance renouvelée du territoire. Sans prétendre réaliser une synthèse de la totalité des données pour l’ensemble de la vallée4, les exemples qui vont suivre illustreront la façon dont le travail d’inventaire apporte réponses et nouvelles interrogations, concernant notamment l’occupation du sol, les paysages et l’architecture de cette partie de l’Agenais. Recherche de l’empreinte d’une époque déterminée, examen de la permanence des paysages bâtis sur la longue durée et observation des traces de mutations et flexions historiques, sont un triple niveau d’analyse attendu dans le cadre d’un inventaire sur un vaste territoire rural.The plan to reintroduce navigation on the Lot in the part of the river that flows through the Lot-et-Garonne department was at the origins of a survey of the heritage along the course of the river. The geographical scope of the survey was large (12 cantons along the river and the period covered by the heritage extends from the Middle ages up to the present day. The variety of buildings to be covered required a rigorous approach and clear objectives. The method of the topographical inventory was tailored to the production of a homogenous heritage audit

  17. Extending cluster lot quality assurance sampling designs for surveillance programs.

    Science.gov (United States)

    Hund, Lauren; Pagano, Marcello

    2014-07-20

    Lot quality assurance sampling (LQAS) has a long history of applications in industrial quality control. LQAS is frequently used for rapid surveillance in global health settings, with areas classified as poor or acceptable performance on the basis of the binary classification of an indicator. Historically, LQAS surveys have relied on simple random samples from the population; however, implementing two-stage cluster designs for surveillance sampling is often more cost-effective than simple random sampling. By applying survey sampling results to the binary classification procedure, we develop a simple and flexible nonparametric procedure to incorporate clustering effects into the LQAS sample design to appropriately inflate the sample size, accommodating finite numbers of clusters in the population when relevant. We use this framework to then discuss principled selection of survey design parameters in longitudinal surveillance programs. We apply this framework to design surveys to detect rises in malnutrition prevalence in nutrition surveillance programs in Kenya and South Sudan, accounting for clustering within villages. By combining historical information with data from previous surveys, we design surveys to detect spikes in the childhood malnutrition rate.

  18. No-slip boundary condition in finite-size dissipative particle dynamics

    Science.gov (United States)

    Ranjith, S. Kumar; Patnaik, B. S. V.; Vedantam, Srikanth

    2013-01-01

    Dissipative particle dynamics (DPD) is an efficient, particle based mesoscopic numerical scheme to simulate dynamics of complex fluids and micro-flows, with spatio-temporal scales in the range of micrometers and microseconds. While the traditional DPD method treated particles as point masses, a modified DPD scheme was introduced recently [W. Pan, I.V. Pivkin, G.E. Karniadakis, Single-particle hydrodynamics in DPD: a new formulation, Europhysics Letters 84 (2008) 10012] by including transverse forces between finite sized particles in addition to the central forces of the standard DPD. The capability of a DPD scheme to solve confined wall bounded flows, depends on its ability to model the flow boundaries and effectively impose the classical no-slip boundary condition. Previous simulations with the modified DPD scheme used boundary conditions from the traditional DPD schemes, resorting to the velocity reversal of re-inserted particles which cross the solid wall. In the present work, a new method is proposed to impose no-slip or tunable slip boundary condition by controlling the non-central dissipative components in the modified DPD scheme. The solid wall is modeled in such a way that the fluid particles feel the presence of a continuous wall rather than a few discrete frozen particles as in conventional wall models. The fluid particles interact with the walls using a modified central repulsive potential to reduce the spurious density fluctuations. Several different benchmark problems (Poiseuille flow, lid-driven cavity and flow past circular cylinder) were solved using the new approach to demonstrate its validity.

  19. Finite-size effect on the dynamic and sensing performances of graphene resonators: the role of edge stress

    OpenAIRE

    Chang-Wan Kim; Mai Duc Dai; Kilho Eom

    2016-01-01

    We have studied the finite-size effect on the dynamic behavior of graphene resonators and their applications in atomic mass detection using a continuum elastic model such as modified plate theory. In particular, we developed a model based on von Karman plate theory with including the edge stress, which arises from the imbalance between the coordination numbers of bulk atoms and edge atoms of graphene. It is shown that as the size of a graphene resonator decreases, the edge stress depending on...

  20. Particle sizing by dynamic light scattering: non-linear cumulant analysis.

    Science.gov (United States)

    Mailer, Alastair G; Clegg, Paul S; Pusey, Peter N

    2015-04-15

    We revisit the method of cumulants for analysing dynamic light scattering data in particle sizing applications. Here the data, in the form of the time correlation function of scattered light, is written as a series involving the first few cumulants (or moments) of the distribution of particle diffusion constants. Frisken (2001 Appl. Opt. 40 4087) has pointed out that, despite greater computational complexity, a non-linear, iterative, analysis of the data has advantages over the linear least-squares analysis used originally. In order to explore further the potential and limitations of cumulant methods we analyse, by both linear and non-linear methods, computer-generated data with realistic 'noise', where the parameters of the distribution can be set explicitly. We find that, with modern computers, non-linear analysis is straightforward and robust. The mean and variance of the distribution of diffusion constants can be obtained quite accurately for distributions of width (standard deviation/mean) up to about 0.6, but there appears to be little prospect of obtaining meaningful higher moments.

  1. Aurora B suppresses microtubule dynamics and limits central spindle size by locally activating KIF4A

    Science.gov (United States)

    Nunes Bastos, Ricardo; Gandhi, Sapan R.; Baron, Ryan D.; Gruneberg, Ulrike; Nigg, Erich A.

    2013-01-01

    Anaphase central spindle formation is controlled by the microtubule-stabilizing factor PRC1 and the kinesin KIF4A. We show that an MKlp2-dependent pool of Aurora B at the central spindle, rather than global Aurora B activity, regulates KIF4A accumulation at the central spindle. KIF4A phosphorylation by Aurora B stimulates the maximal microtubule-dependent ATPase activity of KIF4A and promotes its interaction with PRC1. In the presence of phosphorylated KIF4A, microtubules grew more slowly and showed long pauses in growth, resulting in the generation of shorter PRC1-stabilized microtubule overlaps in vitro. Cells expressing only mutant forms of KIF4A lacking the Aurora B phosphorylation site overextended the anaphase central spindle, demonstrating that this regulation is crucial for microtubule length control in vivo. Aurora B therefore ensures that suppression of microtubule dynamic instability by KIF4A is restricted to a specific subset of microtubules and thereby contributes to central spindle size control in anaphase. PMID:23940115

  2. Evaporation and fluid dynamics of a sessile drop of capillary size.

    Science.gov (United States)

    Barash, L Yu; Bigioni, T P; Vinokur, V M; Shchur, L N

    2009-04-01

    Theoretical description and numerical simulation of an evaporating sessile drop are developed. We jointly take into account the hydrodynamics of an evaporating sessile drop, effects of the thermal conduction in the drop, and the diffusion of vapor in air. A shape of the rotationally symmetric drop is determined within the quasistationary approximation. Nonstationary effects in the diffusion of the vapor are also taken into account. Simulation results agree well with the data of evaporation rate measurements for the toluene drop. Marangoni forces associated with the temperature dependence of the surface tension generate fluid convection in the sessile drop. Our results demonstrate several dynamical stages of the convection characterized by different number of vortices in the drop. During the early stage the array of vortices arises near a surface of the drop and induces a nonmonotonic spatial distribution of the temperature over the drop surface. The initial number of near-surface vortices in the drop is controlled by the Marangoni cell size which is similar to that given by Pearson for flat fluid layers. This number quickly decreases with time resulting in three bulk vortices in the intermediate stage. The vortices finally transform into the single convection vortex in the drop existing during about 1/2 of the evaporation time.

  3. Sorting and cost analysis of reworking items in rejected lots based on non-destructive variable sampling plan

    Directory of Open Access Journals (Sweden)

    H. Y. Alkahby

    1999-12-01

    Full Text Available A mathematical model for a decision criterion for disposing an inspection lot is developed. An expression of the posterior cost is formulated in terms of the quality characteristics $X$ of the items manufactured, the sample size $n$, the lot size $N$, the upper and lower limits of $X$ ($U$, $L$ of the individual items, the sample mean $overline{x}$, the mean $mu$ and variance $sigma^2$ of $X$, also in terms of the economical cost parameters, Optimizing the posterior cost equation leads to the estimation of the decision points. A procedure to accept, reject, screen or scrap the entire lot based on the values of the decision points is developed. Mathematical expressions are derived for the expected cost of lot acceptance, screening and scrapping. In developing the model, the distribution of $X$ and $mu$ are normal. The tested items can be used for their intended purposes after testing. The defective items can be repaired or reworked. Rejected lots are either screened or scrapped. The decision to accept or reject a lot depends on the upper and lower limits of the sample mean, which constitutes the decision points.

  4. Parking Lots at Little Bighorn Battlefield National Monument, Montana

    Data.gov (United States)

    National Park Service, Department of the Interior — This is a vector polygon file showing the parking lots at Little Bighorn Battlefield National Monument (LIBI). The coordinates for this dataset were collected using...

  5. Camp Pendleton Saves 91% in Parking Lot Lighting

    Energy Technology Data Exchange (ETDEWEB)

    None

    2016-01-01

    Case study describes how Camp Pendleton Marine Corps Base replaced high-pressure sodium (HPS) fixtures in one parking lot with high-efficiency induction fixtures for 91% savings in energy use and $5,700 in cost savings annually. This parking lot is estimated to have a simple payback of 2.9 years. Sitewide up-grades yielded annual savings of 1 million kWh.

  6. Localization of Sound Sources in Underground Parking Lots

    OpenAIRE

    Dong Myung Lee; Moo Kyung Jung; Chang Yong Choi; Hongchi Shi

    2014-01-01

    We present a localization of sound sources algorithm for underground parking lots and a compensation algorithm for enhancing localization of sound sources based on the least-squares method (LSM). The proposed localization of sound sources system is designed for the underground parking lots in apartments. The sound location algorithm is referred to as LOCSS, and the localization algorithm enhanced with the compensation algorithm is referred to as LOCSS+LCALSM. We also present the performance c...

  7. Effects of meal size, meal type, body temperature, and body size on the specific dynamic action of the marine toad, Bufo marinus.

    Science.gov (United States)

    Secor, Stephen M; Faulkner, Angela C

    2002-01-01

    Specific dynamic action (SDA), the accumulated energy expended on all physiological processes associated with meal digestion, is strongly influenced by features of both the meal and the organism. We assessed the effects of meal size, meal type, body temperature, and body size on the postprandial metabolic response and calculated SDA of the marine toad, Bufo marinus. Peak postprandial rates of O(2) consumption (.V(O2)) and CO(2) production (.V(CO2)) and SDA increased with meal size (5%-20% of body mass). Postprandial metabolism was impacted by meal type; the digestion of hard-bodied superworms (Zophobas larva) and crickets was more costly than the digestion of soft-bodied earthworms and juvenile rats. An increase in body temperature (from 20 degrees to 35 degrees C) altered the postprandial metabolic profile, decreasing its duration and increasing its magnitude, but did not effect SDA, with the cost of meal digestion remaining constant across body temperatures. Allometric mass exponents were 0.69 for standard metabolic rate, 0.85 for peak postprandial .V(O2), and 1.02 for SDA; therefore, the factorial scope of peak postprandial .V(O2) increased with body mass. The mass of nutritive organs (stomach, liver, intestines, and kidneys) accounted for 38% and 20% of the variation in peak postprandial .V(O2) and SDA, respectively. Toads forced to exercise experienced 25-fold increases in .V(O2) much greater than the 5.5-fold increase experience during digestion. Controlling for meal size, meal type, and body temperature, the specific dynamic responses of B. marinus are similar to those of the congeneric Bufo alvarius, Bufo boreas, Bufo terrestris, and Bufo woodhouseii.

  8. Study of the dynamics of nanoparticle sizes in trinitrotoluene detonation using the VEPP-4M synchrotron radiation

    Science.gov (United States)

    Rubtsov, I. A.; Ten, K. A.; Pruuel, E. R.; Kashkarov, A. O.

    2016-11-01

    Here we present experimental data on measuring condensed carbon nanoparticle sizes in trinitrotoluene (TNT) detonation. Nanoparticle sizes were determined from measured distributions of small-angle x-ray scattering (SAXS). The work was carried out at the VEPP- 4M (BINP) accelerator complex. In this work, we also carried out a SAXS simulation with a real spectrum on the SYRAFEEMA (Synchrotron Radiation Facility for Exploring Energetic Materials) station (wiggler radiation, TNT absorption, absorption of the DIMEX-3 detector). Comparison of the calculated and measured SAXS distribution allows one to obtain the dynamics of the average sizes of carbon nanoparticles behind the detonation front using a pink synchrotron radiation (SR) beam. The measured particle sizes in the chemical reaction zone are ≈ 2 nm. Carbon nanoparticles with a maximum size of ≈ 4-5 nm are found outside the chemical reaction zone.

  9. The effect of apical preparation size on irrigant flow in root canals evaluated using an unsteady Computational Fluid Dynamics model

    NARCIS (Netherlands)

    Boutsioukis, C.; Gogos, C.; Verhaagen, B.; Versluis, M.; Kastrinakis, E.; van der Sluis, L.W.M.

    2010-01-01

    Aim  To evaluate the effect of apical preparation size on irrigant flow inside a root canal during final irrigation with a syringe and two different needles types, using a Computational Fluid Dynamics (CFD) model. Methodology  A validated CFD model was used to simulate the irrigant flow from either

  10. Effective population size dynamics and the demographic collapse of Bornean orang-utans.

    Directory of Open Access Journals (Sweden)

    Reeta Sharma

    Full Text Available Bornean orang-utans experienced a major demographic decline and local extirpations during the Pleistocene and Holocene due to climate change, the arrival of modern humans, of farmers and recent commercially-driven habitat loss and fragmentation. The recent loss of habitat and its dramatic fragmentation has affected the patterns of genetic variability and differentiation among the remaining populations and increased the extinction risk of the most isolated ones. However, the contribution of recent demographic events to such genetic patterns is still not fully clear. Indeed, it can be difficult to separate the effects of recent anthropogenic fragmentation from the genetic signature of prehistoric demographic events. Here, we investigated the genetic structure and population size dynamics of orang-utans from different sites. Altogether 126 individuals were analyzed and a full-likelihood Bayesian approach was applied. All sites exhibited clear signals of population decline. Population structure is known to generate spurious bottleneck signals and we found that it does indeed contribute to the signals observed. However, population structure alone does not easily explain the observed patterns. The dating of the population decline varied across sites but was always within the 200-2000 years period. This suggests that in some sites at least, orang-utan populations were affected by demographic events that started before the recent anthropogenic effects that occurred in Borneo. These results do not mean that the recent forest exploitation did not leave its genetic mark on orang-utans but suggests that the genetic pool of orang-utans is also impacted by more ancient events. While we cannot identify the main cause for this decline, our results suggests that the decline may be related to the arrival of the first farmers or climatic events, and that more theoretical work is needed to understand how multiple demographic events impact the genome of species and

  11. Lane Formation Dynamics of Oppositely Self-Driven Binary Particles: Effects of Density and Finite System Size

    Science.gov (United States)

    Ikeda, Kosuke; Kim, Kang

    2017-04-01

    We examined the lane formation dynamics of oppositely self-driven binary particles by molecular dynamics simulations of a two-dimensional system. Our study comprehensively revealed the effects of the density and system size on the lane formation. The phase diagram distinguishing the no-lane and lane states was systematically determined for various combinations of the anisotropic friction coefficient and the desired velocity. A peculiar clustered structure was observed when the lane was destroyed by considerably increasing the desired velocity. A strong system size effect was demonstrated by the relationship between the temporal and spatial scales of the lane structure. This system size effect can be attributed to an analogy with the driven lattice gas. The transport efficiency was characterized from the scaling relation in terms of the degree of lane formation and the interface thickness between different lanes.

  12. Pattern and dynamics of biomass stock in old growth forests: The role of habitat and tree size

    Science.gov (United States)

    Yuan, Zuoqiang; Gazol, Antonio; Wang, Xugao; Lin, Fei; Ye, Ji; Zhang, Zhaochen; Suo, YanYan; Kuang, Xu; Wang, Yunyun; Jia, Shihong; Hao, Zhanqing

    2016-08-01

    Forest ecosystems play a fundamental role in the global carbon cycle. However, how stand-level changes in tree age and structure influence biomass stock and dynamics in old-growth forests is a question that remains unclear. In this study, we quantified the aboveground biomass (AGB) standing stock, the coarse woody productivity (CWP), and the change in biomass over ten years (2004-2014) in a 25 ha unmanaged broad-leaved Korean pine mixed forest in northeastern China. In addition, we quantified how AGB stock and change (tree growth, recruitment and mortality) estimations are influenced by the variation in habitat heterogeneity, tree size structure and subplot size. Our analysis indicated that Changbai forest had AGB of 265.4 Mg ha-1 in 2004, and gained1.36 Mg ha-1 y-1 between 2004 and 2014. Despite recruitment having better performance in nutrient rich habitat, we found that there is a directional tree growth trend independent of habitat heterogeneity for available nutrients in this old growth forest. The observed increases in AGB stock (∼70%) are mainly attributed to the growth of intermediate size trees (30-70 cm DBH), indicating that this forest is still reaching its mature stage. Meanwhile, we indicated that biomass loss due to mortality reduces living biomass, not increment, may be the primary factor to affect forest biomass dynamics in this area. Also, spatial variation in forest dynamics is large for small sizes (i.e. coefficient of variation in 20 × 20 m subplots is 53.2%), and more than 90 percent of the inherent variability of these coefficients was predicted by a simple model including plot size. Our result provides a mean by which to estimate within-plot variability at a local scale before inferring any directional change in forest dynamics at a regional scale, and information about the variability of forest structure and dynamics are fundamental to design effective sampling strategies in future study.

  13. Grain size dependence of dynamic mechanical behavior of AZ31B magnesium alloy sheet under compressive shock loading

    Energy Technology Data Exchange (ETDEWEB)

    Asgari, H., E-mail: hamed.asgari@usask.ca [Department of Mechanical Engineering, University of Saskatchewan, Saskatoon (Canada); Odeshi, A.G.; Szpunar, J.A. [Department of Mechanical Engineering, University of Saskatchewan, Saskatoon (Canada); Zeng, L.J.; Olsson, E. [Department of Applied Physics, Chalmers University of Technology, Göteborg (Sweden)

    2015-08-15

    The effects of grain size on the dynamic deformation behavior of rolled AZ31B alloy at high strain rates were investigated. Rolled AZ31B alloy samples with grain sizes of 6, 18 and 37 μm, were subjected to shock loading tests using Split Hopkinson Pressure Bar at room temperature and at a strain rate of 1100 s{sup −} {sup 1}. It was found that a double-peak basal texture formed in the shock loaded samples. The strength and ductility of the alloy under the high strain-rate compressive loading increased with decreasing grain size. However, twinning fraction and strain hardening rate were found to decrease with decreasing grain size. In addition, orientation imaging microscopy showed a higher contribution of double and contraction twins in the deformation process of the coarse-grained samples. Using transmission electron microscopy, pyramidal dislocations were detected in the shock loaded sample, proving the activation of pyramidal slip system under dynamic impact loading. - Highlights: • A double-peak basal texture developed in all shock loaded samples. • Both strength and ductility increased with decreasing grain size. • Twinning fraction and strain hardening rate decreased with decreasing grain size. • ‘g.b’ analysis confirmed the presence of dislocations in shock loaded alloy.

  14. A Dynamic Analysis of Bid-Ask Spreads with Multiple Trade Sizes

    OpenAIRE

    Shino Takayama; Han Ozsoylev

    2005-01-01

    This paper studies how the trade size and the historical sequence of trades affect bid-ask spreads, investors’ trading strategies, and the market maker’s learning process in a multi-period economy. First, we show that there is a nonzero cut-off size below which informed traders never buy or sell, and that larger trade sizes have positive bid-ask spreads, while smaller sizes do not. Then, we prove that the cut-off size decreases stochastically . We also derive the functional relationship betwe...

  15. TEMPORAL AND SPATIAL DYNAMICS OF DIFFERENT PARTICLE SIZE OF SUSPENDED SEDIMENT IN THE LIU RIVER CATCHMENTS,CHINA

    Institute of Scientific and Technical Information of China (English)

    Haoming FAN; Qiangguo CAI; Chengjiu GUO; Tieliang WANG

    2006-01-01

    This paper presents information on the particle size characteristics of suspended sediment transported by the Liu River, which has the most serious erosion and sedimentation problems in the northeast of China. The median (d50) particle size for the individual stations on the Liu River ranged from 0.0343 to 0.0588 mm. Particles <0.01 mm ranged from 15.4 to 33.3% and >0.05 mm of ranged from 24.3 to 53.7%. Spatial and temporal variations were noticeable in the particle size composition of suspended sediment within the study basins. At different locations the sediment particles size varies as a result of differences in catchment characteristics. The preferential deposition of the coarser size fractions has resulted in downstream fining of the suspended sediment load. In the flood season the suspended sediment particle size was finer than that in low flow season. The relations among water discharge, suspended sediment concentration, and sediment particle size are complicated. At small water discharge or suspended sediment concentration, with the increase of water discharge or sediment concentration the particle size of suspended sediment decreases to a minimum. However, when the water discharge or sediment concentration exceed certain threshold values (turning points) the particle size increases or remains constant with the increase of water discharge or sediment concentration. The tuning points are different in different rivers. Thus, their relations are double-valued. The negative relation between suspended sediment particle size and flow discharge reflects the importance of supply conditions and the positive relation reflects that the flow and hydraulics take a greater role in sediment transportation. On the whole, variation of the sediment particle size is subject to many factors such as the hydraulic conditions, the type and extent of erosion, human activities, vegetation coverage, hydraulic projects, and sediment supply. The findings reported in this paper

  16. Forensic identification using multiple lot numbers of an implanted device.

    Science.gov (United States)

    Takeshita, H; Nagai, T; Sagi, M; Chiba, S; Kanno, S; Takada, M; Mukai, T

    2014-01-01

    We report a case in which identification of a deceased individual was established using multiple lot numbers printed on a body implantable device. Autopsy of an unknown woman revealed an intramedullary nail inserted within her right femur. The device manufacturer was identified from the configuration of the intramedullary nail, and the "use history" was traced from lot numbers printed on the device's multiple parts. The deceased individual was thus identified as a woman who had attempted suicide by jumping from a height about a year previously and had been transported to a hospital and undergone surgery that included implantation of the intramedullary nail. The main factor contributing to the rapid identification was the manufacturer's and distributor's record of the use history (traceability) of the product, because of their accountability for purposes of quality control. A second contributing factor was multiple lot numbers, resulting in extremely low probability of the same combination of lot numbers being present in multiple individuals. This case confirmed the utility of multiple lot numbers of body implantable devices in forensic identification.

  17. The dynamic evolutionary history of genome size in North American woodland salamanders.

    Science.gov (United States)

    Newman, Catherine E; Gregory, T Ryan; Austin, Christopher C

    2017-04-01

    The genus Plethodon is the most species-rich salamander genus in North America, and nearly half of its species face an uncertain future. It is also one of the most diverse families in terms of genome sizes, which range from 1C = 18.2 to 69.3 pg, or 5-20 times larger than the human genome. Large genome size in salamanders results in part from accumulation of transposable elements and is associated with various developmental and physiological traits. However, genome sizes have been reported for only 25% of the species of Plethodon (14 of 55). We collected genome size data for Plethodon serratus to supplement an ongoing phylogeographic study, reconstructed the evolutionary history of genome size in Plethodontidae, and inferred probable genome sizes for the 41 species missing empirical data. Results revealed multiple genome size changes in Plethodon: genomes of western Plethodon increased, whereas genomes of eastern Plethodon decreased, followed by additional decreases or subsequent increases. The estimated genome size of P. serratus was 21 pg. New understanding of variation in genome size evolution, along with genome size inferences for previously unstudied taxa, provide a foundation for future studies on the biology of plethodontid salamanders.

  18. THE INFLUENCE OF GRAIN SIZE AND TEMPERATURE ON THE MECHANICAL DEFORMATION OF NANOCRYSTALLINE MATERIALS:MOLECULAR DYNAMICS SIMULATION

    Institute of Scientific and Technical Information of China (English)

    WEN YU-HUA; ZHOU FU-XIN; LIU YUE-WU

    2001-01-01

    Nanocrystalline (nc) materials are characterized by a typical grain size of 1-100nm. The uniaxial tensile deformation of computer-generated nc samples, with several average grain sizes ranging from 5.38 to 1.79nm, is simulated by using molecular dynamics with the Finnis-Sinclair potential. The influence of grain size and temperature on the mechanical deformation is studied in this paper. The simulated nc samples show a reverse Hall-Petch effect. Grain boundary sliding and motion, as well as grain rotation are mainly responsible for the plastic deformation. At low temperatures, partial dislocation activities play a minor role during the deformation. This role begins to occur at the strain of 5%, and is progressively remarkable with increasing average grain size. However, at elevated temperatures no dislocation activity is detected, and the diffusion of grain boundaries may come into play.

  19. Modeling the effects of size on patch dynamics of an inert tracer

    Directory of Open Access Journals (Sweden)

    P. Xiu

    2009-08-01

    Full Text Available Mesoscale iron enrichment experiments have revealed that additional iron affects the phytoplankton productivity and carbon cycle. However, the role of initial size of fertilized patch in determining the patch evolution is poorly quantified due to the limited time of research vessels at sea. Using a three-dimensional ocean circulation model, we simulated different sizes of inert tracer patches that were only regulated by physical circulation and diffusion. Model results showed that during the first few days since release of inert tracer, the calculated dilution rate was found to be a linear function with time, which was sensitive to the initial patch size with steeper slope for smaller size patch. After the initial phase of rapid decay, the relationship between dilution rate and time became an exponential function, which was also size dependent. Therefore, larger initial size patches can usually last longer and ultimately affect biogeochemical processes much stronger than smaller patches.

  20. Input related microbial carbon dynamic of soil organic matter in particle size fractions

    Science.gov (United States)

    Gude, A.; Kandeler, E.; Gleixner, G.

    2012-04-01

    This paper investigated the flow of carbon into different groups of soil microorganisms isolated from different particle size fractions. Two agricultural sites of contrasting organic matter input were compared. Both soils had been submitted to vegetation change from C3 (Rye/Wheat) to C4 (Maize) plants, 25 and 45 years ago. Soil carbon was separated into one fast-degrading particulate organic matter fraction (POM) and one slow-degrading organo-mineral fraction (OMF). The structure of the soil microbial community were investigated using phospholipid fatty acids (PLFA), and turnover of single PLFAs was calculated from the changes in their 13C content. Soil enzyme activities involved in the degradation of carbohydrates was determined using fluorogenic MUF (methyl-umbelliferryl phosphate) substrates. We found that fresh organic matter input drives soil organic matter dynamic. Higher annual input of fresh organic matter resulted in a higher amount of fungal biomass in the POM-fraction and shorter mean residence times. Fungal activity therefore seems essential for the decomposition and incorporation of organic matter input into the soil. As a consequence, limited litter input changed especially the fungal community favouring arbuscular mycorrhizal fungi. Altogether, supply and availability of fresh plant carbon changed the distribution of microbial biomass, the microbial community structure and enzyme activities and resulted in different priming of soil organic matter. Most interestingly we found that only at low input the OMF fraction had significantly higher calculated MRT for Gram-positive and Gram-negative bacteria suggesting high recycling of soil carbon or the use of other carbon sources. But on average all microbial groups had nearly similar carbon uptake rates in all fractions and both soils, which contrasted the turnover times of bulk carbon. Hereby the microbial carbon turnover was always faster than the soil organic carbon turnover and higher carbon input

  1. Phase equilibrium calculations of ternary liquid mixtures with binary interaction parameters and molecular size parameters determined from molecular dynamics.

    Science.gov (United States)

    Oh, Suk Yung; Bae, Young Chan

    2010-07-15

    The method presented in this paper was developed to predict liquid-liquid equilibria in ternary liquid mixtures by using a combination of a thermodynamic model and molecular dynamics simulations. In general, common classical thermodynamic models have many parameters which are determined by fitting a model with experimental data. This proposed method, however, provides a simple procedure for calculating liquid-liquid equilibria utilizing binary interaction parameters and molecular size parameters determined from molecular dynamics simulations. This method was applied to mixtures containing water, hydrocarbons, alcohols, chlorides, ketones, acids, and other organic liquids over various temperature ranges. The predicted results agree well with the experimental data without the use of adjustable parameters.

  2. Improving aggregate behavior in parking lots with appropriate local maneuvers

    KAUST Repository

    Rodriguez, Samuel

    2013-11-01

    In this paper we study the ingress and egress of pedestrians and vehicles in a parking lot. We show how local maneuvers executed by agents permit them to create trajectories in constrained environments, and to resolve the deadlocks between them in mixed-flow scenarios. We utilize a roadmap-based approach which allows us to map complex environments and generate heuristic local paths that are feasible for both pedestrians and vehicles. Finally, we examine the effect that some agent-behavioral parameters have on parking lot ingress and egress. © 2013 IEEE.

  3. Effects of growth curve plasticity on size-structured population dynamics

    DEFF Research Database (Denmark)

    Zhang, Lai; Lin, Zhigui; Pedersen, Michael

    2011-01-01

    primarily exerts destabilizing effects on the system but considerably promotes species coexistence, in comparison with the size-independent mechanism. We conclude that the size-dependent mechanism is, to a large extent, a dispensable component of model ingredients when ontogeny is explicitly taken...

  4. Impact of variable body size on pedestrian dynamics by heuristics-based model

    Science.gov (United States)

    Guo, Ning; Hu, Mao-Bin; Jiang, Rui

    2017-01-01

    In the real world, pedestrians can arch the shoulders or rotate their bodies actively to across the narrow space. The method is helpful to reduce the effective size of the body. In this paper, the impact of variable body size on the direction choice has been investigated by an improved heuristic-based model. In the model, it is assumed that the cost of adjusting body size is a factor in the process to evaluate the optimal direction. In a typical simulation scenario, the pedestrian reluctant to adjust body size will pass by the blocks. On the contrary, the pedestrian caring little about body size will traverse through the exit. There is a direction-choice change behavior between bypass and traverse considering block width and the initial location of the pedestrian.

  5. Group-size-mediated habitat selection and group fusion-fission dynamics of bison under predation risk.

    Science.gov (United States)

    Fortin, Daniel; Fortin, Marie-Eve; Beyer, Hawthorne L; Duchesne, Thierry; Courant, Sabrina; Dancose, Karine

    2009-09-01

    For gregarious animals the cost-benefit trade-offs that drive habitat selection may vary dynamically with group size, which plays an important role in foraging and predator avoidance strategies. We examined how habitat selection by bison (Bison bison) varied as a function of group size and interpreted these patterns by testing whether habitat selection was more strongly driven by the competing demands of forage intake vs. predator avoidance behavior. We developed an analytical framework that integrated group size into resource selection functions (RSFs). These group-size-dependent RSFs were based on a matched case-control design and were estimated using conditional logistic regression (mixed and population-averaged models). Fitting RSF models to bison revealed that bison groups responded to multiple aspects of landscape heterogeneity and that selection varied seasonally and as a function of group size. For example, roads were selected in summer, but not in winter. Bison groups avoided areas of high snow water equivalent in winter. They selected areas composed of a large proportion of meadow area within a 700-m radius, and within those areas, bison selected meadows. Importantly, the strength of selection for meadows varied as a function of group size, with stronger selection being observed in larger groups. Hence the bison-habitat relationship depended in part on the dynamics of group formation and division. Group formation was most likely in meadows. In contrast, risk of group fission increased when bison moved into the forest and was higher during the time of day when movements are generally longer and more variable among individuals. We also found that stronger selection for meadows by large rather than small bison groups was caused by longer residence time in individual meadows by larger groups and that departure from meadows appears unlikely to result from a depression in food intake rate. These group-size-dependent patterns were consistent with the hypothesis

  6. Influence of aggregate size and free water on the dynamic behaviour of concrete subjected to impact loading

    Science.gov (United States)

    Erzar, B.; Forquin, P.; Pontiroli, C.; Buzaud, E.

    2010-06-01

    Concrete is a material widely used in civil engineering. Thus the knowledge of its mechanical behaviour is a major safety issue to evaluate the ability of a structure to resist to an intense dynamic loading. In this study, two experimental techniques have been applied to a micro-concrete and a common concrete to assess the influence of the aggregate size on the dynamic response. First, spalling tests on dry and wet specimens have been performed to characterize the tensile strength of concrete at strain rates in the range 30 - 150/s. Then, edge-on impact tests in sarcophagus configuration have been conducted. The cracking pattern of the micro-concrete and the concrete plates in wet and dry conditions have been compared to appraise the influence of aggregate size and free water on the damaging process.

  7. 7 CFR 52.783 - Ascertaining the grade of a lot.

    Science.gov (United States)

    2010-01-01

    ... PROCESSED FOOD PRODUCTS 1 United States Standards for Grades of Canned Red Tart Pitted Cherries 1 Lot Compliance § 52.783 Ascertaining the grade of a lot. The grade of a lot of canned red tart pitted...

  8. Foraging arena size and structural complexity affect the dynamics of food distribution in ant colonies.

    Science.gov (United States)

    Buczkowski, Grzegorz; VanWeelden, Matthew

    2010-12-01

    Food acquisition by ant colonies is a complex process that starts with acquiring food at the source (i.e., foraging) and culminates with food exchange in or around the nest (i.e., feeding). While ant foraging behavior is relatively well understood, the process of food distribution has received little attention, largely because of the lack of methodology that allows for accurate monitoring of food flow. In this study, we used the odorous house ant, Tapinoma sessile (Say) to investigate the effect of foraging arena size and structural complexity on the rate and the extent of spread of liquid carbohydrate food (sucrose solution) throughout a colony. To track the movement of food, we used protein marking and double-antibody sandwich enzyme-linked immunosorbent assay, DAS-ELISA. Variation in arena size, in conjunction with different colony sizes, allowed us to test the effect of different worker densities on food distribution. Results demonstrate that both arena size and colony size have a significant effect on the spread of the food and the number of workers receiving food decreased as arena size and colony size increased. When colony size was kept constant and arena size increased, the percentage of workers testing positive for the marker decreased, most likely because of fewer trophallactic interactions resulting from lower worker density. When arena size was kept constant and colony size increased, the percentage of workers testing positive decreased. Nonrandom (clustered) worker dispersion and a limited supply of food may have contributed to this result. Overall, results suggest that food distribution is more complete is smaller colonies regardless of the size of the foraging arena and that colony size, rather than worker density, is the primary factor affecting food distribution. The structural complexity of foraging arenas ranged from simple, two-dimensional space (empty arenas) to complex, three-dimensional space (arenas filled with mulch). The structural

  9. Size-Dependent Transition to High-Dimensional Chaotic Dynamics in a Two-Dimensional Excitable Medium

    CERN Document Server

    Strain, M C; Strain, Matthew C.; Greenside, Henry S.

