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Sample records for knapsack packing problem

  1. Conceptual design optimization of rectilinear building frames: A knapsack problem approach

    NASA Astrophysics Data System (ADS)

    Sharafi, Pezhman; Teh, Lip H.; Hadi, Muhammad N. S.

    2015-10-01

    This article presents an automated technique for preliminary layout (conceptual design) optimization of rectilinear, orthogonal building frames in which the shape of the building plan, the number of bays and the size of unsupported spans are variables. It adopts the knapsack problem as the applied combinatorial optimization problem, and describes how the conceptual design optimization problem can be generally modelled as the unbounded multi-constraint multiple knapsack problem. It discusses some special cases, which can be modelled more efficiently as the single knapsack problem, the multiple-choice knapsack problem or the multiple knapsack problem. A knapsack contains sub-rectangles that define the floor plan and the location of columns. Particular conditions or preferences for the conceptual design can be incorporated as constraints on the knapsacks and/or sub-rectangles. A bi-objective knapsack problem is defined with the aim of obtaining a conceptual design having minimum cost and maximum plan regularity (minimum structural eccentricity). A multi-objective ant colony algorithm is formulated to solve the combinatorial optimization problem. A numerical example is included to demonstrate the application of the present method and the robustness of the algorithm.

  2. How Humans Solve Complex Problems: The Case of the Knapsack Problem

    PubMed Central

    Murawski, Carsten; Bossaerts, Peter

    2016-01-01

    Life presents us with problems of varying complexity. Yet, complexity is not accounted for in theories of human decision-making. Here we study instances of the knapsack problem, a discrete optimisation problem commonly encountered at all levels of cognition, from attention gating to intellectual discovery. Complexity of this problem is well understood from the perspective of a mechanical device like a computer. We show experimentally that human performance too decreased with complexity as defined in computer science. Defying traditional economic principles, participants spent effort way beyond the point where marginal gain was positive, and economic performance increased with instance difficulty. Human attempts at solving the instances exhibited commonalities with algorithms developed for computers, although biological resource constraints–limited working and episodic memories–had noticeable impact. Consistent with the very nature of the knapsack problem, only a minority of participants found the solution–often quickly–but the ones who did appeared not to realise. Substantial heterogeneity emerged, suggesting why prizes and patents, schemes that incentivise intellectual discovery but discourage information sharing, have been found to be less effective than mechanisms that reveal private information, such as markets. PMID:27713516

  3. Approximating the 0-1 Multiple Knapsack Problem with Agent Decomposition and Market Negotiation

    SciTech Connect

    Smolinski, B.

    1999-09-03

    The 0-1 multiple knapsack problem appears in many domains from financial portfolio management to cargo ship stowing. Methods for solving it range from approximate algorithms, such as greedy algorithms, to exact algorithms, such as branch and bound. Approximate algorithms have no bounds on how poorly they perform and exact algorithms can suffer from exponential time and space complexities with large data sets. This paper introduces a market model based on agent decomposition and market auctions for approximating the 0-1 multiple knapsack problem, and an algorithm that implements the model (M(x)). M(x) traverses the solution space rather than getting caught in a local maximum, overcoming an inherent problem of many greedy algorithms. The use of agents ensures that infeasible solutions are not considered while traversing the solution space and that traversal of the solution space is not just random, but is also directed. M(x) is compared to a bound and bound algorithm (BB) and a simple greedy algorithm with a random shuffle (G(x)). The results suggest that M(x) is a good algorithm for approximating the 0-1 Multiple Knapsack problem. M(x) almost always found solutions that were close to optimal in a fraction of the time it took BB to run and with much less memory on large test data sets. M(x) usually performed better than G(x) on hard problems with correlated data.

  4. a Genetic Algorithm Based on Sexual Selection for the Multidimensional 0/1 Knapsack Problems

    NASA Astrophysics Data System (ADS)

    Varnamkhasti, Mohammad Jalali; Lee, Lai Soon

    In this study, a new technique is presented for choosing mate chromosomes during sexual selection in a genetic algorithm. The population is divided into groups of males and females. During the sexual selection, the female chromosome is selected by the tournament selection while the male chromosome is selected based on the hamming distance from the selected female chromosome, fitness value or active genes. Computational experiments are conducted on the proposed technique and the results are compared with some selection mechanisms commonly used for solving multidimensional 0/1 knapsack problems published in the literature.

  5. A set partitioning reformulation for the multiple-choice multidimensional knapsack problem

    NASA Astrophysics Data System (ADS)

    Voß, Stefan; Lalla-Ruiz, Eduardo

    2016-05-01

    The Multiple-choice Multidimensional Knapsack Problem (MMKP) is a well-known ?-hard combinatorial optimization problem that has received a lot of attention from the research community as it can be easily translated to several real-world problems arising in areas such as allocating resources, reliability engineering, cognitive radio networks, cloud computing, etc. In this regard, an exact model that is able to provide high-quality feasible solutions for solving it or being partially included in algorithmic schemes is desirable. The MMKP basically consists of finding a subset of objects that maximizes the total profit while observing some capacity restrictions. In this article a reformulation of the MMKP as a set partitioning problem is proposed to allow for new insights into modelling the MMKP. The computational experimentation provides new insights into the problem itself and shows that the new model is able to improve on the best of the known results for some of the most common benchmark instances.

  6. A pegging algorithm for separable continuous nonlinear knapsack problems with box constraints

    NASA Astrophysics Data System (ADS)

    Kim, Gitae; Wu, Chih-Hang

    2012-10-01

    This article proposes an efficient pegging algorithm for solving separable continuous nonlinear knapsack problems with box constraints. A well-known pegging algorithm for solving this problem is the Bitran-Hax algorithm, a preferred choice for large-scale problems. However, at each iteration, it must calculate an optimal dual variable and update all free primal variables, which is time consuming. The proposed algorithm checks the box constraints implicitly using the bounds on the Lagrange multiplier without explicitly calculating primal variables at each iteration as well as updating the dual solution in a more efficient manner. Results of computational experiments have shown that the proposed algorithm consistently outperforms the Bitran-Hax in all baseline testing and two real-time application models. The proposed algorithm shows significant potential for many other mathematical models in real-world applications with straightforward extensions.

  7. An improved hybrid encoding cuckoo search algorithm for 0-1 knapsack problems.

    PubMed

    Feng, Yanhong; Jia, Ke; He, Yichao

    2014-01-01

    Cuckoo search (CS) is a new robust swarm intelligence method that is based on the brood parasitism of some cuckoo species. In this paper, an improved hybrid encoding cuckoo search algorithm (ICS) with greedy strategy is put forward for solving 0-1 knapsack problems. First of all, for solving binary optimization problem with ICS, based on the idea of individual hybrid encoding, the cuckoo search over a continuous space is transformed into the synchronous evolution search over discrete space. Subsequently, the concept of confidence interval (CI) is introduced; hence, the new position updating is designed and genetic mutation with a small probability is introduced. The former enables the population to move towards the global best solution rapidly in every generation, and the latter can effectively prevent the ICS from trapping into the local optimum. Furthermore, the greedy transform method is used to repair the infeasible solution and optimize the feasible solution. Experiments with a large number of KP instances show the effectiveness of the proposed algorithm and its ability to achieve good quality solutions. PMID:24527026

  8. An improved hybrid encoding cuckoo search algorithm for 0-1 knapsack problems.

    PubMed

    Feng, Yanhong; Jia, Ke; He, Yichao

    2014-01-01

    Cuckoo search (CS) is a new robust swarm intelligence method that is based on the brood parasitism of some cuckoo species. In this paper, an improved hybrid encoding cuckoo search algorithm (ICS) with greedy strategy is put forward for solving 0-1 knapsack problems. First of all, for solving binary optimization problem with ICS, based on the idea of individual hybrid encoding, the cuckoo search over a continuous space is transformed into the synchronous evolution search over discrete space. Subsequently, the concept of confidence interval (CI) is introduced; hence, the new position updating is designed and genetic mutation with a small probability is introduced. The former enables the population to move towards the global best solution rapidly in every generation, and the latter can effectively prevent the ICS from trapping into the local optimum. Furthermore, the greedy transform method is used to repair the infeasible solution and optimize the feasible solution. Experiments with a large number of KP instances show the effectiveness of the proposed algorithm and its ability to achieve good quality solutions.

  9. Dynamic bin packing problem

    NASA Technical Reports Server (NTRS)

    Dikshit, Piyush; Guimaraes, Katia; Ramamurthy, Maya; Agrawala, Ashok K.; Larsen, Ronald L.

    1989-01-01

    In a previous work we have defined a general architecture model for autonomous systems, which can be mapped easily to describe the functions of any automated system (SDAG-86-01). In this note, we use the model to describe the problem of thermal management in space stations. First we briefly review the architecture, then we present the environment of our application, and finally we detail the specific function for each functional block of the architecture for that environment.

  10. An effective hybrid cuckoo search algorithm with improved shuffled frog leaping algorithm for 0-1 knapsack problems.

    PubMed

    Feng, Yanhong; Wang, Gai-Ge; Feng, Qingjiang; Zhao, Xiang-Jun

    2014-01-01

    An effective hybrid cuckoo search algorithm (CS) with improved shuffled frog-leaping algorithm (ISFLA) is put forward for solving 0-1 knapsack problem. First of all, with the framework of SFLA, an improved frog-leap operator is designed with the effect of the global optimal information on the frog leaping and information exchange between frog individuals combined with genetic mutation with a small probability. Subsequently, in order to improve the convergence speed and enhance the exploitation ability, a novel CS model is proposed with considering the specific advantages of Lévy flights and frog-leap operator. Furthermore, the greedy transform method is used to repair the infeasible solution and optimize the feasible solution. Finally, numerical simulations are carried out on six different types of 0-1 knapsack instances, and the comparative results have shown the effectiveness of the proposed algorithm and its ability to achieve good quality solutions, which outperforms the binary cuckoo search, the binary differential evolution, and the genetic algorithm. PMID:25404940

  11. An effective hybrid cuckoo search algorithm with improved shuffled frog leaping algorithm for 0-1 knapsack problems.

    PubMed

    Feng, Yanhong; Wang, Gai-Ge; Feng, Qingjiang; Zhao, Xiang-Jun

    2014-01-01

    An effective hybrid cuckoo search algorithm (CS) with improved shuffled frog-leaping algorithm (ISFLA) is put forward for solving 0-1 knapsack problem. First of all, with the framework of SFLA, an improved frog-leap operator is designed with the effect of the global optimal information on the frog leaping and information exchange between frog individuals combined with genetic mutation with a small probability. Subsequently, in order to improve the convergence speed and enhance the exploitation ability, a novel CS model is proposed with considering the specific advantages of Lévy flights and frog-leap operator. Furthermore, the greedy transform method is used to repair the infeasible solution and optimize the feasible solution. Finally, numerical simulations are carried out on six different types of 0-1 knapsack instances, and the comparative results have shown the effectiveness of the proposed algorithm and its ability to achieve good quality solutions, which outperforms the binary cuckoo search, the binary differential evolution, and the genetic algorithm.

  12. An Effective Hybrid Cuckoo Search Algorithm with Improved Shuffled Frog Leaping Algorithm for 0-1 Knapsack Problems

    PubMed Central

    Wang, Gai-Ge; Feng, Qingjiang; Zhao, Xiang-Jun

    2014-01-01

    An effective hybrid cuckoo search algorithm (CS) with improved shuffled frog-leaping algorithm (ISFLA) is put forward for solving 0-1 knapsack problem. First of all, with the framework of SFLA, an improved frog-leap operator is designed with the effect of the global optimal information on the frog leaping and information exchange between frog individuals combined with genetic mutation with a small probability. Subsequently, in order to improve the convergence speed and enhance the exploitation ability, a novel CS model is proposed with considering the specific advantages of Lévy flights and frog-leap operator. Furthermore, the greedy transform method is used to repair the infeasible solution and optimize the feasible solution. Finally, numerical simulations are carried out on six different types of 0-1 knapsack instances, and the comparative results have shown the effectiveness of the proposed algorithm and its ability to achieve good quality solutions, which outperforms the binary cuckoo search, the binary differential evolution, and the genetic algorithm. PMID:25404940

  13. Slimhole frac pack tools overcome erosion problems

    SciTech Connect

    Stout, G.; Matte, T.; Rogers, B.

    1997-04-01

    The application of frac pack technology for stimulation and sand control in the Gulf of Mexico`s unconsolidated formations has steadily increased during the past several years. In addition, re-entry drilling has been one of the fastest growing development techniques used by operators for optimizing reservoir productivity. As such, smaller casing sizes are becoming more common in oil and gas producing wells. Gravel pack tools were being used for frac packing in 7-in. casing sizes and larger, but no tools were available to frac pack in the smaller 5-in. and 5{1/2}-in. casing. The erosion problems operators were experiencing in 7-in. gravel pack tools heightened concerns about fracturing through 5-in. tools with even smaller flow areas. Flow cutting in the 7-in. tools was so severe that it caused fluid communication between the gravel pack ports and the return flow holes in the crossover tool. This allowed fluid and proppant to return to the annulus above the packer, which could cause possible early screen-out and sticking of the crossover tool. The flow cutting could also reduce the tool`s pressure and tensile ratings. Any one of these problems could jeopardize the success of the frac pack operation. Therefore, an erosion resistant crossover tool for slimhole casing was developed to address these problems and optimize frac pack success.

  14. Approaches to cutting/packing problems

    SciTech Connect

    Arenales, M.; Morabito, R.

    1994-12-31

    Cutting and Packing Problems (CPP) consist of geometrically combining ordered pieces into large objects such that an objective function is optimized. Depending on the number of dimensions involved, we may have one-dimensional CPP (e.g. Bin Packing Problem), two-dimensional CPP (e.g. Pallet Loading Problem), three-dimensional CPP (e.g. Container Loading Problem), and so on. The authors proposed a solution approach to two-dimensional guillotine cutting problems, and extended it to constrained three-dimensional problems. This approach, based on an and/or-graph representation of the solution space, can also be applied to non-guillotine cutting problems. This present work unifies and generalizes the previous ones.

  15. Multi-Criteria Knapsack Problem for Disease Selection in an Observation Ward

    NASA Astrophysics Data System (ADS)

    Lurkittikul, N.; Kittithreerapronchai, O.

    2014-06-01

    The aging population and the introduction of Thailand universal healthcare have increased inpatients and outpatients to public hospitals, particularly to a hospital that provides special and comprehensive health services. Many inpatient wards have experienced large influx of inpatients as the hospitals have to admit all patients regardless their conditions. These overcrowding wards cause stress to medical staffs, block access between medical departments, hospital-acquired infections, and ineffective uses of resources. One way to manage such inundated inpatient is to select some patients whose conditions require less clinical attention or whose lengths of stay are predictable and short and, then, place them at an observation ward. This intermediate ward increases turnover of beds and reduces unnecessary paperwork as patients are considered to be outpatients. In this article, we studied inpatient data of a tertiary care hospital in which an observation ward was considered to alleviate the overcrowding problem at Internal Medicine Department. The analysis of data showed that the hospital can balance inpatient flow by managing a group of patients who is admitted because of treatments ordered by its special clinics. Having explored several alternatives, we suggested patient selection criteria and proposed a layout at an observation ward. The hospital should increase medical beds in a new building ward because the current observation ward can handle 27.3% of total short stay patients, while the observation ward is projected to handle 80% of total short stay patients.

  16. Inverting sets and the packing problem

    SciTech Connect

    Faber, V.; Goldberg, M.K.; Knill, E.; Spencer, T.H.

    1992-12-01

    Given a set V, a subset S, and a permutation {pi} of V, we say that {pi} permutes S if {pi}(S) {intersection} S = {theta}. Given a collection S = (V; S{sub 1}..., S{sub m}), where S{sub i} {improper_subset} V (i = 1,...,m), we say that S is invertible if there is a permutation {pi} of V such that {pi}(S{sub i}) {improper_subset} V -- S{sub i}. In this paper, we present necessary and sufficient conditions for the invertibility of a collection and construct a polynomial algorithm which determines whether a given collection is invertible. For an arbitrary collection, we give a lower bound for the maximum number of sets that can be inverted. Finally, we consider the problem of constructing a collection of sets such that no sub-collection of size three is invertible. Our constructions of such collections come from solutions to the packing problem with unbounded block sizes. We prove several new lower and upper bounds for the packing problem and present a new explicit construction of packing.

  17. Inverting sets and the packing problem

    SciTech Connect

    Faber, V. ); Goldberg, M.K. . Dept. of Computer Science); Knill, E. . School of Computer Science); Spencer, T.H. . Dept. of Mathematics and Computer Science)

    1992-01-01

    Given a set V, a subset S, and a permutation [pi] of V, we say that [pi] permutes S if [pi](S) [intersection] S = [theta]. Given a collection S = (V; S[sub 1]..., S[sub m]), where S[sub i] [improper subset] V (i = 1,...,m), we say that S is invertible if there is a permutation [pi] of V such that [pi](S[sub i]) [improper subset] V -- S[sub i]. In this paper, we present necessary and sufficient conditions for the invertibility of a collection and construct a polynomial algorithm which determines whether a given collection is invertible. For an arbitrary collection, we give a lower bound for the maximum number of sets that can be inverted. Finally, we consider the problem of constructing a collection of sets such that no sub-collection of size three is invertible. Our constructions of such collections come from solutions to the packing problem with unbounded block sizes. We prove several new lower and upper bounds for the packing problem and present a new explicit construction of packing.

  18. A SAT Encoding for Multi-dimensional Packing Problems

    NASA Astrophysics Data System (ADS)

    Grandcolas, Stéphane; Pinto, Cédric

    The Orthogonal Packing Problem (OPP) consists in determining if a set of items can be packed into a given container. This decision problem is NP-complete. Fekete et al. modelled the problem in which the overlaps between the objects in each dimension are represented by interval graphs. In this paper we propose a SAT encoding of Fekete et al. characterization. Some results are presented, and the efficiency of this approach is compared with other SAT encodings.

  19. Exact solution of the robust knapsack problem☆

    PubMed Central

    Monaci, Michele; Pferschy, Ulrich; Serafini, Paolo

    2013-01-01

    We consider an uncertain variant of the knapsack problem in which the weight of the items is not exactly known in advance, but belongs to a given interval, and an upper bound is imposed on the number of items whose weight differs from the expected one. For this problem, we provide a dynamic programming algorithm and present techniques aimed at reducing its space and time complexities. Finally, we computationally compare the performances of the proposed algorithm with those of different exact algorithms presented so far in the literature for robust optimization problems. PMID:24187428

  20. Are most low-density knapsacks solvable in polynomial time

    SciTech Connect

    Brickell, E.F.

    1983-01-01

    In this paper, we show how techniques similar to those developed for breaking the cryptosystems can be used to solve knapsacks of low density. In the examples we have run, the algorithm has always been successful on knapsacks of density less than or equal to 1/2. We show, based on one assumption, that the algorithm will succeed on most knapsacks of density less than or equal to 1/3.

  1. Heuristic-based energy landscape paving for the circular packing problem with performance constraints of equilibrium

    NASA Astrophysics Data System (ADS)

    Liu, Jingfa; Jiang, Yucong; Li, Gang; Xue, Yu; Liu, Zhaoxia; Zhang, Zhen

    2015-08-01

    The optimal layout problem of circle group in a circular container with performance constraints of equilibrium belongs to a class of NP-hard problem. The key obstacle of solving this problem is the lack of an effective global optimization method. We convert the circular packing problem with performance constraints of equilibrium into the unconstrained optimization problem by using quasi-physical strategy and penalty function method. By putting forward a new updating mechanism of the histogram function in energy landscape paving (ELP) method and incorporating heuristic conformation update strategies into the ELP method, we obtain an improved ELP (IELP) method. Subsequently, by combining the IELP method and the local search (LS) procedure, we put forward a hybrid algorithm, denoted by IELP-LS, for the circular packing problem with performance constraints of equilibrium. We test three sets of benchmarks consisting of 21 representative instances from the current literature. The proposed algorithm breaks the records of all 10 instances in the first set, and achieves the same or even better results than other methods in literature for 10 out of 11 instances in the second and third sets. The computational results show that the proposed algorithm is an effective method for solving the circular packing problem with performance constraints of equilibrium.

  2. Membrane Packing Problems: A short Review on computational Membrane Modeling Methods and Tools

    PubMed Central

    Sommer, Björn

    2013-01-01

    The use of model membranes is currently part of the daily workflow for many biochemical and biophysical disciplines. These membranes are used to analyze the behavior of small substances, to simulate transport processes, to study the structure of macromolecules or for illustrative purposes. But, how can these membrane structures be generated? This mini review discusses a number of ways to obtain these structures. First, the problem will be formulated as the Membrane Packing Problem. It will be shown that the theoretical problem of placing proteins and lipids onto a membrane area differ significantly. Thus, two sub-problems will be defined and discussed. Then, different – partly historical – membrane modeling methods will be introduced. And finally, membrane modeling tools will be evaluated which are able to semi-automatically generate these model membranes and thus, drastically accelerate and simplify the membrane generation process. The mini review concludes with advice about which tool is appropriate for which application case. PMID:24688707

  3. A Column-Generation and Branch-and-Cut Approach to the Bandwidth-Packing Problem.

    PubMed

    Villa, Christine; Hoffman, Karla

    2006-01-01

    The telecommunications problem of assigning calls with point to point demand to a capacitated network where each call can be assigned to at most one path has been called the Bandwidth-Packing Problem. For a given network, with specified arc costs and arc capacities, one wishes to route calls (defined by a starting and ending point) through the network to maximize the profit from the calls routed. Each such call is single path routed and not all calls will be routed. We propose a branch-and-cut methodology coupled with column generation to optimally solve such problems. We examine the alternative approaches in the literature and explain how this new method takes the best of all components of methods suggested previously. The method we suggest is new in that it includes a linear programming-based heuristic for obtaining good lower bounds, uses lifted minimal covers that take into account special-ordered set constraints, and dynamically choose among three alternative branching strategies. In addition, whenever a new column is generated, it is lifted into all existing cuts. We also discuss the need to generate all tied optimal linear optimization solutions if one wishes to assure that the solution obtained is optimal. Our computational results provide solutions to problems previously unsolvable. PMID:27274927

  4. Quantification of emissions from knapsack sprayers: 'the weight method

    NASA Astrophysics Data System (ADS)

    Garcia-Santos, Glenda; Binder, Claudia R.

    2010-05-01

    Misuse of pesticides kill or seriously sicken thousands of people every year and poison the natural environment. Investigations of occupational and environmental risk have received considerable interest over the last decades. And yet, lack of staff and analytical equipments as well the costs of chemical analyses make difficult, if not impossible, the control of the pesticide contamination and residues in humans, air, water, and soils in developing countries. To assess emissions of pesticides (transport and deposition) during spray application and the risk for the human health and the environment, tracers can be useful tools. Uranine was used to quantify drift airborne and later deposition on the neighbouring field and clothes of the applicator after spraying with a knapsack sprayer in one of the biggest areas of potato production in Colombia. Keeping the same setup the amount of wet drift was measured by difference in the weight of high absorbent papers used to collect the tracer. Surprisingly this weight method (Weight-HAP) was able to explain 71% of the drift variance measured with the tracer. Therefore the weight method is presented as a suitable rapid low cost screening tool, complementary to toxicological tests, to assess air pollution, occupational and environmental exposure generated by the emissions from knapsack sprayers during pesticide application. This technique might be important in places were there is lack of analytical instruments.

  5. Front-of-pack nutrition labelling: are multiple formats a problem for consumers?

    PubMed Central

    Adamson, Ashley J.; Clegg, Sue; Malam, Sally; Rigg, Malcolm; Duncan, Sue

    2013-01-01

    Background: Nutrition labels are a potentially valuable tool to assist consumers in making healthy food choices. Front-of-pack labels are a relatively new format and are now widely used across many European countries, but it is unclear which of the many formats in use are best understood by consumers. It is also unclear whether the existence of multiple formats impedes understanding and use. This article addresses this question with findings from a study commissioned by the UK Food Standards Agency to provide evidence to inform policy decisions in this area. Methods: In-depth qualitative interviews were used to explore consumers’ decision-making processes when using two different front-of-pack label formats to judge the relative healthiness of a pair of products. Participants were presented with product pairs differently labelled and a series of structured prompts were used to access their internal dialogues and to identify any difficulties encountered. Results: The interviews revealed that making product comparisons using different label formats was challenging for participants and particularly for those product pairs where there was not an obvious answer. When the label formats on the product pairs lacked a common element, such as text, this also caused difficulties and misinterpretation. The comparisons also took time and effort that would be a deterrent in real-life situations. Conclusions: These findings indicate that the existence of multiple front-of-pack label formats in the marketplace may impede consumer comprehension and discourage use. They suggest that a single format may encourage consumers to use front-of-pack labels in making healthy food choices. PMID:22140250

  6. Avian photoreceptor patterns represent a disordered hyperuniform solution to a multiscale packing problem.

    PubMed

    Jiao, Yang; Lau, Timothy; Hatzikirou, Haralampos; Meyer-Hermann, Michael; Joseph C Corbo; Torquato, Salvatore

    2014-02-01

    Optimal spatial sampling of light rigorously requires that identical photoreceptors be arranged in perfectly regular arrays in two dimensions. Examples of such perfect arrays in nature include the compound eyes of insects and the nearly crystalline photoreceptor patterns of some fish and reptiles. Birds are highly visual animals with five different cone photoreceptor subtypes, yet their photoreceptor patterns are not perfectly regular. By analyzing the chicken cone photoreceptor system consisting of five different cell types using a variety of sensitive microstructural descriptors, we find that the disordered photoreceptor patterns are "hyperuniform" (exhibiting vanishing infinite-wavelength density fluctuations), a property that had heretofore been identified in a unique subset of physical systems, but had never been observed in any living organism. Remarkably, the patterns of both the total population and the individual cell types are simultaneously hyperuniform. We term such patterns "multihyperuniform" because multiple distinct subsets of the overall point pattern are themselves hyperuniform. We have devised a unique multiscale cell packing model in two dimensions that suggests that photoreceptor types interact with both short- and long-ranged repulsive forces and that the resultant competition between the types gives rise to the aforementioned singular spatial features characterizing the system, including multihyperuniformity. These findings suggest that a disordered hyperuniform pattern may represent the most uniform sampling arrangement attainable in the avian system, given intrinsic packing constraints within the photoreceptor epithelium. In addition, they show how fundamental physical constraints can change the course of a biological optimization process. Our results suggest that multihyperuniform disordered structures have implications for the design of materials with novel physical properties and therefore may represent a fruitful area for future

  7. Avian photoreceptor patterns represent a disordered hyperuniform solution to a multiscale packing problem

    NASA Astrophysics Data System (ADS)

    Jiao, Yang; Lau, Timothy; Hatzikirou, Haralampos; Meyer-Hermann, Michael; Corbo, Joseph C.; Torquato, Salvatore

    2014-02-01

    Optimal spatial sampling of light rigorously requires that identical photoreceptors be arranged in perfectly regular arrays in two dimensions. Examples of such perfect arrays in nature include the compound eyes of insects and the nearly crystalline photoreceptor patterns of some fish and reptiles. Birds are highly visual animals with five different cone photoreceptor subtypes, yet their photoreceptor patterns are not perfectly regular. By analyzing the chicken cone photoreceptor system consisting of five different cell types using a variety of sensitive microstructural descriptors, we find that the disordered photoreceptor patterns are "hyperuniform" (exhibiting vanishing infinite-wavelength density fluctuations), a property that had heretofore been identified in a unique subset of physical systems, but had never been observed in any living organism. Remarkably, the patterns of both the total population and the individual cell types are simultaneously hyperuniform. We term such patterns "multihyperuniform" because multiple distinct subsets of the overall point pattern are themselves hyperuniform. We have devised a unique multiscale cell packing model in two dimensions that suggests that photoreceptor types interact with both short- and long-ranged repulsive forces and that the resultant competition between the types gives rise to the aforementioned singular spatial features characterizing the system, including multihyperuniformity. These findings suggest that a disordered hyperuniform pattern may represent the most uniform sampling arrangement attainable in the avian system, given intrinsic packing constraints within the photoreceptor epithelium. In addition, they show how fundamental physical constraints can change the course of a biological optimization process. Our results suggest that multihyperuniform disordered structures have implications for the design of materials with novel physical properties and therefore may represent a fruitful area for future

  8. [The immuno-endocrine system. A new endocrine theory: the problem of the packed transport].

    PubMed

    Csaba, György

    2011-05-15

    Since the eighties of the last century hormone content was justified in immune cells (lymphocytes, granulocytes, monocytes, macrophages and mast cells), which produce, store and secrete these hormones. Although the amount of these materials in immune cells is relatively small, the mass of the producers (immune cells) is so large, that the phenomenon must be considered from endocrinological point of view, underlying the important differences between the "classical" and immuno-endocrine systems. Cells of the classic (built-in) endocrine system are mono-producers, while immune cells can synthesize many types of hormones (polyproducers). In addition, these cells can transport the whole hormone-producing machinery to the site of need, producing a local effect. This can be observed, for example, in the case of endorphin producing immune cells during inflammation and during early pregnancy around the chorionic villi. Hormone producing immune cells also have receptors for many hormones, so that they are poly-receivers. Via hormone producing and receiving capacity there is a bidirectional connection between the neuro-endocrine and immuno-endocrine systems. In addition, there is a network inside the immuno-endocrine system. The packed transport theory attempts to explain the mechanism and importance of the immuno-endocrine system.

  9. Knapsack - TOPSIS Technique for Vertical Handover in Heterogeneous Wireless Network

    PubMed Central

    2015-01-01

    In a heterogeneous wireless network, handover techniques are designed to facilitate anywhere/anytime service continuity for mobile users. Consistent best-possible access to a network with widely varying network characteristics requires seamless mobility management techniques. Hence, the vertical handover process imposes important technical challenges. Handover decisions are triggered for continuous connectivity of mobile terminals. However, bad network selection and overload conditions in the chosen network can cause fallout in the form of handover failure. In order to maintain the required Quality of Service during the handover process, decision algorithms should incorporate intelligent techniques. In this paper, a new and efficient vertical handover mechanism is implemented using a dynamic programming method from the operation research discipline. This dynamic programming approach, which is integrated with the Technique to Order Preference by Similarity to Ideal Solution (TOPSIS) method, provides the mobile user with the best handover decisions. Moreover, in this proposed handover algorithm a deterministic approach which divides the network into zones is incorporated into the network server in order to derive an optimal solution. The study revealed that this method is found to achieve better performance and QoS support to users and greatly reduce the handover failures when compared to the traditional TOPSIS method. The decision arrived at the zone gateway using this operational research analytical method (known as the dynamic programming knapsack approach together with Technique to Order Preference by Similarity to Ideal Solution) yields remarkably better results in terms of the network performance measures such as throughput and delay. PMID:26237221

  10. Unpacking Teachers' Invisible Knapsacks: Social Identity and Privilege in Higher Education

    ERIC Educational Resources Information Center

    Barnett, Pamela E.

    2013-01-01

    Peggy McIntosh (1988) famously unpacked what she called an "invisible knapsack" of privileges socially conferred upon whites, men, and heterosexuals (1988). She argued that not only are women and minorities at a disadvantage, but those with social power enjoy benefits that are both unearned and unjustified. We often accept those…

  11. Security of a Class of Knapsack Public-Key Cryptosystems against Low-Density Attack

    NASA Astrophysics Data System (ADS)

    Nasako, Takeshi; Murakami, Yasuyuki; Kasahara, Masao

    In 2003, Kobayashi et al. proposed a new class of knapsack public-key cryptosystems over Gaussian integer ring. This scheme using two-sequences as the public key. In 2005, Sakamoto and Hayashi proposed an improved version of Kobayashi's scheme. In this paper, we propose the knapsack PKC using l-sequences as the public key and present the low-density attack on it. We have described Schemes R and G for l=2, in which the public keys are constructed over rational integer ring and over Gaussian integer ring, respectively. We discusses on the difference of the security against the low-density attack. We show that the security levels of Schemes R and G differ only slightly.

  12. KNApSAcK Metabolite Activity Database for retrieving the relationships between metabolites and biological activities.

    PubMed

    Nakamura, Yukiko; Afendi, Farit Mochamad; Parvin, Aziza Kawsar; Ono, Naoaki; Tanaka, Ken; Hirai Morita, Aki; Sato, Tetsuo; Sugiura, Tadao; Altaf-Ul-Amin, Md; Kanaya, Shigehiko

    2014-01-01

    Databases (DBs) are required by various omics fields because the volume of molecular biology data is increasing rapidly. In this study, we provide instructions for users and describe the current status of our metabolite activity DB. To facilitate a comprehensive understanding of the interactions between the metabolites of organisms and the chemical-level contribution of metabolites to human health, we constructed a metabolite activity DB known as the KNApSAcK Metabolite Activity DB. It comprises 9,584 triplet relationships (metabolite-biological activity-target species), including 2,356 metabolites, 140 activity categories, 2,963 specific descriptions of biological activities and 778 target species. Approximately 46% of the activities described in the DB are related to chemical ecology, most of which are attributed to antimicrobial agents and plant growth regulators. The majority of the metabolites with antimicrobial activities are flavonoids and phenylpropanoids. The metabolites with plant growth regulatory effects include plant hormones. Over half of the DB contents are related to human health care and medicine. The five largest groups are toxins, anticancer agents, nervous system agents, cardiovascular agents and non-therapeutic agents, such as flavors and fragrances. The KNApSAcK Metabolite Activity DB is integrated within the KNApSAcK Family DBs to facilitate further systematized research in various omics fields, especially metabolomics, nutrigenomics and foodomics. The KNApSAcK Metabolite Activity DB could also be utilized for developing novel drugs and materials, as well as for identifying viable drug resources and other useful compounds.

  13. Design of a tomato packing system by image processing and optimization processing

    NASA Astrophysics Data System (ADS)

    Li, K.; Kumazaki, T.; Saigusa, M.

    2016-02-01

    In recent years, with the development of environmental control systems in plant factories, tomato production has rapidly increased in Japan. However, with the decline in the availability of agricultural labor, there is a need to automate grading, sorting and packing operations. In this research, we designed an automatic packing program with which tomato weight could be estimated by image processing and that they were able to be packed in an optimized configuration. The weight was estimated by using the pixel area properties after an L*a*b* color model conversion, noise rejection, filling holes and boundary preprocessing. The packing optimization program was designed by a 0-1 knapsack algorithm for dynamic combinatorial optimization.

  14. Packing developments improve valve availability

    SciTech Connect

    Aikin, J.

    1994-01-01

    Regulatory environment and clean air legislation demand improvements in valve stuffing box performance. In normally inaccessible or hazardous areas, the cost of valve maintenance and repair in terms of safety, radiation, and toxic gas exposure is very high. AECL Research`s Mechanical Equipment Development (MED) branch at Chalk River Laboratories (Chalk River, Ont.) has researched stem packing leakage problems since the early 1970s. Early research and development (R and D) significantly improved the understanding of operational characteristics of asbestos-based valve packing. Of note was the development of live loading, a stem packing method that reduces valve leakage to near zero under most operating conditions, and significantly prolongs packing life. This article describes how stem packing developments, including live loading techniques, are reducing valve fugitive emissions and leakage.

  15. Packed Bed Reactor Experiment

    NASA Video Gallery

    The purpose of the Packed Bed Reactor Experiment in low gravity is to determine how a mixture of gas and liquid flows through a packed bed in reduced gravity. A packed bed consists of a metal pipe ...

  16. On the Concentration Unsteadiness of Chemical Vapour Deposition with a Precursor Sublimated from Packed Bed of Solid Source. Problems with Multicomponent Coatings

    NASA Astrophysics Data System (ADS)

    Peev, Georgi; Tsibranska, Irene

    In some CVD processes the precursor is introduced into the reactor as vapor obtained by sublimation from particles of solid source forming packed bed in a column, where through a carrier gas passes. A typical example is the deposition of metal or metal oxide using its carbonyl compound. The study evaluates by mathematical modeling the effect of particle size reduction due to sublimation on the composition of the gas phase entering the reactor. A set of differential equations describing the convective solid to gas mass transfer process in the column is formulated. Equations for precursor equilibrium partial pressure, mass transfer coefficient, diffusivity and axial dispersion coefficient found from literature are added and the model is solved numerically by the method of finite differences. On the example of W(CO)6 the influence of the carrier gas flow rate, temperature and CVD duration on the change of the precursor concentration is revealed. The calculated alterations are significant and may spoil the running experiments. As to prevent this problem three approaches are suggested allowing the maintenance of the reactor inlet precursor concentration in reasonable limits: (i) to use a sufficiently high initial bed for saturation of the carrier gas during the entire particular experiment; (ii) to increase step-by- step in time the bed temperature; (iii) to increase step-by-step in time the carrier gas velocity in the column on the account of its stream by-passing the column. In all three approaches the model allows to calculate the necessary factors, i.e. the sufficient bed height, the temperature and velocity increment in time. Some numerical experiments employing the suggested approaches with approximately constant precursor concentrations are illustrated. Approaches how to proceed when multicomponent coating is to be deposited are discussed. The main conclusion is that the CVD processes should be carefully prepared accounting for a possible unsteadiness and the

  17. Knapsack--TOPSIS Technique for Vertical Handover in Heterogeneous Wireless Network.

    PubMed

    Malathy, E M; Muthuswamy, Vijayalakshmi

    2015-01-01

    In a heterogeneous wireless network, handover techniques are designed to facilitate anywhere/anytime service continuity for mobile users. Consistent best-possible access to a network with widely varying network characteristics requires seamless mobility management techniques. Hence, the vertical handover process imposes important technical challenges. Handover decisions are triggered for continuous connectivity of mobile terminals. However, bad network selection and overload conditions in the chosen network can cause fallout in the form of handover failure. In order to maintain the required Quality of Service during the handover process, decision algorithms should incorporate intelligent techniques. In this paper, a new and efficient vertical handover mechanism is implemented using a dynamic programming method from the operation research discipline. This dynamic programming approach, which is integrated with the Technique to Order Preference by Similarity to Ideal Solution (TOPSIS) method, provides the mobile user with the best handover decisions. Moreover, in this proposed handover algorithm a deterministic approach which divides the network into zones is incorporated into the network server in order to derive an optimal solution. The study revealed that this method is found to achieve better performance and QoS support to users and greatly reduce the handover failures when compared to the traditional TOPSIS method. The decision arrived at the zone gateway using this operational research analytical method (known as the dynamic programming knapsack approach together with Technique to Order Preference by Similarity to Ideal Solution) yields remarkably better results in terms of the network performance measures such as throughput and delay. PMID:26237221

  18. The weight method: a new screening method for estimating pesticide deposition from knapsack sprayers in developing countries.

    PubMed

    García-Santos, Glenda; Scheiben, Dominik; Binder, Claudia R

    2011-03-01

    Investigations of occupational and environmental risk caused by the use of agrochemicals have received considerable interest over the last decades. And yet, in developing countries, the lack of staff and analytical equipment as well the costs of chemical analyses make it difficult, if not impossible, to monitor pesticide contamination and residues in humans, air, water, and soils. A new and simple method is presented here for estimation of pesticide deposition in humans and soil after application. The estimate is derived on the basis of water mass balance measured in a given number of high absorbent papers under low evaporative conditions and unsaturated atmosphere. The method is presented as a suitable, rapid, low cost screening tool, complementary to toxicological tests, to assess occupational and environmental exposure caused by knapsack sprayers, where there is a lack of analytical instruments. This new method, called the "weight method", was tested to obtain drift deposition on the neighbouring field and the clothes of the applicator after spraying water with a knapsack sprayer in one of the largest areas of potato production in Colombia. The results were confirmed by experimental data using a tracer and the same set up used for the weight method. The weight method was able to explain 86% of the airborne drift and deposition variance.

  19. Does post septoplasty nasal packing reduce complications?

    PubMed

    Naghibzadeh, Bijan; Peyvandi, Ali Asghar; Naghibzadeh, Ghazal

    2011-01-01

    The main issues in nasal surgery are to stabilize the nose in the good position after surgery and preserve the cartilages and bones in the favorable situation and reduce the risk of deviation recurrence. Also it is necessary to avoid the synechia formation, nasal valve narrowing, hematoma and bleeding. Due to the above mentioned problems and in order to solve and minimize them nasal packing, nasal splint and nasal mold have been advised. Patients for whom the nasal packing used may faced to some problems like naso-pulmonary reflex, intractable pain, sleep disorder, post operation infection and very dangerous complication like toxic shock syndrome. We have two groups of patients and three surgeons (one of the surgeons used post operative nasal packing in his patients and the two others surgeons did not).Complications and morbidities were compared in these two groups. Comparing the two groups showed that the rate of complication and morbidities between these two groups were same and the differences were not valuable, except the pain and discomfort post operatively and at the time of its removal. Nasal packing has several risks for the patients while its effects are not studied. Septoplasty can be safely performed without postoperative nasal packing. Nasal packing had no main findings that compensated its usage. Septal suture is one of the procedures that can be used as alternative method to nasal packing. Therefore the nasal packing after septoplasty should be reserved for the patients with increased risk of bleeding. PMID:21425063

  20. Development of an effective valve packing program

    SciTech Connect

    Hart, K.A.