    1997-01-01

    The spatiotemporal dynamics of an excitable medium with multiple spiral defects is shown to vary smoothly with system size from short-lived transients for small systems to extensive chaos for large systems. A comparison of the Lyapunov dimension density with the average spiral defect density suggests an average dimension per spiral defect varying between three and seven. We discuss some implications of these results for experimental studies of ventricular fibrillation.

  10. Influence of Three Dynamic Predictive Clothing Insulation Models on Building Energy Use, HVAC Sizing and Thermal Comfort

    Directory of Open Access Journals (Sweden)

    Kwang Ho Lee

    2014-03-01

    Full Text Available In building energy simulation, indoor thermal comfort condition, energy use and equipment size are typically calculated based on the assumption that the clothing insulation is equal to a constant value of 0.5 clo during the cooling season and 1.0 clo during the heating season. The assumption is not reflected in practice and thus it may lead to errors. In reality, occupants frequently adjust their clothing depending on the thermal conditions, as opposed to the assumption of constant clothing values above, indicating that the clothing insulation variation should be captured in building simulation software to obtain more reliable and accurate results. In this study, the impact of three newly developed dynamic clothing insulation models on the building simulation is quantitatively assessed using the detailed whole-building energy simulation program, EnergyPlus version 6.0. The results showed that when the heating ventilation and air conditioning system (HVAC is controlled based on indoor temperature the dynamic clothing models do not affect indoor operative temperatures, energy consumption and equipment sizing. When the HVAC is controlled based on the PMV model the use of a fixed clothing insulation during the cooling (0.5 clo and heating (1.0 clo season leads to the incorrect estimation of the indoor operative temperatures, energy consumption and equipment sizing. The dynamic clothing models significantly (p < 0.0001 improve the ability of energy simulation tools to assess thermal comfort. The authors recommend that the dynamic clothing models should be implemented in dynamic building energy simulation software such as EnergyPlus.

  11. Insights into the dynamics of genome size and chromosome evolution in the early diverging angiosperm lineage Nymphaeales (water lilies).

    Science.gov (United States)

    Pellicer, J; Kelly, L J; Magdalena, C; Leitch, I J

    2013-08-01

    Nymphaeales are the most species-rich lineage of the earliest diverging angiosperms known as the ANA grade (Amborellales, Nymphaeales, Austrobaileyales), and they have received considerable attention from morphological, physiological, and ecological perspectives. Although phylogenetic relationships between these three lineages of angiosperms are mainly well resolved, insights at the whole genome level are still limited because of a dearth of information. To address this, genome sizes and chromosome numbers in 34 taxa, comprising 28 species were estimated and analysed together with previously published data to provide an overview of genome size and chromosome diversity in Nymphaeales. Overall, genome sizes were shown to vary 10-fold and chromosome numbers and ploidy levels ranged from 2n = 2x = 18 to 2n = 16x = ∼224. Distinct patterns of genome diversity were apparent, reflecting the differential incidence of polyploidy, changes in repetitive DNA content, and chromosome rearrangements within and between genera. Using model-based approaches, ancestral genome size and basic chromosome numbers were reconstructed to provide insights into the dynamics of genome size and chromosome number evolution. Finally, by combining additional data from Amborellales and Austrobaileyales, a comprehensive overview of genome sizes and chromosome numbers in these early diverging angiosperms is presented.

  12. Effect of adding nanometre-sized heterogeneities on the structural dynamics and the excess wing of a molecular glass former

    Science.gov (United States)

    Gupta, S.; Fischer, J. K. H.; Lunkenheimer, P.; Loidl, A.; Novak, E.; Jalarvo, N.; Ohl, M.

    2016-10-01

    We present the relaxation dynamics of glass-forming glycerol mixed with 1.1 nm sized polyhedral oligomeric silsesquioxane (POSS) molecules using dielectric spectroscopy (DS) and two different neutron scattering (NS) techniques. Both, the reorientational dynamics as measured by DS and the density fluctuations detected by NS reveal a broadening of the α relaxation when POSS molecules are added. Moreover, we find a significant slowing down of the α-relaxation time. These effects are in accord with the heterogeneity scenario considered for the dynamics of glasses and supercooled liquids. The addition of POSS also affects the excess wing in glycerol arising from a secondary relaxation process, which seems to exhibit a dramatic increase in relative strength compared to the α relaxation.

  13. Full-Depth Asphalt Pavements for Parking Lots and Driveways.

    Science.gov (United States)

    Asphalt Inst., College Park, MD.

    The latest information for designing full-depth asphalt pavements for parking lots and driveways is covered in relationship to the continued increase in vehicle registration. It is based on The Asphalt Institute's Thickness Design Manual, Series No. 1 (MS-1), Seventh Edition, which covers all aspects of asphalt pavement thickness design in detail,…

  14. Automotive Parking Lot and Theft Detection through Image Processing

    Directory of Open Access Journals (Sweden)

    2013-10-01

    Full Text Available Automotive parking lot and theft detection through image processing is a smart parking lot which will save time for the owner to park his car in a more organized way and also prevent theft of the car. It is a technology to optimize the checkout process by analysing a database of images of number plates of cars. The heart of the project is based on image processing. The images of number plates will be detected by Matlab and a picture of the driver will be saved in a similar database. As soon as both the images are saved, the garage entrance pole will shift 90 degrees upward using a DC MOTOR and will remain in that position for 30 seconds to allow the car to enter. After 30 seconds it will return back to its previous position. When the car exits the earlier steps will be repeated and Matlab will match both the images that were taken during entering and leaving. Meanwhile the seven segment display will show that a car has left the parking lot, by decrementing a number from its display. The cars are controlled by a microcontroller which is also able to detect and display if a vacant parking space is available. If there is no vacancy a red LED lights up, where as a green LED is used to display presence of parking space along with how many parking spots are available. It is applicable to be used in super market car parking lots and also apartment garages.

  15. MetaZipf. A dynamic meta-analysis of city size distributions

    National Research Council Canada - National Science Library

    Clémentine Cottineau

    2017-01-01

    .... However, little evidence exists as to the factors which influence the level of urban unevenness, as expressed by the slope of the rank-size distribution, partly because the diversity of results found...

  16. Hominin geographical range dynamics and relative brain size: Do non-human primates provide a good analogy?

    Science.gov (United States)

    MacDonald, Katharine; Smaers, Jeroen B; Steele, James

    2015-10-01

    We use climatic and satellite remote sensing data to characterize environmental seasonality in the geographical ranges of extant non-human primates in order to assess the effect of relative brain size on tolerance of more seasonal habitats. Demonstration of such an effect in living non-human primates could provide a comparative framework for modeling hominin dispersals and geographical range dynamics in the Pliocene and Pleistocene. Our analyses found no such effect: there are neither positive nor negative correlations between relative brain size and either geographical range size or the average and range of values for environmental seasonality, whether analysed at the level of all primates, or within parvorders (strepsirrhine, catarrhine, platyrrhine). Independent analyses by other researchers comparing feeding behaviour and ecology at individual primate study sites demonstrate that in seasonal environments, the year-round metabolic costs of maintaining a relatively large brain are met by adaptive behavioural/dietary strategies. However, consistent with our own results, those comparative studies found that there was no overall association, whether positive or negative, between 'raw' environmental seasonality and primate relative brain size. We must therefore look elsewhere for a comparative model of hominin geographical range dynamics in the Pleistocene.

  17. Dynamic finite element modeling of the effects of size on the upper shelf energy of pressure vessel steels

    Energy Technology Data Exchange (ETDEWEB)

    Sidener, S.E. [Missouri Univ., Rolla, MO (United States); Kumar, A.S. [Missouri Univ., Rolla, MO (United States); Oglesby, D.B. [Missouri Univ., Rolla, MO (United States); Schubert, L.E. [Pacific Northwest Lab., Richland, WA (United States); Hamilton, M.L. [Pacific Northwest Lab., Richland, WA (United States); Rosinski, S.T. [Electric Power Research Inst., Inc. (EPRI), Charlotte, NC (United States)

    1996-12-01

    Dynamic finite element modeling (FEM) of the fracture behavior of fatigue-precracked Charpy specimens was performed to determine the effect of single variable changes in ligament size, width, span, and thickness on the upper shelf energy. A tensile fracture-strain based method for modeling crack initiation and propagation was used. It was found that the upper shelf energy of precracked specimens (USE{sub p}) is proportional to b{sup n}, where b is ligament size and n varies from about 1.6 for subsize to 1.9 for full size specimens. The USE{sub p} was found to be proportional to (width){sup 2.5}. The dependence on span was found to be non-linear. The dependence on thickness was found to be linear for all cases studied. Some of the data from the FEM analysis were compared with experimental data and were found to be in reasonable agreement. (orig.).

  18. LABORATORY SIMULATION OF POROUS ASPHALT PARKING LOT SYSTEM AND MIX DESIGN FOR STORM WATER MANAGEMENT

    Directory of Open Access Journals (Sweden)

    M. O. HAMZAH

    2013-04-01

    Full Text Available Porous asphalt pavement was initially developed for the purpose of improving road safety, best candidate material for quiet pavement and to avoid aquaplaning and skidding in wet weather. However, from previous studies, porous asphalt is able to mitigate surface runoff. Porous asphalt parking lots with underlying reservoir course perform as additional temporary water storage matrix that enables reduction of flash flood. This paper elaborates the development of a new porous asphalt aggregate grading design for storm water mitigation using the Nominal Maximum Aggregate Size (NMAS 20 mm. The properties of the mixes were quantified and evaluated in terms of air voids, permeability, abrasion loss and indirect tensile strength. It was found that the proposed gradation has the best permeability and Indirect Tensile Strength (ITS values when compacted at 50 blows per face with a standard Marshal compactor. The porous asphalt slab was prepared using a slab compactor to simulate porous parking lot paving at site. The porous asphalt slab was finally placed inside a locally fabricated water flow simulator to simulate a porous asphalt pavement system for parking lots.

  19. Pupil size dynamics during fixation impact the accuracy and precision of video-based gaze estimation.

    Science.gov (United States)

    Choe, Kyoung Whan; Blake, Randolph; Lee, Sang-Hun

    2016-01-01

    Video-based eye tracking relies on locating pupil center to measure gaze positions. Although widely used, the technique is known to generate spurious gaze position shifts up to several degrees in visual angle because pupil centration can change without eye movement during pupil constriction or dilation. Since pupil size can fluctuate markedly from moment to moment, reflecting arousal state and cognitive processing during human behavioral and neuroimaging experiments, the pupil size artifact is prevalent and thus weakens the quality of the video-based eye tracking measurements reliant on small fixational eye movements. Moreover, the artifact may lead to erroneous conclusions if the spurious signal is taken as an actual eye movement. Here, we measured pupil size and gaze position from 23 human observers performing a fixation task and examined the relationship between these two measures. Results disclosed that the pupils contracted as fixation was prolonged, at both small (pupil contractions were accompanied by systematic errors in gaze position estimation, in both the ellipse and the centroid methods of pupil tracking. When pupil size was regressed out, the accuracy and reliability of gaze position measurements were substantially improved, enabling differentiation of 0.1° difference in eye position. We confirmed the presence of systematic changes in pupil size, again at both small and large scales, and its tight relationship with gaze position estimates when observers were engaged in a demanding visual discrimination task.

  20. Pitfalls and novel applications of particle sizing by dynamic light scattering.

    Science.gov (United States)

    Fischer, Karl; Schmidt, Manfred

    2016-08-01

    After briefly introducing the theoretical equations for DLS based particle size analysis, the need for angular dependent DLS investigations is emphasized to obtain correct particle sizes. Practical examples are given that demonstrate the possible magnitudes of errors in particle size if DLS is measured at one large scattering angle, only, as done by essentially all, most frequently utilized commercial "single angle" particle sizers. The second part is focused on a novel DLS application to sensitively trace (nano)particle interactions with concentrated blood serum or plasma that leads to the formation of large aggregates in a size regime of ≫100 nm. Most likely, such aggregates originate from protein induced bridging of nanoparticles, since it is well known that serum proteins adsorb onto the surface of essentially all nanoparticles utilized in medical applications. Thus, the protein corona around nanoparticles does not only change their biological identity but to a large extend also their size, thus possibly affecting biodistribution and in vivo circulation time.

  1. Grain-size dynamics beneath mid-ocean ridges: Implications for permeability and melt extraction

    CERN Document Server

    Turner, Andrew J; Behn, Mark D

    2014-01-01

    Grain size is an important control on mantle viscosity and permeability, but is difficult or impossible to measure in situ. We construct a two-dimensional, single phase model for the steady-state mean grain size beneath a mid-ocean ridge. The mantle rheology is modelled as a composite of diffusion creep, dislocation creep, dislocation accommodated grain boundary sliding, and a plastic stress limiter. The mean grain size is calculated by the piezometric relationship of Austin and Evans [2007]. We investigate the sensitivity of our model to global variations in grain growth exponent, potential temperature, spreading-rate, and mantle hydration. We interpret the mean mean grain-size field in the context of permeability. The permeability structure due to mean grain size may be approximated as a high permeability region beneath a low permeability region. The transition between high and low permeability regions forms a boundary that is steeply sloped toward the ridge axis. We hypothesise that such a permeability str...

  2. Size distributions of coastal ocean suspended particulate inorganic matter: Amorphous silica and clay minerals and their dynamics

    Science.gov (United States)

    Zhang, Xiaodong; Stavn, Robert H.; Falster, Alexander U.; Rick, Johannes J.; Gray, Deric; Gould, Richard W.

    2017-04-01

    Particulate inorganic matter (PIM) is a key component in estuarine and coastal systems and plays a critical role in trace metal cycling. Better understanding of coastal dynamics and biogeochemistry requires improved quantification of PIM in terms of its concentration, size distribution, and mineral species composition. The angular pattern of light scattering contains detailed information about the size and composition of particles. These volume scattering functions (VSFs) were measured in Mobile Bay, Alabama, USA, a dynamic, PIM dominated coastal environment. From measured VSFs, we determined through inversion the particle size distributions (PSDs) of major components of PIM, amorphous silica and clay minerals. An innovation here is the extension of our reported PSDs significantly into the submicron range. The PSDs of autochthonous amorphous silica exhibit two unique features: a peak centered at about 0.8 μm between 0.2 and 4 μm and a very broad shoulder essentially extending from 4 μm to >100 μm. With an active and steady particle source from blooming diatoms, the shapes of amorphous silica PSDs for sizes 10 μm inside the bay, likely due to wind-induced resuspension of larger frustules that have settled. Compared to autochthonous amorphous silica, the allochthonous clay minerals are denser and exhibit relatively narrower PSDs with peaks located between 1 and 4 μm. Preferential settling of larger mineral particles as well as the smaller but denser illite component further narrowed the size distributions of clay minerals as they were being transported outside the bay. The derived PSDs also indicated a very dynamic situation in Mobile Bay when a cold weather front passed through during the experiment. With northerly winds of speeds up to 15 m s-1, both amorphous silica and clay minerals showed a dramatic increase in concentration and broadening in size distribution outside the exit of the barrier islands, indicative of wind-induced resuspension and subsequent

  3. Dynamical Mueller's Ratchet: Population Size Dependence of Evolutionary Paths in Bacteria

    Science.gov (United States)

    Lorenz, Dirk; Park, Jeong-Man; Deem, Michael; Michael Deem Team

    2011-03-01

    Experimental evolution has recently enabled the complete quantitative description of small-dimensional fitness landscapes. Quasispecies theory allows the mathematical modeling of evolution on such a landscape. Typically, analytic solutions for these models are only exactly solvable for the case of an infinite population. Here we use a functional integral representation of population dynamics and solve it using the Schwinger Boson method. This allows us to compute the first-order correction to the average fitness for finite populations. We will use these results to explain the experimental observations of dynamics of evolution in finite populations.

  4. Predator-prey coevolution driven by size selective predation can cause anti-synchronized and cryptic population dynamics.

    Science.gov (United States)

    Mougi, Akihiko

    2012-03-01

    Population dynamics and evolutionary dynamics can occur on similar time scales, and a coupling of these two processes can lead to novel population dynamics. Recent theoretical studies of coevolving predator-prey systems have concentrated more on the stability of such systems than on the characteristics of cycles when they are unstable. Here I explore the characteristics of the cycles that arise due to coevolution in a system in which prey can increase their ability to escape from predators by becoming either significantly larger or significantly smaller in trait value (i.e., a bidirectional trait axis). This is a reasonable model of body size evolution in some systems. The results show that antiphase population cycles and cryptic cycles (large population fluctuation in one species but almost no change in another species) can occur in the coevolutionary system but not systems where only a single species evolves. Previously, those dynamical patterns have only been theoretically shown to occur in single species evolutionary models and the coevolutionary model which do not involve a bi-directional axis of adaptation. These unusual dynamics may be observed in predator-prey interactions when the density dependence in the prey species is strong.

  5. Size-dependent ligand layer dynamics in semiconductor nanocrystals probed by anisotropy measurements.

    Science.gov (United States)

    Hadar, Ido; Abir, Tsafrir; Halivni, Shira; Faust, Adam; Banin, Uri

    2015-10-12

    Colloidal semiconductor nanocrystals (NC) have reached a high level of synthetic control allowing the tuning of their properties, and their use in various applications. However, the surface of NCs and in particular their size-dependent capping organic ligand behavior, which play an important role in the NC synthesis, dispersibility, and optoelectronic properties, is still not well understood. We study the size-dependent properties of the ligand shell on the surface of NCs, by embedding surface bound dyes as a probe within the ligand shell. The reorientation times for these dyes show a linear dependence on the NC surface curvature indicating size-dependent change in viscosity, which is related to a change in the density of the ligand layer because of the geometry of the surface, a unique feature of NCs. Understanding the properties of the ligand shell will allow rational design of the surface to achieve the desired properties, providing an additional important knob for tuning their functionality.

  6. A Transcultural Model of the Centrality of "Thinking a Lot" in Psychopathologies Across the Globe and the Process of Localization: A Cambodian Refugee Example.

    Science.gov (United States)

    Hinton, Devon E; Barlow, David H; Reis, Ria; de Jong, Joop

    2016-12-01

    We present a general model of why "thinking a lot" is a key presentation of distress in many cultures and examine how "thinking a lot" plays out in the Cambodian cultural context. We argue that the complaint of "thinking a lot" indicates the presence of a certain causal network of psychopathology that is found across cultures, but that this causal network is localized in profound ways. We show, using a Cambodian example, that examining "thinking a lot" in a cultural context is a key way of investigating the local bio-cultural ontology of psychopathology. Among Cambodian refugees, a typical episode of "thinking a lot" begins with ruminative-type negative cognitions, in particular worry and depressive thoughts. Next these negative cognitions may induce mental symptoms (e.g., poor concentration, forgetfulness, and "zoning out") and somatic symptoms (e.g., migraine headache, migraine-like blurry vision such as scintillating scotomas, dizziness, palpitations). Subsequently the very fact of "thinking a lot" and the induced symptoms may give rise to multiple catastrophic cognitions. Soon, as distress escalates, in a kind of looping, other negative cognitions such as trauma memories may be triggered. All these processes are highly shaped by the Cambodian socio-cultural context. The article shows that Cambodian trauma survivors have a locally specific illness reality that centers on dynamic episodes of "thinking a lot," or on what might be called the "thinking a lot" causal network.

  7. DUST DYNAMICS IN PROTOPLANETARY DISK WINDS DRIVEN BY MAGNETOROTATIONAL TURBULENCE: A MECHANISM FOR FLOATING DUST GRAINS WITH CHARACTERISTIC SIZES

    Energy Technology Data Exchange (ETDEWEB)

    Miyake, Tomoya; Suzuki, Takeru K.; Inutsuka, Shu-ichiro, E-mail: miyake.tomoya@e.mbox.nagoya-u.ac.jp, E-mail: stakeru@nagoya-u.jp [Department of Physics, Nagoya University, Nagoya, Aichi 464-8602 (Japan)

    2016-04-10

    We investigate the dynamics of dust grains of various sizes in protoplanetary disk winds driven by magnetorotational turbulence, by simulating the time evolution of the dust grain distribution in the vertical direction. Small dust grains, which are well-coupled to the gas, are dragged upward with the upflowing gas, while large grains remain near the midplane of a disk. Intermediate-size grains float near the sonic point of the disk wind located at several scale heights from the midplane, where the grains are loosely coupled to the background gas. For the minimum mass solar nebula at 1 au, dust grains with size of 25–45 μm float around 4 scale heights from the midplane. Considering the dependence on the distance from the central star, smaller-size grains remain only in an outer region of the disk, while larger-size grains are distributed in a broader region. We also discuss the implications of our result for observations of dusty material around young stellar objects.

  8. A novel test rig for the dynamic characterization of large size tilting pad journal bearings

    Science.gov (United States)

    Forte, P.; Ciulli, E.; Saba, D.

    2016-09-01

    The present work concerns the realization of a test bench for the dynamic characterization of high performance tilting pad journal bearings, within a collaboration between the Department of Civil and Industrial Engineering of Pisa, GE Oil&Gas and AM Testing. The objective is to cover journal diameters of interest of GE, from 150 to 300 mm, with peripheral speeds up to 150 m/s, static load up to 270 kN, dynamic loads up to 30 kN and frequencies up to 350 Hz, performances that make the apparatus very competitive worldwide. The adopted configuration has the test article (TA) floating at the mid-span of a rotor supported by two rolling bearings. The TA is statically loaded by a hydraulic actuator and excited dynamically by two orthogonal hydraulic actuators. Construction was recently concluded and preliminary tests are under way. In order to assess in advance the possible accuracy of the tests, a dynamic lumped parameter model of the test bench was developed to perform virtual experiments, including several possible sources of experimental errors and uncertainties. The model was implemented using reduced stiffness and mass matrices obtained from Finite Element Analysis by Component Modal Synthesis.

  9. Grazing, differential size-class dynamics and survival of the Mediterranean sponge Corticium candelabrum

    NARCIS (Netherlands)

    Caralt, de S.; Uriz, M.J.; Wijffels, R.H.

    2008-01-01

    The growth dynamics and survival of the sponge Corticium candelabrum (Demospongiae: Homosclerophorida) were surveyed in the northwestern Mediterranean for more than 3 yr. Growth and regeneration rates, fission and fusion events and survival were monitored monthly. Moreover, in situ punctual clearanc

  10. Prediction of emulsion particle sizes using a computational fluid dynamics approach

    NARCIS (Netherlands)

    Agterof, W.G.M.; Vaessen, G.E.J.; Haagh, G.A.A.V.; Klahn, J.K.; Janssen, J.M.J.

    2003-01-01

    For many food products emulsification processes play an important role. Examples are ice cream, spreads, sauces, etc. As is well known, droplet break-up and coalescence phenomena are the local processes underlying the control of particle size in an emulsion process. Quite a number of studies have

  11. Population Size and Suicide in U.S. Cities: A Static and Dynamic Exploration

    Science.gov (United States)

    McCall, Patricia L.; Tittle, Charles R.

    2007-01-01

    The relationship between city population size and suicide rates rarely has been examined directly, though scholars often assume such a relationship exists based on studies of the association between suicide rates and urbanization (percent of the population living in cities) in various social contexts. In an effort to determine the basic…

  12. Size-dependent optical properties and carriers dynamics in CdSe/ZnS quantum dots

    Institute of Scientific and Technical Information of China (English)

    Ma Guo-Hong; Wang Wen-Jun; Gao Xue-Xi; Ma Hong-Liang

    2008-01-01

    Size-dependence of optical properties and energy relaxation in CdSe/ZnS quantum dots (QDs) were investigated by two-colour femtosecond (fs) pump-probe (400/800 nm) and picosecond time-resolved photoluminescence (ps TRPL)experiments. Pump-probe measurement results show that there are two components for the excited carriers relaxation,the fast one with a time constant of several ps arises from the Auger-type recombination, which shows almost particle sizeindependence. The slow relaxation component with a time constant of several decades of ns can be clearly determined with ps TRPL spectroscopy in which the slow relaxation process shows strong particle size-dependence. The decay time constants increase from 21 to 34ns with the decrease of particle size from 3.2 to 2.1 nm. The room-temperature decay lifetime is due to the thermal mixing of bright and dark excitons, and the size-dependence of slow relaxation process can be explained very well in terms of simple three-level model.

  13. Prediction of emulsion particle sizes using a computational fluid dynamics approach

    NARCIS (Netherlands)

    Agterof, W.G.M.; Vaessen, G.E.J.; Haagh, G.A.A.V.; Klahn, J.K.; Janssen, J.M.J.

    2003-01-01

    For many food products emulsification processes play an important role. Examples are ice cream, spreads, sauces, etc. As is well known, droplet break-up and coalescence phenomena are the local processes underlying the control of particle size in an emulsion process. Quite a number of studies have ge

  14. Dynamics of a stochastic tuberculosis model with constant recruitment and varying total population size

    Science.gov (United States)

    Liu, Qun; Jiang, Daqing; Shi, Ningzhong; Hayat, Tasawar; Alsaedi, Ahmed

    2017-03-01

    In this paper, we develop a mathematical model for a tuberculosis model with constant recruitment and varying total population size by incorporating stochastic perturbations. By constructing suitable stochastic Lyapunov functions, we establish sufficient conditions for the existence of an ergodic stationary distribution as well as extinction of the disease to the stochastic system.

  15. Determination of supplier-to-supplier and lot-to-lot variability in glycation of recombinant human serum albumin expressed in Oryza sativa.

    Science.gov (United States)

    Frahm, Grant E; Smith, Daryl G S; Kane, Anita; Lorbetskie, Barry; Cyr, Terry D; Girard, Michel; Johnston, Michael J W

    2014-01-01

    The use of different expression systems to produce the same recombinant human protein can result in expression-dependent chemical modifications (CMs) leading to variability of structure, stability and immunogenicity. Of particular interest are recombinant human proteins expressed in plant-based systems, which have shown particularly high CM variability. In studies presented here, recombinant human serum albumins (rHSA) produced in Oryza sativa (Asian rice) (OsrHSA) from a number of suppliers have been extensively characterized and compared to plasma-derived HSA (pHSA) and rHSA expressed in yeast (Pichia pastoris and Saccharomyces cerevisiae). The heterogeneity of each sample was evaluated using size exclusion chromatography (SEC), reversed-phase high-performance liquid chromatography (RP-HPLC) and capillary electrophoresis (CE). Modifications of the samples were identified by liquid chromatography-mass spectrometry (LC-MS). The secondary and tertiary structure of the albumin samples were assessed with far U/V circular dichroism spectropolarimetry (far U/V CD) and fluorescence spectroscopy, respectively. Far U/V CD and fluorescence analyses were also used to assess thermal stability and drug binding. High molecular weight aggregates in OsrHSA samples were detected with SEC and supplier-to-supplier variability and, more critically, lot-to-lot variability in one manufactures supplied products were identified. LC-MS analysis identified a greater number of hexose-glycated arginine and lysine residues on OsrHSA compared to pHSA or rHSA expressed in yeast. This analysis also showed supplier-to-supplier and lot-to-lot variability in the degree of glycation at specific lysine and arginine residues for OsrHSA. Both the number of glycated residues and the degree of glycation correlated positively with the quantity of non-monomeric species and the chromatographic profiles of the samples. Tertiary structural changes were observed for most OsrHSA samples which correlated well

  16. Determination of supplier-to-supplier and lot-to-lot variability in glycation of recombinant human serum albumin expressed in Oryza sativa.

    Directory of Open Access Journals (Sweden)

    Grant E Frahm

    Full Text Available The use of different expression systems to produce the same recombinant human protein can result in expression-dependent chemical modifications (CMs leading to variability of structure, stability and immunogenicity. Of particular interest are recombinant human proteins expressed in plant-based systems, which have shown particularly high CM variability. In studies presented here, recombinant human serum albumins (rHSA produced in Oryza sativa (Asian rice (OsrHSA from a number of suppliers have been extensively characterized and compared to plasma-derived HSA (pHSA and rHSA expressed in yeast (Pichia pastoris and Saccharomyces cerevisiae. The heterogeneity of each sample was evaluated using size exclusion chromatography (SEC, reversed-phase high-performance liquid chromatography (RP-HPLC and capillary electrophoresis (CE. Modifications of the samples were identified by liquid chromatography-mass spectrometry (LC-MS. The secondary and tertiary structure of the albumin samples were assessed with far U/V circular dichroism spectropolarimetry (far U/V CD and fluorescence spectroscopy, respectively. Far U/V CD and fluorescence analyses were also used to assess thermal stability and drug binding. High molecular weight aggregates in OsrHSA samples were detected with SEC and supplier-to-supplier variability and, more critically, lot-to-lot variability in one manufactures supplied products were identified. LC-MS analysis identified a greater number of hexose-glycated arginine and lysine residues on OsrHSA compared to pHSA or rHSA expressed in yeast. This analysis also showed supplier-to-supplier and lot-to-lot variability in the degree of glycation at specific lysine and arginine residues for OsrHSA. Both the number of glycated residues and the degree of glycation correlated positively with the quantity of non-monomeric species and the chromatographic profiles of the samples. Tertiary structural changes were observed for most OsrHSA samples which

  17. Determination of Supplier-to-Supplier and Lot-to-Lot Variability in Glycation of Recombinant Human Serum Albumin Expressed in Oryza sativa

    Science.gov (United States)

    Frahm, Grant E.; Smith, Daryl G. S.; Kane, Anita; Lorbetskie, Barry; Cyr, Terry D.; Girard, Michel; Johnston, Michael J. W.

    2014-01-01

    The use of different expression systems to produce the same recombinant human protein can result in expression-dependent chemical modifications (CMs) leading to variability of structure, stability and immunogenicity. Of particular interest are recombinant human proteins expressed in plant-based systems, which have shown particularly high CM variability. In studies presented here, recombinant human serum albumins (rHSA) produced in Oryza sativa (Asian rice) (OsrHSA) from a number of suppliers have been extensively characterized and compared to plasma-derived HSA (pHSA) and rHSA expressed in yeast (Pichia pastoris and Saccharomyces cerevisiae). The heterogeneity of each sample was evaluated using size exclusion chromatography (SEC), reversed-phase high-performance liquid chromatography (RP-HPLC) and capillary electrophoresis (CE). Modifications of the samples were identified by liquid chromatography-mass spectrometry (LC-MS). The secondary and tertiary structure of the albumin samples were assessed with far U/V circular dichroism spectropolarimetry (far U/V CD) and fluorescence spectroscopy, respectively. Far U/V CD and fluorescence analyses were also used to assess thermal stability and drug binding. High molecular weight aggregates in OsrHSA samples were detected with SEC and supplier-to-supplier variability and, more critically, lot-to-lot variability in one manufactures supplied products were identified. LC-MS analysis identified a greater number of hexose-glycated arginine and lysine residues on OsrHSA compared to pHSA or rHSA expressed in yeast. This analysis also showed supplier-to-supplier and lot-to-lot variability in the degree of glycation at specific lysine and arginine residues for OsrHSA. Both the number of glycated residues and the degree of glycation correlated positively with the quantity of non-monomeric species and the chromatographic profiles of the samples. Tertiary structural changes were observed for most OsrHSA samples which correlated well

  18. Finite-size effect on the dynamic and sensing performances of graphene resonators: the role of edge stress.

    Science.gov (United States)

    Kim, Chang-Wan; Dai, Mai Duc; Eom, Kilho

    2016-01-01

    We have studied the finite-size effect on the dynamic behavior of graphene resonators and their applications in atomic mass detection using a continuum elastic model such as modified plate theory. In particular, we developed a model based on von Karman plate theory with including the edge stress, which arises from the imbalance between the coordination numbers of bulk atoms and edge atoms of graphene. It is shown that as the size of a graphene resonator decreases, the edge stress depending on the edge structure of a graphene resonator plays a critical role on both its dynamic and sensing performances. We found that the resonance behavior of graphene can be tuned not only through edge stress but also through nonlinear vibration, and that the detection sensitivity of a graphene resonator can be controlled by using the edge stress. Our study sheds light on the important role of the finite-size effect in the effective design of graphene resonators for their mass sensing applications.

  19. Comparison of particle sizes between 238PuO2 before aqueous processing, after aqueous processing, and after ball milling

    Energy Technology Data Exchange (ETDEWEB)

    Mulford, Roberta Nancy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-02-06

    Particle sizes determined for a single lot of incoming Russian fuel and for a lot of fuel after aqueous processing are compared with particle sizes measured on fuel after ball-milling. The single samples of each type are believed to have particle size distributions typical of oxide from similar lots, as the processing of fuel lots is fairly uniform. Variation between lots is, as yet, uncharacterized. Sampling and particle size measurement methods are discussed elsewhere.

  20. LOT-G3: Plasma Lamp, Ozonator and CW transmitter

    CERN Document Server

    Gobato, Ricardo; Gobato, Alekssander

    2015-01-01

    The LOT-G3 is designed to be a versatile equipment that perform several simple experiments for use in helping the physics classes for high school. Easy construction, low cost, using easily accessible materials. Its construction involves simple practices and knowledge of electromagnetism. It has the function of a plasma globe to demonstrate the ionization of a low pressure gas, as well as the formation of magnetic field. Can be used as sanitizer closed environments such as automotive vehicles in ozonator function, demonstrating the ionization of oxygen in the atmosphere, producing ozone, essential to life on earth. And as a sparks transmitter, low power, low frequency modulated continuous wave in (CW), for signals in Morse code. Therefore the equipment here called LOT-G3, has three functions: a plasma lamp, ozonator and CW transmitter.

  1. Analysis of Innovative and Modern Technology of Parking Lots

    Directory of Open Access Journals (Sweden)

    Jonas Damidavičius

    2016-04-01

    Full Text Available Management of urban communication systems and ensuring of residents demands are the main tasks of the sustainable city development. One of the most important areas that forms better urban image is sustainable mobility development. It has influence on social, economical viability and environmental quality. Nowadays, intensive rhythm of life and increasing transport demands, usage of cars become a significant problem which regards the air and noise pollution and lack of parking spaces. Due to the daily impossibility of residents to find vacant parking spaces influence unproper usage of public spaces, streets, pedestrian and bicycle paths, children backgrounds, green areas and other territories. This report provides an overview of concepts of parking lots and their technology, and property usage in city center, middle zones, suburban territories and as well an analysis of the evolution of parking spaces. The report presents modern and innovative concepts of parking lots, which improves quality of communication and life in city and improves architectural environment.

  2. Model approach to estimate the probability of accepting a lot of heterogeneously contaminated powdered food using different sampling strategies.