    1996-12-01

    Current data now shows that graphite valve packing installed within the guidance of a controlled program produces not only reliable stem sealing but predictable running loads. By utilizing recent technological developments in valve performance monitoring for both MOV`s and AOV`s, valve packing performance can be enhanced while reducing maintenance costs. Once known, values are established for acceptable valve packing loads, the measurement of actual valve running loads via the current MOV/AOV diagnostic techniques can provide indication of future valve stem sealing problems, improper valve packing installation or identify the opportunity for valve packing program improvements. At times the full benefit of these advances in material and predictive technology remain under utilized due to simple past misconceptions associated with valve packing. This paper will explore the basis for these misconceptions, provide general insight into the current understanding of valve packing and demonstrate how with this new understanding and current valve diagnostic equipment the key aspects required to develop an effective, quality valve packing program fit together. The cost and operational benefits provided by this approach can be significant impact by the: elimination of periodic valve repacking, reduction of maintenance costs, benefits of leak-free valve operation, justification for reduced Post Maintenance Test Requirements, reduced radiation exposure, improved plant appearance.

  1. Optimal packings of superballs

    NASA Astrophysics Data System (ADS)

    Jiao, Y.; Stillinger, F. H.; Torquato, S.

    2009-04-01

    Dense hard-particle packings are intimately related to the structure of low-temperature phases of matter and are useful models of heterogeneous materials and granular media. Most studies of the densest packings in three dimensions have considered spherical shapes, and it is only more recently that nonspherical shapes (e.g., ellipsoids) have been investigated. Superballs (whose shapes are defined by |x1|2p+|x2|2p+|x3|2p≤1 ) provide a versatile family of convex particles (p≥0.5) with both cubic-like and octahedral-like shapes as well as concave particles (0packings for all convex and concave cases. The candidate maximally dense packings are certain families of Bravais lattice packings (in which each particle has 12 contacting neighbors) possessing the global symmetries that are consistent with certain symmetries of a superball. We also provide strong evidence that our packings for convex superballs (p≥0.5) are most likely the optimal ones. The maximal packing density as a function of p is nonanalytic at the sphere point (p=1) and increases dramatically as p moves away from unity. Two more nontrivial nonanalytic behaviors occur at pc∗=1.1509… and po∗=ln3/ln4=0.7924… for “cubic” and “octahedral” superballs, respectively, where different Bravais lattice packings possess the same densities. The packing characteristics determined by the broken rotational symmetry of superballs are similar to but richer than their two-dimensional “superdisk” counterparts [Y. Jiao , Phys. Rev. Lett. 100, 245504 (2008)] and are distinctly different from that of ellipsoid packings. Our candidate optimal superball packings provide a starting point to quantify the equilibrium phase behavior of superball systems, which should deepen our understanding of the statistical thermodynamics of nonspherical-particle systems.

  2. Flat Pack Toy Design

    ERIC Educational Resources Information Center

    Hutcheson, Brian

    2007-01-01

    In this article, the author introduces the concept of flat pack toys. Flat pack toys are designed using a template on a single sheet of letter-sized card stock paper. Before being cut out and built into a three-dimensional toy, they are scanned into the computer and uploaded to a website. With the template accessible from the website, anyone with…

  3. TLC Pack Unpacked

    ERIC Educational Resources Information Center

    Oberhofer, Margret; Colpaert, Jozef

    2015-01-01

    TLC Pack stands for Teaching Languages to Caregivers and is a course designed to support migrants working or hoping to work in the caregiving sector. The TLC Pack resources range from A2 to B2 level of the Common European Framework of Reference for Languages (CEFR), and will be made available online in the six project languages: Dutch, English,…

  4. Graphitic packing removal tool

    SciTech Connect

    Meyers, K.E.; Kolsun, G.J.

    1996-12-31

    Graphitic packing removal tools are described for removal of the seal rings in one piece from valves and pumps. The packing removal tool has a cylindrical base ring the same size as the packing ring with a surface finish, perforations, knurling or threads for adhesion to the seal ring. Elongated leg shanks are mounted axially along the circumferential center. A slit or slits permit insertion around shafts. A removal tool follower stabilizes the upper portion of the legs to allow a spanner wrench to be used for insertion and removal.

  5. Graphitic packing removal tool

    DOEpatents

    Meyers, K.E.; Kolsun, G.J.

    1997-11-11

    Graphitic packing removal tools for removal of the seal rings in one piece are disclosed. The packing removal tool has a cylindrical base ring the same size as the packing ring with a surface finish, perforations, knurling or threads for adhesion to the seal ring. Elongated leg shanks are mounted axially along the circumferential center. A slit or slits permit insertion around shafts. A removal tool follower stabilizes the upper portion of the legs to allow a spanner wrench to be used for insertion and removal. 5 figs.

  6. Graphitic packing removal tool

    DOEpatents

    Meyers, Kurt Edward; Kolsun, George J.

    1997-01-01

    Graphitic packing removal tools for removal of the seal rings in one piece. he packing removal tool has a cylindrical base ring the same size as the packing ring with a surface finish, perforations, knurling or threads for adhesion to the seal ring. Elongated leg shanks are mounted axially along the circumferential center. A slit or slits permit insertion around shafts. A removal tool follower stabilizes the upper portion of the legs to allow a spanner wrench to be used for insertion and removal.

  7. Nasal packing and stenting

    PubMed Central

    Weber, Rainer K.

    2011-01-01

    Nasal packs are indispensable in ENT practice. This study reviews current indications, effectiveness and risks of nasal packs and stents. In endoscopic surgery, nasal packs should always have smooth surfaces to minimize mucosal damage, improve wound healing and increase patient comfort. Functional endoscopic endonasal sinus surgery allows the use of modern nasal packs, since pressure is no longer required. So called hemostatic/resorbable materials are a first step in this direction. However, they may lead to adhesions and foreign body reactions in mucosal membranes. Simple occlusion is an effective method for creating a moist milieu for improved wound healing and avoiding dryness. Stenting of the frontal sinus is recommended if surgery fails to produce a wide, physiologically shaped drainage path that is sufficiently covered by intact tissue. PMID:22073095

  8. Operational reliability of end packing of water and chemical pumps

    SciTech Connect

    Golobev, A.I.

    1984-05-01

    The multiplicity of the designs of end packings of water and chemical pumps is explained by the diversity of their operational conditions and specifications of packings. The following groups of packings having some common constructional features could be identified: packings for chemically neutral media; packings for chemically active media; packings for highly active media; packings for highly abrasive media; and packings for high temperature and low temperature media. Examples are given of some designs of end packings. These packings extensively use siliconized graphites as the friction pair material. The material of the friction pair rings should possess antifriction properties, corrosion resistance, thermal strength and erosion resistance. Rubber rings of circular section are most often used as secondary seals in the design of end packings. Among the main drawbacks of rubber seals is their tendency to aging. Bellows made of rubber, Teflon and metal represent more perfect secondary seals. Springs used in sealing systems absorb all of the vibrations of the packings, they experience variable stresses and undergo fatigue failure. The paper describes the failure modes of each component of end seals in more detail and suggests methods for alleviating the problems associated with each one.

  9. Non-Euclidean geometry of twisted filament bundle packing

    PubMed Central

    Bruss, Isaac R.; Grason, Gregory M.

    2012-01-01

    Densely packed and twisted assemblies of filaments are crucial structural motifs in macroscopic materials (cables, ropes, and textiles) as well as synthetic and biological nanomaterials (fibrous proteins). We study the unique and nontrivial packing geometry of this universal material design from two perspectives. First, we show that the problem of twisted bundle packing can be mapped exactly onto the problem of disc packing on a curved surface, the geometry of which has a positive, spherical curvature close to the center of rotation and approaches the intrinsically flat geometry of a cylinder far from the bundle center. From this mapping, we find the packing of any twisted bundle is geometrically frustrated, as it makes the sixfold geometry of filament close packing impossible at the core of the fiber. This geometrical equivalence leads to a spectrum of close-packed fiber geometries, whose low symmetry (five-, four-, three-, and twofold) reflect non-Euclidean packing constraints at the bundle core. Second, we explore the ground-state structure of twisted filament assemblies formed under the influence of adhesive interactions by a computational model. Here, we find that the underlying non-Euclidean geometry of twisted fiber packing disrupts the regular lattice packing of filaments above a critical radius, proportional to the helical pitch. Above this critical radius, the ground-state packing includes the presence of between one and six excess fivefold disclinations in the cross-sectional order. PMID:22711799

  10. Dense packings of polyhedra: Platonic and Archimedean solids.

    PubMed

    Torquato, S; Jiao, Y

    2009-10-01

    Understanding the nature of dense particle packings is a subject of intense research in the physical, mathematical, and biological sciences. The preponderance of previous work has focused on spherical particles and very little is known about dense polyhedral packings. We formulate the problem of generating dense packings of nonoverlapping, nontiling polyhedra within an adaptive fundamental cell subject to periodic boundary conditions as an optimization problem, which we call the adaptive shrinking cell (ASC) scheme. This optimization problem is solved here (using a variety of multiparticle initial configurations) to find the dense packings of each of the Platonic solids in three-dimensional Euclidean space R3 , except for the cube, which is the only Platonic solid that tiles space. We find the densest known packings of tetrahedra, icosahedra, dodecahedra, and octahedra with densities 0.823..., 0.836..., 0.904..., and 0.947..., respectively. It is noteworthy that the densest tetrahedral packing possesses no long-range order. Unlike the densest tetrahedral packing, which must not be a Bravais lattice packing, the densest packings of the other nontiling Platonic solids that we obtain are their previously known optimal (Bravais) lattice packings. We also derive a simple upper bound on the maximal density of packings of congruent nonspherical particles and apply it to Platonic solids, Archimedean solids, superballs, and ellipsoids. Provided that what we term the "asphericity" (ratio of the circumradius to inradius) is sufficiently small, the upper bounds are relatively tight and thus close to the corresponding densities of the optimal lattice packings of the centrally symmetric Platonic and Archimedean solids. Our simulation results, rigorous upper bounds, and other theoretical arguments lead us to the conjecture that the densest packings of Platonic and Archimedean solids with central symmetry are given by their corresponding densest lattice packings. This can be

  11. Bidispersed Sphere Packing on Spherical Surfaces

    NASA Astrophysics Data System (ADS)

    Atherton, Timothy; Mascioli, Andrew; Burke, Christopher

    Packing problems on spherical surfaces have a long history, originating in the classic Thompson problem of finding the ground state configuration of charges on a sphere. Such packings contain a minimal number of defects needed to accommodate the curvature; this is predictable using the Gauss-Bonnet theorem from knowledge of the topology of the surface and the local symmetry of the ordering. Famously, the packing of spherical particles on a sphere contains a 'scar' transition, where additional defects over those required by topology appear above a certain critical number of particles and self-organize into chains or scars. In this work, we study the packing of bidispersed packings on a sphere, and hence determine the interaction of bidispersity and curvature. The resultant configurations are nearly crystalline for low values of bidispersity and retain scar-like structures; these rapidly become disordered for intermediate values and approach a so-called Appollonian limit at the point where smaller particles can be entirely accommodated within the voids left by the larger particles. We connect our results with studies of bidispersed packings in the bulk and on flat surfaces from the literature on glassy systems and jamming. Supported by a Cottrell Award from the Research Corporation for Science Advancement.

  12. Microstructural characterization of random packings of cubic particles

    PubMed Central

    Malmir, Hessam; Sahimi, Muhammad; Tabar, M. Reza Rahimi

    2016-01-01

    Understanding the properties of random packings of solid objects is of critical importance to a wide variety of fundamental scientific and practical problems. The great majority of the previous works focused, however, on packings of spherical and sphere-like particles. We report the first detailed simulation and characterization of packings of non-overlapping cubic particles. Such packings arise in a variety of problems, ranging from biological materials, to colloids and fabrication of porous scaffolds using salt powders. In addition, packing of cubic salt crystals arise in various problems involving preservation of pavements, paintings, and historical monuments, mineral-fluid interactions, CO2 sequestration in rock, and intrusion of groundwater aquifers by saline water. Not much is known, however, about the structure and statistical descriptors of such packings. We have developed a version of the random sequential addition algorithm to generate such packings, and have computed a variety of microstructural descriptors, including the radial distribution function, two-point probability function, orientational correlation function, specific surface, and mean chord length, and have studied the effect of finite system size and porosity on such characteristics. The results indicate the existence of both spatial and orientational long-range order in the packing, which is more distinctive for higher packing densities. The maximum packing fraction is about 0.57. PMID:27725736

  13. Microstructural characterization of random packings of cubic particles

    NASA Astrophysics Data System (ADS)

    Malmir, Hessam; Sahimi, Muhammad; Tabar, M. Reza Rahimi

    2016-10-01

    Understanding the properties of random packings of solid objects is of critical importance to a wide variety of fundamental scientific and practical problems. The great majority of the previous works focused, however, on packings of spherical and sphere-like particles. We report the first detailed simulation and characterization of packings of non-overlapping cubic particles. Such packings arise in a variety of problems, ranging from biological materials, to colloids and fabrication of porous scaffolds using salt powders. In addition, packing of cubic salt crystals arise in various problems involving preservation of pavements, paintings, and historical monuments, mineral-fluid interactions, CO2 sequestration in rock, and intrusion of groundwater aquifers by saline water. Not much is known, however, about the structure and statistical descriptors of such packings. We have developed a version of the random sequential addition algorithm to generate such packings, and have computed a variety of microstructural descriptors, including the radial distribution function, two-point probability function, orientational correlation function, specific surface, and mean chord length, and have studied the effect of finite system size and porosity on such characteristics. The results indicate the existence of both spatial and orientational long-range order in the packing, which is more distinctive for higher packing densities. The maximum packing fraction is about 0.57.

  14. Numerical optimization method for packing regular convex polygons

    NASA Astrophysics Data System (ADS)

    Galiev, Sh. I.; Lisafina, M. S.

    2016-08-01

    An algorithm is presented for the approximate solution of the problem of packing regular convex polygons in a given closed bounded domain G so as to maximize the total area of the packed figures. On G a grid is constructed whose nodes generate a finite set W on G, and the centers of the figures to be packed can be placed only at some points of W. The problem of packing these figures with centers in W is reduced to a 0-1 linear programming problem. A two-stage algorithm for solving the resulting problems is proposed. The algorithm finds packings of the indicated figures in an arbitrary closed bounded domain on the plane. Numerical results are presented that demonstrate the effectiveness of the method.

  15. Packing of elastic wires in flexible shells

    NASA Astrophysics Data System (ADS)

    Vetter, R.; Wittel, F. K.; Herrmann, H. J.

    2015-11-01

    The packing problem of long thin filaments that are injected into confined spaces is of fundamental interest for physicists and biologists alike. How linear threads pack and coil is well known only for the ideal case of rigid containers, though. Here, we force long elastic rods into flexible spatial confinement borne by an elastic shell to examine under which conditions recently acquired knowledge on wire packing in rigid spheres breaks down. We find that unlike in rigid cavities, friction plays a key role by giving rise to the emergence of two distinct packing patterns. At low friction, the wire densely coils into an ordered toroidal bundle with semi-ellipsoidal cross-section, while at high friction, it packs into a highly disordered, hierarchic structure. These two morphologies are shown to be separated by a continuous phase transition. Our findings demonstrate the dramatic impact of friction and confinement elasticity on filamentous packing and might drive future research on such systems in physics, biology and even medical technology toward including these mutually interacting effects.

  16. Decontamination of pesticide packing using ionizing radiation

    NASA Astrophysics Data System (ADS)

    Duarte, C. L.; Mori, M. N.; Kodama, Yasko; Oikawa, H.; Sampa, M. H. O.

    2007-11-01

    The Brazilian agriculture activities have consumed about 288,000 tons of pesticides per year conditioned in about 107,000,000 packing with weight of approximately 23,000 tons. The discharge of empty plastic packing of pesticides can be an environmental concern causing problems to human health, animals, and plants if done without inspection and monitoring. The objective of this work is to study the ionizing radiation effect in the main pesticides used in Brazil for plastic packing decontamination. Among the commercial pesticides, chlorpyrifos has significant importance because of its wide distribution and extensive use and persistence. The radiation-induced degradation of chlorpyrifos in liquid samples and in polyethylene pack was studied by gamma radiolysis. Packing of high-density polyethylene (HDPE) three layer coextruded, named COEX, contaminated with chlorpyrifos, were irradiated using both a multipurpose Co-60 gamma irradiator and a gamma source with 5000 Ci total activity Gamma cell type. The chemical analysis of the chlorpyrifos was made using a gas chromatography associated to the Mass Spectrometry—GCMS from Shimadzu Model QP 5000. Gamma radiation was efficient for removing chlorpyrifos from the plastic packing, in all studied cases.

  17. Pessimal shapes for packing

    NASA Astrophysics Data System (ADS)

    Kallus, Yoav

    2014-03-01

    The question of which convex shapes leave the most empty space in their densest packing is the subject of Reinhardt's conjecture in two dimensions and Ulam's conjecture in three dimensions. Such conjectures about pessimal packing shapes have proven notoriously difficult to make progress on. I show that the regular heptagon is a local pessimum among all convex shapes, and that the 3D ball is a local pessimum among origin-symmetric shapes. Any shape sufficiently close in the space of shapes to these local pessima can be packed at a greater efficiency than they. In two dimensions and in dimensions above three, the ball is not a local pessimum, so the situation in 3D is unusual and intriguing. I will discuss what conditions conspire to make the 3D ball a local pessimum and whether we can prove that it is also a global pessimum.

  18. The packing of particles

    SciTech Connect

    Cumberland, D.J.; Crawford, R.J.

    1987-01-01

    The wide range of information currently available on the packing of particles is brought together in this monograph. The authors' interest in the subject was initially aroused by the question of whether there is an optimum particle size distribution which would maximise the packing density of particles - a question which has attracted the interest of scientists and engineers for centuries. The densification of a powder mass is of relevance in a great many industries, among them the pharmaceutical, ceramic, powder metallurgy and civil engineering industries. In addition, the packing of regular - or irregular - shaped particles is also of relevance to a surprisingly large number of other industries and subject areas, i.e. the foundry industry, nuclear engineering, chemical engineering, crystallography, geology, biology, telecommunications, and so on. Accordingly, this book is written for a wide audience.

  19. Sun Packs Double Punch

    NASA Video Gallery

    On August 3, the sun packed a double punch, emitting a M6.0-class flare at 9:43 am EDT. This video is of the second, slightly stronger M9.3-class flare at 11:41 pm EDT. Both flares had significant ...

  20. Packing Them In.

    ERIC Educational Resources Information Center

    Carter, Claudia

    1997-01-01

    This activity involves students investigating the mathematics of packaging and exploring various concepts in geometry, including area and the Pythagorean theorem. Mathematics comes out of the discussion of packaging cans into six-packs and focuses on the cost-effectiveness of the horizontal storage area used. Students learn how knowledge of…

  1. Nutrition Action Pack.

    ERIC Educational Resources Information Center

    Sockut, Joanne; Stumpe, Stephanie

    One of five McDonald's Action Packs, these instructional materials integrate elementary school-level nutrition education into other disciplines--biology, sociology, physiology, mathematics, and art. Contents include four units consisting of twelve activities. Unit 1, Why You Need Food, is a self-examination of what is needed for growth, health,…

  2. Economics Action Pack.

    ERIC Educational Resources Information Center

    McDonald's Corp., Oak Brook, IL.

    One of five McDonald's Action Packs, this learning package introduces intermediate grade students to basic economic concepts. The fourteen activities include the topics of consumption (4 activities), production (5), the market system (3), a pretest, and a posttest. Specific titles under consumption include The Wonderful Treasure Tree (introduction…

  3. AUTOmatic Message PACKing Facility

    2004-07-01

    AUTOPACK is a library that provides several useful features for programs using the Message Passing Interface (MPI). Features included are: 1. automatic message packing facility 2. management of send and receive requests. 3. management of message buffer memory. 4. determination of the number of anticipated messages from a set of arbitrary sends, and 5. deterministic message delivery for testing purposes.

  4. Learning dominance relations in combinatorial search problems

    NASA Technical Reports Server (NTRS)

    Yu, Chee-Fen; Wah, Benjamin W.

    1988-01-01

    Dominance relations commonly are used to prune unnecessary nodes in search graphs, but they are problem-dependent and cannot be derived by a general procedure. The authors identify machine learning of dominance relations and the applicable learning mechanisms. A study of learning dominance relations using learning by experimentation is described. This system has been able to learn dominance relations for the 0/1-knapsack problem, an inventory problem, the reliability-by-replication problem, the two-machine flow shop problem, a number of single-machine scheduling problems, and a two-machine scheduling problem. It is considered that the same methodology can be extended to learn dominance relations in general.

  5. Packing Products: Polystyrene vs. Cornstarch

    ERIC Educational Resources Information Center

    Starr, Suzanne

    2009-01-01

    Packing materials such as polystyrene take thousands of years to decompose, whereas packing peanuts made from cornstarch, which some companies are now using, can serve the same purpose, but dissolve in water. The author illustrates this point to her class one rainy day using the sculptures students made from polystyrene and with the cornstarch…

  6. Barrier properties of k-mer packings

    NASA Astrophysics Data System (ADS)

    Lebovka, N.; Khrapatiy, S.; Vygornitskyi; Pivovarova, N.

    2014-08-01

    This work discusses numerical studies of the barrier properties of k-mer packings by the Monte Carlo method. The studied variants of regular and non-regular arrangements on a square lattice included models of random sequential adsorption (RSA) and random deposition (RD). The discrete problem of diffusion through the bonds of a square lattice was considered. The k-mers were perfectly oriented perpendicular to the diffusion direction and blocked certain fraction of bonds fb against diffusion. The barrier efficiency was estimated by calculation of the ratio D/Do where D is diffusion coefficient in direction perpendicular to the orientation of k-mers and Do is the same value for diffusion on the square lattice without blocked bonds, i.e., at fb=0. The value of k varied from 1 to 512 and different lattice sizes up to L=8192 lattice units were used. For dense packings (p=1), the obtained D/Do versus fb dependences deviated from the theoretical prediction of effective medium (EM) theory and deviation was the most obvious for the regular non-staggered arrangement. For loose RSA and RD packings, the percolation like-behavior of D/Do with threshold at fb=p∞ was observed and the data evidenced that their barrier properties at large values of k may be more effective than those of some dense packings. Such anomalous behavior can reflect the details of k-mer spatial organization (aggregation) and structure of pores in RD and RSA packings. The contradictions between simulation data and predictions of EM theory were also discussed.

  7. 7 CFR 51.310 - Packing requirements.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... STANDARDS) United States Standards for Grades of Apples Packing Requirements § 51.310 Packing requirements. (a) Apples tray packed or cell packed in cartons shall be arranged according to approved and... that apples are of the proper size for molds or cell compartments in which they are packed, and...

  8. 7 CFR 51.310 - Packing requirements.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... STANDARDS) United States Standards for Grades of Apples Packing Requirements § 51.310 Packing requirements. (a) Apples tray packed or cell packed in cartons shall be arranged according to approved and... that apples are of the proper size for molds or cell compartments in which they are packed, and...

  9. 7 CFR 51.310 - Packing requirements.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... STANDARDS) United States Standards for Grades of Apples Packing Requirements § 51.310 Packing requirements. (a) Apples tray packed or cell packed in cartons shall be arranged according to approved and... that apples are of the proper size for molds or cell compartments in which they are packed, and...

  10. On the perfect hexagonal packing of rods

    NASA Astrophysics Data System (ADS)

    Starostin, E. L.

    2006-04-01

    In most cases the hexagonal packing of fibrous structures or rods extremizes the energy of interaction between strands. If the strands are not straight, then it is still possible to form a perfect hexatic bundle. Conditions under which the perfect hexagonal packing of curved tubular structures may exist are formulated. Particular attention is given to closed or cycled arrangements of the rods like in the DNA toroids and spools. The closure or return constraints of the bundle result in an allowable group of automorphisms of the cross-sectional hexagonal lattice. The structure of this group is explored. Examples of open helical-like and closed toroidal-like bundles are presented. An expression for the elastic energy of a perfectly packed bundle of thin elastic rods is derived. The energy accounts for both the bending and torsional stiffnesses of the rods. It is shown that equilibria of the bundle correspond to solutions of a variational problem formulated for the curve representing the axis of the bundle. The functional involves a function of the squared curvature under the constraints on the total torsion and the length. The Euler-Lagrange equations are obtained in terms of curvature and torsion and due to the existence of the first integrals the problem is reduced to the quadrature. The three-dimensional shape of the bundle may be readily reconstructed by integration of the Ilyukhin-type equations in special cylindrical coordinates. The results are of universal nature and are applicable to various fibrous structures, in particular, to intramolecular liquid crystals formed by DNA condensed in toroids or packed inside the viral capsids. International Workshop on Biopolymers: Thermodynamics, Kinetics and Mechanics of DNA, RNA and Proteins, 30.05.2005-3.06.2005, The Abdus Salam International Centre for Theoretical Physics (ICTP), Trieste, Italy.

  11. Valve stem and packing assembly

    DOEpatents

    Wordin, John J.

    1991-01-01

    A valve stem and packing assembly is provided in which a rotatable valve stem includes a first tractrix surface for sliding contact with a stem packing and also includes a second tractrix surface for sliding contact with a bonnet. Force is applied by means of a spring, gland flange, and gland on the stem packing so the stem packing seals to the valve stem and bonnet. This configuration serves to create and maintain a reliable seal between the stem packing and the valve stem. The bonnet includes a second complementary tractrix surface for contacting the second sliding tractrix surface, the combination serving as a journal bearing for the entire valve stem and packing assembly. The journal bearing so configured is known as a Schiele's pivot. The Schiele's pivot also serves to maintain proper alignment of the valve stem with respect to the bonnet. Vertical wear between the surfaces of the Schiele's pivot is uniform at all points of contact between the second sliding tractrix surface and the second complementary tractrix surface of a bonnet. The valve stem is connected to a valve plug by means of a slip joint. The valve is opened and closed by rotating the valve stem. The slip joint compensates for wear on the Schiele's pivot and on the valve plug. A ledge is provided on the valve bonnet for the retaining nut to bear against. The ledge prevents overtightening of the retaining nut and the resulting excessive friction between stem and stem packing.

  12. Valve stem and packing assembly

    DOEpatents

    Wordin, J.J.

    1991-09-03

    A valve stem and packing assembly is provided in which a rotatable valve stem includes a first tractrix surface for sliding contact with a stem packing and also includes a second tractrix surface for sliding contact with a bonnet. Force is applied by means of a spring, gland flange, and gland on the stem packing so the stem packing seals to the valve stem and bonnet. This configuration serves to create and maintain a reliable seal between the stem packing and the valve stem. The bonnet includes a second complementary tractrix surface for contacting the second sliding tractrix surface, the combination serving as a journal bearing for the entire valve stem and packing assembly. The journal bearing so configured is known as a Schiele's pivot. The Schiele's pivot also serves to maintain proper alignment of the valve stem with respect to the bonnet. Vertical wear between the surfaces of the Schiele's pivot is uniform at all points of contact between the second sliding tractrix surface and the second complementary tractrix surface of a bonnet. The valve stem is connected to a valve plug by means of a slip joint. The valve is opened and closed by rotating the valve stem. The slip joint compensates for wear on the Schiele's pivot and on the valve plug. A ledge is provided on the valve bonnet for the retaining nut to bear against. The ledge prevents over tightening of the retaining nut and the resulting excessive friction between stem and stem packing. 2 figures.

  13. 7 CFR 982.11 - Pack.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and... Order Regulating Handling Definitions § 982.11 Pack. Pack means a specific commercial classification according to size, internal quality, and external appearance and condition of hazelnuts packed in...

  14. Method for packing chromatographic beds

    DOEpatents

    Freeman, David H.; Angeles, Rosalie M.; Keller, Suzanne

    1991-01-01

    Column chromatography beds are packed through the application of static force. A slurry of the chromatography bed material and a non-viscous liquid is filled into the column plugged at one end, and allowed to settle. The column is transferred to a centrifuge, and centrifuged for a brief period of time to achieve a predetermined packing level, at a range generally of 100-5,000 gravities. Thereafter, the plug is removed, other fixtures may be secured, and the liquid is allowed to flow out through the bed. This results in an evenly packed bed, with no channeling or preferential flow characteristics.

  15. A Branch and Bound Approach for Truss Topology Design Problems with Valid Inequalities

    SciTech Connect

    Cerveira, Adelaide; Agra, Agostinho; Bastos, Fernando; Varum, Humberto

    2010-09-30

    One of the classical problems in the structural optimization field is the Truss Topology Design Problem (TTDP) which deals with the selection of optimal configuration for structural systems for applications in mechanical, civil, aerospace engineering, among others. In this paper we consider a TTDP where the goal is to find the stiffest truss, under a given load and with a bound on the total volume. The design variables are the cross-section areas of the truss bars that must be chosen from a given finite set. This results in a large-scale non-convex problem with discrete variables. This problem can be formulated as a Semidefinite Programming Problem (SDP problem) with binary variables. We propose a branch and bound algorithm to solve this problem. In this paper it is considered a binary formulation of the problem, to take advantage of its structure, which admits a Knapsack problem as subproblem. Thus, trying to improve the performance of the Branch and Bound, at each step, some valid inequalities for the Knapsack problem are included.

  16. Uterovaginal Packing With Rolled Gauze in Postpartum Hemorrhage

    PubMed Central

    Bagga, Rashmi; Jain, Vanita; Chopra, Seema; Kalra, Jasvinder; Gopalan, Sarala

    2004-01-01

    Management options for postpartum hemorrhage (PPH) include oxytocics, prostaglandins, genital tract exploration, ligation or angiographic embolization of uterine/internal iliac arteries, and hysterectomy. After excluding uterine rupture, genital tract lacerations, and retained placental tissue, efforts are directed toward contracting the uterus by bimanual compression and oxytocics. If these are not successful, one must resort to surgical techniques. At this stage, an alternative option to remember is uterovaginal packing. Easy and quick to perform, it may be used to control bleeding by tamponade effect and stabilize the patient until a surgical procedure is arranged. Uterovaginal packing may sometimes obviate the need for surgery altogether. Two cases, a primary and a secondary PPH, managed recently with uterovaginal packing are reported. Despite concerns about concealed hemorrhage or the development of infection with this intervention, none of these problems were encountered, and uterine packing was successful even in the case of secondary PPH with documented infection. PMID:15208561

  17. Are proteins well-packed?

    PubMed

    Liang, J; Dill, K A

    2001-08-01

    The average packing density inside proteins is as high as in crystalline solids. Does this mean proteins are well-packed? We go beyond average densities, and look at the full distribution functions of free volumes inside proteins. Using a new and rigorous Delaunay triangulation method for parsing space into empty and filled regions, we introduce formal definitions of interior and surface packing densities. Although proteins look like organic crystals by the criterion of average density, they look more like liquids and glasses by the criterion of their free volume distributions. The distributions are broad, and the scalings of volume-to-surface, volume-to-cluster-radius, and numbers of void versus volume show that the interiors of proteins are more like randomly packed spheres near their percolation threshold than like jigsaw puzzles. We find that larger proteins are packed more loosely than smaller proteins. And we find that the enthalpies of folding (per amino acid) are independent of the packing density of a protein, indicating that van der Waals interactions are not a dominant component of the folding forces. PMID:11463623

  18. 7 CFR 51.1527 - Standard pack.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Standards for Grades of Fresh Plums and Prunes Standard Pack § 51.1527 Standard pack. (a) Packing. (1) All... plums or prunes in the top layer of any package shall be reasonably representative in quality and size of those in the remainder of the package. (3) “Well filled” means that the plums or prunes packed...

  19. 7 CFR 51.1527 - Standard pack.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Standards for Grades of Fresh Plums and Prunes Standard Pack § 51.1527 Standard pack. (a) Packing. (1) All... plums or prunes in the top layer of any package shall be reasonably representative in quality and size of those in the remainder of the package. (3) “Well filled” means that the plums or prunes packed...

  20. 7 CFR 51.310 - Packing requirements.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... (INSPECTION, CERTIFICATION, AND STANDARDS) United States Standards for Grades of Apples Packing Requirements § 51.310 Packing requirements. (a) Apples tray packed or cell packed in cartons shall be arranged.... 3 2 “Fairly tight” means that apples are of the proper size for molds or cell compartments in...

  1. 7 CFR 51.310 - Packing requirements.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... (INSPECTION, CERTIFICATION, AND STANDARDS) United States Standards for Grades of Apples Packing Requirements § 51.310 Packing requirements. (a) Apples tray packed or cell packed in cartons shall be arranged.... 3 2 “Fairly tight” means that apples are of the proper size for molds or cell compartments in...

  2. 7 CFR 51.1217 - Standard pack.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ..., CERTIFICATION, AND STANDARDS) United States Standards for Grades of Peaches Standard Pack § 51.1217 Standard pack. (a) Each package shall be packed so that the peaches in the shown face shall be reasonably representative in size, color and quality of the contents of the package. (b) Peaches packed in U.S....

  3. 7 CFR 51.1217 - Standard pack.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Standards for Grades of Peaches Standard Pack § 51.1217 Standard pack. (a) Each package shall be packed so that the peaches in the shown face shall be reasonably representative in size, color and quality of the contents of the package. (b) Peaches packed in U.S. Standard bushel baskets, or half-bushel baskets,...

  4. 7 CFR 51.1217 - Standard pack.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Standards for Grades of Peaches Standard Pack § 51.1217 Standard pack. (a) Each package shall be packed so that the peaches in the shown face shall be reasonably representative in size, color and quality of the contents of the package. (b) Peaches packed in U.S. Standard bushel baskets, or half-bushel baskets,...

  5. 7 CFR 51.1217 - Standard pack.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Standards for Grades of Peaches Standard Pack § 51.1217 Standard pack. (a) Each package shall be packed so that the peaches in the shown face shall be reasonably representative in size, color and quality of the contents of the package. (b) Peaches packed in U.S. Standard bushel baskets, or half-bushel baskets,...

  6. 7 CFR 51.1217 - Standard pack.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ..., CERTIFICATION, AND STANDARDS) United States Standards for Grades of Peaches Standard Pack § 51.1217 Standard pack. (a) Each package shall be packed so that the peaches in the shown face shall be reasonably representative in size, color and quality of the contents of the package. (b) Peaches packed in U.S....

  7. Disc pack cleaning table saves computer time

    NASA Technical Reports Server (NTRS)

    Guy, J. T., Sr.

    1970-01-01

    Disc pack holding table is support frame upon which computer disc pack is loaded and protective cover released. This combination permits manual off-line cleaning of disc pack storage units at any time without shutting down the computer, and eliminates on-line disc drive unit to hold pack during cleaning.

  8. The cost-constrained traveling salesman problem

    SciTech Connect

    Sokkappa, P.R.

    1990-10-01

    The Cost-Constrained Traveling Salesman Problem (CCTSP) is a variant of the well-known Traveling Salesman Problem (TSP). In the TSP, the goal is to find a tour of a given set of cities such that the total cost of the tour is minimized. In the CCTSP, each city is given a value, and a fixed cost-constraint is specified. The objective is to find a subtour of the cities that achieves maximum value without exceeding the cost-constraint. Thus, unlike the TSP, the CCTSP requires both selection and sequencing. As a consequence, most results for the TSP cannot be extended to the CCTSP. We show that the CCTSP is NP-hard and that no K-approximation algorithm or fully polynomial approximation scheme exists, unless P = NP. We also show that several special cases are polynomially solvable. Algorithms for the CCTSP, which outperform previous methods, are developed in three areas: upper bounding methods, exact algorithms, and heuristics. We found that a bounding strategy based on the knapsack problem performs better, both in speed and in the quality of the bounds, than methods based on the assignment problem. Likewise, we found that a branch-and-bound approach using the knapsack bound was superior to a method based on a common branch-and-bound method for the TSP. In our study of heuristic algorithms, we found that, when selecting modes for inclusion in the subtour, it is important to consider the neighborhood'' of the nodes. A node with low value that brings the subtour near many other nodes may be more desirable than an isolated node of high value. We found two types of repetition to be desirable: repetitions based on randomization in the subtour buildings process, and repetitions encouraging the inclusion of different subsets of the nodes. By varying the number and type of repetitions, we can adjust the computation time required by our method to obtain algorithms that outperform previous methods.

  9. Nature of packs used in propellant modeling.

    PubMed

    Maggi, F; Stafford, S; Jackson, T L; Buckmaster, J

    2008-04-01

    In recent years we have constructed closely packed spheres using the Lubachevsky-Stillinger algorithm to generate morphological models of heterogeneous solid propellants. Improvements to the algorithm now allow us to create large polydisperse packs on a laptop computer, and to create monodisperse packs with packing fractions greater than 70% which display significant crystal order. The use of these models in the physical context motivates efforts to examine in some detail the nature of the packs, including certain statistical properties. We compare packing fractions for binary packs with long-known experimental data. Also, we discuss the near-neighbor number and the radial distribution function (RDF) for monodisperse packs and make comparisons with experimental data. We also briefly discuss the RDF for bidisperse packs. We also consider bounded monodisperse packs, and pay particular attention to the near-wall structure where we identify significant order.

  10. Valve packings conquer fugitive emissions

    SciTech Connect

    1995-11-01

    In the early 1990s, when the US Environmental Protection Agency (EPA; Washington, D.C.) declared its intent to regulate fugitive emissions from valve-stem leakage, much of the chemical process industries (CPI) responded with fear and uncertainty. The biggest fear was that valve packing would not meet the required limits on leak rates and that expensive bellows seals may be required on many applications. The uncertainly was about how much it would cost. Today, for the most part, these concerns have been mitigated. It is estimated that about 80--90% of valves satisfy the emission requirements. The rest need some improvement in their packing systems to meet the regulations. Generally, these valves can be brought within compliance if the packing designers follow a few basic principles: Employ less-pliable outer rings and more-pliable inner rings; and don`t use excessive packing. While interest in valve packing remains high, mechanical seals continue to become more user-friendly. Many of those covered below are designed to run dry, and some can even tolerate high shaft-wobble without damage. Also look for improved flange gaskets and a host of seals to protect bearings. Twenty-one summaries are presented on new products and services.

  11. Sleeping distance in wild wolf packs

    USGS Publications Warehouse

    Knick, S.T.; Mech, L.D.

    1980-01-01

    Sleeping distances were observed among members of 13 wild wolf (Canis lupus) packs and 11 pairs in northeastern Minnesota to determine if the distances correlated with pack size and composition. The study utilized aerial radio-tracking and observation during winter. Pack size and number of adults per pack were inversely related to pack average sleeping distance and variability. No correlation between sleeping distance and microclimate was observed. Possible relationships between social bonding and our results are discussed.

  12. Entanglement Theories: Packing vs. Percolation

    NASA Astrophysics Data System (ADS)

    Wool, Richard

    2007-03-01

    There are two emergent theories of polymer entanglements, the Packing Model (Fetters, Lohse, Graessley, Milner, Whitten, ˜'98) and the Percolation Model (Wool ˜'93). The Packing model suggests that the entanglement molecular weight Me is determined by Me = K p^3, where the packing length parameter p = V/R^2 in which V is the volume of the chain (V=M/ρNa), R is the end-to end vector of the chain, and K 357 ρNa, is an empirical constant. The Percolation model states that an entanglement network develops when the number of chains per unit area σ, intersecting any load bearing plane, is equal to 3 times the number of chain segments (1/a cross-section), such that when 3aσ =1 at the percolation threshold, Me 31 MjC∞, in which Mj is the step molecular weight and C∞ is the characteristic ratio. There are no fitting parameters in the Percolation model. The Packing model predicts that Me decreases rapidly with chain stiffness, as Me˜1/C∞^3, while the Percolation model predicts that Me increases with C∞, as Me˜C∞. The Percolation model was found to be the correct model based on computer simulations (M. Bulacu et al) and a re-analysis of the Packing model experimental data. The Packing model can be derived from the Percolation model, but not visa versa, and reveals a surprising accidental relation between C∞ and Mj in the front factor K. This result significantly impacts the interpretation of the dynamics of rheology and fracture of entangled polymers.

  13. [Electroflotation packing of mycelial wastes].

    PubMed

    Nikolaev, V B; Karpukhin, V F; Zav'ialova, E V; Faingol'd, Z L

    1989-04-01

    Data on testing a pilot plant for electroflotative packing of mycelial wastes are presented. Both the mycelial wastes and their mixtures were used. Concentration of dry substances raged from 3.5 to 131 g/l. The process was performed with varying flow density and consumption rate of the liquid supplied to the plant. Insoluble magnetite and ruthenium oxide anodes were used. The moister content in the packed phase was 81-97.5 per cent. The study provided specification of the process technological parameters and investigation of the flotator hydroulic characteristics.

  14. Cylinder valve packing nut studies

    SciTech Connect

    Blue, S.C.

    1991-12-31

    The design, manufacture, and use of cylinder valve packing nuts have been studied to improve their resistance to failure from stress corrosion cracking. Stress frozen photoelastic models have been analyzed to measure the stress concentrations at observed points of failure. The load effects induced by assembly torque and thermal expansion of stem packing were observed by strain gaging nuts. The effects of finishing operations and heat treatment were studied by the strain gage hole boring and X-ray methods. Modifications of manufacturing and operation practices are reducing the frequency of stress corrosion failures.

  15. Ecology and Energy Action Pack.

    ERIC Educational Resources Information Center

    McDonald's Corp., Oak Brook, IL.