    Science.gov (United States)

    Valero, Antonio; Pasquali, Frédérique; De Cesare, Alessandra; Manfreda, Gerardo

    2014-08-01

    Current sampling plans assume a random distribution of microorganisms in food. However, food-borne pathogens are estimated to be heterogeneously distributed in powdered foods. This spatial distribution together with very low level of contaminations raises concern of the efficiency of current sampling plans for the detection of food-borne pathogens like Cronobacter and Salmonella in powdered foods such as powdered infant formula or powdered eggs. An alternative approach based on a Poisson distribution of the contaminated part of the lot (Habraken approach) was used in order to evaluate the probability of falsely accepting a contaminated lot of powdered food when different sampling strategies were simulated considering variables such as lot size, sample size, microbial concentration in the contaminated part of the lot and proportion of contaminated lot. The simulated results suggest that a sample size of 100g or more corresponds to the lower number of samples to be tested in comparison with sample sizes of 10 or 1g. Moreover, the number of samples to be tested greatly decrease if the microbial concentration is 1CFU/g instead of 0.1CFU/g or if the proportion of contamination is 0.05 instead of 0.01. Mean contaminations higher than 1CFU/g or proportions higher than 0.05 did not impact on the number of samples. The Habraken approach represents a useful tool for risk management in order to design a fit-for-purpose sampling plan for the detection of low levels of food-borne pathogens in heterogeneously contaminated powdered food. However, it must be outlined that although effective in detecting pathogens, these sampling plans are difficult to be applied since the huge number of samples that needs to be tested. Sampling does not seem an effective measure to control pathogens in powdered food.

  3. Self-consistent field theory based molecular dynamics with linear system-size scaling.

    Science.gov (United States)

    Richters, Dorothee; Kühne, Thomas D

    2014-04-01

    We present an improved field-theoretic approach to the grand-canonical potential suitable for linear scaling molecular dynamics simulations using forces from self-consistent electronic structure calculations. It is based on an exact decomposition of the grand canonical potential for independent fermions and does neither rely on the ability to localize the orbitals nor that the Hamilton operator is well-conditioned. Hence, this scheme enables highly accurate all-electron linear scaling calculations even for metallic systems. The inherent energy drift of Born-Oppenheimer molecular dynamics simulations, arising from an incomplete convergence of the self-consistent field cycle, is circumvented by means of a properly modified Langevin equation. The predictive power of the present approach is illustrated using the example of liquid methane under extreme conditions.

  4. Self-consistent field theory based molecular dynamics with linear system-size scaling

    Energy Technology Data Exchange (ETDEWEB)

    Richters, Dorothee [Institute of Mathematics and Center for Computational Sciences, Johannes Gutenberg University Mainz, Staudinger Weg 9, D-55128 Mainz (Germany); Kühne, Thomas D., E-mail: kuehne@uni-mainz.de [Institute of Physical Chemistry and Center for Computational Sciences, Johannes Gutenberg University Mainz, Staudinger Weg 7, D-55128 Mainz (Germany); Technical and Macromolecular Chemistry, University of Paderborn, Warburger Str. 100, D-33098 Paderborn (Germany)

    2014-04-07

    We present an improved field-theoretic approach to the grand-canonical potential suitable for linear scaling molecular dynamics simulations using forces from self-consistent electronic structure calculations. It is based on an exact decomposition of the grand canonical potential for independent fermions and does neither rely on the ability to localize the orbitals nor that the Hamilton operator is well-conditioned. Hence, this scheme enables highly accurate all-electron linear scaling calculations even for metallic systems. The inherent energy drift of Born-Oppenheimer molecular dynamics simulations, arising from an incomplete convergence of the self-consistent field cycle, is circumvented by means of a properly modified Langevin equation. The predictive power of the present approach is illustrated using the example of liquid methane under extreme conditions.

  5. THz elastic dynamics in finite-size CoFeB-MgO phononic superlattices

    Science.gov (United States)

    Ulrichs, Henning; Meyer, Dennis; Müller, Markus; Wittrock, Steffen; Mansurova, Maria; Walowski, Jakob; Münzenberg, Markus

    2016-10-01

    In this article, we present the observation of coherent elastic dynamics in a nano-scale phononic superlattice, which consists of only 4 bilayers. We demonstrate how ultra-short light pulses with a length of 40 fs can be utilized to excite a coherent elastic wave at 0.535 THz, which persist over about 20 ps. In later steps of the elastic dynamics, modes with frequency of 1.7 THz and above appear. All these modes are related to acoustic band gaps. Thus, the periodicity strongly manifests in the wave physics, although the system under investigation has only a small number of spatial periods. To further illustrate this, we show how by breaking the translational invariance of the superlattice, these features can be suppressed. Discussed in terms of phonon blocking and radiation, we elucidate in how far our structures can be considered as useful building blocks for phononic devices.

  6. Make 'em Laugh (& They'll Learn a Lot More)

    Science.gov (United States)

    Done, Phillip

    2006-01-01

    Learning and laughter go hand in hand. Teachers certainly do not need to be stand-up comedians and spew out one-liners or dress up like clowns to make their classes fun. A little comedy can bring a lot of joy and learning opportunities to the classroom. In this article, the author shares several strategies on how teachers can put in laughter into…

  7. Discrete Dislocation Dynamics Simulations of Twin Size-Effects in Magnesium

    Science.gov (United States)

    2015-01-01

    size-effects in magnesium Haidong Fan1,2*, Sylvie Aubry3, A. Arsenlis3, Jaafar A. El-Awady1* 1 Department of Mechanical Engineering, Johns Hopkins...structural metal, magnesium (Mg) and its alloys have been of practical interest due to their potential use in automotive, aerospace and defense...applications. Magnesium has a hexagonal closed packed (HCP) lattice structure with low crystal symmetry, thus, in addition to dislocation-mediated

  8. Mountain gorilla ranging patterns: influence of group size and group dynamics.

    Science.gov (United States)

    Caillaud, Damien; Ndagijimana, Felix; Giarrusso, Anthony J; Vecellio, Veronica; Stoinski, Tara S

    2014-08-01

    Since the 1980s, the Virunga mountain gorilla population has almost doubled, now reaching 480 individuals living in a 430-km(2) protected area. Analysis of the gorillas' ranging patterns can provide critical information on the extent and possible effects of competition for food and space. We analyzed 12 years of daily ranging data and inter-group encounter data collected on 11 gorilla groups monitored by the Karisoke Research Center in Rwanda. During that period, the study population increased in size by almost 50% and the number of groups tripled. Groups had small yearly home ranges compared to other known gorilla populations, with an average 90% kernel density estimate of 8.07 km2 and large between-group variations (3.17-23.59 km2). Most groups had consistent home range location over the course of the study but for some, we observed gradual range shifts of up to 4 km. Neighboring groups displayed high home range overlap, which increased dramatically after the formation of new groups. On average, each group used only 28.6% of its 90% kernel home range exclusively, and in some areas up to six different groups had overlapping home ranges with little or no exclusive areas. We found a significant intra-group positive relationship between the number of weaned individuals in a group and the home range size, but the fitted models only explained 17.5% and 13.7% of the variance in 50% and 90% kernel home range size estimates, respectively. This suggests that despite the increase in size, the study population is not yet experiencing marked effects of feeding competition. However, the increase in home range overlap resulting from the formation of new groups led to a sixfold increase in the frequency of inter-group encounters, which exposes the population to elevated risks of fight-related injuries and infanticide.

  9. Liquid-Metal Microdroplets Formed Dynamically with Electrical Control of Size and Rate.

    Science.gov (United States)

    Tang, Shi-Yang; Joshipura, Ishan D; Lin, Yiliang; Kalantar-Zadeh, Kourosh; Mitchell, Arnan; Khoshmanesh, Khashayar; Dickey, Michael D

    2016-01-27

    Liquid metal co-injected with electrolyte through a microfluidic flow-focusing orifice forms droplets with diameters and production frequencies controlled in real time by voltage. Applying voltage to the liquid metal controls the interfacial tension via a combination of electrochemistry and electrocapillarity. This simple and effective method can instantaneously tune the size of the microdroplets, which has applications in composites, catalysts, and microsystems.

  10. Size and surface functionalization of iron oxide nanoparticles influence the composition and dynamic nature of their protein corona.

    Science.gov (United States)

    Ashby, Jonathan; Pan, Songqin; Zhong, Wenwan

    2014-09-10

    Nanoparticles (NPs) adsorb proteins when in the biological matrix, and the resulted protein corona could affect NP-cell interactions. The corona has a dynamic nature with the adsorbed proteins constantly exchanging with the free proteins in the matrix at various rates. The rapidly exchanging proteins compose the soft corona, which responds more dynamically to environment changes than the hard corona established by the ones with slow exchange rates. In the present study, the corona formed on the superparamagnetic iron oxide NPs (SPIONs) in human serum was studied by flow field-flow fractionation and ultracentrifugation, which rapidly differentiated the corona proteins based on their exchange rates. By varying the surface hydrophobicity of the SPIONs with a core size around 10 nm, we found out that, the more hydrophobic surface ligand attracted proteins with higher surface hydrophobicity and formed a more dynamic corona with a larger portion of the involved proteins with fast exchange rates. Increasing the core diameter of the SPIONs but keeping the surface ligand the same could also result in a more dynamic corona. A brief investigation of the effect on the cellular uptake of SPIONs using one selected corona protein, transferrin, was conducted. The result showed that, only the stably bound transferrin could significantly enhance cellular uptake, while transferrin bound in a dynamic nature had negligible impact. Our study has led to a better understanding of the relationship between the particle properties and the dynamic nature of the corona, which can help with design of nanomaterials with higher biocompatibility and higher efficacy in biosystems for biomedical applications.

  11. Effective population size and evolutionary dynamics in outbred laboratory populations of Drosophila

    Indian Academy of Sciences (India)

    Laurence D. Mueller; Amitabh Joshi; Marta Santos; Michael R. Rose

    2013-12-01

    Census population size, sex-ratio and female reproductive success were monitored in 10 laboratory populations of Drosophila melanogaster selected for different ages of reproduction. With this demographic information, we estimated eigenvalue, variance and probability of allele loss effective population sizes. We conclude that estimates of effective size based on genefrequency change at a few loci are biased downwards. We analysed the relative roles of selection and genetic drift in maintaining genetic variation in laboratory populations of Drosophila. We suggest that rare, favourable genetic variants in our laboratory populations have a high chance of being lost if their fitness effect is weak, e.g. 1% or less. However, if the fitness effect of this variation is 10% or greater, these rare variants are likely to increase to high frequency. The demographic information developed in this study suggests that some of our laboratory populations harbour more genetic variation than expected. One explanation for this finding is that part of the genetic variation in these outbred laboratory Drosophila populations may be maintained by some form of balancing selection. We suggest that, unlike bacteria, medium-term adaptation of laboratory populations of fruit flies is not primarily driven by new mutations, but rather by changes in the frequency of preexisting alleles.

  12. The Coupled Effect of Loading Rate and Grain Size on Tensile Strength of Sandstones under Dynamic Disturbance

    Directory of Open Access Journals (Sweden)

    Miao Yu

    2017-01-01

    Full Text Available It is of significance to comprehend the effects of rock microstructure on the tensile strength under different loading rates caused by mining disturbance. So, in this paper, three kinds of sandstones drilled from surrounding rocks in Xiao Jihan Coal to simulate the in situ stress state, whose average grain size is 30 μm (fine grain, FG, 105 μm (medium grain, MG, and 231 μm (Coarse grain, CG, are selected with the calculation of optical microscopic technique and moreover processed to Brazilian disc (BD to study the mechanical response of samples. The dynamic Brazilian tests of samples with three kinds of grain sizes are conducted with the Split Hopkinson Pressure Bar (SHPB driven by pendulum hammer, which can produce four different velocities (V=2.0 m/s, 2.5 m/s, 3.3 m/s, and 4.2 m/s when the incident bar is impacted by pendulum hammer. The incident wave produced by pendulum hammer is a slowly rising stress wave, which allows gradual stress accumulation in the specimen and maintains the load at both ends of the specimen in an equilibrium state. The results show that the dynamic strength of three kinds of BD samples represented loading rates dependence, and FG sandstones are more sensitive for loading rates than MG and CG samples. Moreover, the peak strength is observed to increase linearly with an increasing stress rates, and the relationship between the dynamic BD strength and stress rates can be built through a linear equation. Finally, the failure modes of different grain sizes are discussed and explained by microfailure mechanism.

  13. Effect of size, quaternary structure and translational error on the static and dynamic heterogeneity of beta-galactosidase and measurement of electrophoretic dynamic heterogeneity.

    Science.gov (United States)

    Craig, Douglas B; Haslam, Allison M; Silverstein, Harlyn J; Chikamatsu, Miki; Shadabi, Elnaz; Nichols, Ellert R

    2010-08-01

    Single enzyme molecule assays were performed using capillary electrophoresis-based protocols on beta-galactosidase from Lactobacillus delbrueckii, Lactobacillus reuteri, Lactobacillus helveticus and Bacillus circulans. The enzyme was found to show static heterogeneity with respect to catalytic rate and the variance in rate increased with protein size. This is consistent with the proposal that random errors in translation may be an important underlying component of enzyme heterogeneity. Additionally these enzymes were found to show static heterogeneity with respect to electrophoretic mobility. Comparison of wild-type and rpsL E. coli beta-galactosidase expressed in the presence and absence of streptomycin suggested that increases in error do not result in detectable increases in the dynamic heterogeneity of activity with increasing temperature. Finally, a method was developed to measure the dynamic heterogeneity in electrophoretic mobility.

  14. Distribution of domain sizes in the zero temperature Glauber dynamics of the one-dimensional Potts model

    Science.gov (United States)

    Derrida, Bernard; Zeitak, Reuven

    1996-09-01

    For the zero temperature Glauber dynamics of the q-state Potts model, we calculate the exact distribution of domain sizes by mapping the problem on an exactly soluble one-species coagulation model (A+A-->A). In the long time limit, this distribution is universal and, from its (complicated) exact expression, we extract its behavior in various regimes. Our results are tested in a simulation and compared to the predictions of a simple approximation proposed recently. Considering the dynamics of domain walls as a reaction-diffusion model A+A-->A with probability (q-2)/(q-1) and A+A-->θ with probability 1/(q-1), we calculate the pair correlation function in the long time regime.

  15. Dynamic globularization prediction during cogging process of large size TC11 titanium alloy billet with lamellar structure

    Institute of Scientific and Technical Information of China (English)

    Hong-wu SONG; Shi-hong ZHANG; Ming CHENG

    2014-01-01

    The flow behavior and dynamic globularization of TC11 titanium alloy during subtransus deformation are investigated through hot compression tests. A constitutive model is established based on physical-based hardening model and phenomenological softening model. And based on the recrystallization mechanisms of globularization, the Avrami type kinetics model is established for prediction of globularization fraction and globularized grain size under large strain subtransus deformation of TC11 alloy. As the preliminary application of the previous results, the cogging process of large size TC11 alloy billet is simulated. Based on subroutine development of the DEFORM software, the coupled simulation of one fire cogging process is developed. It shows that the predicted results are in good agreement with the experimental results in forging load and microstructure characteristic, which validates the reliability of the developed FEM subroutine models.

  16. Finite-size effects on the lattice dynamics in spin crossover nanomaterials. I. Nuclear inelastic scattering investigation

    Science.gov (United States)

    Mikolasek, Mirko; Félix, Gautier; Peng, Haonan; Rat, Sylvain; Terki, Férial; Chumakov, Aleksandr I.; Salmon, Lionel; Molnár, Gábor; Nicolazzi, William; Bousseksou, Azzedine

    2017-07-01

    We report the investigation of the size evolution of lattice dynamics in spin crossover coordination nanoparticles of [ Fe (pyrazine ) (Ni (CN) 4) ] through nuclear inelastic scattering (NIS) measurements. Vibrational properties in these bistable molecular materials are of paramount importance and NIS permits access to the partial vibrational density of states in both spin states [high spin (HS) and low spin (LS)] from which thermodynamical and mechanical properties can be extracted. We show that the size reduction leads to the presence of inactive metal centers with the coexistence of HS and LS vibrational modes. The confinement effect has only weak impact on the vibrational properties of nanoparticles, especially on the optical modes which remain almost unchanged. On the other hand, the acoustic modes are much more affected which results in the increase of the vibrational entropy and also the Debye sound velocity in the smallest particles (nanoparticles is also highlighted through the matrix dependence of the sound velocity.

  17. Finite size scaling study of dynamical phase transitions in two dimensional models: ferromagnet, symmetric and non symmetric spin glasses

    Energy Technology Data Exchange (ETDEWEB)

    Neumann, A.U.; Derrida, B.

    1988-10-01

    We study the time evolution of two configurations submitted to the same thermal noise for several two dimensional models (Ising ferromagnet, symmetric spin glass, non symmetric spin glass). For all these models, we find a non zero critical temperature above which the two configurations always meet. Using finite size scaling ideas, we determine for these three models this dynamical phase transition and some of the critical exponents. For the ferromagnet, the transition T/sub c/ approx. = 2.25 coincides with the Curie temperature whereas for the two spin glass models +- J distribution of bonds) we obtain T/sub c/ approx. = 1.5-1.7.

  18. Effect of grain size on the behavior of hydrogen/helium retention in tungsten: a cluster dynamics modeling

    Science.gov (United States)

    Zhao, Zhe; Li, Yonggang; Zhang, Chuanguo; Pan, Guyue; Tang, Panfei; Zeng, Zhi

    2017-08-01

    Reducing ion retention in materials is a key factor in the management of tritium inventory, the selection of compatible plasma-facing materials (PFMs), and thus the future development of fusion reactors. In this work, by introducing the cellular sink strength of grain boundaries (GBs) into the cluster dynamics model, the behavior of hydrogen (H) and helium (He) retention in W with different grain sizes is studied under various irradiation conditions systematically. It is found that the H/He retention increases dramatically with decreasing grain size at typical service temperatures, due to the enhancement of H/He capture ratio by GBs. Generally, He retention exists in three forms: He in GBs, in dislocations and in clusters (He m V n , He n and He n I). Our further study shows that, under the irradiation of low energy and low fluence ions, the contribution of He in clusters is negligible. The total He retention is thus dominated by the competing absorption of GBs and dislocations, that is, changing from the dislocation-based to grain boundary-based retention with decreasing grain size. H retention also presents the same behavior. In view of these grain size-related behaviors of H/He retention in W, it is suggested that coarse-grained crystals should be selected for W-based PFMs in practice.

  19. Dynamic finite element modeling of the effects of size on the upper shelf energy of ferritic steels

    Energy Technology Data Exchange (ETDEWEB)

    Sidener, S.E.; Kumar, A.S.; Schubert, L.E.; Hamilton, M.L.; Rosinski, S.T.

    1996-04-01

    Both the fusion and light water reactor program require the use of the subsize specimens to obtain sufficient irradiation data on neutron-induced embrittlement of ferritic steels. While the development of fusion-relevant size effects correlations can proceed analytically, it is more cost-effective at this time to use data currently being obtained on embrittlement of pressure vessel steels to test and expand the correlations developed earlier using fusion relevant steels. Dynamic finite elements modeling of the fracture behavior of fatigue-precracked Charpy Specimens was performed to determine the effect of single variable changes in ligament size, width, span, and thickness on the upper shelf energy. A method based on tensile fracture strain was used for modeling crack initiation and propagation. It was found that the upper shelf energy of precracked specimens (USE{sub p}) is proportional to b{sup n}, where b is ligament size and n varies from about 1.6 for subsize to 1.9 for full size specimens. The USE{sub p} was found to be proportional to width according to W{sup 25}. The dependence on thickness was found to be linear for all cases studied. Some of the data from the FEM analysis were compared with experimental data and were found to be in reasonable agreement.

  20. The Influence of Pore Size on the Indentation Behavior of Metallic Nanoporous Materials: A Molecular Dynamics Study

    Directory of Open Access Journals (Sweden)

    Daniel Esqué-de los Ojos

    2016-05-01

    Full Text Available In general, the influence of pore size is not considered when determining the Young’s modulus of nanoporous materials. Here, we demonstrate that the pore size needs to be taken into account to properly assess the mechanical properties of these materials. Molecular dynamics simulations of spherical indentation experiments on single crystalline nanoporous Cu have been undertaken in systems with: (i a constant degree of porosity and variable pore diameter; and (ii a constant pore diameter and variable porosity degree. The classical Gibson and Ashby expression relating Young’s modulus with the relative density of the nanoporous metal is modified to include the influence of the pore size. The simulations reveal that, for a fixed porosity degree, the mechanical behavior of materials with smaller pores differs more significantly from the behavior of the bulk, fully dense counterpart. This effect is ascribed to the increase of the overall surface area as the pore size is reduced, together with the reduced coordination number of the atoms located at the pores edges.

  1. The Influence of Pore Size on the Indentation Behavior of Metallic Nanoporous Materials: A Molecular Dynamics Study.

    Science.gov (United States)

    Esqué-de Los Ojos, Daniel; Pellicer, Eva; Sort, Jordi

    2016-05-11

    In general, the influence of pore size is not considered when determining the Young's modulus of nanoporous materials. Here, we demonstrate that the pore size needs to be taken into account to properly assess the mechanical properties of these materials. Molecular dynamics simulations of spherical indentation experiments on single crystalline nanoporous Cu have been undertaken in systems with: (i) a constant degree of porosity and variable pore diameter; and (ii) a constant pore diameter and variable porosity degree. The classical Gibson and Ashby expression relating Young's modulus with the relative density of the nanoporous metal is modified to include the influence of the pore size. The simulations reveal that, for a fixed porosity degree, the mechanical behavior of materials with smaller pores differs more significantly from the behavior of the bulk, fully dense counterpart. This effect is ascribed to the increase of the overall surface area as the pore size is reduced, together with the reduced coordination number of the atoms located at the pores edges.

  2. Size-Dependent Biexciton Quantum Yields and Carrier Dynamics of Quasi-Two-Dimensional Core/Shell Nanoplatelets.

    Science.gov (United States)

    Ma, Xuedan; Diroll, Benjamin T; Cho, Wooje; Fedin, Igor; Schaller, Richard D; Talapin, Dmitri V; Gray, Stephen K; Wiederrecht, Gary P; Gosztola, David J

    2017-09-05

    Quasi-two-dimensional nanoplatelets (NPLs) possess fundamentally different excitonic properties from zero-dimensional quantum dots. We study lateral size-dependent photon emission statistics and carrier dynamics of individual NPLs using second-order photon correlation (g((2))(τ)) spectroscopy and photoluminescence (PL) intensity-dependent lifetime analysis. Room-temperature radiative lifetimes of NPLs can be derived from maximum PL intensity periods in PL time traces. It first decreases with NPL lateral size and then stays constant, deviating from the electric dipole approximation. Analysis of the PL time traces further reveals that the single exciton quantum yield in NPLs decreases with NPL lateral size and increases with protecting shell thickness, indicating the importance of surface passivation on NPL emission quality. Second-order photon correlation (g((2))(τ)) studies of single NPLs show that the biexciton quantum yield is strongly dependent on the lateral size and single exciton quantum yield of the NPLs. In large NPLs with unity single exciton quantum yield, the corresponding biexciton quantum yield can reach unity. These findings reveal that by careful growth control and core-shell material engineering, NPLs can be of great potential for light amplification and integrated quantum photonic applications.

  3. Dynamic light scattering-based method to determine primary particle size of iron oxide nanoparticles in simulated gastrointestinal fluid.

    Science.gov (United States)

    Yang, Seung-Chul; Paik, Sae-Yeol-Rim; Ryu, Jina; Choi, Kyeong-Ok; Kang, Tae Seok; Lee, Jong Kwon; Song, Chi Won; Ko, Sanghoon

    2014-10-15

    Simple dynamic light scattering (DLS)-based methodologies were developed to determine primary particle size distribution of iron oxide particles in simulated gastrointestinal fluid. Iron oxide particles, which easily agglomerate in aqueous media, were converted into dispersed particles by modification of surface charge using citric acid and sodium citrate. After the modification, zeta-potential value decreased to -40mV at pH 7. Mean particle diameters in suspensions of iron oxide nano- and microparticles stabilized by the mixture of citric acid and sodium citrate were dramatically decreased to 166 and 358nm, respectively, which were close to the particle size distributions observed in the micrographs. In simulated gastrointestinal fluid, both iron oxide nano- and microparticles were heavily agglomerated with particle diameters of almost 2600 and 5200nm, respectively, due to charge shielding on the citrate-modified surface by ions in the media. For determining primary particle size distribution by using DLS-based approach, the iron oxide particles incubated in the simulated gastrointestinal fluid were converted to monodisperse particles by altering the pH to 7 and electrolyte elimination. The simple DLS-based methodologies are well suited to determine primary particle size distribution of mineral nanoparticles at various physical, chemical, and biological conditions.

  4. Research on Dynamic Distributed Computing System for Small and Medium-Sized Computer Clusters

    Institute of Scientific and Technical Information of China (English)

    Le Kang; Jianliang Xu; Feng Liu

    2012-01-01

      Distributed computing system is a science by which a complex task that need for large amount of computation can be divided into small pieces and calculated by more than one computer,and we can get the final result according to results from each computer.This paper considers a distributed computing system running in the small and medium-sized computer clusters to solve the problem that single computer has a low efficiency,and improve the efficiency of large-scale computing.The experiments show that the system can effectively improve the efficiency and it is a viable program.

  5. IMPACT OF INNOVATION UPON THE DYNAMICS OF ROMANIAN SMALL AND MEDIUM SIZED ENTERPRISES

    Directory of Open Access Journals (Sweden)

    JEANINA CIUREA

    2013-10-01

    Full Text Available Innovation is central to economic growth, as the area in which it develops takes the whole sphere of economic activities: product, process, service, organization, marketing, hence the economic effects they may cause. Creating "innovative enterprises", giving tax cuts to certain periods of time, preferential loans, creating funds 'risk capital' are just some of the measures that European countries which already apply and Romania, willing to encourage innovation. The present paper presents two ways of exposing this issue, using theoretical sources but also real official data concerning the concept of innovation and also the ways of applying it within small and medium sized enterprises.

  6. Interacting spins in a cavity: Finite-size effects and symmetry-breaking dynamics

    DEFF Research Database (Denmark)

    Gammelmark, Søren; Mølmer, Klaus

    2012-01-01

    , and for small chains, we find significant and nontrivial finite-size effects. Below the first-order phase transition, even quite large spin chains of 30–40 spins give rise to a mean photon number and number fluctuations significantly above the mean-field vacuum result. Near the second-order phase critical point......-transition the random character of the measurement process causes a measurement-induced symmetry breaking in the system. This symmetry breaking occurs on the time scale needed for an observer to gather sufficient information to distinguish between the two possible (mean-field) symmetry-broken states....

  7. Shift in a large river fish assemblage: body-size and trophic structure dynamics.

    Directory of Open Access Journals (Sweden)

    Kyle J Broadway

    Full Text Available As the intensity and speed of environmental change increase at both local and global scales it is imperative that we gain a better understanding of the ecological implications of community shifts. While there has been substantial progress toward understanding the drivers and subsequent responses of community change (e.g. lake trophic state, the ecological impacts of food web changes are far less understood. We analyzed Wabash River fish assemblage data collected from 1974-2008, to evaluate temporal variation in body-size structure and functional group composition. Two parameters derived from annual community size-spectra were our major response variables: (1 the regression slope is an index of ecological efficiency and predator-prey biomass ratios, and (2 spectral elevation (regression midpoint height is a proxy for food web capacity. We detected a large assemblage shift, over at least a seven year period, defined by dramatic changes in abundance (measured as catch-per-unit-effort of the dominant functional feeding groups among two time periods; from an assemblage dominated by planktivore-omnivores to benthic invertivores. There was a concurrent increase in ecological efficiency (slopes increased over time following the shift associated with an increase in large-bodied low trophic level fish. Food web capacity remained relatively stable with no clear temporal trends. Thus, increased ecological efficiency occurred simultaneous to a compensatory response that shifted biomass among functional feeding groups.

  8. Diel size distributions reveal seasonal growth dynamics of a coastal phytoplankter

    Science.gov (United States)

    Hunter-Cevera, Kristen R.; Neubert, Michael G.; Solow, Andrew R.; Olson, Robert J.; Shalapyonok, Alexi; Sosik, Heidi M.

    2014-01-01

    Phytoplankton account for roughly half of global primary production; it is vital that we understand the processes that control their abundance. A key process is cell division. We have, however, been unable to estimate division rate in natural populations at the appropriate timescale (hours to days) for extended periods of time (months to years). For phytoplankton, the diel change in cell size distribution is related to division rate, which offers an avenue to obtain estimates from in situ observations. We show that a matrix population model, fit to hourly cell size distributions, accurately estimates division rates of both cultured and natural populations of Synechococcus. Application of the model to Synechococcus at the Martha’s Vineyard Coastal Observatory provides an unprecedented view that reveals a distinct seasonality in division rates. This information allows us to separate the effects of growth and loss quantitatively over an entire seasonal cycle. We find that division and loss processes are tightly coupled throughout the year. The large seasonal changes in cell abundance are the result of periods of time (weeks to months) when there are small systematic differences that favor either net growth or loss. We also find that temperature plays a critical role in limiting division rate during the annual spring bloom. This approach opens a path to quantify the role of Synechococcus in ecological and biogeochemical processes in natural systems. PMID:24958866

  9. Comparing cluster-level dynamic treatment regimens using sequential, multiple assignment, randomized trials: Regression estimation and sample size considerations.

    Science.gov (United States)

    NeCamp, Timothy; Kilbourne, Amy; Almirall, Daniel

    2017-08-01

    Cluster-level dynamic treatment regimens can be used to guide sequential treatment decision-making at the cluster level in order to improve outcomes at the individual or patient-level. In a cluster-level dynamic treatment regimen, the treatment is potentially adapted and re-adapted over time based on changes in the cluster that could be impacted by prior intervention, including aggregate measures of the individuals or patients that compose it. Cluster-randomized sequential multiple assignment randomized trials can be used to answer multiple open questions preventing scientists from developing high-quality cluster-level dynamic treatment regimens. In a cluster-randomized sequential multiple assignment randomized trial, sequential randomizations occur at the cluster level and outcomes are observed at the individual level. This manuscript makes two contributions to the design and analysis of cluster-randomized sequential multiple assignment randomized trials. First, a weighted least squares regression approach is proposed for comparing the mean of a patient-level outcome between the cluster-level dynamic treatment regimens embedded in a sequential multiple assignment randomized trial. The regression approach facilitates the use of baseline covariates which is often critical in the analysis of cluster-level trials. Second, sample size calculators are derived for two common cluster-randomized sequential multiple assignment randomized trial designs for use when the primary aim is a between-dynamic treatment regimen comparison of the mean of a continuous patient-level outcome. The methods are motivated by the Adaptive Implementation of Effective Programs Trial which is, to our knowledge, the first-ever cluster-randomized sequential multiple assignment randomized trial in psychiatry.

  10. Effect of impact angle and projectile size on sputtering efficiency of solid benzene investigated by molecular dynamics simulations

    Energy Technology Data Exchange (ETDEWEB)

    Czerwinski, Bartlomiej, E-mail: bartlomiej.czerwinski@uj.edu.pl [Goszczynski College, pl. Krasinskiego 1, 34-400 Nowy Targ (Poland); Rzeznik, Lukasz; Paruch, Robert [Smoluchowski Institute of Physics, Jagiellonian University, ul. Reymonta 4, 30-059 Krakow (Poland); Garrison, Barbara J. [Department of Chemistry, The Pennsylvania State University, University Park, PA 16802 (United States); Postawa, Zbigniew [Smoluchowski Institute of Physics, Jagiellonian University, ul. Reymonta 4, 30-059 Krakow (Poland)

    2011-07-15

    Molecular dynamics computer simulations have been used to investigate the effect of the cluster size on the sputtering yield dependence on the impact angle. Ar{sub 366} and Ar{sub 2953} cluster projectiles with 14.75 keV of incident energy are directed at the surface of a solid benzene crystal described by a coarse-grained representation at angles between 0 deg. and 70 deg. It is observed that the shape of the angular dependence of sputtering efficiency is strongly affected by the cluster size. For the Ar{sub 366} cluster, the sputtering yield only slightly increases with the impact angle, has a broad maximum around 40 deg., and decreases at larger angles. For the Ar{sub 2953} cluster, the yield strongly increases with the impact angle, has a maximum around 45 deg. followed by a steep decrease at larger angles. For both investigated cluster projectiles the primary energy is deposited so close to the surface so that the sputtering efficiency only weekly benefits from the shift of the deposited energy profile toward the surface which occurs at larger impact angles. In this study, molecular dynamics computer simulations are used to probe the effect of the impact angle on the efficiency of ejection molecules emitted from solid benzene by 14.75 keV Ar{sub 366} and Ar{sub 2953} clusters.

  11. Lotka-Volterra dynamics kills the Red Queen: population size fluctuations and associated stochasticity dramatically change host-parasite coevolution.

    Science.gov (United States)

    Gokhale, Chaitanya S; Papkou, Andrei; Traulsen, Arne; Schulenburg, Hinrich

    2013-11-19

    Host-parasite coevolution is generally believed to follow Red Queen dynamics consisting of ongoing oscillations in the frequencies of interacting host and parasite alleles. This belief is founded on previous theoretical work, which assumes infinite or constant population size. To what extent are such sustained oscillations realistic? Here, we use a related mathematical modeling approach to demonstrate that ongoing Red Queen dynamics is unlikely. In fact, they collapse rapidly when two critical pieces of realism are acknowledged: (i) population size fluctuations, caused by the antagonism of the interaction in concordance with the Lotka-Volterra relationship; and (ii) stochasticity, acting in any finite population. Together, these two factors cause fast allele fixation. Fixation is not restricted to common alleles, as expected from drift, but also seen for originally rare alleles under a wide parameter space, potentially facilitating spread of novel variants. Our results call for a paradigm shift in our understanding of host-parasite coevolution, strongly suggesting that these are driven by recurrent selective sweeps rather than continuous allele oscillations.