    One of five McDonald's Action Packs, these elementary school-level instructional materials are for use as an introduction to existing units of study, supplements to a textbook, or a source of special projects for environmental education. Contents include these six units: Make Your Own Ecology Mini-spinner, Let's Look at a Food Chain, Drip the…

  16. Pack cementation coatings for alloys

    SciTech Connect

    He, Yi-Rong; Zheng, Minhui; Rapp, R.A.

    1996-08-01

    The halide-activated pack cementation process was modified to produce a Ge-doped silicide diffusion coating on a Cr-Cr{sub 2}Nb alloy in a single processing step. The morphology and composition of the coating depended both on the composition of the pack and on the composition and microstructure of the substrate. Higher Ge content in the pack suppressed the formation of CrSi{sub 2} and reduced the growth kinetics of the coating. Ge was not homogeneously distributed in the coatings. In cyclic and isothermal oxidation in air at 700 and 1050{degrees}C, the Ge-doped silicide coating protected the Cr-Nb alloys from significant oxidation by the formation of a Ge-doped silica film. The codeposition and diffusion of aluminum and chromium into low alloy steel have been achieved using elemental Al and Cr powders and a two-step pack cementation process. Sequential process treatments at 925{degrees}C and 1150{degrees}C yield dense and uniform ferrite coatings, whose compositions are close to either Fe{sub 3}Al or else FeAl plus a lower Cr content, when processed under different conditions. The higher content of Al in the coatings was predicted by thermodynamic calculations of equilibrium in the gas phase. The effect of the particle size of the metal powders on the surface composition of the coating has been studied for various combinations of Al and Cr powders.

  17. Wire and Packing Tape Sandwiches

    ERIC Educational Resources Information Center

    Rabinowitz, Sandy

    2009-01-01

    In this article, the author describes how students can combine craft wire with clear packing tape to create a two-dimensional design that can be bent and twisted to create a three-dimensional form. Students sandwich wire designs between two layers of tape. (Contains 1 online resource.)

  18. Interval methods for verifying structural optimality of circle packing configurations in the unit square

    NASA Astrophysics Data System (ADS)

    Markot, Mihaly Csaba

    2007-02-01

    The paper is dealing with the problem of finding the densest packings of equal circles in the unit square. Recently, a global optimization method based exclusively on interval arithmetic calculations has been designed for this problem. With this method it became possible to solve the previously open problems of packing 28, 29, and 30 circles in the numerical sense: tight guaranteed enclosures were given for all the optimal solutions and for the optimum value. The present paper completes the optimality proofs for these cases by determining all the optimal solutions in the geometric sense. Namely, it is proved that the currently best-known packing structures result in optimal packings, and moreover, apart from symmetric configurations and the movement of well-identified free circles, these are the only optimal packings. The required statements are verified with mathematical rigor using interval arithmetic tools.

  19. Packing tube assembly for pumping wells

    SciTech Connect

    Towner, G.F.; Carter, C.A.

    1987-09-22

    A packing tube assembly for replacing a conventional stuffing box is described. The packing tube assembly comprising: a packing tube; a rod adaptor adapted to be coupled between the polished rod and the sucker rod string and adapted to extend throughout the packing tube when positioned therein; compressible packing means on the rod adaptor adapted to provide a seal between the rod adaptor and the packing tube when the rod adaptor is in position within the packing tube; stabilizing means on the rod adaptor adapted to engage the packing tube to stabilize the rod adaptor within the packing tube during operation; and a mounting bushing connected to the top of the packing tube and adapted to be threaded into the pumping tee to secure the packing tube position within the production tubing string. A method of converting a conventional stuffing box-equipped pumping well to a packing tube-equipped well is described. It consists of: disconnecting the polished rod of the pumping well from the sucker rod string while suspending the sucker rod string within the well by the use of slips; unthreading the conventional stuffing box from the pumping tee of the well and removing the stuffing box; attaching the polished rod to the upper end of a rod adaptor of a packing tube assembly, inserting the rod adaptor with the polished rod attached into the packing tube of the packing tube assembly; aligning the packing tube assembly with the sucker rod string; connecting the lower end of the rod adaptor to the sucker rod string; removing the slips and lowering the packer tube assembly through the pumping tee; and connecting the upper end of the packing tube to the pumping tee.

  20. Is antibiotic prophylaxis in nasal packing for anterior epistaxis needed?

    PubMed

    Pérez, Francisco; Rada, Gabriel

    2016-01-07

    Epistaxis is an extremely common problem that sometimes requires anterior nasal packing. Antibiotics are frequently indicated to prevent infectious complications, although the role of this measure is controversial. Searching in Epistemonikos database, which is maintained by screening 30 databases, we identified one systematic review including three primary studies, none of them randomized. We combined the evidence using meta-analysis and generated a summary of findings table following the GRADE approach. We concluded it is not clear whether prophylactic antibiotics reduce infectious complications in patients with nasal packing for anterior epistaxis because the certainty of the evidence is very low.

  1. Is antibiotic prophylaxis in nasal packing for anterior epistaxis needed?

    PubMed

    Pérez, Francisco; Rada, Gabriel

    2016-01-01

    Epistaxis is an extremely common problem that sometimes requires anterior nasal packing. Antibiotics are frequently indicated to prevent infectious complications, although the role of this measure is controversial. Searching in Epistemonikos database, which is maintained by screening 30 databases, we identified one systematic review including three primary studies, none of them randomized. We combined the evidence using meta-analysis and generated a summary of findings table following the GRADE approach. We concluded it is not clear whether prophylactic antibiotics reduce infectious complications in patients with nasal packing for anterior epistaxis because the certainty of the evidence is very low. PMID:26817470

  2. Measured Black Carbon Deposition on the Sierra Nevada Snow Pack and Implication for Snow Pack Retreat

    SciTech Connect

    Hadley, O.L.; Corrigan, C.E.; Kirchstetter, T.W.; Cliff, S.S.; Ramanathan, V.

    2010-01-12

    Modeling studies show that the darkening of snow and ice by black carbon deposition is a major factor for the rapid disappearance of arctic sea ice, mountain glaciers and snow packs. This study provides one of the first direct measurements for the efficient removal of black carbon from the atmosphere by snow and its subsequent deposition to the snow packs of California. The early melting of the snow packs in the Sierras is one of the contributing factors to the severe water problems in California. BC concentrations in falling snow were measured at two mountain locations and in rain at a coastal site. All three stations reveal large BC concentrations in precipitation, ranging from 1.7 ng/g to 12.9 ng/g. The BC concentrations in the air after the snow fall were negligible suggesting an extremely efficient removal of BC by snow. The data suggest that below cloud scavenging, rather than ice nuclei, was the dominant source of BC in the snow. A five-year comparison of BC, dust, and total fine aerosol mass concentrations at multiple sites reveals that the measurements made at the sampling sites were representative of large scale deposition in the Sierra Nevada. The relative concentration of iron and calcium in the mountain aerosol indicates that one-quarter to one-third of the BC may have been transported from Asia.

  3. Inverse statistical mechanics, lattice packings, and glasses

    NASA Astrophysics Data System (ADS)

    Marcotte, Etienne

    Computer simulation methods enable the investigation of systems and properties that are intractable by purely analytical or experimental approaches. Each chapter of this dissertation contains an application of simulation methods to solve complex physical problems consisting of interacting many-particle or many-spin systems. The problems studied in this dissertation can be divided up into the following two broad categories: inverse and forward problems. The inverse problems considered are those in which we construct an interaction potential such that the corresponding ground state is a targeted configuration. In Chapters 2 and 3, we devise convex pair-potential functions that result in low-coordinated ground states. Chapter 2 describes targeted ground states that are the square and honeycomb crystals, while in Chapter 3 the targeted ground state is the diamond crystal. Chapter 4 applies similar techniques to explicitly enumerate all unique ground states up to a given system size, for spin configurations that interact according to generalized isotropic Ising potentials with finite range. We also consider forward statistical-mechanical problems. In Chapter 5, we adapt a linear programming algorithm to find the densest lattice packings across Euclidean space dimensions. In Chapter 6, we demonstrate that for two different glass models a signature of the glass transition is apparent well before the transition temperature is reached. In both models, this signature appears as nonequilibrium length scales that grow upon supercooling.

  4. 7 CFR 984.15 - Pack.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE WALNUTS GROWN IN CALIFORNIA Order Regulating Handling Definitions § 984.15 Pack. Pack means to bleach, clean, grade, shell or otherwise prepare walnuts for market as inshell or shelled walnuts....

  5. 7 CFR 984.15 - Pack.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE WALNUTS GROWN IN CALIFORNIA Order Regulating Handling Definitions § 984.15 Pack. Pack means to bleach, clean, grade, shell or otherwise prepare walnuts for market as inshell or shelled walnuts....

  6. 7 CFR 984.15 - Pack.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE WALNUTS GROWN IN CALIFORNIA Order Regulating Handling Definitions § 984.15 Pack. Pack means to bleach, clean, grade, shell or otherwise prepare walnuts for market as inshell or shelled walnuts....

  7. 7 CFR 984.15 - Pack.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE WALNUTS GROWN IN CALIFORNIA Order Regulating Handling Definitions § 984.15 Pack. Pack means to bleach, clean, grade, shell or otherwise prepare walnuts for market as inshell or shelled walnuts....

  8. 7 CFR 984.15 - Pack.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE WALNUTS GROWN IN CALIFORNIA Order Regulating Handling Definitions § 984.15 Pack. Pack means to bleach, clean, grade, shell or otherwise prepare walnuts for market as inshell or shelled walnuts....

  9. Designing gravel pack for uranium ISL wells

    NASA Astrophysics Data System (ADS)

    Ber, A. A.; Minaev, K. M.; Ber, L. M.; Isaev, Ye D.; Ulyanova, O. S.

    2016-09-01

    The paper describes the improvement of gravel packing technique applied for the production wells. The authors have suggested new design of gravel pack for gravel packing of productive formations. The issue is currently topical because gravel packing at drillhole ISL is less time- and money-consuming. The subject of the research is gravel pack design and content. The purpose defined by the authors is to design the gravel pack and to suggest the composition of gravel cement agent. As a result of the research, the authors have described different designs of the gravel pack, its optimal shape, as well as a choice and justification of cement agents, a hold cover of the gravel pack, and suggested the methods of experimental research.

  10. 7 CFR 51.1527 - Standard pack.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ..., CERTIFICATION, AND STANDARDS) United States Standards for Grades of Fresh Plums and Prunes Standard Pack § 51... the approved and recognized methods. (2) The plums or prunes in the top layer of any package shall be...” means that the plums or prunes packed in loose or volume filled containers are packed within 1 inch...

  11. 7 CFR 51.1527 - Standard pack.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ..., CERTIFICATION, AND STANDARDS) United States Standards for Grades of Fresh Plums and Prunes Standard Pack § 51... the approved and recognized methods. (2) The plums or prunes in the top layer of any package shall be...” means that the plums or prunes packed in loose or volume filled containers are packed within 1 inch...

  12. 7 CFR 966.11 - Pack.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE TOMATOES GROWN IN FLORIDA Order Regulating Handling Definitions § 966.11 Pack. Pack means any of the packs of tomatoes as defined and set forth in the United States Standards for Fresh Tomatoes issued by the United States Department of Agriculture (§§...

  13. 7 CFR 966.11 - Pack.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE TOMATOES GROWN IN FLORIDA Order Regulating Handling Definitions § 966.11 Pack. Pack means any of the packs of tomatoes as defined and set forth in the United States Standards for Fresh Tomatoes issued by the United States Department of Agriculture (§§...

  14. 7 CFR 966.11 - Pack.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE TOMATOES GROWN IN FLORIDA Order Regulating Handling Definitions § 966.11 Pack. Pack means any of the packs of tomatoes as defined and set forth in the United States Standards for Fresh Tomatoes issued by the United States Department of Agriculture (§§...

  15. 7 CFR 966.11 - Pack.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE TOMATOES GROWN IN FLORIDA Order Regulating Handling Definitions § 966.11 Pack. Pack means any of the packs of tomatoes as defined and set forth in the United States Standards for Fresh Tomatoes issued by the United States Department of Agriculture (§§...

  16. 7 CFR 966.11 - Pack.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE TOMATOES GROWN IN FLORIDA Order Regulating Handling Definitions § 966.11 Pack. Pack means any of the packs of tomatoes as defined and set forth in the United States Standards for Fresh Tomatoes issued by the United States Department of Agriculture (§§...

  17. 7 CFR 51.1527 - Standard pack.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... package. The number of plums or prunes in California peach boxes or lug boxes shall not vary more than 4... Standards for Grades of Fresh Plums and Prunes Standard Pack § 51.1527 Standard pack. (a) Packing. (1) All... plums or prunes in the top layer of any package shall be reasonably representative in quality and...

  18. Diffusion in Jammed Particle Packs.

    PubMed

    Bolintineanu, Dan S; Grest, Gary S; Lechman, Jeremy B; Silbert, Leonardo E

    2015-08-21

    Using random walk simulations we explore diffusive transport through monodisperse sphere packings over a range of packing fractions ϕ in the vicinity of the jamming transition at ϕ(c). Various diffusion properties are computed over several orders of magnitude in both time and packing pressure. Two well-separated regimes of normal "Fickian" diffusion, where the mean squared displacement is linear in time, are observed. The first corresponds to diffusion inside individual spheres, while the latter is the long-time bulk diffusion. The intermediate anomalous diffusion regime and the long-time value of the diffusion coefficient are both shown to be controlled by particle contacts, which in turn depend on proximity to ϕ(c). The time required to recover normal diffusion t* scales as (ϕ-ϕ(c))(-0.5) and the long-time diffusivity D(∞)∼(ϕ-ϕ(c))0.5, or D(∞)∼1/t*. It is shown that the distribution of mean first passage times associated with the escape of random walkers between neighboring particles controls both t* and D(∞) in the limit ϕ→ϕ(c).

  19. Polyolefin Blend Miscibility and Packing

    NASA Astrophysics Data System (ADS)

    Lohse, David J.

    2000-03-01

    Over the last several years data have been obtained on the miscibility of a wide range of polyolefins, covering some 200 blends involving about 75 different components. Despite the fact that there are no 'specific interactions' between these saturated hydrocarbon polymers, every kind of phase behavior has been observed, including UCST, LCST, and even negative values of the Flory interaction parameter. The key factor that determines how these polyolefins mix is the way that they pack. Very often, polyolefins mix regularly, that is, the interaction energy is determined by the cohesive energies of the pure components. When they do mix regularly, miscibility is achieved by a close match in the packing lengths of the components. Favorable irregular mixing appears to be the result of some specific packing arrangements. Recent data on the effects of pressure and temperature on the mixing of several polyolefin blends shows that the interaction energies depend only on density (and not on T and P independently) for UCST blends far from a critical point. As a result, the effects of pressure on miscibility can be predicted for such blends from knowledge of the effects of temperature on the interactions combined with PVT data. This remarkable simplification appears to be related to the van der Waals nature of the interactions between saturated hydrocarbons. Density dependence predicts the trends correctly for LCST polyolefin blends, but for these mixtures the interactions depend in a more complex way on T and P.

  20. Diffusion in Jammed Particle Packs.

    PubMed

    Bolintineanu, Dan S; Grest, Gary S; Lechman, Jeremy B; Silbert, Leonardo E

    2015-08-21

    Using random walk simulations we explore diffusive transport through monodisperse sphere packings over a range of packing fractions ϕ in the vicinity of the jamming transition at ϕ(c). Various diffusion properties are computed over several orders of magnitude in both time and packing pressure. Two well-separated regimes of normal "Fickian" diffusion, where the mean squared displacement is linear in time, are observed. The first corresponds to diffusion inside individual spheres, while the latter is the long-time bulk diffusion. The intermediate anomalous diffusion regime and the long-time value of the diffusion coefficient are both shown to be controlled by particle contacts, which in turn depend on proximity to ϕ(c). The time required to recover normal diffusion t* scales as (ϕ-ϕ(c))(-0.5) and the long-time diffusivity D(∞)∼(ϕ-ϕ(c))0.5, or D(∞)∼1/t*. It is shown that the distribution of mean first passage times associated with the escape of random walkers between neighboring particles controls both t* and D(∞) in the limit ϕ→ϕ(c). PMID:26340211

  1. GlobiPack v. 1.0

    2010-03-31

    GlobiPack contains a small collection of optimization globalization algorithms. These algorithms are used by optimization and various nonlinear equation solver algorithms.Used as the line-search procedure with Newton and Quasi-Newton optimization and nonlinear equation solver methods. These are standard published 1-D line search algorithms such as are described in the book Nocedal and Wright Numerical Optimization: 2nd edition, 2006. One set of algorithms were copied and refactored from the existing open-source Trilinos package MOOCHO where themore » linear search code is used to globalize SQP methods. This software is generic to any mathematical optimization problem where smooth derivatives exist. There is no specific connection or mention whatsoever to any specific application, period. You cannot find more general mathematical software.« less

  2. GlobiPack v. 1.0

    SciTech Connect

    Bartlett, Roscoe

    2010-03-31

    GlobiPack contains a small collection of optimization globalization algorithms. These algorithms are used by optimization and various nonlinear equation solver algorithms.Used as the line-search procedure with Newton and Quasi-Newton optimization and nonlinear equation solver methods. These are standard published 1-D line search algorithms such as are described in the book Nocedal and Wright Numerical Optimization: 2nd edition, 2006. One set of algorithms were copied and refactored from the existing open-source Trilinos package MOOCHO where the linear search code is used to globalize SQP methods. This software is generic to any mathematical optimization problem where smooth derivatives exist. There is no specific connection or mention whatsoever to any specific application, period. You cannot find more general mathematical software.

  3. Implementation of Bin Packing Model for Reed Switch Production Planning

    SciTech Connect

    Parra, Rainier Romero

    2010-06-17

    This paper presents a form to resolve a real problem of efficient material election in reed switch manufacturing. The carrying out of the consumer demands depends on the stochastic results of the classification process where each lot of switches is distributed into bins according to an electric measure value. Various glass types are employed for the switch manufacturing. The effect caused by the glass type variation on the switch classification results was investigated. Based on real data statistic analysis, the problem is reduced to the lot number minimizing taking into consideration the glass type, and interpreted as a bin packing problem generalization. On difference to the classic bin packing problem, in the considered case, an item represents a set of pieces; a container is divided into a number of bins (sub-containers); the bin capacity is variable; there are the assignment restrictions between bins and sets of pieces; the items are allowed to be fragmented into bins and containers. The problem has a high complexity. A heuristic offline algorithm is proposed to find the quantity, types and packing sequence of containers, the item fragments associated with containers and bins. The bin capacities do not affect the algorithm.

  4. Adhesive loose packings of small dry particles

    NASA Astrophysics Data System (ADS)

    Liu, Wenwei; Li, Shuiqing; Baule, Adrian; Makse, Hernán A.

    We explore adhesive loose packings of dry small spherical particles of micrometer size using 3D discrete-element simulations with adhesive contact mechanics. A dimensionless adhesion parameter ($Ad$) successfully combines the effects of particle velocities, sizes and the work of adhesion, identifying a universal regime of adhesive packings for $Ad>1$. The structural properties of the packings in this regime are well described by an ensemble approach based on a coarse-grained volume function that includes correlations between bulk and contact spheres. Our theoretical and numerical results predict: (i) An equation of state for adhesive loose packings that appears as a continuation from the frictionless random close packing (RCP) point in the jamming phase diagram; (ii) The existence of a maximal loose packing point at the coordination number $Z=2$ and packing fraction $\\phi=1/2^{3}$. Our results highlight that adhesion leads to a universal packing regime at packing fractions much smaller than the random loose packing, which can be described within a statistical mechanical framework. We present a general phase diagram of jammed matter comprising frictionless, frictional, adhesive as well as non-spherical particles, providing a classification of packings in terms of their continuation from the spherical frictionless RCP.

  5. Kinetics of pack aluminization of nickel

    NASA Technical Reports Server (NTRS)

    Seigle, L. L.; Gupta, B. K.; Shankar, R.; Sarkhel, A. K.

    1978-01-01

    The kinetics of pack aluminization of unalloyed nickel in packs of varying aluminum activity with various halide activators were studied. Surface compositions of the coatings as functions of time, temperature, and pack composition were obtained in order to establish the boundary conditions for diffusion in the system. The structure of the packs was also examined in order to clarify the mechanism of aluminum transport. The results indicate that the kinetics of pack aluminization are controlled jointly by gas diffusion in the pack and solid diffusion in the coating. Levine and Caves' model for gas diffusion was combined with calculations of rates of diffusion in the solid to formulate a more complete theory for the kinetics of pack aluminization.

  6. Systematization of the protein sequence diversity in enzymes related to secondary metabolic pathways in plants, in the context of big data biology inspired by the KNApSAcK motorcycle database.

    PubMed

    Ikeda, Shun; Abe, Takashi; Nakamura, Yukiko; Kibinge, Nelson; Hirai Morita, Aki; Nakatani, Atsushi; Ono, Naoaki; Ikemura, Toshimichi; Nakamura, Kensuke; Altaf-Ul-Amin, Md; Kanaya, Shigehiko

    2013-05-01

    Biology is increasingly becoming a data-intensive science with the recent progress of the omics fields, e.g. genomics, transcriptomics, proteomics and metabolomics. The species-metabolite relationship database, KNApSAcK Core, has been widely utilized and cited in metabolomics research, and chronological analysis of that research work has helped to reveal recent trends in metabolomics research. To meet the needs of these trends, the KNApSAcK database has been extended by incorporating a secondary metabolic pathway database called Motorcycle DB. We examined the enzyme sequence diversity related to secondary metabolism by means of batch-learning self-organizing maps (BL-SOMs). Initially, we constructed a map by using a big data matrix consisting of the frequencies of all possible dipeptides in the protein sequence segments of plants and bacteria. The enzyme sequence diversity of the secondary metabolic pathways was examined by identifying clusters of segments associated with certain enzyme groups in the resulting map. The extent of diversity of 15 secondary metabolic enzyme groups is discussed. Data-intensive approaches such as BL-SOM applied to big data matrices are needed for systematizing protein sequences. Handling big data has become an inevitable part of biology.

  7. Diffusion in jammed particle packs

    NASA Astrophysics Data System (ADS)

    Bolintineanu, Dan S.; Silbert, Leonardo E.; Grest, Gary S.; Lechman, Jeremy B.

    2015-03-01

    Diffusive transport in jammed particle packs is of interest for a number of applications, as well as being a potential indicator of structural properties near the jamming point. To this end, we report stochastic simulations of equilibrium diffusion through monodisperse sphere packs near the jamming point in the limit of a perfectly insulating surrounding medium. The time dependence of various diffusion properties is resolved over several orders of magnitude. Two time regimes of expected Fickian diffusion are observed, separated by an intermediate regime of anomalous diffusion. This intermediate regime grows as the particle volume fraction approaches the critical jamming transition. The diffusion behavior is fully controlled by the extent of the contacts between neighboring particles, which in turn depend on proximity to the jamming point. In particular, the mean first passage time associated with the escape of random walkers between neighboring particles is shown to control both the time to recover Fickian diffusion and the long time diffusivity. Scaling laws are established that relate these quantities to the difference between the actual and critical jamming volume fractions. Sandia National Laboratories is a multiprogram laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's NNSA under Contract DE- AC04-94AL85000.

  8. The Packing of Granular Polymer Chains

    SciTech Connect

    Zou, Ling-Nan; Cheng, Xiang; Rivers, Mark L.; Jaeger, Heinrich M.; Nagel, Sidney R.; UC

    2009-12-01

    Rigid particles pack into structures, such as sand dunes on the beach, whose overall stability is determined by the average number of contacts between particles. However, when packing spatially extended objects with flexible shapes, additional concepts must be invoked to understand the stability of the resulting structure. Here, we examine the disordered packing of chains constructed out of flexibly connected hard spheres. Using x-ray tomography, we find that long chains pack into a low-density structure whose mechanical rigidity is mainly provided by the backbone. On compaction, randomly oriented, semi-rigid loops form along the chain, and the packing of chains can be understood as the jamming of these elements. Finally, we uncover close similarities between the packing of chains and the glass transition in polymers.

  9. 7 CFR 982.11 - Pack.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE HAZELNUTS GROWN IN OREGON AND WASHINGTON... according to size, internal quality, and external appearance and condition of hazelnuts packed in...

  10. 7 CFR 982.11 - Pack.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE HAZELNUTS GROWN IN OREGON AND WASHINGTON... according to size, internal quality, and external appearance and condition of hazelnuts packed in...

  11. 7 CFR 982.11 - Pack.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE HAZELNUTS GROWN IN OREGON AND WASHINGTON... according to size, internal quality, and external appearance and condition of hazelnuts packed in...

  12. 7 CFR 982.11 - Pack.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE HAZELNUTS GROWN IN OREGON AND WASHINGTON... according to size, internal quality, and external appearance and condition of hazelnuts packed in...

  13. Random packing of spheres in Menger sponge.

    PubMed

    Cieśla, Michał; Barbasz, Jakub

    2013-06-01

    Random packing of spheres inside fractal collectors of dimension 2 < d < 3 is studied numerically using Random Sequential Adsorption (RSA) algorithm. The paper focuses mainly on the measurement of random packing saturation limit. Additionally, scaling properties of density autocorrelations in the obtained packing are analyzed. The RSA kinetics coefficients are also measured. Obtained results allow to test phenomenological relation between random packing saturation density and collector dimension. Additionally, performed simulations together with previously obtained results confirm that, in general, the known dimensional relations are obeyed by systems having non-integer dimension, at least for d < 3.

  14. Imaging of body packing: errors and medico-legal issues.

    PubMed

    Reginelli, Alfonso; Russo, Anna; Urraro, Fabrizio; Maresca, Duilia; Martiniello, Ciro; D'Andrea, Alfredo; Brunese, Luca; Pinto, Antonio

    2015-10-01

    Body packing is the ingestion or insertion in the human body of packed illicit substances. Over the last 20 years, drug smuggling has increased global and new means of transport of narcotics have emerged. Among these, the most frequent one is the gastrointestinal tract: from mouth to anus, vagina, and ears. Cocaine is one of the most traded drugs, followed by heroin. Condoms, latex gloves, and balloons are typically used as drug packets for retention in the body. There are different radiologic modalities to detect illicit drugs in body packing: Plain radiography, computed tomography (CT), ultrasound, and magnetic resonance. Current protocols recommend the use of radiography to confirm packet retention and, in case of doubt, the use of abdominal CT scan with reduced mAs. In case of packet rupture, catastrophic effects can occur. Management of patients carrying packets of drugs is a recurrent medico-legal problem. To improve diagnostic accuracy and prevent hazardous complications, radiologists and emergency physicians should be familiar with radiologic features of body packing. The radiologist plays both a social and a medico-legal role in their assessment, and it should not be limited only to the identification of the packages but must also provide accurate information about their number and their exact location. In this review, we focus on diagnostic errors and medico-legal issues related to the radiological assessment of body packers. PMID:26063072

  15. Imaging of body packing: errors and medico-legal issues.

    PubMed

    Reginelli, Alfonso; Russo, Anna; Urraro, Fabrizio; Maresca, Duilia; Martiniello, Ciro; D'Andrea, Alfredo; Brunese, Luca; Pinto, Antonio

    2015-10-01

    Body packing is the ingestion or insertion in the human body of packed illicit substances. Over the last 20 years, drug smuggling has increased global and new means of transport of narcotics have emerged. Among these, the most frequent one is the gastrointestinal tract: from mouth to anus, vagina, and ears. Cocaine is one of the most traded drugs, followed by heroin. Condoms, latex gloves, and balloons are typically used as drug packets for retention in the body. There are different radiologic modalities to detect illicit drugs in body packing: Plain radiography, computed tomography (CT), ultrasound, and magnetic resonance. Current protocols recommend the use of radiography to confirm packet retention and, in case of doubt, the use of abdominal CT scan with reduced mAs. In case of packet rupture, catastrophic effects can occur. Management of patients carrying packets of drugs is a recurrent medico-legal problem. To improve diagnostic accuracy and prevent hazardous complications, radiologists and emergency physicians should be familiar with radiologic features of body packing. The radiologist plays both a social and a medico-legal role in their assessment, and it should not be limited only to the identification of the packages but must also provide accurate information about their number and their exact location. In this review, we focus on diagnostic errors and medico-legal issues related to the radiological assessment of body packers.

  16. Minimally packed phases in holography

    NASA Astrophysics Data System (ADS)

    Donos, Aristomenis; Gauntlett, Jerome P.

    2016-03-01

    We numerically construct asymptotically AdS black brane solutions of D = 4 Einstein-Maxwell theory coupled to a pseudoscalar. The solutions are holographically dual to d = 3 CFTs at finite chemical potential and in a constant magnetic field, which spontaneously break translation invariance leading to the spontaneous formation of abelian and momentum magnetisation currents flowing around the plaquettes of a periodic Bravais lattice. We analyse the three-dimensional moduli space of lattice solutions, which are generically oblique, and show, for a specific value of the magnetic field, that the free energy is minimised by the triangular lattice, associated with minimal packing of circles in the plane. We show that the average stress tensor for the thermodynamically preferred phase is that of a perfect fluid and that this result applies more generally to spontaneously generated periodic phases. The triangular structure persists at low temperatures indicating the existence of novel crystalline ground states.

  17. Chain packing in polycarbonate glasses

    NASA Astrophysics Data System (ADS)

    Stueber, Dirk; Yu, Tsyr-Yan; Hess, Berk; Kremer, Kurt; O'Connor, Robert D.; Schaefer, Jacob

    2010-03-01

    Chain packing in homogeneous blends of carbonate C13-labeled bisphenol A polycarbonate with either (i) CF3-labeled bisphenol A polycarbonate or (ii) ring-F-labeled bisphenol A polycarbonate has been characterized using C13{F19} rotational-echo double-resonance (REDOR) nuclear magnetic resonance. In both blends, the C13 observed spin was at high concentration, and the F19 dephasing or probe spin was at low concentration. In this situation, an analysis in terms of a distribution of isolated heteronuclear pairs of spins is valid. Nearest-neighbor separation of C13 and F19 labels was determined by accurately mapping the initial dipolar evolution using a shifted-pulse version of REDOR. Based on the results of this experiment, the average distance from a ring-fluorine to the nearest C13O is more than 1.2 Å greater than the corresponding CF3C13O distance. Next-nearest and more-distant-neighbor separations of labels were measured in a 416-rotor-cycle constant-time version of REDOR for both blends. Statistically significant local order was established for the nearest-neighbor labels in the methyl-labeled blend. These interchain packing results are in qualitative agreement with predictions based on coarse-grained simulations of a specially adapted model for bisphenol A polycarbonate. The model itself has been previously used to determine static and dynamic properties of polycarbonate with results in good agreement with those from rheological and neutron scattering experiments.

  18. Confined disordered strictly jammed binary sphere packings

    NASA Astrophysics Data System (ADS)

    Chen, D.; Torquato, S.

    2015-12-01

    Disordered jammed packings under confinement have received considerably less attention than their bulk counterparts and yet arise in a variety of practical situations. In this work, we study binary sphere packings that are confined between two parallel hard planes and generalize the Torquato-Jiao (TJ) sequential linear programming algorithm [Phys. Rev. E 82, 061302 (2010), 10.1103/PhysRevE.82.061302] to obtain putative maximally random jammed (MRJ) packings that are exactly isostatic with high fidelity over a large range of plane separation distances H , small to large sphere radius ratio α , and small sphere relative concentration x . We find that packing characteristics can be substantially different from their bulk analogs, which is due to what we term "confinement frustration." Rattlers in confined packings are generally more prevalent than those in their bulk counterparts. We observe that packing fraction, rattler fraction, and degree of disorder of MRJ packings generally increase with H , though exceptions exist. Discontinuities in the packing characteristics as H varies in the vicinity of certain values of H are due to associated discontinuous transitions between different jammed states. When the plane separation distance is on the order of two large-sphere diameters or less, the packings exhibit salient two-dimensional features; when the plane separation distance exceeds about 30 large-sphere diameters, the packings approach three-dimensional bulk packings. As the size contrast increases (as α decreases), the rattler fraction dramatically increases due to what we call "size-disparity" frustration. We find that at intermediate α and when x is about 0.5 (50-50 mixture), the disorder of packings is maximized, as measured by an order metric ψ that is based on the number density fluctuations in the direction perpendicular to the hard walls. We also apply the local volume-fraction variance στ2(R ) to characterize confined packings and find that these

  19. Probe with integrated heater and thermocouple pack

    SciTech Connect

    McCulloch, R.W.; Dial, R.E.; Finnell, W.F.R.

    1988-02-16

    This patent describes a gamma thermometer probe for detecting heat produced within the thermometer probe. It comprises: an outer elongate thermometer sheath; an elongate rod; annular recesses; a longitudinal bore; and an integrated thermocouple pack. The thermocouple pack comprises: a first type wire, and second type wires. The second type wires comprises: an outer section; and an inner segment.

  20. Pack Density Limitations of Hybrid Parachutes

    NASA Technical Reports Server (NTRS)

    Zwicker, Matthew L.; Sinclair, Robert J.

    2013-01-01

    The development and testing of the Orion crew capsule parachute system has provided a unique opportunity to study dense parachute packing techniques and limits, in order to establish a new baseline for future programs. The density of parachute packs has a significant influence on vibration loads, retention system stresses, and parachute mortar performance. Material compositions and pack densities of existing designs for space capsule recovery were compared, using the pack density of the Apollo main parachutes as the current baseline. The composition of parachutes has changed since Apollo, incorporating new materials such as Kevlar , Vectran , Teflon and Spectra . These materials have different specific densities than Nylon, so the densities of hybrid parachute packs cannot be directly compared to Nylon parachutes for determination of feasibility or volume allocation. Six parachute packs were evaluated in terms of weighted average solid density in order to achieve a non-dimensional comparison of packing density. Means of mitigating damage due to packing pressure and mortar firing were examined in light of the Capsule Parachute Assembly System (CPAS) and Apollo experience. Parachute design improvements including incorporation of modern materials and manufacturing processes serves to make CPAS the new knowledge base on which future spacecraft parachute systems will be built.

  1. Kid's PACK: Population Awareness Campaign Kit.

    ERIC Educational Resources Information Center

    Zero Population Growth, Inc., Washington, DC.

    This fun and educational kit is designed specifically for elementary students. The "Kid's PACK" (Population Awareness Campaign Kit) entertains and informs children on the environment and human population growth through stories, games, and concrete ideas for making a difference. In three booklets, the "Kid's PACK" offers elementary students…

  2. Cluster and constraint analysis in tetrahedron packings.

    PubMed

    Jin, Weiwei; Lu, Peng; Liu, Lufeng; Li, Shuixiang

    2015-04-01

    The disordered packings of tetrahedra often show no obvious macroscopic orientational or positional order for a wide range of packing densities, and it has been found that the local order in particle clusters is the main order form of tetrahedron packings. Therefore, a cluster analysis is carried out to investigate the local structures and properties of tetrahedron packings in this work. We obtain a cluster distribution of differently sized clusters, and peaks are observed at two special clusters, i.e., dimer and wagon wheel. We then calculate the amounts of dimers and wagon wheels, which are observed to have linear or approximate linear correlations with packing density. Following our previous work, the amount of particles participating in dimers is used as an order metric to evaluate the order degree of the hierarchical packing structure of tetrahedra, and an order map is consequently depicted. Furthermore, a constraint analysis is performed to determine the isostatic or hyperstatic region in the order map. We employ a Monte Carlo algorithm to test jamming and then suggest a new maximally random jammed packing of hard tetrahedra from the order map with a packing density of 0.6337.

  3. Pack rats (Neotoma spp.): Keystone ecological engineers?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The potential role of two species of pack rats (Neotoma albigula and Neotoma micropus) as keystone ecological engineers was examined by estimating the species diversity of invertebrates living in the nest middens, and nitrogen mineralization rates in soils associated with the middens. Although pack-...

  4. 7 CFR 51.2338 - Standard pack.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... packed in containers with cell compartments, cardboard fillers or molded trays shall be of proper size for the cells, fillers, or molds in which they are packed, and conform to the marked count. (2) In... angles to a line from stem to blossom end. (f) In order to allow for variations incident to proper...

  5. 7 CFR 51.2338 - Standard pack.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... packed in containers with cell compartments, cardboard fillers or molded trays shall be of proper size for the cells, fillers, or molds in which they are packed, and conform to the marked count. (2) In... angles to a line from stem to blossom end. (f) In order to allow for variations incident to proper...

  6. 7 CFR 51.2338 - Standard pack.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    .... (c) Boxes, flats, lugs, or cartons: (1) Fruit packed in containers with cell compartments, cardboard fillers or molded trays shall be of proper size for the cells, fillers, or molds in which they are packed...” means the greatest dimension measured at right angles to a line from stem to blossom end. (f) In...

  7. 7 CFR 51.3152 - Standard pack.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...) Nectarines packed in containers equipped with cell compartments, cardboard fillers or molded trays shall be of the proper size for the cells, fillers, or molds in which they are packed, and the number of... angles to a line from stem to blossom end of the fruit. (h) Tolerances. In order to allow for...

  8. 7 CFR 51.2338 - Standard pack.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... packed in containers with cell compartments, cardboard fillers or molded trays shall be of proper size for the cells, fillers, or molds in which they are packed, and conform to the marked count. (2) In... angles to a line from stem to blossom end. (f) In order to allow for variations incident to proper...

  9. 7 CFR 51.3152 - Standard pack.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...) Nectarines packed in containers equipped with cell compartments, cardboard fillers or molded trays shall be of the proper size for the cells, fillers, or molds in which they are packed, and the number of... angles to a line from stem to blossom end of the fruit. (h) Tolerances. In order to allow for...

  10. 7 CFR 51.2338 - Standard pack.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    .... (c) Boxes, flats, lugs, or cartons: (1) Fruit packed in containers with cell compartments, cardboard fillers or molded trays shall be of proper size for the cells, fillers, or molds in which they are packed...” means the greatest dimension measured at right angles to a line from stem to blossom end. (f) In...

  11. 7 CFR 906.10 - Pack.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and... GRANDE VALLEY IN TEXAS Order Regulating Handling Definitions § 906.10 Pack. Pack means the specific grade, quality, size, or arrangement of fruit in a particular container or containers....

  12. Record high Wolf, Canis lupus, pack density

    USGS Publications Warehouse

    Mech, L.D.; Tracy, S.

    2004-01-01

    This report documents a year-around Wolf (Canis lupus) density of 18.2/100 km2 and a summer density of 30.8/100 km2, in a northeastern Minnesota Wolf pack. The previous record was a summer density of 14.1/100 km2, for a Wolf pack on Vancouver Island, British Columbia, Canada.

  13. Record high wolf, Canis lupus, pack density

    USGS Publications Warehouse

    Mech, L.D.; Tracy, S.

    2004-01-01

    This report documents a year-around wolf (Canis lupus) density of 18.2/100 m2 and summer density of 30.8/100 km2, in a northeastern Minnesota wolf pack. The previous record was a summer density of 14.1/100 km2, for a wolf pack on Vancouver Island, BC, Canada.

  14. Method of gravel packing a well

    SciTech Connect

    Almond, S. W.; Himes, R. E.

    1985-11-12

    The present invention relates to a thermally stable crosslinked gel gravel packing fluid for use in the treatment of highly deviated well bores penetrating a subterranean formation. The gravel packing fluid comprises an aqueous liquid, a gelling agent comprising a selected modified cellulose ether, a crosslinking agent, a breaker, a particulate agent and any additional additives that may be present.

  15. 21 CFR 890.5700 - Cold pack.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Cold pack. 890.5700 Section 890.5700 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5700 Cold pack. (a) Identification....

  16. 21 CFR 890.5700 - Cold pack.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cold pack. 890.5700 Section 890.5700 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5700 Cold pack. (a) Identification....

  17. 21 CFR 890.5700 - Cold pack.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Cold pack. 890.5700 Section 890.5700 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5700 Cold pack. (a) Identification....

  18. Coalescence preference in densely packed microbubbles

    SciTech Connect

    Kim, Yeseul; Lim, Su Jin; Gim, Bopil; Weon, Byung Mook

    2015-01-13

    A bubble merged from two parent bubbles with different size tends to be placed closer to the larger parent. This phenomenon is known as the coalescence preference. Here we demonstrate that the coalescence preference can be blocked inside a densely packed cluster of bubbles. We utilized high-speed high-resolution X-ray microscopy to clearly visualize individual coalescence events inside densely packed microbubbles with a local packing fraction of ~40%. Thus, the surface energy release theory predicts an exponent of 5 in a relation between the relative coalescence position and the parent size ratio, whereas our observation for coalescence in densely packed microbubbles shows a different exponent of 2. We believe that this result would be important to understand the reality of coalescence dynamics in a variety of packing situations of soft matter.

  19. Coalescence preference in densely packed microbubbles

    DOE PAGESBeta

    Kim, Yeseul; Lim, Su Jin; Gim, Bopil; Weon, Byung Mook

    2015-01-13

    A bubble merged from two parent bubbles with different size tends to be placed closer to the larger parent. This phenomenon is known as the coalescence preference. Here we demonstrate that the coalescence preference can be blocked inside a densely packed cluster of bubbles. We utilized high-speed high-resolution X-ray microscopy to clearly visualize individual coalescence events inside densely packed microbubbles with a local packing fraction of ~40%. Thus, the surface energy release theory predicts an exponent of 5 in a relation between the relative coalescence position and the parent size ratio, whereas our observation for coalescence in densely packed microbubblesmore » shows a different exponent of 2. We believe that this result would be important to understand the reality of coalescence dynamics in a variety of packing situations of soft matter.« less

  20. Fracture dimensions in frac&pack stimulation

    SciTech Connect

    Fan, Y.; Economides, M.J.