  12. Lotka–Volterra dynamics kills the Red Queen: population size fluctuations and associated stochasticity dramatically change host-parasite coevolution

    Science.gov (United States)

    2013-01-01

    Background Host-parasite coevolution is generally believed to follow Red Queen dynamics consisting of ongoing oscillations in the frequencies of interacting host and parasite alleles. This belief is founded on previous theoretical work, which assumes infinite or constant population size. To what extent are such sustained oscillations realistic? Results Here, we use a related mathematical modeling approach to demonstrate that ongoing Red Queen dynamics is unlikely. In fact, they collapse rapidly when two critical pieces of realism are acknowledged: (i) population size fluctuations, caused by the antagonism of the interaction in concordance with the Lotka-Volterra relationship; and (ii) stochasticity, acting in any finite population. Together, these two factors cause fast allele fixation. Fixation is not restricted to common alleles, as expected from drift, but also seen for originally rare alleles under a wide parameter space, potentially facilitating spread of novel variants. Conclusion Our results call for a paradigm shift in our understanding of host-parasite coevolution, strongly suggesting that these are driven by recurrent selective sweeps rather than continuous allele oscillations. PMID:24252104

  13. Effect of fluid dynamics on particle size distribution in particulate processes

    Energy Technology Data Exchange (ETDEWEB)

    Marchisio, D.L.; Barresi, A.A.; Baldi, G. [Dipartimento di Scienza Materiali e Ingegneria Chimica, Politecnico di Torino, C.so Duca degli Abruzzi 24, I-10129 Torino (Italy); Soos, M.; Morbidelli, M. [Institut fuer Chemie- und Bioingenieurswissenschaften, Swiss Federal Institute of Technology Zuerich, ETH Hoenggerberg/HCL, CH-8093 Zuerich (Switzerland); Sefcik, J. [Department of Chemical and Process Engineering, University of Strathclyde, James Weir Building, 75 Montrose Street, Glasgow G1 1XJ, Scotland (United Kingdom)

    2006-02-01

    The final product quality of crystallization and precipitation processes is often determined by the interplay between mixing and relevant phenomena such as, nucleation, molecular growth, aggregation and breakage. In this work the attention is focused on the aggregation and breakage processes and on the level of details needed to accurately describe them. Different modeling approaches are tested and compared for two different shear devices: a Taylor-Couette cell and a stirred tank. Results show that when aggregation and breakage processes are much slower than mixing a simplified homogeneous model can be used whereas when aggregation and breakage occur on a time-scale comparable with that of mixing then a detailed approach based on computational fluid dynamics (CFD) is needed. The very common lumped model, used to derive kinetic expressions for aggregation and breakage rates, can eventually lead to serious errors. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  14. Dynamic finite element analysis of third size charpy specimens of V-4Cr-4Ti

    Energy Technology Data Exchange (ETDEWEB)

    Lansberry, M.R.; Kumar, A.S.; Mueller, G.E. [Univ. of Missouri, Rolla, MO (United States); Kurtz, R.J. [Pacific Northwest National Lab., Richland, WA (United States)

    1997-04-01

    A 2-D finite element analysis was performed on precracked, one third scale CVN specimens to investigate the sensitivity of model results to key material parameters such as yield strength, failure strain and work hardening characteristics. Calculations were carried out at temperatures of -196{degree}C and 50{degree}C. The dynamic finite element analyses were conducted using ABAQUS/Explicit V5.4. The finite element results were compared to experimental results for the production-scale heat of V-4Cr-4Ti (ANL Heat No. 832665) as a benchmark. Agreement between the finite element model and experimental data was very good at -196{degree}C, whereas at 50{degree}C the model predicted a slightly lower absorbed energy than actually measured.

  15. Impact of cannibalism on predator-prey dynamics: size-structured interactions and apparent mutualism.

    Science.gov (United States)

    Rudolf, Volker H W

    2008-06-01

    Direct and indirect interactions between two prey species can strongly alter the dynamics of predator-prey systems. Most predators are cannibalistic, and as a consequence, even systems with only one predator and one prey include two prey types: conspecifics and heterospecifics. The effects of the complex direct and indirect interactions that emerge in such cannibalistic systems are still poorly understood. This study examined how the indirect interaction between conspecific and heterospecific prey affects cannibalism and predation rates and how the direct interactions between both species indirectly alter the effect of the cannibalistic predator. I tested for these effects using larvae of the stream salamanders Eurycea cirrigera (prey) and Pseudotriton ruber (cannibalistic predator) by manipulating the relative densities of the conspecific and heterospecific prey in the presence and absence of the predator in experimental streams. The rates of cannibalism and heterospecific predation were proportional to the respective densities and negatively correlated, indicating a positive indirect interaction between conspecific and heterospecific prey, similar to "apparent mutualism." Direct interactions between prey species did not alter the effect of the predator. Although both types of prey showed a similar 30% reduction in night activity and switch in microhabitat use in response to the presence of the predator, cannibalism rates were three times higher than heterospecific predation rates irrespective of the relative densities of the two types of prey. Cumulative predation risks differed even more due to the 48% lower growth rate of conspecific prey. Detailed laboratory experiments suggest that the 3:1 difference in cannibalism and predation rate was due to the higher efficiency of heterospecific prey in escaping immediate attacks. However, no difference was observed when the predator was a closely related salamander species, Gyrinophilus porphyriticus, indicating that

  16. Spatial patterns of sediment dynamics within a medium-sized watershed over an extreme storm event

    Science.gov (United States)

    Gao, Peng; Zhang, Zhirou

    2016-08-01

    In this study, we quantified spatial patterns of sediment dynamics in a watershed of 311 km2 over an extreme storm event using watershed modeling and statistical analyses. First, we calibrated a watershed model, Dynamic Watershed Simulation Model (DWSM) by comparing the predicted with calculated hydrograph and sedigraph at the outlet for this event. Then we predicted values of event runoff volume (V), peak flow (Qpeak), and two types of event sediment yields for lumped morphological units that contain 42 overland elements and 21 channel segments within the study watershed. Two overland elements and the connected channel segment form a first-order subwatershed, several of which constitute a larger nested subwatershed. Next we examined (i) the relationships between these variables and area (A), precipitation (P), mean slope (S), soil erodibility factor, and percent of crop and pasture lands for all overland elements (i.e., the small spatial scale, SSS), and (ii) those between sediment yield, Qpeak, A, P, and event runoff depth (h) for the first-order and nested subwatersheds along two main creeks of the study watershed (i.e., the larger spatial scales, LSS). We found that at the SSS, sediment yield was nonlinearly well related to A and P, but not Qpeak and h; whereas at the LSS, linear relationships between sediment yield and Qpeak existed, so did the Qpeak-A, and Qpeak-P relationships. This linearity suggests the increased connectivity from the SSS to LSS, which was caused by ignorance of channel processes within overland elements. It also implies that sediment was transported at capacity during the extreme event. So controlling sediment supply from the most erodible overland elements may not efficiently reduce the downstream sediment load.

  17. Toxicity of parking lot runoff after application of simulated rainfall.

    Science.gov (United States)

    Greenstein, D; Tiefenthaler, L; Bay, S

    2004-08-01

    Stormwater runoff is an important source of toxic substances to the marine environment, but the effects of antecedent dry period, rainfall intensity, and duration on the toxicity of runoff are not well understood. In this study, simulated rainfall was applied to parking lots to examine the toxicity of runoff while controlling for antecedent period, intensity, and duration of rainfall. Parking areas were divided into high and low use and maintained and unmaintained treatments. The parking stalls were cleaned by pressure washing at time zero. Simulated rainfall was then applied to subplots of the parking lots so that antecedent periods of 1, 2, and 3 months were achieved, and all of the runoff was collected for analysis. On a separate parking lot, rainfall was applied at a variety of intensities and durations after a 3-month antecedent period. Runoff samples were tested for toxicity using the purple sea urchin fertilization test. Every runoff sample tested was found to be toxic. Mean toxicity for the sea urchin fertilization test ranged from 2.0 to 12.1 acute toxic units. The toxicity increased rapidly during the first month but then decreased approximately to precleaning levels and remained there. No difference in toxicity was found between the different levels of use or maintenance treatments. The intensity and duration of rainfall were inversely related to degree of toxicity. For all intensities tested, toxicity was always greatest in the first sampling time interval. Dissolved zinc was most likely the primary cause of toxicity based on toxicant characterization of selected runoff samples.

  18. Effects of imidazolium-based ionic surfactants on the size and dynamics of phosphatidylcholine bilayers with saturated and unsaturated chains.

    Science.gov (United States)

    Lee, Hwankyu

    2015-07-01

    Imidazolium-based ionic surfactants of different sizes were simulated with 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), and 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) bilayers. Regardless of the phospholipid type, larger surfactants at higher concentrations more significantly insert into the bilayer and increase the bilayer-surface size, in agreement with experiments and previous simulations. Insertion of surfactants only slightly decreases the bilayer thickness, as also observed in experiments. Although the surfactant insertion and its effect on the bilayer size and thickness are similar in different types of bilayers, the volume fractions of surfactants in the bilayer are higher for DMPC bilayers than for POPC and DOPC bilayers. In particular, ionic surfactants with four hydrocarbons yield their volume fractions of 4.6% and 8.7%, respectively, in POPC and DMPC bilayers, in quantitative agreement with experimental values of ∼5% and ∼10%. Also, the inserted surfactants increase the lateral diffusivity of the bilayer, which depends on the bilayer type. These findings indicate that although the surfactant insertion does not depend on the bilayer type, the effects of surfactants on the volume fraction and bilayer dynamics occur more significantly in the DMPC bilayer because of the smaller area per lipid and shorter saturated tails, which helps explain the experimental observations regarding different volume fractions of surfactants in POPC and DMPC bilayers.

  19. How group size affects vigilance dynamics and time allocation patterns: the key role of imitation and tempo.

    Directory of Open Access Journals (Sweden)

    Pablo Michelena

    Full Text Available In the context of social foraging, predator detection has been the subject of numerous studies, which acknowledge the adaptive response of the individual to the trade-off between feeding and vigilance. Typically, animals gain energy by increasing their feeding time and decreasing their vigilance effort with increasing group size, without increasing their risk of predation ('group size effect'. Research on the biological utility of vigilance has prevailed over considerations of the mechanistic rules that link individual decisions to group behavior. With sheep as a model species, we identified how the behaviors of conspecifics affect the individual decisions to switch activity. We highlight a simple mechanism whereby the group size effect on collective vigilance dynamics is shaped by two key features: the magnitude of social amplification and intrinsic differences between foraging and scanning bout durations. Our results highlight a positive correlation between the duration of scanning and foraging bouts at the level of the group. This finding reveals the existence of groups with high and low rates of transition between activities, suggesting individual variations in the transition rate, or 'tempo'. We present a mathematical model based on behavioral rules derived from experiments. Our theoretical predictions show that the system is robust in respect to variations in the propensity to imitate scanning and foraging, yet flexible in respect to differences in the duration of activity bouts. The model shows how individual decisions contribute to collective behavior patterns and how the group, in turn, facilitates individual-level adaptive responses.

  20. Size effect in the melting and freezing behaviors of Al/Ti core-shell nanoparticles using molecular dynamics simulations

    Science.gov (United States)

    Jin-Ping, Zhang; Yang-Yang, Zhang; Er-Ping, Wang; Cui-Ming, Tang; Xin-Lu, Cheng; Qiu-Hui, Zhang

    2016-03-01

    The thermal stability of Ti@Al core/shell nanoparticles with different sizes and components during continuous heating and cooling processes is examined by a molecular dynamics simulation with embedded atom method. The thermodynamic properties and structure evolution during continuous heating and cooling processes are investigated through the characterization of the potential energy, specific heat distribution, and radial distribution function (RDF). Our study shows that, for fixed Ti core size, the melting temperature decreases with Al shell thickness, while the crystallizing temperature and glass formation temperature increase with Al shell thickness. Diverse melting mechanisms have been discovered for different Ti core sized with fixed Al shell thickness nanoparticles. The melting temperature increases with the Ti core radius. The trend agrees well with the theoretical phase diagram of bimetallic nanoparticles. In addition, the glass phase formation of Al-Ti nanoparticles for the fast cooling rate of 12 K/ps, and the crystal phase formation for the low cooling rate of 0.15 K/ps. The icosahedron structure is formed in the frozen 4366 Al-Ti atoms for the low cooling rate. Project supported by the National Natural Science Foundation of China (Grant No. 21401064), the Science & Technology Development Program of Henan Province, China (Grant No. 142300410282), and the Program of Henan Educational Committee, China (Grant No. 13B140986).

  1. Pore invasion dynamics during fluid front displacement in porous media determine functional pore size distribution and phase entrapment

    Science.gov (United States)

    Moebius, F.; Or, D.

    2012-12-01

    Dynamics of fluid fronts in porous media shape transport properties of the unsaturated zone and affect management of petroleum reservoirs and their storage properties. What appears macroscopically as smooth and continuous motion of a displacement fluid front may involve numerous rapid interfacial jumps often resembling avalanches of invasion events. Direct observations using high-speed camera and pressure sensors in sintered glass micro-models provide new insights on the influence of flow rates, pore size, and gravity on invasion events and on burst size distribution. Fundamental differences emerge between geometrically-defined pores and "functional" pores invaded during a single burst (invasion event). The waiting times distribution of individual invasion events and decay times of inertial oscillations (following a rapid interfacial jump) are characteristics of different displacement regimes. An invasion percolation model with gradients and including the role of inertia provide a framework for linking flow regimes with invasion sequences and phase entrapment. Model results were compared with measurements and with early studies on invasion burst sizes and waiting times distribution during slow drainage processes by Måløy et al. [1992]. The study provides new insights into the discrete invasion events and their weak links with geometrically-deduced pore geometry. Results highlight factors controlling pore invasion events that exert strong influence on macroscopic phenomena such as front morphology and residual phase entrapment shaping hydraulic properties after the passage of a fluid front.

  2. Studying Dynamic Processes of Nano-sized Objects in Liquid using Scanning Transmission Electron Microscopy.

    Science.gov (United States)

    Hermannsdörfer, Justus; de Jonge, Niels

    2017-02-05

    Samples fully embedded in liquid can be studied at a nanoscale spatial resolution with Scanning Transmission Electron Microscopy (STEM) using a microfluidic chamber assembled in the specimen holder for Transmission Electron Microscopy (TEM) and STEM. The microfluidic system consists of two silicon microchips supporting thin Silicon Nitride (SiN) membrane windows. This article describes the basic steps of sample loading and data acquisition. Most important of all is to ensure that the liquid compartment is correctly assembled, thus providing a thin liquid layer and a vacuum seal. This protocol also includes a number of tests necessary to perform during sample loading in order to ensure correct assembly. Once the sample is loaded in the electron microscope, the liquid thickness needs to be measured. Incorrect assembly may result in a too-thick liquid, while a too-thin liquid may indicate the absence of liquid, such as when a bubble is formed. Finally, the protocol explains how images are taken and how dynamic processes can be studied. A sample containing AuNPs is imaged both in pure water and in saline.

  3. Dependence of calculus retropulsion dynamics on fiber size and radiant exposure during Ho:YAG lithotripsy.

    Science.gov (United States)

    Lee, Ho; Ryan, Robert T; Kim, Jeehyun; Choi, Bernard; Arakeri, Navanit V; Teichman, Joel M H; Welch, A J

    2004-08-01

    During pulsed laser lithotripsy, the calculus is subject to a strong recoil momentum which moves the calculus away from laser delivery and prolongs the operation. This study was designed to quantify the recoil momentum during Ho:YAG laser lithotripsy. The correlation among crater shape, debris trajectory, laser-induced bubble and recoil momentum was investigated. Calculus phantoms made from plaster of Paris were ablated with free running Ho:YAG lasers. The dynamics of recoil action of a calculus phantom was monitored by a high-speed video camera and the laser ablation craters were examined with Optical Coherent Tomography (OCT). Higher radiant exposure resulted in larger ablation volume (mass) which increased the recoil momentum. Smaller fibers produced narrow craters with a steep contoured geometry and decreased recoil momentum compared to larger fibers. In the presence of water, recoil motion of the phantom deviated from that of phantom in air. Under certain conditions, we observed the phantom rocking towards the fiber after the laser pulse. The shape of the crater is one of the major contributing factors to the diminished recoil momentum of smaller fibers. The re-entrance flow of water induced by the bubble collapse is considered to be the cause of the rocking of the phantom.

  4. Computational Fluid Dynamics (CFD-Based Droplet Size Estimates in Emulsification Equipment

    Directory of Open Access Journals (Sweden)

    Jo Janssen

    2016-12-01

    Full Text Available While academic literature shows steady progress in combining multi-phase computational fluid dynamics (CFD and population balance modelling (PBM of emulsification processes, the computational burden of this approach is still too large for routine use in industry. The challenge, thus, is to link a sufficiently detailed flow analysis to the droplet behavior in a way that is both physically relevant and computationally manageable. In this research article we propose the use of single-phase CFD to map out the local maximum stable droplet diameter within a given device, based on well-known academic droplet break-up studies in quasi-steady 2D linear flows. The results of the latter are represented by analytical correlations for the critical capillary number, which are valid across a wide viscosity ratio range. Additionally, we suggest a parameter to assess how good the assumption of quasi-steady 2D flow is locally. The approach is demonstrated for a common lab-scale rotor-stator device (Ultra-Turrax, IKA-Werke GmbH, Staufen, Germany. It is found to provide useful insights with minimal additional user coding and little increase in computational effort compared to the single-phase CFD simulations of the flow field, as such. Some suggestions for further development are briefly discussed.

  5. A hybrid adaptive large neighborhood search algorithm applied to a lot-sizing problem

    DEFF Research Database (Denmark)

    Muller, Laurent Flindt; Spoorendonk, Simon

    This paper presents a hybrid of a general heuristic framework that has been successfully applied to vehicle routing problems and a general purpose MIP solver. The framework uses local search and an adaptive procedure which choses between a set of large neighborhoods to be searched. A mixed integer...

  6. A hybrid adaptive large neighborhood search heuristic for lot-sizing with setup times

    DEFF Research Database (Denmark)

    Muller, Laurent Flindt; Spoorendonk, Simon; Pisinger, David

    2012-01-01

    This paper presents a hybrid of a general heuristic framework and a general purpose mixed-integer programming (MIP) solver. The framework is based on local search and an adaptive procedure which chooses between a set of large neighborhoods to be searched. A mixed integer programming solver and its......, and the upper bounds found by the commercial MIP solver ILOG CPLEX using state-of-the-art MIP formulations. Furthermore, we improve the best known solutions on 60 out of 100 and improve the lower bound on all 100 instances from the literature...

  7. A Forward Algorithm for the Capacitated Lot Size Model with Stockouts.

    Science.gov (United States)

    1987-05-15

    unit produced is distributed before the second (FIF0). It is then shown that switching the distribution of theme two units from FIF0 to LIFO will...VA* ebm usla wi h k + I Iu leh i -7 Tw Wn f pwdms mm i W, ho ftM who T < k + . the snad %lInT ) k + L ftr a @iWTlu I T k I.Le whlv for V(I), V(2

  8. Remanufacturing lot-sizing under alternative perceptions of returned units' quality

    Directory of Open Access Journals (Sweden)

    Zikopoulos, C.

    2012-01-01

    Full Text Available One of the critical parameters in reverse supply chain management is the increased variability of the quality condition of used, returned products. The volatile nature of returns' quality often dictates the establishment of quality assessment procedures and the development of technologies that facilitate the fast, accurate and inexpensive classification of returns. The appropriate degree in which a firm has to allocate resources for acquiring information on the quality of returned units, naturally, depends on the anticipated improvement of recovery activities' profitability. Therefore, the quantification of the savings associated with confronting or resolving quality uncertainty is a necessary input during the determination of the proper recovery procedures' configuration. In the current paper, we study a remanufacturing system in a multi-period setting in which returns' quality information is exploited during remanufacturing planning. However, in the decision-making process, certain aspects of the problem examined, such as the quantification of shortage cost, are overlooked or simplified. The objective is to examine the advisability of acquiring advanced quality information in order to be used during sub-optimal decision-making processes, in comparison with alternative policies which do not take explicitly into account returns' quality information. Moreover, through an extensive numerical analysis we examine the implications of alternative considerations regarding returned units' quality on remanufacturing planning, lead-time and service-levels and evaluate their impact on the overall system operational cost.

  9. Polynomial Transfer Lot Sizing Techniques for Batch Processing on Consecutive Machines

    Science.gov (United States)

    1989-09-01

    batch, while still specifying sizable batches? Goldratt , the developer of OPT (Optimized Production Technology) [7; 12, pp. 692-715; 101, answered this...and Jeffrey L Rummel, Batching to Minimize Flow Times on One Machine, Management Science, 33, #6, 1987, pp. 784-799. [71 Goldratt , Eliyahu and Robert

  10. Lot-Sizing Decisions under Trade Credit Depending on the Ordering Quantity in Fuzzy Annual Demand

    Directory of Open Access Journals (Sweden)

    Chui-Yu Chiu

    2009-01-01

    Full Text Available Problem statement: In reality, there are of various products such as liquids, volatile, medicines and materials, in which the rate of deterioration is very large. However, little attention has been mentioned what the effects of deterioration occur in most inventory systems. Also, the loss of the deterioration should not be neglected as an important issue. Approach: In this study, we proposed the problem of determining the Economic Order Quantity (EOQ for exponentially deteriorating items under the conditions of permissible delay in payments. Recent researches revealed that the payment for the product must be made forthwith when the order quantity is less than the allowable delay in payments. The fixed trade credit period was permitted, or else. Therefore, we utilized the fuzzy theory to implement more considerable answers via numerical examples which were provided to illustrate the results clearly at the end of study. Results: This study discussed the optimal replenishment cycle time for an exponentially deteriorating product under conditions of permissible delay in payments to take the order quantity into account. Conclusion/Recommendations: This study presented another fuzzy environment inventory model which accounts for the permissible delay in payments offered by supplier to the retailer. From the results, it can be concluded that another point of view to decision makers in uncertainty.

  11. Correlation between the Quantifiable Parameters of Whole Solitary Pulmonary Nodules Perfusion Imaging Derived with Dynamic CT and Nodules Size

    Directory of Open Access Journals (Sweden)

    Shiyuan LIU

    2009-05-01

    Full Text Available Background and objective The solitary pulmonary nodules (SPNs is one of the most common findings on chest radiographs. The blood flow patterns of the biggest single SPNs level has been studied. This assessment may be only a limited sample of the entire region of interest (ROI and is unrepresentative of the SPNs as a volume. Ideally, SPNs volume perfusion should be measured. The aim of this study is to evaluate the correlation between the quantifiableparameters of SPNs volume perfusion imaging derived with 16-slice spiral CT and 64-slice spiral CT and nodules size. Methods Sixty-five patients with SPNs (diameter≤3 cm; 42 malignant; 12 active inflammatory; 11 benign underwent multi-location dynamic contrast material-enhanced serial CT scanning mode with stable table were performed; The mean values of valid sections were calculated, as the quantifiable parameters of volume SPNs perfusion imaging derived with16-slice spiral CT and 64-slice spiral CT. The correlation between the quantifiable parameters of SPNs volume perfusion imaging derived with 16-slice spiral CT and 64-slice spiral CT and nodules size were assessed by means of linear regression analysis. Results No significant correlations were found between the nodules size and each of the peak height (PHSPN (32.15 Hu±14.55 Hu,ratio of peak height of the SPN to that of the aorta (SPN-to-A ratio(13.20±6.18%, perfusion(PSPN (29.79±19.12 mLmin-1100 g-1 and mean transit time (12.95±6.53 s (r =0.081, P =0.419; r =0.089, P =0.487; r =0.167, P =0.077; r =0.023, P =0.880. Conclusion No significant correlations were found between the quantifiable parameters of SPNs volume perfusion imaging derived with 16-slice spiral CT and 64-slice spiral CT and nodules size.

  12. Size and diffusion phenomena of AOT/alcohol/water system in the presence of morin by dynamic light scattering.

    Science.gov (United States)

    Bhattarai, Ajaya; Wilczura-Wachnik, Hanna

    2015-01-30

    Presented paper is a continuation of our studies on morin interaction with AOT (sodium bis(2-ethylhexyl) sulfosuccinate) reversed micelles solutions in two solvents: ethanol and n-decanol. Now we focused on morin influence on size and diffusion phenomena in the system morin/solvent/AOT/water. In this paper precise measurements of dynamic light scattering (DLS) of the effects of temperature, solvents (alcohols), water on the size and diffusion of AOT reversed micelles in the morin/AOT/alcohol/water system are reported. The concentrations of AOT were varied from 0.51 to 0.78mol/L. Morin concentration in during auto-correlation function registration was not the same in each solvent because of its different solubility depending on the solvent. Water concentration in the studied systems was defined by R parameter according to relation: R=(H2O)/(AOT) and was equal 0 and 30 in ethanol, and 0 in n-decanol. DLS measurements were done at 298.15 and 308.15K. DLS experiment involved on detection two relaxation modes (fast and slow) in the systems containing AOT reversed micelles, water, morin and solvents (ethanol and n-decanol). The DLS data clearly show the solvent influence as well as morin presence on AOT reversed micelles size and consequently their diffusion coefficients. Contrary to n-decanol strong competition between morin and ethanol molecules in AOT reversed micelles palisade layer has been found. It suggests that morin molecules replaced ethanol in AOT reversed micelles and locate in their palisade layer strongly increasing AOT reversed micelles size. Furthermore, it was found a sharp increase in correlation radii of slow modes of AOT reversed micelles containing morin molecules and their diffusion coefficients diminishing.

  13. Characteristics of particle coagulation in an underground parking lot.

    Science.gov (United States)

    Zhao, Yu; Kato, Shinsuke; Zhao, Jianing

    2015-12-01

    Particles in vehicle exhaust plumes in underground parking lots have adverse health effects due to the enclosed environment in which they are released and the temperature difference between the tailpipe and ambient environment; at the same time, particle coagulation might be obvious near the tailpipe in an underground parking lot. In the present study, airflow and temperature fields were calculated using the Realizable k-ε model, and the Eulerian particle transport model was selected in the numerical simulation of particle concentration dispersion. Polydisperse thermal coagulation due to Brownian collisions was employed to calculate the particle coagulation. The results show that particle coagulation rate and half-time were significant within 1 m from the tailpipe. The variations in the particle coagulation rate and half-time were similar, but their directions were opposite. Air exhaust time was nearly four times longer than averaged half-time and 40 times longer than minimum half-time. The peak particle diameter increased approximately 1.43 times due to coagulation. A double particle concentration at the tailpipe caused the fourfold rise in the particle coagulation rate in the distance ranging less than 1 m from the tailpipe. An increase in exhaust velocity at the tailpipe could shorten the obvious range of particle coagulation along the centerline of the tailpipe from 1 to 0.8 m in the study.

  14. Subcellular Size

    Science.gov (United States)

    Marshall, Wallace F.

    2015-01-01

    All of the same conceptual questions about size in organisms apply equally at the level of single cells. What determines the size, not only of the whole cell, but of all of its parts? What ensures that subcellular components are properly proportioned relative to the whole cell? How does alteration in organelle size affect biochemical function? Answering such fundamental questions requires us to understand how the size of individual organelles and other cellular structures is determined. Knowledge of organelle biogenesis and dynamics has advanced rapidly in recent years. Does this knowledge give us enough information to formulate reasonable models for organelle size control, or are we still missing something? PMID:25957302

  15. A Hybrid Algorithm for Solving the Economic Lot and Delivery Scheduling Problem in the Common Cycle Case

    DEFF Research Database (Denmark)

    Ju, Suquan; Clausen, Jens

    2004-01-01

    The ELDSP problem is a combined lot sizing and sequencing problem. A supplier produces and delivers components of different component types to a consumer in batches. The task is to determine the cycle time, i.e. that time between deliveries, which minimizes the total cost per time unit. This incl......The ELDSP problem is a combined lot sizing and sequencing problem. A supplier produces and delivers components of different component types to a consumer in batches. The task is to determine the cycle time, i.e. that time between deliveries, which minimizes the total cost per time unit....... This includes the determination of the production sequence of the component types within each cycle. We investigate the computational behavior of two published algorithms, a heuristic and an optimal algorithm. With large number of component types, the optimal algorithm has long running times. We devise a hybrid...

  16. Various sizes of sliding event bursts in the plastic flow of metallic glasses based on a spatiotemporal dynamic model

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Jingli, E-mail: renjl@zzu.edu.cn, E-mail: g.wang@shu.edu.cn; Chen, Cun [School of Mathematics and Statistics, Zhengzhou University, Zhengzhou 450001 (China); Wang, Gang, E-mail: renjl@zzu.edu.cn, E-mail: g.wang@shu.edu.cn [Laboratory for Microstructures, Shanghai University, Shanghai 200444 (China); Cheung, Wing-Sum [Department of Mathematics, The University of HongKong, HongKong (China); Sun, Baoan; Mattern, Norbert [IFW-dresden, Institute for Complex Materials, P.O. Box 27 01 16, D-01171 Dresden (Germany); Siegmund, Stefan [Department of Mathematics, TU Dresden, D-01062 Dresden (Germany); Eckert, Jürgen [IFW-dresden, Institute for Complex Materials, P.O. Box 27 01 16, D-01171 Dresden (Germany); Institute of Materials Science, TU Dresden, D-01062 Dresden (Germany)

    2014-07-21

    This paper presents a spatiotemporal dynamic model based on the interaction between multiple shear bands in the plastic flow of metallic glasses during compressive deformation. Various sizes of sliding events burst in the plastic deformation as the generation of different scales of shear branches occurred; microscopic creep events and delocalized sliding events were analyzed based on the established model. This paper discusses the spatially uniform solutions and traveling wave solution. The phase space of the spatially uniform system applied in this study reflected the chaotic state of the system at a lower strain rate. Moreover, numerical simulation showed that the microscopic creep events were manifested at a lower strain rate, whereas the delocalized sliding events were manifested at a higher strain rate.

  17. Dynamic Electronic Dispersion Equalization in Coherent Optical Networks Using Variable-Step-Size Least-Mean-Square Algorithm

    CERN Document Server

    Li, Liang

    2016-01-01

    In coherent detection employing digital signal processing, chromatic dispersion (CD) can be compensated effectively in the electrical domain. In practical optical transport networks, the signal lightpaths between two terminal nodes can be different due to current network conditions. Accordingly, the transmission distance and the accumulated dispersion in the lightpath cannot be predicted. Therefore, the adaptive compensation of dynamic dispersion such as the use of least-mean-square (LMS) algorithm is necessary in such optical fiber networks to enable a flexible routing and switching. In this paper, we present a detailed analysis on the adaptive dispersion compensation using the LMS algorithms in coherent optical transmission networks. Numerical simulations have been carried out accordingly. It can be found that the variable-step-size LMS equalizer can achieve the adaptive CD equalization with a lower complexity, compared to the traditional LMS algorithm.

  18. Estimation of the particle size distribution of colloids from multiangle dynamic light scattering measurements with particle swarm optimization

    Directory of Open Access Journals (Sweden)

    L. A. Bermeo

    2015-04-01

    Full Text Available In this paper particle Swarm Optimization (PSO algorithms are applied to estimate the particle size distribution (PSD of a colloidal system from the average PSD diameters, which are measured by multi-angle dynamic light scattering. The system is considered a nonlinear inverse problem, and for this reason the estimation procedure requires a Tikhonov regularization method. The inverse problem is solved through several PSO strategies. The evaluated PSOs are tested through three simulated examples corresponding to polystyrene (PS latexes with different PSDs, and two experimental examples obtained by simply mixing 2 PS standards. In general, the evaluation results of the PSOs are excellent; and particularly, the PSO with the Trelea’s parameter set shows a better performance than other implemented PSOs.

  19. A hybrid algorithm for solving the economic lot and delivery scheduling problem in the common cycle case

    DEFF Research Database (Denmark)

    Clausen, Jens; Ju, S.

    2006-01-01

    The ELDSP problem is a combined lot sizing and sequencing problem. A supplier produces and delivers components of different types to a consumer in batches. The task is to determine the cycle time, i.e., the time between deliveries, which minimizes the total cost per time unit. This includes the d...... is both optimal and efficient. (c) 2005 Elsevier B.V. All rights reserved....

  20. Heterogeneity in the distribution of genetically modified and conventional oilseed rape within fields and seed lots.

    Science.gov (United States)

    Begg, Graham S; Elliott, Martin J; Cullen, Danny W; Iannetta, Pietro P M; Squire, Geoff R

    2008-10-01

    The implementation of co-existence in the commercialisation of GM crops requires GM and non-GM products to be segregated in production and supply. However, maintaining segregation in oilseed rape will be made difficult by the highly persistent nature of this species. An understanding of its population dynamics is needed to predict persistence and develop potential strategies for control, while to ensure segregation is being achieved, the production of GM oilseed rape must be accompanied by the monitoring of GM levels in crop or seed populations. Heterogeneity in the spatial distribution of oilseed rape has the potential to affect both control and monitoring and, although a universal phenomenon in arable weeds and harvested seed lots, spatial heterogeneity in oilseed rape populations remains to be demonstrated and quantified. Here we investigate the distribution of crop and volunteer populations in a commercial field before and during the cultivation of the first conventional oilseed rape (winter) crop since the cultivation of a GM glufosinate-tolerant oilseed rape crop (spring) three years previously. GM presence was detected by ELISA for the PAT protein in each of three morphologically distinguishable phenotypes: autumn germinating crop-type plants (3% GM), autumn-germinating 'regrowths' (72% GM) and spring germinating 'small-type' plants (17% GM). Statistical models (Poisson log-normal and binomial logit-normal) were used to describe the spatial distribution of these populations at multiple spatial scales in the field and of GM presence in the harvested seed lot. Heterogeneity was a consistent feature in the distribution of GM and conventional oilseed rape. Large trends across the field (50 x 400 m) and seed lot (4 x 1.5 x 1.5 m) were observed in addition to small-scale heterogeneity, less than 20 m in the field and 20 cm in the seed lot. The heterogeneity was greater for the 'regrowth' and 'small' phenotypes, which were likely to be volunteers and included most

  1. Enhanced TDMA Based Anti-Collision Algorithm with a Dynamic Frame Size Adjustment Strategy for Mobile RFID Readers

    Science.gov (United States)

    Shin, Kwang Cheol; Park, Seung Bo; Jo, Geun Sik

    2009-01-01

    In the fields of production, manufacturing and supply chain management, Radio Frequency Identification (RFID) is regarded as one of the most important technologies. Nowadays, Mobile RFID, which is often installed in carts or forklift trucks, is increasingly being applied to the search for and checkout of items in warehouses, supermarkets, libraries and other industrial fields. In using Mobile RFID, since the readers are continuously moving, they can interfere with each other when they attempt to read the tags. In this study, we suggest a Time Division Multiple Access (TDMA) based anti-collision algorithm for Mobile RFID readers. Our algorithm automatically adjusts the frame size of each reader without using manual parameters by adopting the dynamic frame size adjustment strategy when collisions occur at a reader. Through experiments on a simulated environment for Mobile RFID readers, we show that the proposed method improves the number of successful transmissions by about 228% on average, compared with Colorwave, a representative TDMA based anti-collision algorithm. PMID:22399942

  2. Enhanced TDMA Based Anti-Collision Algorithm with a Dynamic Frame Size Adjustment Strategy for Mobile RFID Readers

    Directory of Open Access Journals (Sweden)

    Kwang Cheol Shin

    2009-02-01

    Full Text Available In the fields of production, manufacturing and supply chain management, Radio Frequency Identification (RFID is regarded as one of the most important technologies. Nowadays, Mobile RFID, which is often installed in carts or forklift trucks, is increasingly being applied to the search for and checkout of items in warehouses, supermarkets, libraries and other industrial fields. In using Mobile RFID, since the readers are continuously moving, they can interfere with each other when they attempt to read the tags. In this study, we suggest a Time Division Multiple Access (TDMA based anti-collision algorithm for Mobile RFID readers. Our algorithm automatically adjusts the frame size of each reader without using manual parameters by adopting the dynamic frame size adjustment strategy when collisions occur at a reader. Through experiments on a simulated environment for Mobile RFID readers, we show that the proposed method improves the number of successful transmissions by about 228% on average, compared with Colorwave, a representative TDMA based anti-collision algorithm.