    1995-12-31

    A model is introduced to predict dynamic fracture dimensions in frac&pack stimulation. Design aspects of the two-in-one step treatment techniques, required by soft and high-permeability reservoirs are discussed. A pressure-dependent leakoff model, based on the transient flow of a non-Newtonian fluid displacing a reservoir fluid has been developed and incorporated with fracture mechanics concepts to simulate the entire process of frac&pack treatments including fracture propagation, inflation, proppant packing and closure. Results obtained in this study indicate the considerable difference between traditional fracturing and frac&pack treatments. In the latter, fracture length is much less important than fracture conductivity. This work shows how to terminate the fracture growth at the appropriate time, and how to design frac&packs resulting in fracture widths several times larger than those for traditional fracturing.

  1. Condensation in Nanoporous Packed Beds.

    PubMed

    Ally, Javed; Molla, Shahnawaz; Mostowfi, Farshid

    2016-05-10

    In materials with tiny, nanometer-scale pores, liquid condensation is shifted from the bulk saturation pressure observed at larger scales. This effect is called capillary condensation and can block pores, which has major consequences in hydrocarbon production, as well as in fuel cells, catalysis, and powder adhesion. In this study, high pressure nanofluidic condensation studies are performed using propane and carbon dioxide in a colloidal crystal packed bed. Direct visualization allows the extent of condensation to be observed, as well as inference of the pore geometry from Bragg diffraction. We show experimentally that capillary condensation depends on pore geometry and wettability because these factors determine the shape of the menisci that coalesce when pore filling occurs, contrary to the typical assumption that all pore structures can be modeled as cylindrical and perfectly wetting. We also observe capillary condensation at higher pressures than has been done previously, which is important because many applications involving this phenomenon occur well above atmospheric pressure, and there is little, if any, experimental validation of capillary condensation at such pressures, particularly with direct visualization.

  2. Condensation in Nanoporous Packed Beds.

    PubMed

    Ally, Javed; Molla, Shahnawaz; Mostowfi, Farshid

    2016-05-10

    In materials with tiny, nanometer-scale pores, liquid condensation is shifted from the bulk saturation pressure observed at larger scales. This effect is called capillary condensation and can block pores, which has major consequences in hydrocarbon production, as well as in fuel cells, catalysis, and powder adhesion. In this study, high pressure nanofluidic condensation studies are performed using propane and carbon dioxide in a colloidal crystal packed bed. Direct visualization allows the extent of condensation to be observed, as well as inference of the pore geometry from Bragg diffraction. We show experimentally that capillary condensation depends on pore geometry and wettability because these factors determine the shape of the menisci that coalesce when pore filling occurs, contrary to the typical assumption that all pore structures can be modeled as cylindrical and perfectly wetting. We also observe capillary condensation at higher pressures than has been done previously, which is important because many applications involving this phenomenon occur well above atmospheric pressure, and there is little, if any, experimental validation of capillary condensation at such pressures, particularly with direct visualization. PMID:27115446

  3. Improved Taxation Rate for Bin Packing Games

    NASA Astrophysics Data System (ADS)

    Kern, Walter; Qiu, Xian

    A cooperative bin packing game is a N-person game, where the player set N consists of k bins of capacity 1 each and n items of sizes a 1, ⋯ ,a n . The value of a coalition of players is defined to be the maximum total size of items in the coalition that can be packed into the bins of the coalition. We present an alternative proof for the non-emptiness of the 1/3-core for all bin packing games and show how to improve this bound ɛ= 1/3 (slightly). We conjecture that the true best possible value is ɛ= 1/7.

  4. Leadership in wolf, Canis lupus, packs

    USGS Publications Warehouse

    Mech, L. David

    2000-01-01

    I examine leadership in Wolf (Canis lupus) packs based on published observations and data gathered during summers from 1986 to 1998 studying a free-ranging pack of Wolves on Ellesmere Island that were habituated to my presence. The breeding male tended to initiate activities associated with foraging and travel, and the breeding female to initiate, and predominate in, pup care and protection. However, there was considerable overlap and interaction during these activities such that leadership could be considered a joint function. In packs with multiple breeders, quantitative information about leadership is needed.

  5. Packing a Box with Bricks.

    ERIC Educational Resources Information Center

    Jepsen, Charles H.

    1991-01-01

    Presented are solutions to variations of a combinatorics problem from a recent International Mathematics Olympiad. In particular, the matrix algebra solution illustrates an interaction among the undergraduate areas of geometry, combinatorics, linear algebra, and group theory. (JJK)

  6. An amino acid code to define a protein's tertiary packing surface.

    PubMed

    Fraga, Keith J; Joo, Hyun; Tsai, Jerry

    2016-02-01

    One difficult aspect of the protein-folding problem is characterizing the nonspecific interactions that define packing in protein tertiary structure. To better understand tertiary structure, this work extends the knob-socket model by classifying the interactions of a single knob residue packed into a set of contiguous sockets, or a pocket made up of 4 or more residues. The knob-socket construct allows for a symbolic two-dimensional mapping of pockets. The two-dimensional mapping of pockets provides a simple method to investigate the variety of pocket shapes to understand the geometry of protein tertiary surfaces. The diversity of pocket geometries can be organized into groups of pockets that share a common core, which suggests that some interactions in pockets are ancillary to packing. Further analysis of pocket geometries displays a preferred configuration that is right-handed in α-helices and left-handed in β-sheets. The amino acid composition of pockets illustrates the importance of nonpolar amino acids in packing as well as position specificity. As expected, all pocket shapes prefer to pack with hydrophobic knobs; however, knobs are not selective for the pockets they pack. Investigating side-chain rotamer preferences for certain pocket shapes uncovers no strong correlations. These findings allow a simple vocabulary based on knobs and sockets to describe protein tertiary packing that supports improved analysis, design, and prediction of protein structure.

  7. 48-Pack low level waste storage facility

    SciTech Connect

    Bilik, T.J.

    1995-11-01

    ComEd has completed a design for a low level radioactive waste (LLW) storage facility, dubbed the {open_quotes}48-Pack{close_quotes}. The 48-Pack, so named because of its ability to hold 48 high integrity containers (HICs), is a modular, heavily shielded, concrete bunker. The facility was designed to serve as an effective means of augmenting the Company`s existing process waste storage capacity if and when the need arose. This paper identifies how ComEd addressed the potential need to supplement the storage capacity at its six nuclear stations through the development of the 48-Pack. Based on the criteria of meeting safety and regulatory requirements, low cost, short lead time for construction, universal design, and modularity, the 48-Pack concept was anticipated to meet and exceed the Company`s storage needs which were anticipated to end with the availability of a Central Midwest Compact (CMC) disposal facility.

  8. Packing and Entanglements in Polymer Melts

    NASA Astrophysics Data System (ADS)

    Ozisik, Rahmi; Sternstein, Sandy S.

    2004-03-01

    The idea of obtaining the properties of polymers simply from the chemical structure is a very attractive one. Recent work on entanglements and packing indicates that the entanglement molecular weight is related to packing length (= M/(ρ N_a), where M is the molecular weight, ρ is the density, R is the end-to-end vector, and Na is the Avogadro number). The exact relationship is given as follows: Me = 218 ρ p^3. This simple equation holds for a very large group of polymers and is temperature insensitive. In this study, we studied the packing and tried to obtain a scaling between packing and M_e, and extended the concept to cyclic polymers.

  9. Combination gravel packing device and method

    SciTech Connect

    Salerni, J. V.; Zachman, J. R.

    1985-09-17

    An apparatus for gravel packing a screen positioned adjacent the casing perforations of a subterranean well incorporates an annular sealing surface immediately above the gravel pack screen. A flapper valve is mounted for movement about a horizontal pivot axis into engagement with the annular valve seat. The flapper valve and the cooperating valve seat are both provided with spherical segment sealing surfaces so as to prevent leakage through the valve due to any misalignment of the pivot axis of the flapper valve with respect to the annular valve seat. With this apparatus, the withdrawal of the gravel packing apparatus at the completion of the gravel packing operations prevents the entry of undesired fluids and contaminates into the producing formation.

  10. Contact breaking in frictionless granular packings

    NASA Astrophysics Data System (ADS)

    Wu, Qikai; Bertrand, Thibault; O'Hern, Corey; Shattuck, Mark

    We numerically study the breaking of interparticle contact networks in static granular packings of frictionless bidisperse disks that are subjected to vibrations. The packings are created using an isotropic compression protocol at different values of the total potential energy per particle Ep. We first add displacements along a single vibrational mode i of the dynamical matrix to a given packing and calculate the minimum amplitude Ai of the perturbation at which the first interparticle contact breaks. We then identify the minimum amplitude Amin over all perturbations along each mode and study the distribution of Amin from an ensemble of packings at each Ep. We then study two-, three-, and multi-mode excitations and determine the dependence of Amin on the number of modes that are included in the perturbation. W. M. Keck Foundation Science and Engineering Grant.

  11. Groundwater well with reactive filter pack

    DOEpatents

    Gilmore, Tyler J.; Holdren, Jr., George R.; Kaplan, Daniel I.

    1998-01-01

    A method and apparatus for the remediation of contaminated soil and ground water wherein a reactive pack material is added to the annular fill material utilized in standard well construction techniques.

  12. Groundwater well with reactive filter pack

    DOEpatents

    Gilmore, T.J.; Holdren, G.R. Jr.; Kaplan, D.I.

    1998-09-08

    A method and apparatus are disclosed for the remediation of contaminated soil and ground water wherein a reactive pack material is added to the annular fill material utilized in standard well construction techniques. 3 figs.

  13. A Versatile, Automatic Chromatographic Column Packing Device

    ERIC Educational Resources Information Center

    Barry, Eugene F.; And Others

    1977-01-01

    Describes an inexpensive apparatus for packing liquid and gas chromatographic columns of high efficiency. Consists of stainless steel support struts, an Automat Getriebmotor, and an associated three-pulley system capable of 10, 30, and 300 rpm. (MLH)

  14. Distillation of light hydrocarbons in packed columns

    SciTech Connect

    Strigle, R.F.

    1985-04-01

    Newly developed design procedures have led to a wider acceptance of packed columns for distillation operations, especially those operating at atmospheric or higher pressures. Based on these new design methods, modern IMTP packing has been used in a wide variety of services to revamp over 300 distillation columns previously equipped with trays. A few of these columns are listed. These revamps were justified by capacity increase and by greater product recovery. In addition, energy savings were realized from reduction of reflux ratio.

  15. Software For Nearly Optimal Packing Of Cargo

    NASA Technical Reports Server (NTRS)

    Fennel, Theron R.; Daughtrey, Rodney S.; Schwaab, Doug G.

    1994-01-01

    PACKMAN computer program used to find nearly optimal arrangements of cargo items in storage containers, subject to such multiple packing objectives as utilization of volumes of containers, utilization of containers up to limits on weights, and other considerations. Automatic packing algorithm employed attempts to find best positioning of cargo items in container, such that volume and weight capacity of container both utilized to maximum extent possible. Written in Common LISP.

  16. Modeling and verification of a lithium iron phosphate battery pack system for automotive applications

    NASA Astrophysics Data System (ADS)

    Guo, Lin

    In recent years, Lithium chemistry based batteries have gained popularity with all automotive manufacturers. Thousands of battery cells are put into a battery pack to satisfy the need of power consumption of vehicles using electric traction. Managing the battery pack for hybrid and electric vehicles is a challenging problem. Despite the advantage of power density and charge retaining capabilities, Lithium ion batteries do not handle over-charge and over-discharge very well compared to other battery chemistries. Therefore, creating an accurate model to predict the battery pack behavior is essential in research and development for battery management systems. This work presents a general technique to extend accepted modeling methodologies for single cells to models for large packs. The theoretical framework is accompanied by parameter identification process based on the circuit model, and experimental verification procedures supporting the validity of this approach.

  17. Patchy particle packing under electric fields.

    PubMed

    Song, Pengcheng; Wang, Yufeng; Wang, Yu; Hollingsworth, Andrew D; Weck, Marcus; Pine, David J; Ward, Michael D

    2015-03-01

    Colloidal particles equipped with two, three, or four negatively charged patches, which endow the particles with 2-fold, 3-fold, or tetrahedral symmetries, form 1D chains, 2D layers, and 3D packings when polarized by an AC electric field. Two-patch particles, with two patches on opposite sides of the particle (2-fold symmetry) pack into the cmm plane group and 3D packings with I4mm space group symmetry, in contrast to uncharged spherical or ellipsoidal colloids that typically crystallize into a face-centered ABC layer packing. Three-patch particles (3-fold symmetry) form chains having a 21 screw axis symmetry, but these chains pair in a manner such that each individual chain has one-fold symmetry but the pair has 21 screw axis symmetry, in an arrangement that aligns the patches that would favor Coulombic interactions along the chain. Surprisingly, some chain pairs form unanticipated double-helix regions that result from mutual twisting of the chains about each other, illustrating a kind of polymorphism that may be associated with nucleation from short chain pairs. Larger 2D domains of the three-patch particles crystallize in the p6m plane group with alignment (with respect to the field) and packing densities that suggest random disorder in the domains, whereas four-patch particles form 2D domains in which close-packed rows are aligned with the field.

  18. Patchy particle packing under electric fields.

    PubMed

    Song, Pengcheng; Wang, Yufeng; Wang, Yu; Hollingsworth, Andrew D; Weck, Marcus; Pine, David J; Ward, Michael D

    2015-03-01

    Colloidal particles equipped with two, three, or four negatively charged patches, which endow the particles with 2-fold, 3-fold, or tetrahedral symmetries, form 1D chains, 2D layers, and 3D packings when polarized by an AC electric field. Two-patch particles, with two patches on opposite sides of the particle (2-fold symmetry) pack into the cmm plane group and 3D packings with I4mm space group symmetry, in contrast to uncharged spherical or ellipsoidal colloids that typically crystallize into a face-centered ABC layer packing. Three-patch particles (3-fold symmetry) form chains having a 21 screw axis symmetry, but these chains pair in a manner such that each individual chain has one-fold symmetry but the pair has 21 screw axis symmetry, in an arrangement that aligns the patches that would favor Coulombic interactions along the chain. Surprisingly, some chain pairs form unanticipated double-helix regions that result from mutual twisting of the chains about each other, illustrating a kind of polymorphism that may be associated with nucleation from short chain pairs. Larger 2D domains of the three-patch particles crystallize in the p6m plane group with alignment (with respect to the field) and packing densities that suggest random disorder in the domains, whereas four-patch particles form 2D domains in which close-packed rows are aligned with the field. PMID:25692316

  19. Pharyngeal Packing during Rhinoplasty: Advantages and Disadvantages

    PubMed Central

    Razavi, Majid; Taghavi Gilani, Mehryar; Bameshki, Ali Reza; Behdani, Reza; Khadivi, Ehsan; Bakhshaee, Mahdi

    2015-01-01

    Introduction: Controversy remains as to the advantages and disadvantages of pharyngeal packing during septorhinoplasty. Our study investigated the effect of pharyngeal packing on postoperative nausea and vomiting and sore throat following this type of surgery or septorhinoplasty. Materials and Methods: This clinical trial was performed on 90 American Society of Anesthesiologists (ASA) I or II patients who were candidates for septorhinoplasty. They were randomly divided into two groups. Patients in the study group had received pharyngeal packing while those in the control group had not. The incidence of nausea and vomiting and sore throat based on the visual analog scale (VAS) was evaluated postoperatively in the recovery room as well as at 2, 6 and 24 hours. Results: The incidence of postoperative nausea and vomiting (PONV) was 12.3%, with no significant difference between the study and control groups. Sore throat was reported in 50.5% of cases overall (56.8% on pack group and 44.4% on control). Although the severity of pain was higher in the study group at all times, the incidence in the two groups did not differ significantly. Conclusion: The use of pharyngeal packing has no effect in reducing the incidence of nausea and vomiting and sore throat after surgery. Given that induced hypotension is used as the routine method of anesthesia in septorhinoplasty surgery, with a low incidence of hemorrhage and a high risk of unintended retention of pharyngeal packing, its routine use is not recommended for this procedure. PMID:26788486

  20. Snow Pack and Lake Ice Pack Remote Sensing using Wideband Autocorrelation Radiometry

    NASA Astrophysics Data System (ADS)

    Mousavi, S.; De Roo, R. D.; Sarabandi, K.; England, A. W.

    2015-12-01

    A novel microwave radiometric technique, wideband autocorrelation radiometry (WiBAR), offers a deterministic method of remotely sensing the propagation time τdelay of microwaves through low loss layers at the bottom of the atmosphere. Terrestrial examples are the snow and lake ice packs. This technique is based on the Planck radiation from the surface beneath the pack which travels upwards through the pack towards the radiometer; such a signal we call a direct signal. On the other hand, part of this radiation reflects back from the pack's upper interface then from its lower interface, before traveling towards the radiometer's antenna. Thus, there are two signals received by the radiometer, the direct signal and a delayed copy of it. The microwave propagation time τdelay through the pack yields a measure of its vertical extent. We report a time series of measurements of the ice pack on Lake Superior from February to April 2014 to demonstrate this technique. The observations are done at frequencies from 7 to 10 GHz. At these frequencies, the volume and surface scattering are small in the ice pack. This technique is inherently low-power since there is no transmitter as opposed to active remote sensing techniques. The results of this paper is to present the WiBAR technique and show that the microwave travel time within a dry snow pack and lake ice pack can be deterministically measured for different thicknesses using this technique.

  1. 27 CFR 24.308 - Bottled or packed wine record.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Bottled or packed wine... BUREAU, DEPARTMENT OF THE TREASURY LIQUORS WINE Records and Reports § 24.308 Bottled or packed wine record. A proprietor who bottles, packs, or receives bottled or packed beverage wine in bond...

  2. 21 CFR 880.5760 - Chemical cold pack snakebite kit.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Chemical cold pack snakebite kit. 880.5760 Section... Therapeutic Devices § 880.5760 Chemical cold pack snakebite kit. (a) Identification. A chemical cold pack snakebit kit is a device consisting of a chemical cold pack and tourniquet used for first-aid treatment...

  3. 21 CFR 880.5760 - Chemical cold pack snakebite kit.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Chemical cold pack snakebite kit. 880.5760 Section... Therapeutic Devices § 880.5760 Chemical cold pack snakebite kit. (a) Identification. A chemical cold pack snakebit kit is a device consisting of a chemical cold pack and tourniquet used for first-aid treatment...

  4. 21 CFR 880.5760 - Chemical cold pack snakebite kit.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Chemical cold pack snakebite kit. 880.5760 Section... Therapeutic Devices § 880.5760 Chemical cold pack snakebite kit. (a) Identification. A chemical cold pack snakebit kit is a device consisting of a chemical cold pack and tourniquet used for first-aid treatment...

  5. 21 CFR 880.5760 - Chemical cold pack snakebite kit.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Chemical cold pack snakebite kit. 880.5760 Section... Therapeutic Devices § 880.5760 Chemical cold pack snakebite kit. (a) Identification. A chemical cold pack snakebit kit is a device consisting of a chemical cold pack and tourniquet used for first-aid treatment...

  6. 21 CFR 880.5760 - Chemical cold pack snakebite kit.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Chemical cold pack snakebite kit. 880.5760 Section... Therapeutic Devices § 880.5760 Chemical cold pack snakebite kit. (a) Identification. A chemical cold pack snakebit kit is a device consisting of a chemical cold pack and tourniquet used for first-aid treatment...

  7. Efficient linear programming algorithm to generate the densest lattice sphere packings.

    PubMed

    Marcotte, Étienne; Torquato, Salvatore

    2013-06-01

    Finding the densest sphere packing in d-dimensional Euclidean space R(d) is an outstanding fundamental problem with relevance in many fields, including the ground states of molecular systems, colloidal crystal structures, coding theory, discrete geometry, number theory, and biological systems. Numerically generating the densest sphere packings becomes very challenging in high dimensions due to an exponentially increasing number of possible sphere contacts and sphere configurations, even for the restricted problem of finding the densest lattice sphere packings. In this paper we apply the Torquato-Jiao packing algorithm, which is a method based on solving a sequence of linear programs, to robustly reproduce the densest known lattice sphere packings for dimensions 2 through 19. We show that the TJ algorithm is appreciably more efficient at solving these problems than previously published methods. Indeed, in some dimensions, the former procedure can be as much as three orders of magnitude faster at finding the optimal solutions than earlier ones. We also study the suboptimal local density-maxima solutions (inherent structures or "extreme" lattices) to gain insight about the nature of the topography of the "density" landscape. PMID:23848802

  8. Quasistatic packings of droplets in flat microfluidic channels

    NASA Astrophysics Data System (ADS)

    Kadivar, Erfan

    2016-02-01

    As observed in recent experiments, monodisperse droplets self-assemble spontaneously in different ordered packings. In this work, we present a numerical study of the droplet packings in the flat rectangular microfluidic channels. Employing the boundary element method, we numerically solve the Stokes equation in two-dimension and investigate the appearance of droplet packing and transition between one and two-row packings of monodisperse emulsion droplets. By calculating packing force applied on the droplet interface, we investigate the effect of flow rate, droplet size, and surface tension on the packing configurations of droplets and transition between different topological packings.