  3. Effect of Size and Surface Charge of Gold Nanoparticles on their Skin Permeability: A Molecular Dynamics Study.

    Science.gov (United States)

    Gupta, Rakesh; Rai, Beena

    2017-03-28

    Molecular level understanding of permeation of nanoparticles through human skin establishes the basis for development of novel transdermal drug delivery systems and design and formulation of cosmetics. Recent experiments suggest that surface coated nano-sized gold nanoparticles (AuNPs) can penetrate the rat and human skin. However, the mechanisms by which these AuNPs penetrate are not well understood. In this study, we have carried out coarse grained molecular dynamics simulations to explore the permeation of dodecanethiol coated neutral hydrophobic AuNPs of different sizes (2-5 nm) and surface charges (cationic and anionic) through the model skin lipid membrane. The results indicate that the neutral hydrophobic AuNPs disrupted the bilayer and entered in it with in ~200 ns, while charged AuNPs were adsorbed on the bilayer headgroup. The permeation free energy calculation revealed that at the head group of the bilayer, a very small barrier existed for neutral hydrophobic AuNP while a free energy minimum was observed for charged AuNPs. The permeability was maximum for neutral 2 nm gold nanoparticle (AuNP) and minimum for 3 nm cationic AuNP. The obtained results are aligned with recent experimental findings. This study would be helpful in designing customized nanoparticles for cosmetic and transdermal drug delivery application.

  4. Effect of Size and Surface Charge of Gold Nanoparticles on their Skin Permeability: A Molecular Dynamics Study

    Science.gov (United States)

    Gupta, Rakesh; Rai, Beena

    2017-01-01

    Molecular level understanding of permeation of nanoparticles through human skin establishes the basis for development of novel transdermal drug delivery systems and design and formulation of cosmetics. Recent experiments suggest that surface coated nano-sized gold nanoparticles (AuNPs) can penetrate the rat and human skin. However, the mechanisms by which these AuNPs penetrate are not well understood. In this study, we have carried out coarse grained molecular dynamics simulations to explore the permeation of dodecanethiol coated neutral hydrophobic AuNPs of different sizes (2–5 nm) and surface charges (cationic and anionic) through the model skin lipid membrane. The results indicate that the neutral hydrophobic AuNPs disrupted the bilayer and entered in it with in ~200 ns, while charged AuNPs were adsorbed on the bilayer headgroup. The permeation free energy calculation revealed that at the head group of the bilayer, a very small barrier existed for neutral hydrophobic AuNP while a free energy minimum was observed for charged AuNPs. The permeability was maximum for neutral 2 nm gold nanoparticle (AuNP) and minimum for 3 nm cationic AuNP. The obtained results are aligned with recent experimental findings. This study would be helpful in designing customized nanoparticles for cosmetic and transdermal drug delivery application. PMID:28349970

  5. Size-dependent dynamic stability analysis of microbeams actuated by piezoelectric voltage based on strain gradient elasticity theory

    Energy Technology Data Exchange (ETDEWEB)

    Sahmani, Saeid; Bahrami, Mohsen [Amirkabir University of Technology, Tehran (Iran, Islamic Republic of)

    2015-01-15

    In the current paper, dynamic stability analysis of microbeams subjected to piezoelectric voltage is presented in which the microbeam is integrated with piezoelectric layers on the lower and upper surfaces. Both of the flutter and divergence instabilities of microbeams with clamped-clamped and clamped-free boundary conditions are predicted corresponding to various values of applied voltage. To take size effect into account, the classical Timoshenko beam theory in conjunction with strain gradient elasticity theory is utilized to develop nonclassical beam model containing three additional internal length scale parameters. By using Hamilton's principle, the higher-order governing differential equations and associated boundary conditions are derived. Afterward, generalized differential quadrature method is employed to discretize the size-dependent governing differential equations along with clamped-clamped and clamped-free end supports. The critical piezoelectric voltages corresponding to various values dimensionless length scale parameter are evaluated and compared with those predicted by the classical beam theory. It is revealed that in the case of clamped-free boundary conditions, the both of flutter and divergence instabilities occur. However, for the clamped-clamped microbeams, only divergence instability takes place.

  6. Size and surface chemistry of nanoparticles lead to a variant behavior in the unfolding dynamics of human carbonic anhydrase

    Science.gov (United States)

    Nasir, Irem; Lundqvist, Martin; Cabaleiro-Lago, Celia

    2015-10-01

    The adsorption induced conformational changes of human carbonic anhydrase I (HCAi) and pseudo wild type human carbonic anhydrase II truncated at the 17th residue at the N-terminus (trHCAii) were studied in presence of nanoparticles of different sizes and polarities. Isothermal titration calorimetry (ITC) studies showed that the binding to apolar surfaces is affected by the nanoparticle size in combination with the inherent protein stability. 8-Anilino-1-naphthalenesulfonic acid (ANS) fluorescence revealed that HCAs adsorb to both hydrophilic and hydrophobic surfaces, however the dynamics of the unfolding at the nanoparticle surfaces drastically vary with the polarity. The size of the nanoparticles has opposite effects depending on the polarity of the nanoparticle surface. The apolar nanoparticles induce seconds timescale structural rearrangements whereas polar nanoparticles induce hours timescale structural rearrangements on the same charged HCA variant. Here, a simple model is proposed where the difference in the timescales of adsorption is correlated with the energy barriers for initial docking and structural rearrangements which are firmly regulated by the surface polarity. Near-UV circular dichorism (CD) further supports that both protein variants undergo structural rearrangements at the nanoparticle surfaces regardless of being ``hard'' or ``soft''. However, the conformational changes induced by the apolar surfaces differ for each HCA isoform and diverge from the previously reported effect of silica nanoparticles.The adsorption induced conformational changes of human carbonic anhydrase I (HCAi) and pseudo wild type human carbonic anhydrase II truncated at the 17th residue at the N-terminus (trHCAii) were studied in presence of nanoparticles of different sizes and polarities. Isothermal titration calorimetry (ITC) studies showed that the binding to apolar surfaces is affected by the nanoparticle size in combination with the inherent protein stability. 8-Anilino

  7. Parking lots owned and maintained by the U.S. Fish and Wildlife Service

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — U.S. Fish and Wildlife Service parking lot inventory includes parking lots owned and maintained by the U.S. Fish and Wildlife Service on National Wildlife Refuges,...

  8. Parking lots owned and maintained by the U.S. Fish and Wildlife Service

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — U.S. Fish and Wildlife Service parking lot inventory includes parking lots owned and maintained by the U.S. Fish and Wildlife Service on National Wildlife Refuges,...

  9. Molecular Dynamics Study on the Photothermal Actuation of a Glassy Photoresponsive Polymer Reinforced with Gold Nanoparticles with Size Effect.

    Science.gov (United States)

    Choi, Joonmyung; Chung, Hayoung; Yun, Jung-Hoon; Cho, Maenghyo

    2016-09-14

    We investigated the optical and thermal actuation behavior of densely cross-linked photoresponsive polymer (PRP) and polymer nanocomposites containing gold nanoparticles (PRP/Au) using all-atom molecular dynamics (MD) simulations. The modeled molecular structures contain a large number of photoreactive mesogens with linear orientation. Flexible side chains are interconnected through covalent bonds under periodic boundary conditions. A switchable dihedral potential was applied on a diazene moiety to describe the photochemical trans-to-cis isomerization. To quantify the photoinduced molecular reorientation and its effect on the macroscopic actuation of the neat PRP and PRP/Au materials, we characterized the photostrain and other material properties including elastic stiffness and thermal stability according to the photoisomerization ratio of the reactive groups. We particularly examined the effect of nanoparticle size on the photothermal actuation by varying the diameter of the nanofiller (10-20 Å) under the same volume fraction of 1.62%. The results indicated that the insertion of the gold nanoparticles enlarges the photostrain of the material while enhancing its mechanical stiffness and thermal stability. When the diameter of the nanoparticle reaches a size similar to or smaller than the length of the mesogen, the interfacial energy between the nanofiller and the surrounding polymer matrix does not significantly affect the alignment of the mesogens, but rather the adsorption energy at the interface generates a stable interphase layer. Hence, these improvements were more effective as the size of the gold nanoparticle decreased. The present findings suggest a wider analysis of the nanofiller-reinforced PRP composites and could be a guide for the mechanical design of the PRP actuator system.

  10. Heritage plaza parking lots improvement project- Solar PV installation

    Energy Technology Data Exchange (ETDEWEB)

    Hooks, Todd [Agua Caliente Indian Reservation, Palm Springs, CA (United States)

    2017-03-31

    The Agua Caliente Band of Cahuilla Indians (ACBCI or the “Tribe”) installed a 79.95 kW solar photovoltaic (PV) system to offset the energy usage costs of the Tribal Education and Family Services offices located at the Tribe's Heritage Plaza office building, 90I Tahquitz Way, Palm Springs, CA, 92262 (the "Project"). The installation of the Solar PV system was part of the larger Heritage Plaza Parking Lot Improvements Project and mounted on the two southern carport shade structures. The solar PV system will offset 99% of the approximately 115,000 kWh in electricity delivered annually by Southern California Edison (SCE) to the Tribal Education and Family Services offices at Heritage Plaza, reducing their annual energy costs from approximately $22,000 annually to approximately $200. The total cost of the proposed solar PV system is $240,000.

  11. 7 CFR 52.1010 - Ascertaining the grade of a lot.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Ascertaining the grade of a lot. 52.1010 Section 52.1010 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards....1010 Ascertaining the grade of a lot. The grade of a lot of the processed product covered by...

  12. Solute and solvent dynamics in confined equal-sized aqueous environments of charged and neutral reverse micelles: a combined dynamic fluorescence and all-atom molecular dynamics simulation study.

    Science.gov (United States)

    Guchhait, Biswajit; Biswas, Ranjit; Ghorai, Pradip K

    2013-03-28

    Here a combined dynamic fluorescence and all-atom molecular dynamics simulation study of aqueous pool-size dependent solvation energy and rotational relaxations of a neutral dipolar solute, C153, trapped in AOT (charged) and IGPAL (neutral) reverse micelles (RMs) at 298 K, is described. RMs in simulations have been represented by a reduced model where SPC/E water molecules interact with a trapped C153 that possesses realistic charge distributions for both ground and excited states. In large aqueous pools, measured average solvation and rotation rates are smaller for the neutral RMs than those in charged ones. Interestingly, while the measured average solvation and rotation rates increase with pool size for the charged RMs, the average rotation rates for the neutral RMs exhibit a reverse dependence. Simulations have qualitatively reproduced this experimental trend and suggested interfacial location for the solute for all cases. The origin for the subnanosecond Stokes shift dynamics has been investigated and solute-interface interaction contribution quantified. Simulated layer-wise translational and rotational diffusions of water molecules re-examine the validity of the core-shell model and provide a resolution to a debate regarding the origin of the subnanosecond solvation component in dynamic Stokes shift measurements with aqueous RMs but not detected in ultrafast IR measurements.

  13. Tracking of Vehicle Movement on a Parking Lot Based on Video Detection

    Directory of Open Access Journals (Sweden)

    Ján HALGAŠ

    2014-06-01

    Full Text Available This article deals with topic of transport vehicles identification for dynamic and static transport based on video detection. It explains some of the technologies and approaches necessary for processing of specific image information (transport situation. The paper also describes a design of algorithm for vehicle detection on parking lot and consecutive record of trajectory into virtual environment. It shows a new approach to moving object detection (vehicles, people, and handlers on an enclosed area with emphasis on secure parking. The created application enables automatic identification of trajectory of specific objects moving within the parking area. The application was created in program language C++ with using an open source library OpenCV.

  14. HyPEP FY-07 Report: Initial Calculations of Component Sizes, Quasi-Static, and Dynamics Analyses

    Energy Technology Data Exchange (ETDEWEB)

    Chang Oh

    2007-07-01

    The Very High Temperature Gas-Cooled Reactor (VHTR) coupled to the High Temperature Steam Electrolysis (HTSE) process is one of two reference integrated systems being investigated by the U.S. Department of Energy and Idaho National Laboratory for the production of hydrogen. In this concept a VHTR outlet temperature of 900 °C provides thermal energy and high efficiency electricity for the electrolysis of steam in the HTSE process. In the second reference system the Sulfur Iodine (SI) process is coupled to the VHTR to produce hydrogen thermochemically. This report describes component sizing studies and control system strategies for achieving plant production and operability goals for these two reference systems. The optimal size and design condition for the intermediate heat exchanger, one of the most important components for integration of the VHTR and HTSE plants, was estimated using an analytic model. A partial load schedule and control system was designed for the integrated plant using a quasi-static simulation. Reactor stability for temperature perturbations in the hydrogen plant was investigated using both a simple analytic method and a dynamic simulation. Potential efficiency improvements over the VHTR/HTSE plant were investigated for an alternative design that directly couples a High Temperature Steam Rankin Cycle (HTRC) to the HTSE process. This work was done using the HYSYS code and results for the HTRC/HTSE system were compared to the VHTR/HTSE system. Integration of the VHTR with SI process plants was begun. Using the ASPEN plus code the efficiency was estimated. Finally, this report describes planning for the validation and verification of the HYPEP code.

  15. Pedestrian and traffic safety in parking lots at SNL/NM : audit background report.

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, Paul Ernest

    2009-03-01

    This report supplements audit 2008-E-0009, conducted by the ES&H, Quality, Safeguards & Security Audits Department, 12870, during fall and winter of FY 2008. The study evaluates slips, trips and falls, the leading cause of reportable injuries at Sandia. In 2007, almost half of over 100 of such incidents occurred in parking lots. During the course of the audit, over 5000 observations were collected in 10 parking lots across SNL/NM. Based on benchmarks and trends of pedestrian behavior, the report proposes pedestrian-friendly features and attributes to improve pedestrian safety in parking lots. Less safe pedestrian behavior is associated with older parking lots lacking pedestrian-friendly features and attributes, like those for buildings 823, 887 and 811. Conversely, safer pedestrian behavior is associated with newer parking lots that have designated walkways, intra-lot walkways and sidewalks. Observations also revealed that motorists are in widespread noncompliance with parking lot speed limits and stop signs and markers.

  16. Heuristic for Critical Machine Based a Lot Streaming for Two-Stage Hybrid Production Environment

    Science.gov (United States)

    Vivek, P.; Saravanan, R.; Chandrasekaran, M.; Pugazhenthi, R.

    2017-03-01

    Lot streaming in Hybrid flowshop [HFS] is encountered in many real world problems. This paper deals with a heuristic approach for Lot streaming based on critical machine consideration for a two stage Hybrid Flowshop. The first stage has two identical parallel machines and the second stage has only one machine. In the second stage machine is considered as a critical by valid reasons these kind of problems is known as NP hard. A mathematical model developed for the selected problem. The simulation modelling and analysis were carried out in Extend V6 software. The heuristic developed for obtaining optimal lot streaming schedule. The eleven cases of lot streaming were considered. The proposed heuristic was verified and validated by real time simulation experiments. All possible lot streaming strategies and possible sequence under each lot streaming strategy were simulated and examined. The heuristic consistently yielded optimal schedule consistently in all eleven cases. The identification procedure for select best lot streaming strategy was suggested.

  17. Dramatic effect of pore size reduction on the dynamics of hydrogen adsorbed in metal–organic materials

    KAUST Repository

    Nugent, Patrick

    2014-07-21

    The effects of pore size reduction on the dynamics of hydrogen sorption in metal-organic materials (MOMs) were elucidated by studying SIFSIX-2-Cu and its doubly interpenetrated polymorph SIFSIX-2-Cu-i by means of sorption, inelastic neutron scattering (INS), and computational modeling. SIFSIX-2-Cu-i exhibits much smaller pore sizes, which possess high H2 sorption affinity at low loadings. Experimental H2 sorption measurements revealed that the isosteric heat of adsorption (Qst) for H2 in SIFSIX-2-Cu-i is nearly two times higher than that for SIFSIX-2-Cu (8.6 vs. 4.6 kJ mol-1). The INS spectrum for H2 in SIFSIX-2-Cu-i is rather unique for a porous material, as only one broad peak appears at low energies near 6 meV, which simply increases in intensity with loading until the pores are filled. The value for this rotational transition is lower than that in most neutral metal-organic frameworks (MOFs), including those with open Cu sites (8-9 meV), which is indicative of a higher barrier to rotation and stronger interaction in the channels of SIFSIX-2-Cu-i than the open Cu sites in MOFs. Simulations of H2 sorption in SIFSIX-2-Cu-i revealed two hydrogen sorption sites in the MOM: direct interaction with the equatorial fluorine atom (site 1) and between two equatorial fluorine atoms on opposite walls (site 2). The calculated rotational energy levels and rotational barriers for the two sites in SIFSIX-2-Cu-i are in good agreement with INS data. Furthermore, the rotational barriers and binding energies for site 2 are slightly higher than that for site 1, which is consistent with INS results. The lowest calculated transition for the primary site in SIFSIX-2-Cu is also in good agreement with INS data. In addition, this transition in the non-interpenetrating material is higher than any of the sites in SIFSIX-2-Cu-i, which indicates a significantly weaker interaction with the host as a result of the larger pore size. This journal is © the Partner Organisations 2014.

  18. Using Ansys Fluent to Study Gas-Dynamic and Thermal Processes in Small-Sized Two-Stroke Engine

    Directory of Open Access Journals (Sweden)

    S. V. Lukachev

    2014-01-01

    Full Text Available The article presents a developed and verified technique for modelling the thermal processes in the piston aero-modelling internal combustion engine (ICE of low power using modern software packages of computer-aided design and engineering analysis (CAD/CAE technologies. The solution of this problem is one of the challenges in ICE design.At the first stage a three-dimensional model of the small-sized ICE was created in the modern SolidWorks package for designing. Then an internal volume of the engine flow path was designed by means subtraction operations of volumes. The flow path of the engine was cut into nine volumes according to authors’ developed technique to prepare three-dimensional models for imposing the grid elements.Design of grid based on the Workbench platform was created in the ANSYS Meshing grid generator. When specifying the grid parameters the choice was as follows: a range of grid element sizes within 0.5 – 1.5 mm, a growth gradient of grid elements equal to 1.05, and a type of the final element is tetrahedron. For correctly working option of layer-by-layer update of grid, the grid element of 0.5 mm in size and the type of the final element being a hexahedron were specified for calculating the cylinder and sub-piston area in volume. Boundary surfaces of inlet to the flow path and working flow-out of it were defined as well. Names and boundary conditions of permeability (Interface are automatically appropriated to coinciding surfaces of various volumes.To ensure desirable accuracy of calculations the model of turbulence k-εwas chosen, which is relevant to this task. In menu of entering the boundary conditions, desirable parameters at the model borders were specified. Further, grid intersection zones were adjusted. This adjustment is necessary to have a moving grid and adjust a permeability of borders between the predicted zones. Adjusting the moving grid parameters and specifying a dynamic model of the moving grid and its key

  19. Effects of spatial size, lattice doubling and source operator on the hadron spectrum with dynamical staggered quarks

    CERN Document Server

    Bitar, K M; Gottlieb, S; Heller, U M; Kennedy, A D; Kogut, J B; Krasnitz, A; Liu, W; Ogilvie, M C; Renken, R L; Sinclair, D K; Sugar, R L; Toussaint, D; Wang, K C; Bitar, Khalil M.; Gottlieb, Steven; Ogilvie, Michael C.

    1994-01-01

    We have extended our previous study of the lattice QCD spectrum with 2 flavors of staggered dynamical quarks at $6/g^2=5.6$ and $am_q=0.025$ and 0.01 to larger lattices, with better statistics and with additional sources for the propagators. The additional sources allowed us to estimate the $\\Delta$ mass and to measure the masses of all mesons whose operators are local in time. These mesons show good evidence for flavor symmetry restoration, except for the masses of the Goldstone and non-Goldstone pions. PCAC is observed in that $m_\\pi^2 \\propto m_q$, and $f_\\pi$ is estimated. Use of undoubled lattices removes problems with the pion propagator found in our earlier work. Previously we found a large change in the nucleon mass at a quark mass of $am_q=0.01$ when we increased the spatial size from 12 to 16. No such effect is observed at the larger quark mass, $am_q=0.025$. Two kinds of wall source were used, and we have found difficulties in getting consistent results for the nucleon mass between the two sources.

  20. Size, dynamics and structure of the lesser horseshoe bat (Rhinolophus hipposideros winter aggregations in central Italy

    Directory of Open Access Journals (Sweden)

    Pierangelo Crucitti

    2002-12-01

    Full Text Available Abstract The paper presents a study regarding the aggregations of the Lesser Horseshoe bat Rhinolophus hipposideros in Latium, Central Italy, based on data collected during 27 years in natural caves (limestone and artificial buildings (abandoned mines, ancient monuments and others. Furthermore some parameters including size, dynamics, sex ratio and age structures are investigated. The number of bats that occur at the hibernacula in winter is low over the whole territory of this region, the most numerous aggregations being 18 individual bats with an average of about 4 bats/visit. In the shelters of the area, the highest numbers of R. hipposideros, a stenotherm thermophilous species, is reached at the end of January, while at the beginning of spring (April few bats are generally observed. As in many other European populations, males are more commonly represented in winter samples; some caves harbour only adult males over a long time span, about 20 years. The results would suggest that some conservation measures should be introduced to protect this widespread but uncommon and threatened species.

  1. Finite-size effects in molecular dynamics simulations: Static structure factor and compressibility. II. Application to a model krypton fluid

    Science.gov (United States)

    Salacuse, J. J.; Denton, A. R.; Egelstaff, P. A.; Tau, M.; Reatto, L.

    1996-03-01

    The method described in the preceding paper [J. J. Salacuse, A. R. Denton, and P. A. Egelstaff, preceding paper, Phys. Rev. E 53, 2382 (1996)] for computing the static structure factor S(Q) of a bulk fluid is used to analyze molecular dynamics computer simulation data for a model krypton fluid whose atoms interact via a truncated Aziz pair potential. Simulations have been carried out for two system sizes of N=706 and 2048 particles and two thermodynamic states, described by a common reduced temperature T*=1.51 and reduced densities ρ*=0.25 and 0.4. Results presented include the N-particle radial distribution function gN(r) and the bulk static structure factor S(Q). In addition we calculate the direct correlation function c(r) from the full S(Q). In comparison with corresponding predictions of the modified hypernetted chain theory, the results are generally in excellent agreement at all r and Q, to within random statistical errors in the simulation data.

  2. Bed Sediment Grain Size Distribution and Flow Dynamics of Indianhead Reservoir, St. Croix River, MN/WI

    Science.gov (United States)

    Jackson, K. J.; MacGregor, K. R.; Hornbach, D. J.

    2010-12-01

    Dams alter sediment transport and flow dynamics in rivers by acting as a physical barrier to the downstream movement of bed sediment, decreasing water velocity, and allowing suspended material to settle. The St. Croix River, a National Scenic Riverway located along the border of Minnesota and Wisconsin, is subject to such alterations. Interstate Park, located several kilometers below the St. Croix Falls Dam, is host to a large population of native mussels, including threatened and endangered species. Over the past 20 years Hornbach and others (2009) have documented a ~90% decrease in the juvenile mussel population at this site, concurrent with a decrease in river bed grain size, from mixed sand/gravel to sand. One hypothesis is that the Indianhead Reservoir above the dam may be a significant source of the fine sediment found at Interstate Park as a result of extensive reservoir infilling. Changes in dam operation to run-of-river in the last decade may also drive sand transport across the dam. In this study we focus on characterizing spatial and temporal variability in hydrology and sediment transport in the Indianhead Reservoir, the impoundment behind the St. Croix Falls Dam. Our objective is to determine if the sediment at Interstate Park could originate from the river upstream of the dam. To quantify grain size distribution at the bed, measure suspended and bedload sediment in transport across a range of water discharges, and characterize flow dynamics of Indianhead Reservoir, samples were collected across a 2 km stretch of the reservoir just above the dam in 2009 and 2010. Grab samples and gravity cores of bed sediment, suspended sediment concentration (SSC) samples, vertical water velocity profiles using an Acoustic Doppler Current Profiler (ADCP), and high resolution bathymetry readings were collected at 3 points along 13 transects. Bathymetric data show depths ranging from 2-15 m, confirming significant infilling in the last 40 years. Vertical velocity

  3. Accurate Size and Size-Distribution Determination of Polystyrene Latex Nanoparticles in Aqueous Medium Using Dynamic Light Scattering and Asymmetrical Flow Field Flow Fractionation with Multi-Angle Light Scattering

    Directory of Open Access Journals (Sweden)

    Shinichi Kinugasa

    2012-01-01

    Full Text Available Accurate determination of the intensity-average diameter of polystyrene latex (PS-latex by dynamic light scattering (DLS was carried out through extrapolation of both the concentration of PS-latex and the observed scattering angle. Intensity-average diameter and size distribution were reliably determined by asymmetric flow field flow fractionation (AFFFF using multi-angle light scattering (MALS with consideration of band broadening in AFFFF separation. The intensity-average diameter determined by DLS and AFFFF-MALS agreed well within the estimated uncertainties, although the size distribution of PS-latex determined by DLS was less reliable in comparison with that determined by AFFFF-MALS.

  4. Data Compilation for AGR-1 Baseline Compact Lot LEU01-46T-Z

    Energy Technology Data Exchange (ETDEWEB)

    Hunn, John D [ORNL; Montgomery, Fred C [ORNL; Pappano, Peter J [ORNL

    2006-08-01

    This document is a compilation of characterization data for the AGR-1 baseline compact lot LEU01-46T-Z. The compacts were produced by ORNL for the Advanced Gas Reactor Fuel Development and Qualification (AGR) program for the first AGR irradiation test train (AGR-1). This compact lot was fabricated using particle composite LEU01-46T, which was a composite of four batches of TRISO-coated 350 {micro}m diameter 19.7% low enrichment uranium oxide/uranium carbide kernels (LEUCO). The AGR-1 TRISO-coated particles consist of a spherical kernel coated with an {approx} 50% dense carbon buffer layer (100 {micro}m nominal thickness), followed by a dense inner pyrocarbon layer (40 {micro}m nominal thickness), followed by a SiC layer (35 {micro}m nominal thickness), followed by another dense outer pyrocarbon layer (40 {micro}m nominal thickness). The kernels were obtained from BWXT and identified as composite G73D-20-69302. The BWXT kernel lot G73D-20-69302 was riffled into sublots for characterization and coating by ORNL and identified as LEU01-?? (where ?? is a series of integers beginning with 01). A data compilation for the AGR-1 baseline coated particle composite LEU01-46T can be found in ORNL/TM-2006/019. The AGR-1 Fuel product Specification and Characterization Guidance (INL EDF-4380) provides the requirements necessary for acceptance of the fuel manufactured for the AGR-1 irradiation test. Section 6.2 of EDF-4380 provides the property requirements for the heat treated compacts. The Statistical Sampling Plan for AGR Fuel materials (INL EDF-4542) provides additional guidance regarding statistical methods for product acceptance and recommended sample sizes. The procedures for characterizing and qualifying the compacts are outlined in ORNL product inspection plan AGR-CHAR-PIP-05. the inspection report forms generated by this product inspection plan document the product acceptance for the property requirements listed in section 6.2 of EDF-4380.

  5. Data Compilation for AGR-1 Variant 2 Compact Lot LEU01-48T-Z

    Energy Technology Data Exchange (ETDEWEB)

    Hunn, John D [ORNL; Montgomery, Fred C [ORNL; Pappano, Peter J [ORNL

    2006-08-01

    This document is a compilation of characterization data for the AGR-1 variant 2 compact lot LEU01-48T-Z. The compacts were produced by ORNL for the Advanced Gas Reactor Fuel Development and Qualification (AGR) program for the first AGR irradiation test train (AGR-1). This compact lot was fabricated using particle composite LEU01-48T, which was a composite of three batches of TRISO-coated 350 {micro}m diameter 19.7% low enrichment uranium oxide/uranium carbide kernels (LEUCO). The AGR-1 TRISO-coated particles consist of a spherical kernel coated with an {approx} 50% dense carbon buffer layer (100 {micro}m nominal thickness), followed by a dense inner pyrocarbon layer (40 {micro}m nominal thickness), followed by a SiC layer (35 {micro}m nominal thickness), followed by another dense outer pyrocarbon layer (40 {micro}m nominal thickness). The kernels were obtained from BWXT and identified as composite G73D-20-69302. The BWXT kernel lot G73D-20-69302 was riffled into sublots for characterization and coating by ORNL and identified as LEU01-?? (where ?? is a series of integers beginning with 01). A data compilation for the AGR-1 variant 2 coated particle composite LEU01-48T can be found in ORNL/TM-2006/021. The AGR-1 Fuel Product Specification and Characterization Guidance (INL EDF-4380) provides the requirements necessary for acceptance of the fuel manufactured for the AGR-1 irradiation test. Section 6.2 of EDF-4380 provides the property requirements for the heat treated compacts. The Statistical Sampling Plan for AGR Fuel materials (INL EDF-4542) provides additional guidance regarding statistical methods for product acceptance and recommended sample sizes. The procedures for characterizing and qualifying the compacts are outlined in ORNL product inspection plan AGR-CHAR-PIP-05. The inspection report forms generated by this product inspection plan document the product acceptance for the property requirements listed in section 6.2 of EDF-4380.

  6. Data Compilation for AGR-1 Variant 1 Compact Lot LEU01-47T-Z

    Energy Technology Data Exchange (ETDEWEB)

    Hunn, John D [ORNL; Montgomery, Fred C [ORNL; Pappano, Peter J [ORNL

    2006-08-01

    This document is a compilation of characterization data for the AGR-1 variant 1 compact lot LEU01-47T-Z. The compacts were produced by ORNL for the ADvanced Gas Reactor Fuel Development and Qualification (AGR) program for the first AGR irradiation test train (AGR-1). This compact lot was fabricated using particle composite LEU01-47T, which was a composite of three batches of TRISO-coated 350 {micro}m diameter 19.7% low enrichment uranium oxide/uranium carbide kernels (LEUCO). The AGR-1 TRISO-coated particles consist of a spherical kernel coated with an {approx} 50% dense carbon buffer layer (100 {micro}m nominal thickness), followed by a dense inner pyrocarbon layer (40 {micro}m nominal thickness), followed by a SiC layer (35 {micro}m nominal thickness), followed by another dense outer pyrcoarbon layer (40 {micro}m nominal thickness). The kernels were obtained from BWXT and identified as composite G73D-20-69302. The BWXT kernel lot G73D-20-69302 was riffled into sublots for characterization and coating by ORNL and identified at LEU01-?? (where ?? is a series of integers beginning with 01). A data compilation for the AGR-1 variant 1 coated particle composite LEU01-47T can be found in ORNL/TM-2006/020. The AGR-1 Fuel Product Specification and Characterization Guidance (INL EDF-4380) provides the requirements necessary for acceptance of the fuel manufactured for the AGR-1 irradiation test. Section 6.2 of EDF-4380 provides the property requirements for the heat treated compacts. The Statistical Sampling Plan for AGR Fuel Materials (INL EDF-4542) provides additional guidance regarding statistical methods for product acceptance and recommended sample sizes. The procedures for characterizing and qualifying the compacts are outlined in ORNL product inspection plan AGR-CHAR-PIP-05. The inspection report forms generated by this product inspection plan document the product acceptance for the property requirements listed in section 6.2 of EDF-4380.

  7. A Dynamic Hashing Algorithm Suitable for Embedded System

    Directory of Open Access Journals (Sweden)

    Li Jianwei

    2013-06-01

    Full Text Available With the increasing of the data numbers, the linear hashing will be a lot of overflow blocks result from Data skew and the index size of extendible hash will surge so as to waste too much memory. This lead to the above two Typical Dynamic hashing algorithm don’t suitable for embedded system that need certain real-time requirements and memory resources are very scarce. To solve this problem, this paper was proposed a dynamic hashing algorithm suitable for embedded system combining with the characteristic of extendible hashing and linear hashing.it is no overflow buckets and the index size is proportional to the adjustment number.

  8. Thirteen years of Aeolian dust dynamics in a desert region (Negev desert, Israel): analysis of horizontal and vertical dust flux, vertical dust distribution and dust grain size

    NARCIS (Netherlands)

    Offer, Z.Y.; Goossens, D.

    2004-01-01

    At Sede Boqer (northern Negev desert, Israel), aeolian dust dynamics have been measured during the period 1988–2000. This study focuses on temporal records of the vertical and horizontal dust flux, the vertical distribution of the dust particles in the atmosphere, and the grain size of the particles

  9. Effects of the molecular weight and the valency of guest-modified poly(ethylene glycol)s on the stability, size and dynamics of supramolecular nanoparticles

    NARCIS (Netherlands)

    Stoffelen, C.; Staltari-Ferraro, E.; Huskens, Jurriaan

    2015-01-01

    The influence of the polymer length and the valency of guest-modified poly(ethylene glycol) (PEG) on the stability, size tunability and formation dynamics of supramolecular nanoparticles (SNPs) has been studied. SNPs were formed by molecular recognition between multi- and monovalent supramolecular

  10. Molecular characterisation of soybean polysaccharides: an approach by size exclusion chromatography, dynamic and static light scattering methods.

    Science.gov (United States)

    Wang, Qi; Huang, Xiaoqing; Nakamura, Akihiro; Burchard, Walther; Hallett, F Ross

    2005-12-12

    Water soluble polysaccharides from soybean (SSPS) have a pectin-like structure and are used as stabilisers in acidified beverages. Physicochemical properties such as structure, molecular weight and shape or conformation are primary factors controlling their functional properties. Two soybean polysaccharides, a native SSPS and a modified SSPS treated with beta-(1-->4)-D-galactosidase (GPase/SSPS) were studied by dynamic and static light scattering (DLS, SLS) and size exclusion chromatography (SEC). Consecutive filtrations using a range of membrane pore size removed a small fraction of macromolecular aggregates from dilute polysaccharide solutions with relatively little effect on the major component molecules as monitored by DLS and SEC measurements. Access to aggregate-free dilute solutions of SSPS and GPase/SSPS allowed the direct measurement of molecular characteristics. SLS results showed that SSPS had a weight average molecular weight of (645+/-11)x 10(3)g/mol and a radius of gyration, Rg, of (23.5+/-2.8)nm. By comparing R(g) with the hydrodynamic radius, Rh (21.1+/-0.5 nm) obtained from DLS, the structural parameter rho (Rg/Rh) was found to be 1.1, suggesting that SSPS has an overall globular shape due to a highly branched structure. The modified SSPS had a significantly lower molecular weight (287+/-18)x 10(3)g/mol but a similar radius of gyration (23.2+/-1.7 nm). The structure parameter rho of GPase/SSPS was higher (rho=1.3) because of a smaller hydrodynamic radius (17.7+/-1.8 nm). This suggests that GPase/SSPS has a much less branched structure yet still differs significantly from a linear random coil conformation (rho=1.7-2.0). The results derived from SLS and DLS are in agreement with the conclusions obtained from a chemical analysis where the reduction of molecular weight of GPase/SSPS was caused by the cleavage of galactan side chains.

  11. Egg and a lot of science: an interdisciplinary experiment

    Directory of Open Access Journals (Sweden)

    M. C. Gayer

    2014-08-01

    Full Text Available Egg and a lot of science: an interdisciplinary experimentGayer, M.C.1,2;Rodrigues, D.T.1,2; Escoto, D.F.1; Denardin, E.L.G.2, Roehrs, R.1,21Interdisciplinary Research Group on Teaching Practice, Graduate Program in Biochemistry, Unipampa, RS, Brazil2Laboratory of Physicochemical Studies and Natural Products, Post Graduate Program in Biochemistry, Unipampa, RS, BrazilIntroduction: How to tell if an egg is rotten? How to calculate the volume of an egg? Because the rotten egg float? Why has this characteristic rotten egg smell? Because the gray-green color is formed on the surface of the cooked egg yolk? These issues are commonplace and unnoticed in day-to-day. Our grandmothers know how to tell if an egg is rotten or not, you just put the egg in a glass of water. If it is rotten floating, sinking is good. But why this happens? That they do not know answer. With only one egg chemical reactions work, macromolecules (proteins, density, membranes and conservation of matter. Hydrogen sulphide is responsible for the aroma of a freshly cooked egg. This gas as they break down the molecules of albumin, a protein present in the egg is formed. The color comes from a sulfide precipitation, this time with the Fe2+ ion contained in the yolk (Fe2+ + S2  FeS. The use of simple and easy to perform experiments, correlating various knowledge proves a very useful tool in science education. Objectives: Develop multidisciplinary learning contents through the problem. Materials and methods: The teacher provides students with a boiled egg, salt, a syringe and a cup, a plate and water. The teacher lays the aforementioned issues for students and allows them to exchange information with each other, seeking answers through experimentation. Results and discussion: Students engaged with the activity and interaction of groups in order to solve the proposed problem. Still, through trial and error have sought in various ways to find the answers. This tool takes the student to

  12. Simultaneous Optimal Placement of Distributed Generation and Electric Vehicle Parking Lots Based on Probabilistic EV Model

    Directory of Open Access Journals (Sweden)

    M.H. Amini

    2013-12-01

    Full Text Available High penetration of distributed generations and the increasing demand for using electric vehicles provide a lot of issues for the utilities. If these two effective elements of the future power system are used in an unscheduled manner, it may lead to the loss increment in distribution networks, dramatically. In this paper, the simultaneous allocation of distributed generations (DGs and electric vehicles (EVs parking lots has been studied in a radial distribution network. A distribution network which is upgrading and equipped with DGs is considered and these resources' optimal placement is achieved in interaction with the EV parking lots in order to minimize the power distribution network loss. The proposed method considers not only the loss minimization but also the reliability of the parking lot from the investor's point of view. The output of this model is the daily electricity demand of parking lot. The proposed method includes two levels. At the first level of the proposed algorithm, the parking lot investor makes decision and selects three candidate buses for each parking based on three main criteria. After making decision by the parking lot investor, the candidate buses are introduced to the distribution network operator. At the second stage, the distribution network operator allocates the DGs and EV parking lots based on the candidate buses of investor in order to achieve the minimum loss of the distribution network. Finally, the effectiveness of the proposed method is evaluated by allocating of DGs and EV parking lots simultaneously on the standard distribution test system.

  13. 7 CFR 51.2284 - Size classification.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Size classification. 51.2284 Section 51.2284... Size classification. The following classifications are provided to describe the size of any lot... shall conform to the requirements of the specified classification as defined below: (a) Halves....

  14. The Dynamic Tracking Acquisition System for DAΦNE esize="-1">+/esize="-1">--Collider

    CERN Document Server

    Drago, A; Serio, M

    2001-01-01

    The goal of this paper is to describe the dynamic tracking acquisition system implemented for the DAΦNE e+/e--collider at LNF/INFN. We have been using the system since last year and it has been possible to collect useful information to tune-up the machine. A four-button BPM is used to obtain the sum and difference signals in both the transverse planes. The signals are acquired and recorded by a LeCroy LC574A oscilloscope with the capability to sample the input waveforms using a beam synchronous external clock generated by the DaFne Timing System. The start of acquisition is synchronised to a horizontal kick given by an injection kicker. After capturing up to 5000 consecutive turns, data are sent through a GPIB interface to a PC, for processing, presentation and storage. A calibration routine permits to convert voltage data to millimeters values. The acquisition and control program first shows the decay time in number of turns. Then it draws a trajectory in the phase space (position and speed) in bot...

  15. NMR studies of organic liquids confined in mesoporous materials: (1) Pore size distribution and (2) Phase behaviour and dynamic studies in restricted geometry

    Energy Technology Data Exchange (ETDEWEB)

    Foerland, Kjersti

    2005-07-01

    In the thesis NMR spectroscopy is used for studying liquids confined in various porous materials. In the first part, pore size distributions of mesoporous silicas and controlled pore glasses were determined by measuring the 1H NMR signal from the non-frozen fraction of the confined liquid as a function of temperature, using benzene, acetonitrile and HMDS as probe molecules. In the second part, the molecular dynamics of acetonitrile, hexamethyldisilane, cyclohexane and cyclopentane confined in mesoporous materials were studied as a function of temperature. 6 papers are included with titles: 1) Pore-size determination of mesoporous materials by 1H NMR spectroscopy. 2) Pore-size distribution in mesoporous materials as studied by 1H NMR. 3) Dynamic 1H and 2H NMR investigations of acetonitrile confined in porous silica. 4) NMR investigations of hexamethyldisilane confined in controlled pore glasses: Pore size distribution and molecular dynamics studies. 5) 1H and 2H NMR studies of cyclohexane nano crystals in controlled pore glasses. 6) 1H NMR relaxation and diffusion studies of cyclohexane and cyclopentane confined in MCM-41.

  16. Forming of the dynamics of the changes in convergent production system depending on size of production party

    Directory of Open Access Journals (Sweden)

    Bożena Zwolińska

    2017-09-01

    Full Text Available Background: In terms of Lean Six Sigma, the whole process focuses on clients and their needs. Existence of a client generates the supply of companies. Extended customization has a negative impact for a structure of the production system. Dynamics of changes and no predictability of system’s state in time t+1 lead to increase of the operational costs. It particularly affects those companies which are producing goods using MTO (make – to – order method in short series. The goal of this article is to establish a mathematical model defining how the structure of a production system is subject to change depending on the volume of the production batch for a production system in accordance with MTO. Furthermore pilot calculations have been presented which determine the probability value, how subsequent random variables are contained within three standard deviations (±3δ from the determined expected value (ET for the entire production structure. Months of analysis and research on introducing selected lean toolbox components to a polish company from the small and medium enterprises sector resulted in the models presented in the article. The production structure of the discussed actual facility is complex and is of converged nature in accordance with MTO, while the final products are manufactured in short production series with a relatively wide customization options. Materials and results: Wrought models consider theories of  Klir and Maserovicz [Mesarovic 1964] and also theory of mass operation (one of the probability areas.  In the article there are results from two models which are fundamental in defining problems in logistics engineering and production in scientific research. Important attribute of presented models is a fact that they consider relations between variables in a structure of consecutive processes and also consider relations between a size of production party and a real object. Presented models are not only theoretical coverage

  17. 7 CFR 56.37 - Lot marking of officially identified shell eggs.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Lot marking of officially identified shell eggs. 56.37... (CONTINUED) VOLUNTARY GRADING OF SHELL EGGS Grading of Shell Eggs Identifying and Marking Products § 56.37 Lot marking of officially identified shell eggs. Shell eggs identified with the grademarks shown...

  18. Identification of Anguina funesta from annual ryegrass (Lolium multiflorum) seed lots in Oregon

    Science.gov (United States)

    In 2010, seed galls containing Anguina sp. were isolated from 14 annual ryegrass (Lolium multiflorum) seed lots submitted for phytosanitary testing. To identify the species present, the ITS1 region of the ribosomal DNA of the nematodes from the seed lots was analyzed using a PCR-RFLP method (11). ...

  19. Statistical assessment of DNA extraction reagent lot variability in real-time quantitative PCR

    Science.gov (United States)

    Bushon, R.N.; Kephart, C.M.; Koltun, G.F.; Francy, D.S.; Schaefer, F. W.; Lindquist, H.D. Alan

    2010-01-01

    Aims: The aim of this study was to evaluate the variability in lots of a DNA extraction kit using real-time PCR assays for Bacillus anthracis, Francisella tularensis and Vibrio cholerae. Methods and Results: Replicate aliquots of three bacteria were processed in duplicate with three different lots of a commercial DNA extraction kit. This experiment was repeated in triplicate. Results showed that cycle threshold values were statistically different among the different lots. Conclusions: Differences in DNA extraction reagent lots were found to be a significant source of variability for qPCR results. Steps should be taken to ensure the quality and consistency of reagents. Minimally, we propose that standard curves should be constructed for each new lot of extraction reagents, so that lot-to-lot variation is accounted for in data interpretation. Significance and Impact of the Study: This study highlights the importance of evaluating variability in DNA extraction procedures, especially when different reagent lots are used. Consideration of this variability in data interpretation should be an integral part of studies investigating environmental samples with unknown concentrations of organisms. ?? 2010 The Society for Applied Microbiology.

  20. Design Schematics for a Sustainable Parking Lot: Building 2-2332, ENRD Classroom, Fort Bragg, NC

    Science.gov (United States)

    2003-06-01

    Museum of Science and Industry..................................... 20 13 Bioretention schematic design for parking lots...paving surfaces • use bioretention areas to manage and treat stormwater • encourage shared parking and maximum use of existing pavement • shade...have overflow inlets. Figure 13 shows a design for a parking lot bioretention system provided by the Stormwater Manger’s Resource Center. Figure

  1. Correlation between the quantifiable parameters of blood flow pattern derived with dynamic CT in maliagnant solitary pulmonary nodules and tumor size

    Directory of Open Access Journals (Sweden)

    Chenshi ZHANG

    2008-02-01

    Full Text Available Background and Objective The solitary pulmonary nodules (SPNs is one of the most common findings on chest radiographs. It becomes possible to provide more accurately quantitative information about blood flow patterns of solitary pulmonary nodules (SPNs with multi-slice spiral computed tomography (MSCT. The aim of this study is to evaluate the correlation between the quantifiable parameters of blood flow pattern derived with dynamic CT in maliagnant solitary pulmonary nodules and tumor size. Methods 68 patients with maliagnant solitary pulmonary nodules (SPNs (diameter <=4 cmunderwent multi-location dynamic contrast material-enhanced (nonionic contrast material was administrated via the antecubital vein at a rate of 4mL/s by an autoinjector, 4*5mm or 4*2.5mm scanning mode with stable table were performed. serial CT. Precontrast and postcontrast attenuation on every scan was recorded. Perfusion (PSPN, peak height (PHSPNratio of peak height of the SPN to that of the aorta (SPN-to-A ratioand mean transit time(MTT were calculated. The correlation between the quantifiable parameters of blood flow pattern derived with dynamic CT in maliagnant solitary pulmonary nodules and tumor size were assessed by means of linear regression analysis. Results No significant correlations were found between the tumor size and each of the peak height (PHSPN ratio of peak height of the SPN to that of the aorta (SPN-to-A ratio perfusion(PSPNand mean transit time (r=0.18, P=0.14; r=0.20,P=0.09; r=0.01, P=0.95; r=0.01, P=0.93. Conclusion No significant correlation is found between the tumor size and each of the quantifiable parameters of blood flow pattern derived with dynamic CT in maliagnant solitary pulmonary nodules.

  2. Complementary study of molecular dynamics and domain sizes in heterogenous nanocomposites PBT/DA-C{sub 60} and PBT/TCNEO-C{sub 60}

    Energy Technology Data Exchange (ETDEWEB)

    Woźniak-Braszak, A., E-mail: abraszak@amu.edu.pl; Baranowski, M.; Jurga, K.; Hołderna-Natkaniec, K. [High Pressure Physics Division, Department of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznan (Poland); Jurga, J. [Polymer Processing Division, Institute of Materials Technology, Poznań University of Technology, Piotrowo 3, 61-138 Poznan (Poland); Brycki, B. [Laboratory of Microbiocides Chemistry, Department of Chemistry, Adam Mickiewicz University, Grunwaldzka 6, 60-780 Poznan (Poland); Mikuli, E. [Department of Chemistry, Jagiellonian University, Ingardena Street 9, Krakow (Poland)

    2014-05-28

    A comprehensive study of molecular dynamics and structure in new heterogenous nanocomposites based on poly(butylene terephthalate) and nanoparticles C{sub 60} modified by n-decylamine or tetracyanoethylene oxide has been performed. The domain structure of new nanocomposites has been investigated by Fourier transform infrared spectroscopy, wide-angle X-ray scattering, and differential scanning calorimetry techniques. Solid-state {sup 1}H NMR techniques were used to study molecular dynamics and domain sizes in new nanocomposites. Information about the electronic properties of these nanocomposites was obtained by means of electron paramagnetic resonance method. It was shown that the structure and molecular dynamics of new nanocomposites were strongly dependent on the properties and concentration of fullerene derivates.

  3. Choosing a Cluster Sampling Design for Lot Quality Assurance Sampling Surveys.

    Science.gov (United States)

    Hund, Lauren; Bedrick, Edward J; Pagano, Marcello

    2015-01-01

    Lot quality assurance sampling (LQAS) surveys are commonly used for monitoring and evaluation in resource-limited settings. Recently several methods have been proposed to combine LQAS with cluster sampling for more timely and cost-effective data collection. For some of these methods, the standard binomial model can be used for constructing decision rules as the clustering can be ignored. For other designs, considered here, clustering is accommodated in the design phase. In this paper, we compare these latter cluster LQAS methodologies and provide recommendations for choosing a cluster LQAS design. We compare technical differences in the three methods and determine situations in which the choice of method results in a substantively different design. We consider two different aspects of the methods: the distributional assumptions and the clustering parameterization. Further, we provide software tools for implementing each method and clarify misconceptions about these designs in the literature. We illustrate the differences in these methods using vaccination and nutrition cluster LQAS surveys as example designs. The cluster methods are not sensitive to the distributional assumptions but can result in substantially different designs (sample sizes) depending on the clustering parameterization. However, none of the clustering parameterizations used in the existing methods appears to be consistent with the observed data, and, consequently, choice between the cluster LQAS methods is not straightforward. Further research should attempt to characterize clustering patterns in specific applications and provide suggestions for best-practice cluster LQAS designs on a setting-specific basis.

  4. Eco-evolutionary dynamics in urbanized landscapes: evolution, species sorting and the change in zooplankton body size along urbanization gradients.

    Science.gov (United States)

    Brans, Kristien I; Govaert, Lynn; Engelen, Jessie M T; Gianuca, Andros T; Souffreau, Caroline; De Meester, Luc

    2017-01-19

    Urbanization causes both changes in community composition and evolutionary responses, but most studies focus on these responses in isolation. We performed an integrated analysis assessing the relative contribution of intra- and interspecific trait turnover to the observed change in zooplankton community body size in 83 cladoceran communities along urbanization gradients quantified at seven spatial scales (50-3200 m radii). We also performed a quantitative genetic analysis on 12 Daphnia magna populations along the same urbanization gradient. Body size in zooplankton communities generally declined with increasing urbanization, but the opposite was observed for communities dominated by large species. The contribution of intraspecific trait variation to community body size turnover with urbanization strongly varied with the spatial scale considered, and was highest for communities dominated by large cladoceran species and at intermediate spatial scales. Genotypic size at maturity was smaller for urban than for rural D. magna populations and for animals cultured at 24°C compared with 20°C. While local genetic adaptation likely contributed to the persistence of D. magna in the urban heat islands, buffering for the phenotypic shift to larger body sizes with increasing urbanization, community body size turnover was mainly driven by non-genetic intraspecific trait change.This article is part of the themed issue 'Human influences on evolution, and the ecological and societal consequences'.

  5. Dynamics of aggregate size and shape properties under sequenced flocculation in a turbulent Taylor-Couette reactor.

    Science.gov (United States)

    Guérin, Léa; Coufort-Saudejaud, Carole; Liné, Alain; Frances, Christine

    2017-04-01

    This paper concerns experimental investigation of the sequenced flocculation of latex particles in a Taylor-Couette reactor. The aim of this work was to investigate the evolution of both the size and the shape of aggregates under sequenced hydrodynamics. A number of studies have focused on the evolution of the aggregate size or size distribution during steps of growth-breakage-regrowth, but aggregates generally experience steps of breakage-regrowth on repeated occasions in real operating conditions (passages near the impeller or during the transfer processes, for example). The experiments conducted in this work consisted thus of an alternation of six steps with alternately low and high shear rates under turbulent conditions. The particle size distributions were monitored throughout the sequencing, and the circularity and convexity (shape parameters) distributions were measured, enabling a more precise description of the entire floc population, rather than a fractal dimension. While the aggregate size distribution was clearly controlled by hydrodynamics, the shape distributions continuously evolved during the sequencing. The main new finding of our work notes the independence between the aggregate shape and hydrodynamics. Indeed, after multiples steps of breakage-regrowth, regardless of the aggregate size distribution and hydrodynamics, the aggregate shape seemed to reach a unique steady-state morphological distribution.

  6. QTL mapping in multiple populations and development stages reveals dynamic quantitative trait loci for fruit size in cucumbers of different market classes.

    Science.gov (United States)

    Weng, Yiqun; Colle, Marivi; Wang, Yuhui; Yang, Luming; Rubinstein, Mor; Sherman, Amir; Ophir, Ron; Grumet, Rebecca

    2015-09-01

    QTL analysis in multi-development stages with different QTL models identified 12 consensus QTLs underlying fruit elongation and radial growth presenting a dynamic view of genetic control of cucumber fruit development. Fruit size is an important quality trait in cucumber (Cucumis sativus L.) of different market classes. However, the genetic and molecular basis of fruit size variations in cucumber is not well understood. In this study, we conducted QTL mapping of fruit size in cucumber using F2, F2-derived F3 families and recombinant inbred lines (RILs) from a cross between two inbred lines Gy14 (North American picking cucumber) and 9930 (North China fresh market cucumber). Phenotypic data of fruit length and diameter were collected at three development stages (anthesis, immature and mature fruits) in six environments over 4 years. QTL analysis was performed with three QTL models including composite interval mapping (CIM), Bayesian interval mapping (BIM), and multiple QTL mapping (MQM). Twenty-nine consistent and distinct QTLs were detected for nine traits from multiple mapping populations and QTL models. Synthesis of information from available fruit size QTLs allowed establishment of 12 consensus QTLs underlying fruit elongation and radial growth, which presented a dynamic view of genetic control of cucumber fruit development. Results from this study highlighted the benefits of QTL analysis with multiple QTL models and different mapping populations in improving the power of QTL detection. Discussion was presented in the context of domestication and diversifying selection of fruit length and diameter, marker-assisted selection of fruit size, as well as identification of candidate genes for fruit size QTLs in cucumber.

  7. Evaluation of Radon Pollution in Underground Parking Lots by Discomfort Index

    Directory of Open Access Journals (Sweden)

    AH Bu-Olayan

    2016-06-01

    Full Text Available Introduction Recent studies of public underground parking lots showed the influence of radon concentration and the probable discomfort caused by parking cars. Materials and Methods Radon concentration was measured in semi-closed public parking lots in the six governorates of Kuwait, using Durridge RAD7radon detector (USA. Results The peak radon concentration in the parking lots of Kuwait governorates was relatively higher during winter (63.15Bq/m3 compared to summer (41.73 Bq/m3. Radon in the evaluated parking lots revealed a mean annual absorbed dose (DRn: 0.02mSv/y and annual effective dose (HE: 0.06mSv/y.  Conclusion This study validated the influence of relative humidity and temperature as the major components of discomfort index (DI. The mean annual absorbed and effective dose  of radon in the evaluated parking lots were found below the permissible limits. However, high radon DRn and HE were reported when the assessment included the parking lots, the surrounding residential apartments, and office premises. Furthermore, the time-series analysis indicated significant variations of the seasonal and site-wise distribution of radon concentrations in the indoor evaluated parking lots of the six Kuwait governorates

  8. A comprehensive mathematical model for hybrid flexible flowshop lot streaming problem

    Directory of Open Access Journals (Sweden)

    Fantahun M. Defersha

    2011-04-01

    Full Text Available Lot streaming is a technique of splitting production lots into smaller sublots in a multi-stage manufacturing systems so that operations of a given lot can be overlapped. This technique can reduce manufacturing makespan and is an effective tool for time-based manufacturing strategy. Several research articles appeared in literature to solve this problem and most of these studies are limited to pure flowshop environments where there is only a single machine in each stage. On the other hand, because of the applicability of hybrid flowshops in different manufacturing settings, the scheduling of these types of shops is also extensively studied by several authors. However, the issue of lot streaming in hybrid flowshop environment is not well studied. In this paper, we aim to initiate research in bridging the gap between the research efforts in flowshop lot streaming and hybrid flowshop scheduling. We present a comprehensive mathematical model for scheduling flexible hybrid flowshop with lot streaming. Numerical example demonstrated that lot streaming can result in larger makespan reduction in hybrid flowshop where there is a limited research than in pure flowshop where research is abundant.

  9. Behind every great detector, there are lots of great people!

    CERN Multimedia

    Pauline Gagnon

    Remember all these pictures you sent out last year for a poster project? At last, after a few unsuccessful attempts, the "ATLAS People poster" is out. This mosaic picture was built out of the 600 or so photos collected for the poster, including the 120 or so portraits taken by Claudia Marcelloni di Oliveira. Each photo appears roughly 15 times to fill the 9000 pixels of the poster. Sorry: there is no key to help you locate your photo but you can buy a copy of the poster at the ATLAS secretariat to stare at it as much as you like. They are on sale for only 4 CHF (or 3 CHF a piece for 10 or more copies). I hope many of you will display it in your office and at your home institute to give a sense of the size of the human effort involved to build this experiment and make it a bit less anonymous. The new poster showing the faces of many of those who have contributed to the making of the ATLAS detector.

  10. Microchannel-induced change of chemical wave propagation dynamics: importance of ratio between the inlet and the channel sizes.

    Science.gov (United States)

    Nabika, Hideki; Sato, Mami; Unoura, Kei

    2013-01-07

    The ability to control chemical wave propagation dynamics could stimulate the science and technology of artificial and biological spatiotemporal oscillating phenomena. In contrast to the conventional chemical approaches to control the wave front dynamics, here we report a physical approach to tune the propagation dynamics under the same chemical conditions. By using well-designed microchannels with different channel widths and depths, the propagation velocity was successfully controlled based on two independent effects: (i) a transition in the proton diffusion mode and (ii) the formation of a slanted wave front. Numerical analysis yielded a simple relationship between the propagation velocity and the microchannel configuration, which offers a simple and general way of controlling chemical wave propagation.

  11. Evaluation of Radon Pollution in Underground Parking Lots by Discomfort Index

    OpenAIRE

    AH Bu-Olayan; BV Thomas

    2016-01-01

    Introduction Recent studies of public underground parking lots showed the influence of radon concentration and the probable discomfort caused by parking cars. Materials and Methods Radon concentration was measured in semi-closed public parking lots in the six governorates of Kuwait, using Durridge RAD7radon detector (USA). Results The peak radon concentration in the parking lots of Kuwait governorates was relatively higher during winter (63.15Bq/m3) compared to summer (41.73 Bq/m3). Radon in ...

  12. Influence of season, size and sex on the dynamic of gill metazoan parasite infesting the Balistes capriscus (Teleostei: Balistidae of the Gulf of Gabès (Tunisia

    Directory of Open Access Journals (Sweden)

    Hichem Kacem

    2015-04-01

    Full Text Available Objective: To investigate the effects of season, size and sex on the dynamic of gill metazoan parasite infesting the Balistes capriscus (Gmelin, 1788 (Teleostei: Balistidae (B. capriscus of the Gulf of Gabès (Southern Tunisia, Central Mediterranean Sea. Methods: A parasitological survey of the grey triggerfish B. capriscus from the Gulf of Gabès (Southern Tunisia, Central Mediterranean Sea was conducted monthly from June 2011 to June 2012. A total of 1080 fish were collected from commercial catches by pelagic trawl net at different fishing ports at Chebba (34°14' N, 11°06' E, Kerkennah (34°45' N, 11°17' E and Zarzis (33°41' N, 11°48' E. The weight, size, sex, date and area of capture of each specimen were recorded. Then, B. capriscus was examined to search for ectoparasites. For each parasite species, parasitological indices were calculated. Results: The parasite species are indentified as two copepods: Naobranchia variabilis, Taneacanthus ballistae and a monogenean: Ancyrocephalus balisticus. The parasitological indices depend significantly on seasonality; the highest prevalence of Naobranchia variabilis, Taneacanthus ballistae and Ancyrocephalus balisticus (28.89%, 35.93% and 55.56% respectively was recorded during summer season (June–August, while the lowest prevalence of each (6.3%, 4.44%, 8.15% recorded during winter season (December–February. Furthermore the parasitological indices depend significantly on the host size but not on host sex. Conclusions: Our data suggest that the dynamic of gill metazoan parasite infesting B. capriscus is a result of a complex of biotic and abiotic factors. It is the first study on the effects of season, size and sex on the dynamic of gill metazoan parasite infesting B. capriscus (Teleostei: Balistidae of the Gulf of Gabès (Southern Tunisia, Central Mediterranean Sea.

  13. Dying Stars Indicate Lots of Dark Matter in Giant Galaxy

    Science.gov (United States)

    1994-04-01

    nebulae at once. In view of the very long exposure times needed, this is an absolute must in order to perform these observations within the available telescope time. Before the observations can begin, the exact positions of the planetary nebulae are measured. A metal mask is then prepared with holes that permit the light from these objects to pass into EMMI, but at the same time blocks most of the much brighter, disturbing light emitted the by Earth's atmosphere. With an additional optical filter, all but the green light is effectively filtered out; this further ``removes'' unwanted light and improves the chances of effective registration of the faint light from the planetary nebulae in NGC 1399. VELOCITIES OF PLANETARY NEBULAE IN NGC 1399 The careful preparations paid off and this observational strategy was successful. During two of the allocated nights (the third was lost due to bad weather), the Australian observers (Magda Arnaboldi and Ken Freeman) were able for the first time to measure individual velocities for 37 planetary nebulae in NGC 1399. Some of these are indicated on the picture that accompanies this Press Release. The difficulty of this observation is illustrated by the fact that in order to catch enough light from these faint objects, the total exposure time was no less than 5 hours and only one field on either side of the galaxy could be observed per night. Already at the telescope the astronomers realised that the new results are very exciting; this was fully confirmed by the following long and complicated process of data reduction. In fact, although the inner parts of this galaxy rotate quite slowly, the planetary nebulae in the outer regions are in rapid motion and clearly indicate a fast rotation of these parts of the galaxy. This new observation is just as expected from the above described theory for the formation of giant galaxies and therefore provides very strong support for this theory. LOTS OF DARK MATTER IN NGC 1399 Perhaps the most exciting

  14. Dust Dynamics in Protoplanetary Disk Winds Driven by Magneto-Rotational Turbulence: A Mechanism for Floating Dust Grains with Characteristic Size

    CERN Document Server

    Miyake, Tomoya; Inutsuka, Shu-ichiro

    2015-01-01

    We investigate the dynamics of dust grains with various sizes in protoplanetary disk winds driven by magnetorotational turbulence, by simulating the time evolution of the dust grain distribution in the vertical direction. Small dust grains, which are well coupled to the gas, are dragged upward with the upflowing gas, while large grains remain near the midplane of a disk. Intermediate--size grains float at several scale heights from the midplane in time-averated force balance between the downward gravity and the upward gas drag. For the minimum mass solar nebula at 1 AU, dust grains with size of 20 -- 40 $\\mu m$ float at 5-10 scale heights from the midplane. Considering the dependence on the distance from the central star, smaller-size grains remain only in an outer region of the disk, while larger-size grains are distributed in a broader region. This implies that the dust depletion is expected to take place in small-to-large and inside-out manners. We also discuss the implication of our result to the observat...

  15. The 'Thinking a Lot' Idiom of Distress and PTSD: An Examination of Their Relationship among Traumatized Cambodian Refugees Using the 'Thinking a Lot' Questionnaire

    NARCIS (Netherlands)

    Hinton, D.E.; Reis, R.; de Jong, J.

    2015-01-01

    "Thinking a lot" (TAL)—also referred to as "thinking too much"—is a key complaint in many cultural contexts, and the current article profiles this idiom of distress among Cambodian refugees. The article also proposes a general model of how TAL generates various types of distress that then cause PTSD

  16. Lots of Physicists Are Nervous about the Speed of Light%Lots of Physicists Are Nervous about the Speed of Light

    Institute of Scientific and Technical Information of China (English)

    Eric Randall

    2011-01-01

    [1] Physicists spent their weekends walking back media hype over an experiment that at first glance seems to disprove Einstein's famed theory of relativity. They preached dispassionate skepticism, but behind all that careful cynicism, there seemed a lot of hand-wringing.

  17. Dynamics of some forests in Kwa Zulu-Natal, South Africa, based on ordinations and size-class distributions

    CSIR Research Space (South Africa)

    Everard, DA

    1995-12-01

    Full Text Available Indigenous forest in Kwa Zulu-Natal has been fairly well described, however, very little has been published on its dynamics. There is, to our knowledge, nothing published on disturbances regimes, dendrology and life histories of constituent species...

  18. Biological conversion of biomass to methane beef lot manure studies. Semiannual progress report, June 1, 1976--November 30, 1977

    Energy Technology Data Exchange (ETDEWEB)

    Pfeffer, J T; Quindry, G E

    1978-05-01

    A series of experiments was conducted to determine the performance characteristics of the methane fermentation process using beef feed lot manure as a substrate. Manure was obtained from the University of Illinois beef farm. This manure was processed through four parallel fermentors each having a capacity of 775 liters. A continuous feed system was employed to determine the conversion efficiency. The effluent from the fermentation units was evaluated to determine its dewatering characteristics and the quality of the liquid and solid residues. A simple simulation model was developed to evaluate the effect of various operating conditions on processing costs and the net income. These studies clearly show that thermophilic fermentation (58 to 60/sup 0/C) substantially increase the gas yield and the rate of gas production over that obtained at the mesophilic fermentation temperature. System stability is very good. Substantial decreases in temperature or significant increases in loadings did not disrupt the process. Solids recovery from the fermented slurry was accomplished with screens, vacuum drum filters and centrifuge. Solids capture was poor unless massive dosags of conditioning chemicals were added. In terms of investment and operating costs, simple screens (20 mesh size) would capture 75 to 80 percent of the recoverable suspended solids. Manure that is obtained from open lots, especially when it has been exposed to the environment for extended periods, offers little potential for methane production. The biodegradability of this material is so low that the cost of producing the gas far exceeds its value. Fresh manure such as that obtained from environmental lots produced significant quantities of gas. It is probable that an economic system can be developed using this material as a substrate.

  19. Size-dependent modulation of graphene oxide-aptamer interactions for an amplified fluorescence-based detection of aflatoxin B1 with a tunable dynamic range.

    Science.gov (United States)

    Zhang, JingJing; Li, Zengmei; Zhao, Shancang; Lu, Yi

    2016-06-20

    Aflatoxin B1 (AFB1) is a common toxin found in many foods. While AFB1 sensors have been reported, few studies have shown amplified detection with tunable dynamic ranges. We herein report a simple and highly sensitive amplified aptamer-based fluorescent sensor for AFB1, which relies on the ability of nano-graphene oxide (GO) to protect aptamers from nuclease cleavage for amplified detection and on the nanometer size effect of GO to tune the dynamic range and sensitivity. The assay was performed by simply mixing the carboxyl-X-rhodamine (ROX)-labeled AFB1 aptamer, the GO, the nuclease, and the AFB1 samples. Modulating the size of the GO nanosheet resulted in three dynamic ranges, i.e., 12.5 to 312.5 ng mL(-1), 1.0 to 100 ng mL(-1), and 5.0 to 50 ng mL(-1), with corresponding limits of detection of 10.0 ng mL(-1), 0.35 ng mL(-1) and 15.0 ng mL(-1), respectively. The sensor was highly selective against other aflatoxins and common molecules in foods, and its performance was verified in corn samples spiked with known concentration of AFB1.

  20. The Importance of Reagent Lot Registration in External Quality Assurance/Proficiency Testing Schemes

    National Research Council Canada - National Science Library

    Stavelin, Anne; Riksheim, Berit Oddny; Christensen, Nina Gade; Sandberg, Sverre

    2016-01-01

    Providers of external quality assurance (EQA)/proficiency testing schemes have traditionally focused on evaluation of measurement procedures and participant performance and little attention has been given to reagent lot variation...

  1. MOTIVASI PEREMPUAN MEMBUKA USAHA SEKTOR INFORMAL DI DAYA TARIK WISATA TANAH LOT, TABANAN

    Directory of Open Access Journals (Sweden)

    Luh Putu Aritiana Kumala Pratiwi

    2016-08-01

    Full Text Available The development of tourism in Tanah Lot has been able to open up opportunities for local women. The businesses that mostly cultivated by women are the selling of traditional snacks of klepon, postcards, and hairpins.Women who participate should reconsider their decision to choose a dual role, both as housewives and sellers in Tanah Lot.This article analyzes the motivation of Women in opening a business in Tanah Lot area.The results showed that the motivation of women to open a business in the informal sector in Tanah Lot, namely to be able to meet the physiological needs, safety needs, affiliations, appreciation, self-actualization, and add to work experience. The factors that affect women’s motivations are internal factors such as age, educational background, family income, and marital status. While the external factors namely selling location, the condition of selling place, and having their own income.

  2. The Interdictor’s Lot: A Dynamic Model of the Market for Drug Smuggling Services

    Science.gov (United States)

    1988-02-01

    University of Michigan and RAND colleagues Arthur Alexander, James Hosek, and Emmett Keeler. Responsibility for any errors remains with the authors. Ř 0 OF. O...previous analyses of this issue (e.g., Reuter and Kleinman , 1986) have assumed that the drug import market can be viewed in terms of static equilibrium...March 1986 (mimeo.). Reuter, P. and M. Kleinman , "Risks and Prices: An Economic Analysis of Drug Enforcement," M. Tonry and N. Morris (eds.), Crime

  3. How patch size and refuge availability change interaction strength and population dynamics: a combined individual- and population-based modeling experiment

    Science.gov (United States)

    Brose, Ulrich; Meyer, Katrin

    2017-01-01

    Knowledge on how functional responses (a measurement of feeding interaction strength) are affected by patch size and habitat complexity (represented by refuge availability) is crucial for understanding food-web stability and subsequently biodiversity. Due to their laborious character, it is almost impossible to carry out systematic empirical experiments on functional responses across wide gradients of patch sizes and refuge availabilities. Here we overcame this issue by using an individual-based model (IBM) to simulate feeding experiments. The model is based on empirically measured traits such as body-mass dependent speed and capture success. We simulated these experiments in patches ranging from sizes of petri dishes to natural patches in the field. Moreover, we varied the refuge availability within the patch independently of patch size, allowing for independent analyses of both variables. The maximum feeding rate (the maximum number of prey a predator can consume in a given time frame) is independent of patch size and refuge availability, as it is the physiological upper limit of feeding rates. Moreover, the results of these simulations revealed that a type III functional response, which is known to have a stabilizing effect on population dynamics, fitted the data best. The half saturation density (the prey density where a predator consumes half of its maximum feeding rate) increased with refuge availability but was only marginally influenced by patch size. Subsequently, we investigated how patch size and refuge availability influenced stability and coexistence of predator-prey systems. Following common practice, we used an allometric scaled Rosenzweig–MacArthur predator-prey model based on results from our in silico IBM experiments. The results suggested that densities of both populations are nearly constant across the range of patch sizes simulated, resulting from the constant interaction strength across the patch sizes. However, constant densities with

  4. Pre-sowing treatment for breaking dormancy in Acer velutinum Boiss.seed lots

    Institute of Scientific and Technical Information of China (English)

    Mostafa Farhadi; Mulualem Tigabu; Alireza Ghasemi Arian; Mehdi Sharifani; Abolfazl Daneshvar; Per Christer Oden

    2013-01-01

    Acer velutinum Boiss is a valuable tree species native to Iran,and its seeds possess physiological dormancy that hampers seedling production in the nursery for large-scale reforestation efforts.The aim of this study was to determine the optimal dormancy breaking treatments for A.velutinum seeds.We conducted a factorial experiment involving six seed lots collected along an elevation gradient from 300 to 1800 m at 300 m interval and four cold-moist stratification periods (0,4,8 and 16 weeks) at 4℃ and 70% relative humidity.The result shows that the germination of cold-moist stratified seeds was significantly (p < 0.0001)higher than the control for all seed lots.The highest germination capacity was recorded after 16 weeks of cold-moist stratification for all seed lots (68%-88% depending on the seed lot) except those collected from mid altitude sites (600 and 900 m) that germinated equally well (≥ 75%) after 4-and 8-week of clod-moist stratification compared to the other seed lots.The mean germination time was significantly shorter (12 to 19 days,depending on the seed lot) for seeds stratified for 16 weeks than for untreated seeds.It can be concluded that:(1) cold-moist stratification for 16 weeks is the best pre-sowing treatment for breaking dormancy in A.velutinum seeds; and (2) seeds should be collected from mid altitude sites (600 and 900 m) to get more than 80% germination within 15 days,and these seed lots even required shorter cold-moist stratification period (eight weeks) than other seed lots.

  5. Dynamics in National Agri-environmental Policy implementation under Changing EU Policy Priorities: does one size fit all?

    DEFF Research Database (Denmark)

    Vesterager, Jens Peter; Frederiksen, Pia; Kristensen, Søren Bech Pilgaard

    2016-01-01

    directiveobjectives nationally in the future. In this paper, we first investigate the dynamics in the implementationof national Agri-Environmental Schemes (AES) through changes in (i) AES policy objectives over time,(ii) administrative implementation structures, and (iii) administrative policy decision structures...... in theNetherlands, Denmark, Greece, Austria and Romania. Second, we examine the extent to which variousfactors have influenced the development of national policies over time. The study identifies developmentbased on the theory of ‘process of institutional change’, i.e. we qualitatively estimate the costs...... and trans-formation, which are characteristic of the national responses to changing AEP at the EU level. We discussAES dynamics; whether policy content or structures should be in focus for future policy design and theimplications of these findings for the future role of AEP in fulfilling environmental...

  6. Coal-tar-based parking lot sealcoat: An unrecognized source of PAH to settled house dust

    Science.gov (United States)

    Mahler, B.J.; Van Metre, P.C.; Wilson, J.T.; Musgrove, M.; Burbank, T.L.; Ennis, T.E.; Bashara, T.J.

    2010-01-01

    Despite much speculation, the principal factors controlling concentrations of polycyclic aromatic hydrocarbons (PAH) in settled house dust (SHD) have not yet been identified. In response to recent reports that dust from pavement with coaltar-based sealcoat contains extremely high concentrations of PAH, we measured PAH in SHD from 23 apartments and in dust from their associated parking lots, one-half of which had coal-tar-based sealcoat (CT). The median concentration of total PAH (T-PAH) in dust from CT parking lots (4760 ??g/g, n = 11) was 530 times higher than that from parking lots with other pavement surface types (asphalt-based sealcoat, unsealed asphalt, concrete [median 9.0 ??g/g, n = 12]). T-PAH in SHD from apartments with CT parking lots (median 129 ??g/g) was 25 times higher than that in SHD from apartments with parking lots with other pavement surface types (median 5.1 ??g/g). Presence or absence of CT on a parking lot explained 48% of the variance in log-transformed T-PAH in SHD. Urban land-use intensity near the residence also had a significant but weaker relation to T-PAH. No other variables tested, including carpeting, frequency of vacuuming, and indoor burning, were significant. ?? 2010 American Chemical Society.

  7. Structure design and kinematics simulation of a novel arm-type single stereo parking lot

    Directory of Open Access Journals (Sweden)

    Dongliang Chu

    2015-09-01

    Full Text Available Space-saving, high-density stereo parking lots have gained considerable attention because of emerging limitations in ground and underground space. In this article, a novel arm-type single stereo parking lot is proposed to realize convenience and environmental friendliness. Many technical difficulties should be resolved before the safety performance of the stereo parking lot can be enhanced. Therefore, the structural characteristics, the load state and the motion situation should be analysed by numerical simulation to develop a reasonable design scheme. Finite element analysis was conducted on the steel tray platform, and kinematic analysis was performed on the end of novel arm-type single stereo parking lot. As a result, the position, velocity and acceleration curves as well as the maximum workspace were demonstrated by simulation in Pro/E. The simulation results demonstrate the correctness and accuracy of the stereo parking lot under motion mode feasible in residential areas and agency units and that the proposed parking lot can become popular in practice because of characteristics such as simplicity, convenience, easy development and promotion.

  8. Coal-tar-based parking lot sealcoat: an unrecognized source of PAH to settled house dust.

    Science.gov (United States)

    Mahler, Barbara J; Metre, Peter C Van; Wilson, Jennifer T; Musgrove, Marylynn; Burbank, Teresa L; Ennis, Thomas E; Bashara, Thomas J

    2010-02-01

    Despite much speculation, the principal factors controlling concentrations of polycyclic aromatic hydrocarbons (PAH) in settled house dust (SHD) have not yet been identified. In response to recent reports that dust from pavement with coal-tar-based sealcoat contains extremely high concentrations of PAH, we measured PAH in SHD from 23 apartments and in dust from their associated parking lots, one-half of which had coal-tar-based sealcoat (CT). The median concentration of total PAH (T-PAH) in dust from CT parking lots (4760 microg/g, n = 11) was 530 times higher than that from parking lots with other pavement surface types (asphalt-based sealcoat, unsealed asphalt, concrete [median 9.0 microg/g, n = 12]). T-PAH in SHD from apartments with CT parking lots (median 129 microg/g) was 25 times higher than that in SHD from apartments with parking lots with other pavement surface types (median 5.1 microg/g). Presence or absence of CT on a parking lot explained 48% of the variance in log-transformed T-PAH in SHD. Urban land-use intensity near the residence also had a significant but weaker relation to T-PAH. No other variables tested, including carpeting, frequency of vacuuming, and indoor burning, were significant.

  9. Effect of repeat purchase and dynamic market size on diffusion of an innovative technological consumer product in a segmented market

    DEFF Research Database (Denmark)

    Aggarwal, S.; Gupta, A.; Govindan, K.

    2014-01-01

    This study develops diffusion models for technological consumer products under the marketing environment when a product is marketed in a segmented market and observes two distinctive promotional strategies of mass and differentiated promotion; an under explored study area. Mass promotion strategy...... creates a spectrum effect in market with an aim to create wider product awareness and influence the market size. Whereas the differentiated promotion strategy plays major role in external influence component in the respective segment and target for adoption by the current potential segment. Previous...... studies on segmented diffusion models assumed only first time purchase and constant market size which may yield underestimated results and fail to give appropriate insight of the diffusion process. The study develops and validates generalized diffusion models for segmented market incorporating...

  10. Impact of matric potential and pore size distribution on growth dynamics of filamentous and non-filamentous soil bacteria.

    Directory of Open Access Journals (Sweden)

    Alexandra B Wolf

    Full Text Available The filamentous growth form is an important strategy for soil microbes to bridge air-filled pores in unsaturated soils. In particular, fungi perform better than bacteria in soils during drought, a property that has been ascribed to the hyphal growth form of fungi. However, it is unknown if, and to what extent, filamentous bacteria may also display similar advantages over non-filamentous bacteria in soils with low hydraulic connectivity. In addition to allowing for microbial interactions and competition across connected micro-sites, water films also facilitate the motility of non-filamentous bacteria. To examine these issues, we constructed and characterized a series of quartz sand microcosms differing in matric potential and pore size distribution and, consequently, in connection of micro-habitats via water films. Our sand microcosms were used to examine the individual and competitive responses of a filamentous bacterium (Streptomyces atratus and a motile rod-shaped bacterium (Bacillus weihenstephanensis to differences in pore sizes and matric potential. The Bacillus strain had an initial advantage in all sand microcosms, which could be attributed to its faster growth rate. At later stages of the incubation, Streptomyces became dominant in microcosms with low connectivity (coarse pores and dry conditions. These data, combined with information on bacterial motility (expansion potential across a range of pore-size and moisture conditions, suggest that, like their much larger fungal counterparts, filamentous bacteria also use this growth form to facilitate growth and expansion under conditions of low hydraulic conductivity. The sand microcosm system developed and used in this study allowed for precise manipulation of hydraulic properties and pore size distribution, thereby providing a useful approach for future examinations of how these properties influence the composition, diversity and function of soil-borne microbial communities.

  11. The effect of the size of the system, aspect ratio and impurities concentration on the dynamic of emergent magnetic monopoles in artificial spin ice systems

    Energy Technology Data Exchange (ETDEWEB)

    León, Alejandro, E-mail: alejandro.leon@udp.cl

    2013-08-15

    In this work we study the dynamical properties of a finite array of nanomagnets in artificial kagome spin ice at room temperature. The dynamic response of the array of nanomagnets is studied by implementing a “frustrated celular autómata” (FCA), based in the charge model and dipolar model. The FCA simulations allow us to study in real-time and deterministic way, the dynamic of the system, with minimal computational resource. The update function is defined according to the coordination number of vertices in the system. Our results show that for a set geometric parameters of the array of nanomagnets, the system exhibits high density of Dirac strings and high density emergent magnetic monopoles. A study of the effect of disorder in the arrangement of nanomagnets is incorporated in this work. - Highlights: • The dynamics of magnetic monopoles in spin ice systems strongly dependent on the size of the system. • Number of emerging magnetic monopoles, in the phase of magnetic reversal, depend of the aspect. • Different systems can be created based on this idea, for information technology.

  12. Cluster size convergence of the density matrix embedding theory and its dynamical cluster formulation: A study with an auxiliary-field quantum Monte Carlo solver

    Science.gov (United States)

    Zheng, Bo-Xiao; Kretchmer, Joshua S.; Shi, Hao; Zhang, Shiwei; Chan, Garnet Kin-Lic

    2017-01-01

    We investigate the cluster size convergence of the energy and observables using two forms of density matrix embedding theory (DMET): the original cluster form (CDMET) and a new formulation motivated by the dynamical cluster approximation (DCA-DMET). Both methods are applied to the half-filled one- and two-dimensional Hubbard models using a sign-problem free auxiliary-field quantum Monte Carlo impurity solver, which allows for the treatment of large impurity clusters of up to 100 sites. While CDMET is more accurate at smaller impurity cluster sizes, DCA-DMET exhibits faster asymptotic convergence towards the thermodynamic limit. We use our two formulations to produce new accurate estimates for the energy and local moment of the two-dimensional Hubbard model for U /t =2 ,4 ,6 . These results compare favorably with the best data available in the literature, and help resolve earlier uncertainties in the moment for U /t =2 .

  13. STUDY OF LOT-TO-LOT REPRODUCIBILITIES OF BOND ELUT CERTIFY AND CLEAN SCREEN DAU MIXED-MODE SOLID-PHASE EXTRACTION COLUMNS IN THE EXTRACTION OF DRUGS FROM WHOLE-BLOOD

    NARCIS (Netherlands)

    CHEN, XH; FRANKE, JP; WIJSBEEK, J; DEZEEUW, RA

    1993-01-01

    The lot-to-lot reproducibilities of Bond Elut Certify and Clean Screen DAU columns are described. The recoveries of five test drugs obtained from twelve lots of Bond Elut Certify columns ranged from 84 to 104% with standard deviations of less than 9%. The recoveries of five test drugs obtained from

  14. The effect of decrease in salinity on the dynamics of abundance and the cell size of Corethron Hystrix (Bacillariophyta) in laboratory culture

    Science.gov (United States)

    Aizdaicher, Nina A.; Markina, Zhanna V.

    2010-03-01

    Effect of salinity on abundance dynamics and cell size of microalga Corethron hystrix Hensen (Bacillariophyta) were studied. C. hystrix can normally grow within a rather narrow salinity range between 32 and 28‰. The viable cells of this microalga change their morphological characters at a salinity of 24‰. This salinity level probably marks the beginning of cell division restriction, because the general number of cells by the end of the experiment was lower than in the control. The decrease of salinity to 16‰ caused pronounced irreversible morphological changes: cell height increased, chloroplasts compressed, protoplasm became granular, cytoplasm retracted, and spines shortened.

  15. Optimal timing of retinal scanning during dark adaptation, in the presence of fixation on a target: the role of pupil size dynamics

    Science.gov (United States)

    Gramatikov, Boris I.; Irsch, Kristina; Guyton, David

    2014-10-01

    While validating our newly developed vision screener based on a double-pass retinal scanning system, we noticed that in all patients the signals from the retina were significantly higher when measurements were performed within a certain time interval referenced to the initial moment when the lights were dimmed and the test subject was asked to fixate on a target. This appeared to be most likely attributable to pupil size dynamics and triggered the present study, whose aim was to assess the pupillary "lights-off" response while fixating on a target in the presence of an accommodative effort. We found that pupil size increases in the first 60 to 70 s after turning off the room lights, and then it decreases toward the baseline in an exponential decay. Our results suggest that there is an optimal time window during which pupil size is expected to be maximal, that is during the second minute after dimming the room lights. During this time, window retinal diagnostic instruments based on double-pass measurement technology should deliver an optimal signal-to-noise ratio. We also propose a mathematical model that can be used to approximate the behavior of the normalized pupil size.

  16. Optimal timing of retinal scanning during dark adaptation, in the presence of fixation on a target: the role of pupil size dynamics.

    Science.gov (United States)

    Gramatikov, Boris I; Irsch, Kristina; Guyton, David

    2014-01-01

    While validating our newly developed vision screener based on a double-pass retinal scanning system, we noticed that in all patients the signals from the retina were significantly higher when measurements were performed within a certain time interval referenced to the initial moment when the lights were dimmed and the test subject was asked to fixate on a target. This appeared to be most likely attributable to pupil size dynamics and triggered the present study, whose aim was to assess the pupillary “lights-off” response while fixating on a target in the presence of an accommodative effort. We found that pupil size increases in the first 60 to 70 s after turning off the room lights, and then it decreases toward the baseline in an exponential decay. Our results suggest that there is an optimal time window during which pupil size is expected to be maximal, that is during the second minute after dimming the room lights. During this time, window retinal diagnostic instruments based on double-pass measurement technology should deliver an optimal signal-to-noise ratio. We also propose a mathematical model that can be used to approximate the behavior of the normalized pupil size.

  17. Study on lot-splitting method for multi-objective flexible Job-Shop scheduling problem%多目标柔性车间作业调度分批方法研究

    Institute of Scientific and Technical Information of China (English)

    许秀林; 胡克瑾

    2011-01-01

    针对柔性分批有可能导致不规则的分批方案,提出了基于批量规则的有序分批方法,并按照最大批量规则,分析了影响确定最佳额定批量的主要因素,设计了一种基于工件工序时间分布的差异批量的分批方案.通过实例仿真,结果表明该方案的调度周期等主要指标均优于相同批量的分批方案,对实际生产调度具有指导作用.%Flexible size lot-splitting method, for multi-objective flexible Job-Shop scheduling problem, may produce irregular lot-splitting scheme. To resolve this problem, proposed the idea of regular lot-splitting. According to the rule of maximum batch size, it analysed the main factors which determined the best batch size. It presented a lot-splitting scheme that determined batch size by process time of each job. Experiment shows that main indexes of the scheme with different batch size, including make span, are better than one with same batch size, and the scheme can provide reference for production practice.

  18. Atomistic Simulations of High-intensity XFEL Pulses on Diffractive Imaging of Nano-sized System Dynamics

    Science.gov (United States)

    Ho, Phay; Knight, Christopher; Bostedt, Christoph; Young, Linda; Tegze, Miklos; Faigel, Gyula

    2016-05-01

    We have developed a large-scale atomistic computational method based on a combined Monte Carlo and Molecular Dynamics (MC/MD) method to simulate XFEL-induced radiation damage dynamics of complex materials. The MD algorithm is used to propagate the trajectories of electrons, ions and atoms forward in time and the quantum nature of interactions with an XFEL pulse is accounted for by a MC method to calculate probabilities of electronic transitions. Our code has good scalability with MPI/OpenMP parallelization, and it has been run on Mira, a petascale system at the Argonne Leardership Computing Facility, with particle number >50 million. Using this code, we have examined the impact of high-intensity 8-keV XFEL pulses on the x-ray diffraction patterns of argon clusters. The obtained patterns show strong pulse parameter dependence, providing evidence of significant lattice rearrangement and diffuse scattering. Real-space electronic reconstruction was performed using phase retrieval methods. We found that the structure of the argon cluster can be recovered with atomic resolution even in the presence of considerable radiation damage. This work was supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences Division.

  19. Dynamic adsorption of diarrhetic shellfish poisoning (DSP) toxins in passive sampling relates to pore size distribution of aromatic adsorbent.

    Science.gov (United States)

    Li, Aifeng; Ma, Feifei; Song, Xiuli; Yu, Rencheng

    2011-03-18

    Solid-phase adsorption toxin tracking (SPATT) technology was developed as an effective passive sampling method for dissolved diarrhetic shellfish poisoning (DSP) toxins in seawater. HP20 and SP700 resins have been reported as preferred adsorption substrates for lipophilic algal toxins and are recommended for use in SPATT testing. However, information on the mechanism of passive adsorption by these polymeric resins is still limited. Described herein is a study on the adsorption of OA and DTX1 toxins extracted from Prorocentrum lima algae by HP20 and SP700 resins. The pore size distribution of the adsorbents was characterized by a nitrogen adsorption method to determine the relationship between adsorption and resin porosity. The Freundlich equation constant showed that the difference in adsorption capacity for OA and DTX1 toxins was not determined by specific surface area, but by the pore size distribution in particular, with micropores playing an especially important role. Additionally, it was found that differences in affinity between OA and DTX1 for aromatic resins were as a result of polarity discrepancies due to DTX1 having an additional methyl moiety.

  20. Effective population size dynamics reveal impacts of historic climatic events and recent anthropogenic pressure in African elephants.

    Science.gov (United States)

    Okello, J B A; Wittemyer, G; Rasmussen, H B; Arctander, P; Nyakaana, S; Douglas-Hamilton, I; Siegismund, H R

    2008-09-01

    Two hundred years of elephant hunting for ivory, peaking in 1970-1980s, caused local extirpations and massive population declines across Africa. The resulting genetic impacts on surviving populations have not been studied, despite the importance of understanding the evolutionary repercussions of such human-mediated events on this keystone species. Using Bayesian coalescent-based genetic methods to evaluate time-specific changes in effective population size, we analysed genetic variation in 20 highly polymorphic microsatellite loci from 400 elephants inhabiting the greater Samburu-Laikipia region of northern Kenya. This area experienced a decline of between 80% and 90% in the last few decades when ivory harvesting was rampant. The most significant change in effective population size, however, occurred approximately 2500 years ago during a mid-Holocene period of climatic drying in tropical Africa. Contrary to expectations, detailed analyses of four contemporary age-based cohorts showed that the peak poaching epidemic in the 1970s caused detectable temporary genetic impacts, with genetic diversity rebounding as juveniles surviving the poaching era became reproductively mature. This study demonstrates the importance of climatic history in shaping the distribution and genetic history of a keystone species and highlights the utility of coalescent-based demographic approaches in unravelling ancestral demographic events despite a lack of ancient samples. Unique insights into the genetic signature of mid-Holocene climatic change in Africa and effects of recent poaching pressure on elephants are discussed.

  1. Ammonia losses and nitrogen partitioning at a southern High Plains open lot dairy

    Science.gov (United States)

    Todd, Richard W.; Cole, N. Andy; Hagevoort, G. Robert; Casey, Kenneth D.; Auvermann, Brent W.

    2015-06-01

    Animal agriculture is a significant source of ammonia (NH3). Cattle excrete most ingested nitrogen (N); most urinary N is converted to NH3, volatilized and lost to the atmosphere. Open lot dairies on the southern High Plains are a growing industry and face environmental challenges as well as reporting requirements for NH3 emissions. We quantified NH3 emissions from the open lot and wastewater lagoons of a commercial New Mexico dairy during a nine-day summer campaign. The 3500-cow dairy consisted of open lot, manure-surfaced corrals (22.5 ha area). Lactating cows comprised 80% of the herd. A flush system using recycled wastewater intermittently removed manure from feeding alleys to three lagoons (1.8 ha area). Open path lasers measured atmospheric NH3 concentration, sonic anemometers characterized turbulence, and inverse dispersion analysis was used to quantify emissions. Ammonia fluxes (15-min) averaged 56 and 37 μg m-2 s-1 at the open lot and lagoons, respectively. Ammonia emission rate averaged 1061 kg d-1 at the open lot and 59 kg d-1 at the lagoons; 95% of NH3 was emitted from the open lot. The per capita emission rate of NH3 was 304 g cow-1 d-1 from the open lot (41% of N intake) and 17 g cow-1 d-1 from lagoons (2% of N intake). Daily N input at the dairy was 2139 kg d-1, with 43, 36, 19 and 2% of the N partitioned to NH3 emission, manure/lagoons, milk, and cows, respectively.

  2. Validity of Dynamic Light Scattering Method to Analyze a Range of Gold and Copper Nanoparticle Sizes Attained by Solids Laser Ablation in Liquid

    Directory of Open Access Journals (Sweden)

    Yu. V. Golubenko

    2014-01-01

    Full Text Available Nanoparticles of metals possess a whole series of features, concerned with it’s sizes, this leads to appearing or unusual electromagnetic and optical properties, which are untypical for particulates.An extended method of receiving nanoparticles by means of laser radiation is pulse laser ablation of hard targets in liquid medium.Varying the parameters of laser radiation, such as wavelength of laser radiation, energy density, etc., we can operate the size and shape of the resultant particles.The greatest trend of application in medicine have the nanoparticles of iron, copper, silver, silicon, magnesium, gold and zinc.The subject matter in this work is nanoparticles of copper and gold, received by means of laser ablation of hard targets in liquid medium.The aim of exploration, represented in the article, is the estimation of application of the dynamic light scattering method for determination of the range of nanoparticles sizes in the colloidal solution.For studying of the laser ablation process was chosen the second harmonic of Nd:YAG laser with the wavelength of 532 nm. Special attention was spared for the description of the experiment technique of receiving of nanoparticles.As the liquid medium ethanol and distillation water were used.For exploration of the received colloidal system have been used the next methods: DLS, transmission electron microscopy (TEM and scanning electron microscopy (SEM.The results of measuring by DLS method showed that colloidal solution of the copper in the ethanol is the steady system. Copper nanoparticle’s size reaches 200 nm and is staying in the same size for some time.Received system from the gold’s nanoparticles is polydisperse, unsteady and has a big range of the nanoparticle’s sizes. This fact was confirmed by means of photos, got from the TEM FEI Tecnai G2F20 + GIF and SEM Helios NanoLab 660. The range of the gold nanoparticle’s sizes is from 5 to 60 nm. So, it has been proved that the DLS method is

  3. Critical anomaly and finite size scaling of the self-diffusion coefficient for Lennard-Jones fluids by non-equilibrium molecular dynamic simulation

    Institute of Scientific and Technical Information of China (English)

    Ahmed Asad; Wu Jiang-Tao

    2011-01-01

    We use non-equilibrium molecular dynamics simulations to calculate the self-diffusion coefficient,D,of a Lennard Jones fluid over a wide density and temperature range.The change in self-diffusion coefficient with temperature decreases by increasing density.For density p* =pσ3 =0.84 we observe a peak at the value of the self-diffusion coefficient and the critical temperature T* =kT/ε =1.25.The value of the self-diffusion coefficient strongly depends on system size.The data of the self-diffusion coefficient are fitted to a simple analytic relation based on hydrodynamic arguments.This correction scales as N-α,where α is an adjustable parameter and N is the number of particles.It is observed that the values of α < 1 provide quite a good correction to the simulation data.The system size dependence is very strong for lower densities,but it is not as strong for higher densities.The self-diffusion coefficient calculated with non-equilibrium molecular dynamic simulations at different temperatures and densities is in good agreement with other calculations from the literature.

  4. Size-dependent dynamic pull-in instability of vibrating electrically actuated microbeams based on the strain gradient elasticity theory

    Science.gov (United States)

    Sedighi, Hamid M.

    2014-02-01

    This paper presents the impact of vibrational amplitude on the dynamic pull-in instability and fundamental frequency of actuated microbeams by introducing the second order frequency-amplitude relationship. The nonlinear governing equation of microbeam predeformed by an electric force including the fringing field effect, based on the strain gradient elasticity theory is considered. The predicted results of the strain gradient elasticity theory are compared with the outcomes that arise from the classical and modified couple stress theory. The influences of basic nondimensional parameters on the pull-in instability as well as the natural frequency are investigated by a powerful asymptotic approach namely the Parameter Expansion Method (PEM). It is demonstrated that two terms in series expansions are sufficient to produce an acceptable solution of the microstructure. The phase portrait of the microstructure shows that by increasing the actuation voltage parameter, the stable center point loses its stability and coalesces with unstable saddle node.

  5. Size-dependent free vibration and dynamic analyses of piezo-electro-magnetic sandwich nanoplates resting on viscoelastic foundation

    Science.gov (United States)

    Arefi, Mohammad; Zenkour, Ashraf M.

    2017-09-01

    In this paper, size-dependent free vibration analysis of a sandwich nanoplate is presented. The sandwich nanoplate is including an elastic nano core and two piezo-electro-magnetic face-sheets as sensor and actuator actuated by electric and magnetic potentials. The sandwich nanoplate is resting on visco-Pasternak's foundation. Hamilton's principle is employed to derive the governing equations of motion based on Kirchhoff plate and nonlocal elasticity theory. The numerical results are presented to study the influence of important parameters of the problem such as applied electric and magnetic potentials, nonlocal parameter and visco-Pasternak's parameters. Furthermore, the influence of various boundary conditions is discussed on the vibration characteristics of the sandwich nanoplate.

  6. Effective population size dynamics reveal impacts of historic climatic events and recent anthropogenic pressure in African elephants

    DEFF Research Database (Denmark)

    Okello, J B A; Wittemyer, G; Rasmussen, Henrik Barner

    2008-01-01

    Two hundred years of elephant hunting for ivory, peaking in 1970-1980s, caused local extirpations and massive population declines across Africa. The resulting genetic impacts on surviving populations have not been studied, despite the importance of understanding the evolutionary repercussions...... of northern Kenya. This area experienced a decline of between 80% and 90% in the last few decades when ivory harvesting was rampant. The most significant change in effective population size, however, occurred approximately 2500 years ago during a mid-Holocene period of climatic drying in tropical Africa....... Contrary to expectations, detailed analyses of four contemporary age-based cohorts showed that the peak poaching epidemic in the 1970s caused detectable temporary genetic impacts, with genetic diversity rebounding as juveniles surviving the poaching era became reproductively mature. This study demonstrates...

  7. Potential for localized groundwater contamination in a porous pavement parking lot setting in Rhode Island

    Science.gov (United States)

    Boving, Thomas B.; Stolt, Mark H.; Augenstern, Janelle; Brosnan, Brian

    2008-08-01

    The control of polluted surface runoff and the assessment of possible impacts on groundwater is a concern at the local and regional scale. On this background, a study investigates possible impacts of organic and inorganic pollutants (including bacteria) originating from a permeable asphalt parking lot on the water quality immediately beneath it. The functioning of the permeable pavement, including clogging and restricted vertical percolation, was also evaluated. Four nested sample ports (shallow and deep) were installed below low- and high-traffic areas, including one port outside the parking lot. At least initially there was a good hydraulic connection between the parking surface and the shallow sample ports. The presence of a geotextile layer at the base of the parking lot structure, however, was identified in lab tests as one factor restricting vertical percolation to the deeper ports. Clogging of the permeable surface was most pronounced in heavy traffic areas and below snow pile storage areas. Corroborated by high electric conductivity and chloride measurements, sand brought in by cars during winter was the principal cause for clogging. No bacteria or BOD were found in percolating water. Polycyclic aromatic hydrocarbons (PAH) were present at concentrations near minimum detection limit. Nutrients (nitrate and phosphate) were being leached into the ground via the permeable parking lot surface at annual flux rates of 0.45 0.84 g/m2/year. A multi-species tracer test demonstrated a retention capacity of the permeable parking lot structure of >90% for metals and 27% for nutrients, respectively.

  8. The orbital PDF: the dynamical state of Milky Way sized haloes and the intrinsic uncertainty in the determination of their masses

    CERN Document Server

    Han, Jiaxin; Cole, Shaun; Frenk, Carlos S

    2015-01-01

    Using realistic cosmological simulations of Milky Way sized haloes, we study their dynamical state and the accuracy of inferring their mass profiles with steady-state models of dynamical tracers. We use a new method that describes the phase-space distribution of a steady-state tracer population in a spherical potential without any assumption regarding the distribution of their orbits. Applying the method to five haloes from the Aquarius $\\Lambda$CDM N-body simulation, we find that dark matter particles are an accurate tracer that enables the halo mass and concentration parameters to be recovered with an accuracy of $5\\%$. Assuming a potential profile of the NFW form does not significantly affect the fits in most cases, except for halo A whose density profile differs significantly from the NFW form, leading to a $30\\%$ bias in the dynamically fitted parameters. The existence of substructures in the dark matter tracers only affects the fits by $\\sim 1\\%$. Applying the method to mock stellar haloes generated by ...

  9. Molecular dynamics simulations of the effect of shape and size of SiO2 nanoparticle dopants on insulation paper cellulose

    Science.gov (United States)

    Tang, Chao; Zhang, Song; Li, Xu; Zhou, Qu

    2016-12-01

    The effect of silica nanoparticle (Nano-SiO2) dopants on insulation paper cellulose, and the interaction between them, was investigated using molecular dynamics simulations. The mechanical properties, interactions, and cellulose-Nano-SiO2 compatibility of composite models of cellulose doped with Nano-SiO2 were studied. An increase in Nano-SiO2 size leads to a decrease in the mechanical properties, and a decrease in the anti-deformation ability of the composite model. The binding energies and bond energies per surface area of the composite models indicate that the bonding interaction between spherical Nano-SiO2 and cellulose is the strongest among the four different Nano-SiO2 shapes that are investigated. The solubilities of the four composite models decrease with increasing Nano-SiO2 size, and the difference between the solubility of pure cellulose and those of the composite models increases with increasing Nano-SiO2 size. Good doping effects with the highest cellulose-Nano-SiO2 compatibility are achieved for the cellulose model doped with spherical Nano-SiO2 of 10 Å in diameter. These findings provide a method for modifying the mechanical properties of cellulose by doping, perhaps for improving insulation dielectrics.

  10. Molecular dynamics simulations of the effect of shape and size of SiO2 nanoparticle dopants on insulation paper cellulose

    Directory of Open Access Journals (Sweden)

    Chao Tang

    2016-12-01

    Full Text Available The effect of silica nanoparticle (Nano-SiO2 dopants on insulation paper cellulose, and the interaction between them, was investigated using molecular dynamics simulations. The mechanical properties, interactions, and cellulose-Nano-SiO2 compatibility of composite models of cellulose doped with Nano-SiO2 were studied. An increase in Nano-SiO2 size leads to a decrease in the mechanical properties, and a decrease in the anti-deformation ability of the composite model. The binding energies and bond energies per surface area of the composite models indicate that the bonding interaction between spherical Nano-SiO2 and cellulose is the strongest among the four different Nano-SiO2 shapes that are investigated. The solubilities of the four composite models decrease with increasing Nano-SiO2 size, and the difference between the solubility of pure cellulose and those of the composite models increases with increasing Nano-SiO2 size. Good doping effects with the highest cellulose-Nano-SiO2 compatibility are achieved for the cellulose model doped with spherical Nano-SiO2 of 10 Å in diameter. These findings provide a method for modifying the mechanical properties of cellulose by doping, perhaps for improving insulation dielectrics.

  11. Dynamics and sources of last glacial aeolian deposition in southwest France derived from dune patterns, grain-size gradients and geochemistry, and reconstruction of efficient wind directions

    Science.gov (United States)

    Sitzia, Luca; Bertran, Pascal; Sima, Adriana; Chery, Philippe; Queffelec, Alain; Rousseau, Denis-Didier

    2017-08-01

    Dune pattern, grain-size gradients and geochemistry were used to investigate the sources and dynamics of aeolian deposition during the last glacial in southwest France. The coversands form widespread fields of low-amplitude ridges (zibars), whereas Younger Dryas parabolic dunes mainly concentrate in corridors and along rivers. Spatial modelling of grain-size gradients combined with geochemical analysis points to a genetic relationship between coversands and loess, the latter resulting primarily from dust produced by aeolian abrasion of the coversands. The alluvium of the Garonne river provided also significant amounts of dust at a more local scale. The geochemical composition of loess shows much lower scattering than that of coversands, due to stronger homogenisation during transport in the atmosphere. Overall, sandy loess and loess deposits decrease in thickness away from the coversands. Dune orientation and grain-size gradients suggest that the efficient winds blew respectively from the W to the NW during the glacial, and the W-SW during the Younger Dryas. A comparison between the wind directions derived from the proxy data and those provided by palaeoclimatic simulations suggests a change of the main transport season. Ground surface conditions and their evolution throughout the year, i.e. the length of the season with snow and frozen or moist topsoil, and the seasonal distribution of wind speeds able to cause deflation are thought to have been the main factors that controlled the transport season in the study area.

  12. A simple and fast method to study the hydrodynamic size difference of protein disulfide isomerase in oxidized and reduced form using gold nanoparticles and dynamic light scattering.

    Science.gov (United States)

    Zheng, Tianyu; Cherubin, Patrick; Cilenti, Lucia; Teter, Ken; Huo, Qun

    2016-02-07

    The hydrodynamic dimension of a protein is a reflection of both its molecular weight and its tertiary structures. Studying the hydrodynamic dimensions of proteins in solutions can help elucidate the structural properties of proteins. Here we report a simple and fast method to measure the hydrodyamic size of a relatively small protein, protein disulfide isomerase (PDI), using gold nanoparticle probes combined with dynamic light scattering. Proteins can readily adsorb to citrate-capped gold nanoparticles to form a protein corona. By measuring the average diameter of the gold nanoparticles before and after protein corona formation, the hydrodynamic diameter of the protein can be deduced from the net particle size increase of the assay solution. This study found that when the disulfide bonds in PDI are reduced to thiols, the reduced PDI exhibits a smaller hydrodynamic diameter than the oxided PDI. This finding is in good agreement with the X-ray diffraction analysis of PDI in single crystals. In comparison with other techniques that are used for protein hydrodynamic size analysis, the current method is easy to use, requires a trace amount of protein samples, with results obtained in minutes instead of hours.

  13. Impact of the 2013-2015 weather variability on seasonal growth dynamics and daily stem-size changes of three coexisting broadleaved tree species

    Science.gov (United States)

    van der Maaten, Ernst; Pape, Jonas; van der Maaten Theunissen, Marieke; Scharnweber, Tobias; Smiljanic, Marko; Wilmking, Martin

    2016-04-01

    Dendrometers are measurement devices that continuously monitor stem-size changes of trees without invasive sampling of the cambium. Dendrometers record both irreversible tree growth as well as reversible signals of stem water storage and depletion, making them important tools for studying tree water status, tree physiology and short-term growth responses of trees to weather fluctuations. In this study, a three-year dendrometer dataset (2013-2015) is used to study seasonal growth dynamics and daily stem-size changes of three coexisting broadleaved tree species (common hornbeam (Carpinus betulus L.), European beech (Fagus sylvatica L.), and pedunculate oak (Quercus robur L.)), growing in an unmanaged forest in northeastern Germany. Seasonal growth patterns (i.e. growth onset, cessation and duration) are analyzed in relation to environmental conditions, and forest meteorological factors driving daily stem-size changes are identified. Following dry conditions in 2014, especially the growth of beech was reduced. Oak was less affected, and displayed a distinct early growth onset for all study years.

  14. A 2-year follow-up study on muscle size and dynamic strength in teenage tennis players.

    Science.gov (United States)

    Kanehisa, H; Kuno, S; Katsuta, S; Fukunaga, T

    2006-04-01

    Growth trends in the cross-sectional area of the quadriceps femoris (CSA(QF)) and its dynamic strength in 12 teenage tennis players (six boys and six girls), aged from 10.7 to 13.2 years at the onset of the study, were investigated through a 2-year follow-up survey. CSA(QF) values at the three levels (proximal, mid, and distal to the knee joint) and dynamic torques during knee extensions at three pre-set velocities (1.05, 3.14, and 5.24 rad/s) were determined year by year, i.e., three times (T1, T2, and T3), using magnetic resonance imaging and an isokinetic dynamometer, respectively. In both genders, the CSA(QF) values at the three levels tended to increase across the measurement times, with greater gains in the boys than in the girls at the levels mid and distal to the knee joint. Among these changes, only the CSA(QF) at the level proximal to the knee joint significantly increased regardless of changes in both skeletal age and body height. The ratios of torque to the sum of CSA(QF) at the three levels (T/CSA) at 3.14 and 5.24 rad/s for the boys and at 5.24 rad/s for the girls were significantly higher in T2 and T3 than T1. Further, the relative increases in torque and T/CSA values at 3.14 and 5.24 rad/s were greater in the boys than the girls. The findings presented here indicate that young tennis players who are in the earlier stage of adolescence increase the CSA of the QF muscle beyond normally expected growth change at the level proximal to the knee joint and show a predominant development in torque generation capability during high-velocity knee extensions, with a greater gain in boys compared with girls.

  15. Trend and dynamic cause of sediment particle size on the adjacent continental shelf of the Yangtze Estuary

    Science.gov (United States)

    Yang, Yun-ping; Zhang, Ming-jin; Li, Yi-tian; Fan, Yong-yang

    2016-12-01

    Based on the measured data in recent 20 years, the variation trends of the median grain size of the surface sediment, the sand-silt boundary and the mud area on the adjacent continental shelf of the Yangtze Estuary were analyzed in depth, and the effects of natural mechanism and human activities were discussed. The results show that: (1) In recent years (2006-2013), the median grain size of sediment and the distribution pattern of grouped sediments in the adjacent continental shelf area to the Yangtze Estuary have presented no obvious change compared with those before 2006; (2) The median diameter of the surface sediment in the continental shelf area displayed a coarsening trend with the decrease of sediment discharge from the basin and the drop in suspended sediment concentration in the shore area; (3) In 2004-2007, the sand-silt boundary in the north part (31°30'N) of the continental shelf area presented no significant changes, while that in the south part (31°30'S) moved inwards; In 2008-2013, both the sand-silt boundaries in the north and south parts of the continental shelf area moved inwards, mainly due to the fact that in the dry season, a relatively enhanced hydrodynamic force of the tides was generated in the Yangtze River, as well as a decreased suspended sediment concentration and a flow along the banks in North Jiangsu; (4) The mud area where the maximum deposition rate is found in the Yangtze Estuary, tends to shrink due to the drop in sediment discharge from the basin, and the decrease in suspended sediment concentration in the shore area and erosion in the delta. Moreover, it tended to shift to the south at the same time because the implement of the training works on the deep-water channel of the North Passage changed the split ratio between the North and South Passages with an increase in the power of the discharged runoff in the South Passage.

  16. Dynamic Morphological Changes Induced By GM1 and Protein Interactions on the Surface of Cell-Sized Liposomes

    Directory of Open Access Journals (Sweden)

    Masahiro Takagi

    2013-06-01

    Full Text Available It is important to understand the physicochemical mechanisms that are responsible for the morphological changes in the cell membrane in the presence of various stimuli such as osmotic pressure. Lipid rafts are believed to play a crucial role in various cellular processes. It is well established that Ctb (Cholera toxin B subunit recognizes and binds to GM1 (monosialotetrahexosylganglioside on the cell surface with high specificity and affinity. Taking advantage of Ctb-GM1 interaction, we examined how Ctb and GM1 molecules affect the dynamic movement of liposomes. GM1 a natural ligand for cholera toxin, was incorporated into liposome and the interaction between fluorescent Ctb and the liposome was analyzed. The interaction plays an important role in determining the various surface interaction phenomena. Incorporation of GM1 into membrane leads to an increase of the line tension leading to either rupture of liposome membrane or change in the morphology of the membrane. This change in morphology was found to be GM1 concentration specific. The interaction between Ctb-GM1 leads to fast and easy rupture or to morphological changes of the liposome. The interactions of Ctb and the glycosyl chain are believed to affect the surface and the curvature of the membrane. Thus, the results are highly beneficial in the study of signal transduction processes.

  17. Dynamical Expansion of H II Regions from Ultracompact to Compact Sizes in Turbulent, Self-Gravitating Molecular Clouds

    CERN Document Server

    MacLow, M M; Oishi, J S; Abel, T; Low, Mordecai-Mark Mac; Toraskar, Jayashree; Oishi, Jeffrey S.; Abel, Tom

    2006-01-01

    The nature of ultracompact H II regions (UCHRs) remains poorly determined. In particular, they are about an order of magnitude more common than would be expected if they formed around young massive stars and lasted for one dynamical time, around 10^4 yr. We here perform three-dimensional numerical simulations of the expansion of an H II region into self-gravitating, radiatively cooled gas, both with and without supersonic turbulent flows. In the laminar case, we find that H II region expansion in a collapsing core produces nearly spherical shells, even if the ionizing source is off-center in the core. This agrees with analytic models of blast waves in power-law media. In the turbulent case, we find that the H II region does not disrupt the central collapsing region, but rather sweeps up a shell of gas in which further collapse occurs. Although this does not constitute triggering, as the swept-up gas would eventually have collapsed anyway, it does expose the collapsing regions to ionizing radiation. We suggest...

  18. Clustered lot quality assurance sampling: a tool to monitor immunization coverage rapidly during a national yellow fever and polio vaccination campaign in Cameroon, May 2009.

    Science.gov (United States)

    Pezzoli, L; Tchio, R; Dzossa, A D; Ndjomo, S; Takeu, A; Anya, B; Ticha, J; Ronveaux, O; Lewis, R F

    2012-01-01

    We used the clustered lot quality assurance sampling (clustered-LQAS) technique to identify districts with low immunization coverage and guide mop-up actions during the last 4 days of a combined oral polio vaccine (OPV) and yellow fever (YF) vaccination campaign conducted in Cameroon in May 2009. We monitored 17 pre-selected districts at risk for low coverage. We designed LQAS plans to reject districts with YF vaccination coverage <90% and with OPV coverage <95%. In each lot the sample size was 50 (five clusters of 10) with decision values of 3 for assessing OPV and 7 for YF coverage. We 'rejected' 10 districts for low YF coverage and 14 for low OPV coverage. Hence we recommended a 2-day extension of the campaign. Clustered-LQAS proved to be useful in guiding the campaign vaccination strategy before the completion of the operations.

  19. An economic lot and delivery scheduling problem with the fuzzy shelf life in a flexible job shop with unrelated parallel machines

    Directory of Open Access Journals (Sweden)

    S. Dousthaghi

    2012-08-01

    Full Text Available This paper considers an economic lot and delivery scheduling problem (ELDSP in a fuzzy environment with the fuzzy shelf life for each product. This problem is formulated in a flexible job shop with unrelated parallel machines, when the planning horizon is finite and it determines lot sizing, scheduling and sequencing, simultaneously. The proposed model of this paper is based on the basic period (BP approach. In this paper, a mixed-integer nonlinear programming (MINLP model is presented and then it is changed into two models in the fuzzy shelf life. The main model is dependent to the multiple basic periods and it is difficult to solve the resulted proposed model for large-scale problems in reasonable amount of time; thus, an efficient heuristic method is proposed to solve the problem. The performance of the proposed model is demonstrated using some numerical examples.

  20. Sampling hazelnuts for aflatoxin: Effects of sample size and accetp/reject limit on reducing risk of misclassifying lots

    Science.gov (United States)

    About 100 countries have established regulatory limits for aflatoxin in food and feeds. Because these limits vary widely among regulating countries, the Codex Committee on Food Additives and Contaminants (CCFAC) began work in 2004 to harmonize aflatoxin limits and sampling plans for aflatoxin in alm...

  1. Pricing and lot sizing optimization in a two-echelon supply chain with a constrained Logit demand function

    Directory of Open Access Journals (Sweden)

    Yeison Díaz-Mateus

    2017-07-01

    Full Text Available Decision making in supply chains is influenced by demand variations, and hence sales, purchase orders and inventory levels are therefore concerned. This paper presents a non-linear optimization model for a two-echelon supply chain, for a unique product. In addition, the model includes the consumers’ maximum willingness to pay, taking socioeconomic differences into account. To do so, the constrained multinomial logit for discrete choices is used to estimate demand levels. Then, a metaheuristic approach based on particle swarm optimization is proposed to determine the optimal product sales price and inventory coordination variables. To validate the proposed model, a supply chain of a technological product was chosen and three scenarios are analyzed: discounts, demand segmentation and demand overestimation. Results are analyzed on the basis of profits, lotsizing and inventory turnover and market share. It can be concluded that the maximum willingness to pay must be taken into consideration, otherwise fictitious profits may mislead decision making, and although the market share would seem to improve, overall profits are not in fact necessarily better.

  2. Primal-Dual Interior-Point Algorithms with Dynamic Step-Size Based on Kernel Functions for Linear Programming%用于线性优化的基于核函数的动态步长原-对偶内点算法

    Institute of Scientific and Technical Information of China (English)

    钱忠根; 白延琴

    2005-01-01

    In this paper, primal-dual interior-point algorithm with dynamic step size is implemented for linear programming (LP) problems. The algorithms are based on a few kernel functions, including both self-regular functions and non-self-regular ones. The dynamic step size is compared with fixed step size for the algorithms in inner iteration of Newton step. Numerical tests show that the algorithms with dynamic step size are more efficient than those with fixed step size.

  3. Thermo-hydro-geochemical modelling of the bentonite buffer. LOT A2 experiment

    Energy Technology Data Exchange (ETDEWEB)

    Sena, Clara; Salas, Joaquin; Arcos, David (Amphos 21 Consulting S.L., Barcelona (Spain))

    2010-12-15

    The Swedish Nuclear Fuel and waste management company (SKB) is conducting a series of long term buffer material (LOT) tests at the Aespoe Hard Rock Laboratory (HRL) to test the behaviour of the bentonite buffer under conditions similar to those expected in a KBS-3 deep geological repository for high level nuclear waste (HLNW). In the present work a numerical model is developed to simulate (i) the thermo-hydraulic, (ii) transport and (iii) geochemical processes that have been observed in the LOT A2 test parcel. The LOT A2 test lasted approximately 6 years, and consists of a 4 m long vertical borehole drilled in diorite rock, from the ground of the Aespoe HRL tunnel. The borehole is composed of a central heater, maintained at 130 deg C in the lower 2 m of the borehole, a copper tube surrounding the heater and a 100 mm thick ring of pre-compacted Wyoming MX-80 bentonite around the copper tube /Karnland et al. 2009/. The numerical model developed here is a 1D axis-symmetric model that simulates the water saturation of the bentonite under a constant thermal gradient; the transport of solutes; and, the geochemical reactions observed in the bentonite blocks. Two cases have been modelled, one considering the highest temperature reached by the bentonite (at 3 m depth in the borehole, where temperatures of 130 and 85 deg C have been recorded near the copper tube and near the granitic host rock, respectively) and the other case assuming a constant temperature of 25 deg C, representing the upper part of borehole, where the bentonite has not been heated. In the LOT A2 test, the initial partially saturated bentonite becomes progressively water saturated, due to the injection of Aespoe granitic groundwater at granite - bentonite interface. The transport of solutes during the bentonite water saturation stage is believed to be controlled by water uptake from the surrounding groundwater to the wetting front and, additionally, in the case of heated bentonite, by a cyclic evaporation

  4. The Accidental Technology Steward: Or, How You Can Gamble Very Little and Gain a Lot

    Science.gov (United States)

    White, Nancy

    2007-01-01

    Technology stewardship is important in learning communities, where technology is not a primary focus and there is a lot of second-wave adoption. In schools, the students are usually first-wave adopters. Teachers, parents, and administrators are often the second wave; less comfortable with, interested in, or adept at technology adoption. Stewarding…

  5. Inter- and intra-manufacturer variability in pharmaceutical grades and lots of xanthan gum.

    Science.gov (United States)

    Thacker, Ankur; Fu, Shao; Boni, Riccardo L; Block, Lawrence H

    2010-12-01

    A pharmaceutical formulation typically contains one or more excipients in addition to the active pharmaceutical ingredient(s). Though excipients have been considered inert components of a formulation, variability in their properties has been shown to affect the performance of drug dosage forms and delivery systems. This study investigates the inter- and intra-manufacturer variability among different NF grades and lots of xanthan gum made by two manufacturers. As many formulators rely on compendial standards to monitor and control the variability of excipients, this study focuses on the adequacy of the NF specifications, in particular the viscosity specification, to discern the variability in solution properties of different pharmaceutical grades and lots of xanthan gum. All the grades and lots in this study were NF grade materials. Xanthan gum solutions were prepared in accordance with NF test methodology and were rheologically evaluated using a rotational rheometer. Both steady shear measurements and small amplitude oscillatory measurements were carried out on 1% w/w xanthan gum solutions. Results showed significant inter- and intra-manufacturer variability among the NF grades and lots of xanthan gum that was not reflected in the NF viscosity test specifications.

  6. Performance of engineered soil and trees in a parking lot bioswale

    Science.gov (United States)

    Qingfu Xiao; Gregory McPherson

    2011-01-01

    A bioswale integrating an engineered soil and trees was installed in a parking lot to evaluate its ability to reduce storm runoff, pollutant loading, and support tree growth. The adjacent control and treatment sites each received runoff from eight parking spaces and were identical except that there was no bioswale for the control site. A tree was planted at both sites...

  7. Scheduling and order acceptance for the customised stochastic lot scheduling problem

    NARCIS (Netherlands)

    van Foreest, Nicky D.; Wijngaard, Jacob; van der Vaart, Taco

    2010-01-01

    This paper develops and analyses several customer order acceptance policies to achieve high bottleneck utilisation for the customised stochastic lot scheduling problem (CSLSP) with large setups and strict order due dates. To compare the policies, simulation is used as the main tool, due to the compl

  8. Quality assesment of a lot of frozen mackerel, respective frozen handcut mackerel fillets (Scomber scombrus)

    NARCIS (Netherlands)

    Bruenner, K.K.

    2003-01-01

    At the request of Van Ameyde Marine in Amsterdam, RIVO BV assessed the quality of a number of blocks of frozen mackerel and a number of blocks of frozen handcut mackerel fillets (Scomber scombrus) by means of sensorial and chemical analysis. The samples were taken from a lot, which was partial "dama

  9. Chinese plasma-derived products supply under the lot release management system in 2007-2011.

    Science.gov (United States)

    Zhang, Xuejun; Ye, Shengliang; Du, Xi; Yuan, Jing; Zhao, Chaoming; Li, Changqing

    2013-11-01

    In 2007, the Chinese State Food and Drug Administration (SFDA) implemented a management system for lot release of all plasma-derived products. Since then, there have been only a few systematic studies of the blood supply, which is a concern when considering the small amount of plasma collected per capita (approximately 3 L/1000 people). As a result, there may be a threat to the safety of the available blood supply. In this study, we examined the characteristics of the supply of Chinese plasma-derived products. We investigated the reports of lot-released biological products derived from all 8 national or regional regulatory authorities in China from 2007 to 2011. The market supply characteristics of Chinese plasma-derived products were analyzed by reviewing the changes in supply varieties, the batches of lot-released plasma-derived products and the actual supply. As a result, the national regulatory authorities can more accurately develop a specific understanding of the production and quality management information provided by Chinese plasma product manufacturers. The implementation of the lot release system further ensures the clinical validity of the plasma-derived products in China and improves the safety of using plasma-derived products. This work provides an assessment of the future Chinese market supply of plasma-derived products and can function as a theoretical basis for the establishment of hemovigilance. Copyright © 2013 The International Alliance for Biological Standardization. Published by Elsevier Ltd. All rights reserved.

  10. Variation in quality of individual seeds within a seed lot of soybean (Glycine max (L.) Merrill)

    NARCIS (Netherlands)

    Illipronti, R.A.

    1997-01-01

    The research described in this thesis aimed at increasing insight into the sources of variation in quality attributes of individual seeds within a soybean seed lot, into the relations between physical attributes and performance of seeds in seed tests and in controlled seed production

  11. Parking Lot Runoff Quality and Treatment Efficiency of a Stormwater-Filtration Device, Madison, Wisconsin, 2005-07

    Science.gov (United States)

    Horwatich, Judy A.; Bannerman, Roger T.

    2010-01-01

    To evaluate the treatment efficiency of a stormwater-filtration device (SFD) for potential use at Wisconsin Department of Transportation (WisDOT) park-and-ride facilities, a SFD was installed at an employee parking lot in downtown Madison, Wisconsin. This type of parking lot was chosen for the test site because the constituent concentrations and particle-size distributions (PSDs) were expected to be similar to those of a typical park-and-ride lot operated by WisDOT. The objective of this particular installation was to reduce loads of total suspended solids (TSS) in stormwater runoff to Lake Monona. This study also was designed to provide a range of treatment efficiencies expected for a SFD. Samples from the inlet and outlet were analyzed for 33 organic and inorganic constituents, including 18 polycyclic aromatic hydrocarbons (PAHs). Samples were also analyzed for physical properties, including PSD. Water-quality samples were collected for 51 runoff events from November 2005 to August 2007. Samples from all runoff events were analyzed for concentrations of suspended sediment (SS). Samples from 31 runoff events were analyzed for 15 constituents, samples from 15 runoff events were analyzed for PAHs, and samples from 36 events were analyzed for PSD. The treatment efficiency of the SFD was calculated using the summation of loads (SOL) and the efficiency ratio methods. Constituents for which the concentrations and (or) loads were decreased by the SFD include TSS, SS, volatile suspended solids, total phosphorous (TP), total copper, total zinc, and PAHs. The efficiency ratios for these constituents are 45, 37, 38, 55, 22, 5, and 46 percent, respectively. The SOLs for these constituents are 32, 37, 28, 36, 23, 8, and 48 percent, respectively. The SOL for chloride was -21 and the efficiency ratio was -18. Six chemical constituents or properties-dissolved phosphorus, chemical oxygen demand, dissolved zinc, total dissolved solids, dissolved chemical oxygen demand, and

  12. Size-dependent dynamic pull-in analysis of geometric non-linear micro-plates based on the modified couple stress theory

    Science.gov (United States)

    Askari, Amir R.; Tahani, Masoud

    2017-02-01

    This paper focuses on the size-dependent dynamic pull-in instability in rectangular micro-plates actuated by step-input DC voltage. The present model accounts for the effects of in-plane displacements and their non-classical higher-order boundary conditions, von Kármán geometric non-linearity, non-classical couple stress components and the inherent non-linearity of distributed electrostatic pressure on the micro-plate motion. The governing equations of motion, which are clearly derived using Hamilton's principle, are solved through a novel computationally very efficient Galerkin-based reduced order model (ROM) in which all higher-order non-classical boundary conditions are completely satisfied. The present findings are compared and successfully validated by available results in the literature as well as those obtained by three-dimensional finite element simulations carried out using COMSOL Multyphysics. A detailed parametric study is also conducted to illustrate the effects of in-plane displacements, plate aspect ratio, couple stress components and geometric non-linearity on the dynamic instability threshold of the system.

  13. A smart dynamic self-induced orientable multiple size nano-roughness with amphiphilic feature as a stain-repellent hydrophilic surface.

    Science.gov (United States)

    Dastjerdi, Roya; Montazer, Majid; Stegmaier, Thomas; Moghadam, M B

    2012-03-01

    Recently developing bioinspired super-hydrophobic surfaces to achieve self-cleaning properties has been driving numerous researches. However, hydrophilicity is one of the most important features of garment comfort. Therefore, accomplishing self-cleaning and stain repellency on hydrophilic surfaces would be a high topic of interest. This research is concerned with wettability mechanism; static and dynamic study of contact angle through water droplet absorption on the multiple scale nano-roughness covered by different weight ratio of oppositely charged inorganic nanoparticles and amino-functionalized polysiloxane. The results revealed that the second layer of the resin formed on the surface can show an amphiphilic hybrid block copolymer-like feature whose dual action can be intensified during water droplet absorption by the created multiple size nano-roughness. This unique structure can create a stain repellent but hydrophilic surface with exceptional advantages. The mechanism has been deeply discussed according to the evidence on droplet edge interfacial energy changes as a driving force to overcome meta-stable Cassie state on the multiple size nano-roughness with amphiphilic feature. A lotus-like nano-roughness has been also observed on the SEM micrographs. Based on a statistically approached experimental design, the effect of variant factors on droplet absorption time, static, advancing, receding contact angles and self-cleaning properties has been mathematically modeled according to the response surface methodology (RSM).

  14. Characterization of Sizes of Aggregates of Insulin Analogs and the Conformations of the Constituent Protein Molecules: A Concomitant Dynamic Light Scattering and Raman Spectroscopy Study.

    Science.gov (United States)

    Zhou, Chen; Qi, Wei; Lewis, E Neil; Carpenter, John F

    2016-02-01

    To generate aggregates, 3 insulin analogs, lispro, aspart, and glulisine, were incubated without phenolic preservatives for 30 days at 37 °C. As a function of incubation time, aggregation was quantified with size exclusion chromatography, and the sizes of aggregates and the conformations of the constituent molecules were characterized with concomitant dynamic light scattering and Raman spectroscopy. During incubation, lispro was progressively converted into soluble aggregates with hydrodynamic diameters of circa 15 nm, and 95% of the native protein had aggregated at day 30. Raman spectroscopy documented that aggregation resulted in conversion of a large fraction of native alpha helix into nonnative beta sheet structure and a distortion of disulfide bonds. In contrast, for aspart and glulisine only 20% of the native proteins aggregated after 30 days, and minimal structural perturbations were detected. In addition, consistent with the relative aggregation rates during isothermal incubation, Raman spectroscopy showed that during heating the onset temperature for secondary structural perturbations of lispro occurred 7 °C-10 °C lower than those for aspart or glulisine. Overall the results of this study demonstrated that-as in the case during formation of amyloid fibrils from insulin-formation of soluble aggregates of lispro resulted in a high level of conversion of alpha helix into beta sheet. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  15. Complex flow patterns in a real-size intracranial aneurysm phantom: phase contrast MRI compared with particle image velocimetry and computational fluid dynamics.

    Science.gov (United States)

    van Ooij, P; Guédon, A; Poelma, C; Schneiders, J; Rutten, M C M; Marquering, H A; Majoie, C B; VanBavel, E; Nederveen, A J

    2012-01-01

    The aim of this study was to validate the flow patterns measured by high-resolution, time-resolved, three-dimensional phase contrast MRI in a real-size intracranial aneurysm phantom. Retrospectively gated three-dimensional phase contrast MRI was performed in an intracranial aneurysm phantom at a resolution of 0.2 × 0.2 × 0.3 mm(3) in a solenoid rat coil. Both steady and pulsatile flows were applied. The phase contrast MRI measurements were compared with particle image velocimetry measurements and computational fluid dynamics simulations. A quantitative comparison was performed by calculating the differences between the magnitude of the velocity vectors and angles between the velocity vectors in corresponding voxels. Qualitative analysis of the results was executed by visual inspection and comparison of the flow patterns. The root-mean-square errors of the velocity magnitude in the comparison between phase contrast MRI and computational fluid dynamics were 5% and 4% of the maximum phase contrast MRI velocity, and the medians of the angle distribution between corresponding velocity vectors were 16° and 14° for the steady and pulsatile measurements, respectively. In the phase contrast MRI and particle image velocimetry comparison, the root-mean-square errors were 12% and 10% of the maximum phase contrast MRI velocity, and the medians of the angle distribution between corresponding velocity vectors were 19° and 15° for the steady and pulsatile measurements, respectively. Good agreement was found in the qualitative comparison of flow patterns between the phase contrast MRI measurements and both particle image velocimetry measurements and computational fluid dynamics simulations. High-resolution, time-resolved, three-dimensional phase contrast MRI can accurately measure complex flow patterns in an intracranial aneurysm phantom. Copyright © 2011 John Wiley & Sons, Ltd.

  16. Aggregation dynamics and magnetic properties of magnetic micrometer-sized particles dispersed in a fluid under the action of rotating magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Llera, María [Instituto de Ciencias, Universidad Nacional de General Sarmiento, Buenos Aires (Argentina); Codnia, Jorge [Instituto de Ciencias, Universidad Nacional de General Sarmiento, Buenos Aires (Argentina); Centro de Investigaciones en Láseres y Aplicaciones, CITEDEF-CONICET, Buenos Aires (Argentina); Jorge, Guillermo A., E-mail: gjorge@ungs.edu.ar [Instituto de Ciencias, Universidad Nacional de General Sarmiento, Buenos Aires (Argentina)

    2015-06-15

    We present a dynamic study of soft magnetic, commercial Fe and Ni micrometer-sized particles dispersed in oleic acid and subjected to a variable (rotating) magnetic field in the horizontal plane. A very complex structure is formed after the particles decant towards the bottom liquid–solid interface and the magnetic field is applied for several minutes. The dynamics of structure formation was studied by means of the registration and analysis of microscopic video images, through a Matlab image analysis script. Several parameters, such as the number of clusters, the perimeter-based fractal dimension and circularity, were calculated as a function of time. The time evolution of the number of clusters was found to follow a power-law behavior, with an exponent consistent with that found in other studies for magnetic systems, whereas the typical formation time depends on the particle diameter and field configuration. Complementarily, the magnetic properties of the formed structure were studied, reproducing the experiment with liquid paraffin as the containing fluid, and then letting it solidify. The sample obtained was studied by vibrating sample magnetometry. The magnetization curves show that the material obtained is a planar magnetically anisotropic material, which could eventually be used as an anisotropic magnetic sensor or actuator. - Highlights: • Dynamic study of Fe and Ni particles in oleic acid under rotating fields. • A very complex system of interconnected clusters was observed. • Larger particles had a smaller aggregation time. • A power law behavior of the number of clusters vs. time. • A Fe-paraffin sample with planar anisotropy characterized.

  17. The orbital PDF: the dynamical state of Milky Way sized haloes and the intrinsic uncertainty in the determination of their masses

    Science.gov (United States)

    Han, Jiaxin; Wang, Wenting; Cole, Shaun; Frenk, Carlos S.

    2016-02-01

    Using realistic cosmological simulations of Milky Way sized haloes, we study their dynamical state and the accuracy of inferring their mass profiles with steady-state models of dynamical tracers. We use a new method that describes the phase-space distribution of a steady-state tracer population in a spherical potential without any assumption regarding the distribution of their orbits. Applying the method to five haloes from the Aquarius Λ cold dark matter (ΛCDM) N-body simulation, we find that dark matter particles are an accurate tracer that enables the halo mass and concentration parameters to be recovered with an accuracy of 5 per cent. Assuming a potential profile of the Navarro, Frenk & White (NFW) form does not significantly affect the fits in most cases, except for halo A whose density profile differs significantly from the NFW form, leading to a 30 per cent bias in the dynamically fitted parameters. The existence of substructures in the dark matter tracers only affects the fits by ˜1 per cent. Applying the method to mock stellar haloes generated by a particle-tagging technique, we find the stars are farther from equilibrium than dark matter particles, yielding a systematic bias of ˜20 per cent in the inferred mass and concentration parameter. The level of systematic biases obtained from a conventional distribution function fit to stars is comparable to ours, while similar fits to dark matter tracers are significantly biased in contrast to our fits. In line with previous studies, the mass bias is much reduced near the tracer half-mass radius.

  18. Spatial and temporal dynamics of size-structured photosynthetic parameters (PAM) and primary production (13C) of pico- and nano-phytoplankton in an atoll lagoon.

    Science.gov (United States)

    Lefebvre, Sébastien; Claquin, Pascal; Orvain, Francis; Véron, Benoît; Charpy, Loïc

    2012-01-01

    Atoll lagoons display a high diversity of trophic states due mainly to their specific geomorphology, and probably to their level and mode of human exploitation. We investigated the functioning of the Ahe atoll lagoon, utilized for pearl oyster farming, through estimations of photosynthetic parameters (pulse amplitude modulation fluorometry) and primary production ((13)C incorporation) measurements of the size structured phytoplankton biomass (2 μm). Spatial and temporal scales of variability were surveyed during four seasons, over 16 months, at four sites within the lagoon. While primary production (P) was dominated by the picophytoplankton, its biomass specific primary productivity (P(B)) was lower than in other atoll lagoons. The variables size fraction of the phytoplankton, water temperature, season, the interaction term station*fraction and site, explained significantly the variance of the data set using redundancy analysis. No significant trends over depth were observed in the range of 0-20 m. A clear spatial pattern was found which was persistent over the seasons: south and north sites were different from the two central stations for most of the measured variables. This pattern could possibly be explained by the existence of water cells showing different water residence time within the lagoon. Photoacclimation strategies of the two size fractions differed through their light saturation coefficient (higher for picophytoplankton), but not through their maximum photosynthetic capacity (ETR(max)). Positive linear relationships between photosynthetic parameters indicated that their dynamic was independent of light availability in this ecosystem, but most probably dependent on nutrient availability and/or rapid changes in the community structure. Spatial and temporal patterns of the measured processes are then further discussed in the context of nutrient availability and the possible role of cultured oysters in nutrient recycling.

  19. Size-Resolved Ultrafine Particle Deposition and Brownian Coagulation from Gasoline Vehicle Exhaust in an Environmental Test Chamber.

    Science.gov (United States)

    Zhao, Yu; Wang, Fang; Zhao, Jianing

    2015-10-20

    Size-resolved deposition rates and Brownian coagulation of particles between 20 and 900 nm (mobility diameter) were estimated in a well-mixed environmental chamber from a gasoline vehicle exhaust with a total peak particle concentration of 10(5)-10(6) particles/cm(3) at 12.24-25.22 °C. A deposition theory with modified friction velocity and coagulation model was also employed to predict particle concentration decay. Initially during particle decay, approximately 85% or more of the particles had diameters of vehicle exhaust particle dynamics and assess human exposure to vehicle particle pollutants in urban areas, tunnels, and underground parking lots.

  20. A software development for establishing optimal production lots and its application in academic and business environments

    Directory of Open Access Journals (Sweden)

    Javier Valencia Mendez

    2014-11-01

    Full Text Available The recent global economic downturn has increased an already perceived need in organizations for cost savings. To cope with such need, companies can opt for different strategies. This paper focuses on optimizing processes and, more specifically, determining the optimal lot production. To determine the optimal lot of a specific production process, a new software was developed that not only incorporates various productive and logistical elements in its calculations but also affords users a practical way to manage the large number of input parameters required to determine the optimal batch. The developed software has not only been validated by several companies, both Spanish and Mexican, who achieved significant savings, but also used as a teaching tool in universities with highly satisfactory results from the point of view of student learning. A special contribution of this work is that the developed tool can be sent to the interested reader free of charge upon request.