  9. [Research progress on the management of no packing after septoplasty].

    PubMed

    Lu, Sheng; Zhang, Longcheng; Li, Jieen

    2016-01-01

    Packing the nose after septoplasty is common practice. The use of postoperative packing has been proposed to reduce the dead space between the subperichondrial flaps and minimize postoperative complications such as hemorrhage, septal hematoma, and formation of synechiae. Additionally, postoperative packing is thought to stabilize the remaining cartilaginous septum and minimize persistence or recurrence of septal deviation. Despite these theoretic advantages, evidence to support the use of postoperative packing is lacking. Additionally, nasal packing is not an innocuous procedure. The use of nasal packing actually cause these complications such as postop- erative pain, mucosal injury, bleeding, worsening of breathing due to sleep disorders, and postoperative infections. Routine use of anterior nasal packing after septoplasty should be challenged for not presenting proven benefit. As alternatives to traditional packing, septal suturing, septal stapler and fibrin glue have been used recently. The purpose of this article is to summarize the progress of traditional packing to no packing after septoplasty. PMID:27197467

  10. Coalescence preference in dense packing of bubbles

    NASA Astrophysics Data System (ADS)

    Kim, Yeseul; Gim, Bopil; Gim, Bopil; Weon, Byung Mook

    2015-11-01

    Coalescence preference is the tendency that a merged bubble from the contact of two original bubbles (parent) tends to be near to the bigger parent. Here, we show that the coalescence preference can be blocked by densely packing of neighbor bubbles. We use high-speed high-resolution X-ray microscopy to clearly visualize individual coalescence phenomenon which occurs in micro scale seconds and inside dense packing of microbubbles with a local packing fraction of ~40%. Previous theory and experimental evidence predict a power of -5 between the relative coalescence position and the parent size. However, our new observation for coalescence preference in densely packed microbubbles shows a different power of -2. We believe that this result may be important to understand coalescence dynamics in dense packing of soft matter. This work (NRF-2013R1A22A04008115) was supported by Mid-career Researcher Program through NRF grant funded by the MEST and also was supported by Ministry of Science, ICT and Future Planning (2009-0082580) and by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry and Education, Science and Technology (NRF-2012R1A6A3A04039257).

  11. Deterioration of organic packing materials commonly used in air biofiltration: effect of VOC-packing interactions.

    PubMed

    Lebrero, Raquel; Estrada, José M; Muñoz, Raúl; Quijano, Guillermo

    2014-05-01

    The abiotic deterioration of three conventional organic packing materials used in biofiltration (compost, wood bark and Macadamia nutshells) caused by their interaction with toluene (used as a model volatile organic compound) was here studied. The deterioration of the materials was evaluated in terms of structural damage, release of co-substrates and increase of the packing biodegradability. After 21 days of exposure to toluene, all packing materials released co-substrates able to support microbial growth, which were not released by the control materials not exposed to toluene. Likewise, the exposure to toluene increased the packing material biodegradability by 26% in wood bark, 20% in compost and 17% in Macadamia nutshells. Finally, scanning electron microscopy analysis confirmed the deterioration in the structure of the packing materials evaluated due to the exposure to toluene, Macadamia nutshells being the material with the highest resistance to volatile organic compound attack.

  12. Deterioration of organic packing materials commonly used in air biofiltration: effect of VOC-packing interactions.

    PubMed

    Lebrero, Raquel; Estrada, José M; Muñoz, Raúl; Quijano, Guillermo

    2014-05-01

    The abiotic deterioration of three conventional organic packing materials used in biofiltration (compost, wood bark and Macadamia nutshells) caused by their interaction with toluene (used as a model volatile organic compound) was here studied. The deterioration of the materials was evaluated in terms of structural damage, release of co-substrates and increase of the packing biodegradability. After 21 days of exposure to toluene, all packing materials released co-substrates able to support microbial growth, which were not released by the control materials not exposed to toluene. Likewise, the exposure to toluene increased the packing material biodegradability by 26% in wood bark, 20% in compost and 17% in Macadamia nutshells. Finally, scanning electron microscopy analysis confirmed the deterioration in the structure of the packing materials evaluated due to the exposure to toluene, Macadamia nutshells being the material with the highest resistance to volatile organic compound attack. PMID:24603032

  13. The Pack Method for Compressive Tests of Thin Specimens of Materials Used in Thin-Wall Structures

    NASA Technical Reports Server (NTRS)

    Aitchison, C S; Tuckerman, L B

    1939-01-01

    The strength of modern lightweight thin-wall structures is generally limited by the strength of the compression members. An adequate design of these members requires a knowledge of the compressive stress-strain graph of the thin-wall material. The "pack" method was developed at the National Bureau of Standards with the support of the National Advisory Committee for Aeronautics to make possible a determination of compressive stress-strain graphs for such material. In the pack test an odd number of specimens are assembled into a relatively stable pack, like a "pack of cards." Additional lateral stability is obtained from lateral supports between the external sheet faces of the pack and outside reactions. The tests seems adequate for many problems in structural research.

  14. GraSPI (Graphical Structured Packing Interface)

    SciTech Connect

    Almedia, Valmor de

    2004-06-10

    GraSPI is a collection of macros (computer programs) written to work in concert with Fluent Inc. software GAMBIT and FLUENT for modeling and design of structured packing columns used in the chemical industry (the application focus is in distillation but other applications such as gas absorbers, and other chemical contactors can also be analyzed). GraSPI is an accessory to GAMBIT and FLUENT that drives the process of complex geometry creation, domain setup, and mesh generation. In addition, GraSPI manages automatic flow analysis in the aforementioned domain via either serial or parallel computing using FLUENT. A library of typical commercial structured packing elements is included in GraSPI, so is the capability for user-defined creation of new packings.

  15. Safety considerations for fabricating lithium battery packs

    NASA Technical Reports Server (NTRS)

    Ciesla, J. J.

    1986-01-01

    Lithium cell safety is a major issue with both manufacturers and end users. Most manufacturers have taken great strides to develop the safest cells possible while still maintaining performance characteristics. The combining of lithium cells for higher voltages, currents, and capacities requires the fabricator of lithium battery packs to be knowledgable about the specific electrochemical system being used. Relatively high rate, spirally wound (large surface area) sulfur oxychloride cells systems, such as Li/Thionyl or Sulfuryl chloride are considered. Prior to the start of a design of a battery pack, a review of the characterization studies for the cells should be conducted. The approach for fabricating a battery pack might vary with cell size.

  16. GraSPI (Graphical Structured Packing Interface)

    2004-06-10

    GraSPI is a collection of macros (computer programs) written to work in concert with Fluent Inc. software GAMBIT and FLUENT for modeling and design of structured packing columns used in the chemical industry (the application focus is in distillation but other applications such as gas absorbers, and other chemical contactors can also be analyzed). GraSPI is an accessory to GAMBIT and FLUENT that drives the process of complex geometry creation, domain setup, and mesh generation.more » In addition, GraSPI manages automatic flow analysis in the aforementioned domain via either serial or parallel computing using FLUENT. A library of typical commercial structured packing elements is included in GraSPI, so is the capability for user-defined creation of new packings.« less

  17. Spontaneous Crystallization in Athermal Polymer Packings

    PubMed Central

    Karayiannis, Nikos Ch.; Foteinopoulou, Katerina; Laso, Manuel

    2013-01-01

    We review recent results from extensive simulations of the crystallization of athermal polymer packings. It is shown that above a certain packing density, and for sufficiently long simulations, all random assemblies of freely-jointed chains of tangent hard spheres of uniform size show a spontaneous transition into a crystalline phase. These polymer crystals adopt predominantly random hexagonal close packed morphologies. An analysis of the local environment around monomers based on the shape and size of the Voronoi polyhedra clearly shows that Voronoi cells become more spherical and more symmetric as the system transits to the ordered state. The change in the local environment leads to an increase in the monomer translational contribution to the entropy of the system, which acts as the driving force for the phase transition. A comparison of the crystallization of hard-sphere polymers and monomers highlights similarities and differences resulting from the constraints imposed by chain connectivity. PMID:23263666

  18. An integrated model of ring pack performance

    NASA Technical Reports Server (NTRS)

    Keribar, R.; Dursunkaya, Z.; Flemming, M. F.

    1991-01-01

    This paper describes an integrated model developed for the detailed characterization and simulation of piston ring pack behavior in internal combustion engines and the prediction of ring pack performance. The model includes comprehensive and coupled treatments of (1) ring-liner hydrodynamic and boundary lubrication and friction; (2) ring axial, radial, and (toroidal) twist dynamics; (3) inter-ring gas dynamics and blowby. The physics of each of these highly inter-related phenomena are represented by submodels, which are intimately coupled to form a design-oriented predictive tool aimed at the calculation of ring film thicknesses, ring motions, land pressures, engine friction, and blowby. The paper also describes the results of a series of analytical studies investigating effects of engine speed and load and ring pack design parameters, on ring motions, film thicknesses, and inter-ring pressures, as well as ring friction and blowby.

  19. Characterization of maximally random jammed sphere packings. II. Correlation functions and density fluctuations.

    PubMed

    Klatt, Michael A; Torquato, Salvatore

    2016-08-01

    In the first paper of this series, we introduced Voronoi correlation functions to characterize the structure of maximally random jammed (MRJ) sphere packings across length scales. In the present paper, we determine a variety of different correlation functions that arise in rigorous expressions for the effective physical properties of MRJ sphere packings and compare them to the corresponding statistical descriptors for overlapping spheres and equilibrium hard-sphere systems. Such structural descriptors arise in rigorous bounds and formulas for effective transport properties, diffusion and reactions constants, elastic moduli, and electromagnetic characteristics. First, we calculate the two-point, surface-void, and surface-surface correlation functions, for which we derive explicit analytical formulas for finite hard-sphere packings. We show analytically how the contact Dirac delta function contribution to the pair correlation function g_{2}(r) for MRJ packings translates into distinct functional behaviors of these two-point correlation functions that do not arise in the other two models examined here. Then we show how the spectral density distinguishes the MRJ packings from the other disordered systems in that the spectral density vanishes in the limit of infinite wavelengths; i.e., these packings are hyperuniform, which means that density fluctuations on large length scales are anomalously suppressed. Moreover, for all model systems, we study and compute exclusion probabilities and pore size distributions, as well as local density fluctuations. We conjecture that for general disordered hard-sphere packings, a central limit theorem holds for the number of points within an spherical observation window. Our analysis links problems of interest in material science, chemistry, physics, and mathematics. In the third paper of this series, we will evaluate bounds and estimates of a host of different physical properties of the MRJ sphere packings that are based on the

  20. Characterization of maximally random jammed sphere packings. II. Correlation functions and density fluctuations

    NASA Astrophysics Data System (ADS)

    Klatt, Michael A.; Torquato, Salvatore

    2016-08-01

    In the first paper of this series, we introduced Voronoi correlation functions to characterize the structure of maximally random jammed (MRJ) sphere packings across length scales. In the present paper, we determine a variety of different correlation functions that arise in rigorous expressions for the effective physical properties of MRJ sphere packings and compare them to the corresponding statistical descriptors for overlapping spheres and equilibrium hard-sphere systems. Such structural descriptors arise in rigorous bounds and formulas for effective transport properties, diffusion and reactions constants, elastic moduli, and electromagnetic characteristics. First, we calculate the two-point, surface-void, and surface-surface correlation functions, for which we derive explicit analytical formulas for finite hard-sphere packings. We show analytically how the contact Dirac delta function contribution to the pair correlation function g2(r ) for MRJ packings translates into distinct functional behaviors of these two-point correlation functions that do not arise in the other two models examined here. Then we show how the spectral density distinguishes the MRJ packings from the other disordered systems in that the spectral density vanishes in the limit of infinite wavelengths; i.e., these packings are hyperuniform, which means that density fluctuations on large length scales are anomalously suppressed. Moreover, for all model systems, we study and compute exclusion probabilities and pore size distributions, as well as local density fluctuations. We conjecture that for general disordered hard-sphere packings, a central limit theorem holds for the number of points within an spherical observation window. Our analysis links problems of interest in material science, chemistry, physics, and mathematics. In the third paper of this series, we will evaluate bounds and estimates of a host of different physical properties of the MRJ sphere packings that are based on the

  1. Prediction of packing of secondary structure.

    PubMed

    Nagano, K; Ponnuswamy, P K

    1984-01-01

    An improved method of picking up candidates for predicting the packing arrangement of beta-strands and alpha-helices of the alpha/beta type domains is described here. The method of judging whether the region of the protein would fold into the alpha/beta type or not is also described. The folding constraints of globular proteins are analysed and presented in this article for application to the prediction of packing of secondary structure. The analysis of the residue-fluctuations is also applicable for the purpose.

  2. Close packing of rods on spherical surfaces.

    PubMed

    Smallenburg, Frank; Löwen, Hartmut

    2016-04-28

    We study the optimal packing of short, hard spherocylinders confined to lie tangential to a spherical surface, using simulated annealing and molecular dynamics simulations. For clusters of up to twelve particles, we map out the changes in the geometry of the closest-packed configuration as a function of the aspect ratio L/D, where L is the cylinder length and D the diameter of the rods. We find a rich variety of cluster structures. For larger clusters, we find that the best-packed configurations up to around 100 particles are highly dependent on the exact number of particles and aspect ratio. For even larger clusters, we find largely disordered clusters for very short rods (L/D = 0.25), while slightly longer rods (L/D = 0.5 or 1) prefer a global baseball-like geometry of smectic-like domains, similar to the behavior of large-scale nematic shells. Intriguingly, we observe that when compared to their optimal flat-plane packing, short rods adapt to the spherical geometry more efficiently than both spheres and longer rods. Our results provide predictions for experimentally realizable systems of colloidal rods trapped at the interface of emulsion droplets.

  3. Close packing of rods on spherical surfaces

    NASA Astrophysics Data System (ADS)

    Smallenburg, Frank; Löwen, Hartmut

    2016-04-01

    We study the optimal packing of short, hard spherocylinders confined to lie tangential to a spherical surface, using simulated annealing and molecular dynamics simulations. For clusters of up to twelve particles, we map out the changes in the geometry of the closest-packed configuration as a function of the aspect ratio L/D, where L is the cylinder length and D the diameter of the rods. We find a rich variety of cluster structures. For larger clusters, we find that the best-packed configurations up to around 100 particles are highly dependent on the exact number of particles and aspect ratio. For even larger clusters, we find largely disordered clusters for very short rods (L/D = 0.25), while slightly longer rods (L/D = 0.5 or 1) prefer a global baseball-like geometry of smectic-like domains, similar to the behavior of large-scale nematic shells. Intriguingly, we observe that when compared to their optimal flat-plane packing, short rods adapt to the spherical geometry more efficiently than both spheres and longer rods. Our results provide predictions for experimentally realizable systems of colloidal rods trapped at the interface of emulsion droplets.

  4. Packing frustration in dense confined fluids.

    PubMed

    Nygård, Kim; Sarman, Sten; Kjellander, Roland

    2014-09-01

    Packing frustration for confined fluids, i.e., the incompatibility between the preferred packing of the fluid particles and the packing constraints imposed by the confining surfaces, is studied for a dense hard-sphere fluid confined between planar hard surfaces at short separations. The detailed mechanism for the frustration is investigated via an analysis of the anisotropic pair distributions of the confined fluid, as obtained from integral equation theory for inhomogeneous fluids at pair correlation level within the anisotropic Percus-Yevick approximation. By examining the mean forces that arise from interparticle collisions around the periphery of each particle in the slit, we calculate the principal components of the mean force for the density profile--each component being the sum of collisional forces on a particle's hemisphere facing either surface. The variations of these components with the slit width give rise to rather intricate changes in the layer structure between the surfaces, but, as shown in this paper, the basis of these variations can be easily understood qualitatively and often also semi-quantitatively. It is found that the ordering of the fluid is in essence governed locally by the packing constraints at each single solid-fluid interface. A simple superposition of forces due to the presence of each surface gives surprisingly good estimates of the density profiles, but there remain nontrivial confinement effects that cannot be explained by superposition, most notably the magnitude of the excess adsorption of particles in the slit relative to bulk.

  5. Simple Cloud Chambers Using Gel Ice Packs

    ERIC Educational Resources Information Center

    Kamata, Masahiro; Kubota, Miki

    2012-01-01

    Although cloud chambers are highly regarded as teaching aids for radiation education, school teachers have difficulty in using cloud chambers because they have to prepare dry ice or liquid nitrogen before the experiment. We developed a very simple and inexpensive cloud chamber that uses the contents of gel ice packs which can substitute for dry…

  6. Monkey Baker in bio-pack

    NASA Technical Reports Server (NTRS)

    1959-01-01

    A squirrel monkey, Baker, in bio-pack couch being readied for Jupiter (AM-18 flight). Jupiter, AM-18 mission, also carried an American-born rhesus monkey, Able into suborbit. The flight was successful and both monkeys were recovered in good condition. AM-18 was launched on May 28, 1959.

  7. The benefits of using customized procedure packs.

    PubMed

    Baines, R; Colquhoun, G; Jones, N; Bateman, R

    2001-01-01

    Discrete item purchasing is the traditional approach for hospitals to obtain consumable supplies for theatre procedures. Although most items are relatively low cost, the management and co-ordination of the supply chain, raising orders, controlling stock, picking and delivering to each operating theatre can be complex and costly. Customized procedure packs provide a solution. PMID:11892113

  8. Stuffed Derivatives of Close-Packed Structures

    ERIC Educational Resources Information Center

    Douglas, Bodie E.

    2007-01-01

    Decades ago Buerger described and later Palmer reviewed stuffed silica crystal structures widely used by mineralogists. Many publications and books have discussed common crystal structures in terms of close-packing of one set of atoms or ions (P sites) with other atoms or ions in tetrahedral (T) or octahedral (O) sites. Douglas and Ho described…

  9. The General Heating Multi-Project Pack

    ERIC Educational Resources Information Center

    Cowking A.; And Others

    1978-01-01

    Describes a multi-project pack on central heating systems, developed into an educational game, used for teaching a variety of subjects in high school. The students examine the basic decision to install a central heating system, for a particular house, and the economics involved. (GA)

  10. 7 CFR 917.13 - Pack.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 8 2012-01-01 2012-01-01 false Pack. 917.13 Section 917.13 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE FRESH PEARS AND PEACHES GROWN IN...

  11. 7 CFR 917.13 - Pack.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 8 2013-01-01 2013-01-01 false Pack. 917.13 Section 917.13 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE FRESH PEARS AND PEACHES GROWN IN...

  12. 7 CFR 917.13 - Pack.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 8 2014-01-01 2014-01-01 false Pack. 917.13 Section 917.13 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE FRESH PEARS AND PEACHES GROWN IN...

  13. 7 CFR 917.13 - Pack.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Pack. 917.13 Section 917.13 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE FRESH PEARS AND PEACHES GROWN IN...

  14. 7 CFR 917.13 - Pack.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 8 2011-01-01 2011-01-01 false Pack. 917.13 Section 917.13 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE FRESH PEARS AND PEACHES GROWN IN...

  15. Random close packing in protein cores

    NASA Astrophysics Data System (ADS)

    Ohern, Corey

    Shortly after the determination of the first protein x-ray crystal structures, researchers analyzed their cores and reported packing fractions ϕ ~ 0 . 75 , a value that is similar to close packing equal-sized spheres. A limitation of these analyses was the use of `extended atom' models, rather than the more physically accurate `explicit hydrogen' model. The validity of using the explicit hydrogen model is proved by its ability to predict the side chain dihedral angle distributions observed in proteins. We employ the explicit hydrogen model to calculate the packing fraction of the cores of over 200 high resolution protein structures. We find that these protein cores have ϕ ~ 0 . 55 , which is comparable to random close-packing of non-spherical particles. This result provides a deeper understanding of the physical basis of protein structure that will enable predictions of the effects of amino acid mutations and design of new functional proteins. We gratefully acknowledge the support of the Raymond and Beverly Sackler Institute for Biological, Physical, and Engineering Sciences, National Library of Medicine training grant T15LM00705628 (J.C.G.), and National Science Foundation DMR-1307712 (L.R.).

  16. Radiological and practical aspects of body packing

    PubMed Central

    Reginelli, A; Pinto, F; Sica, G; Scaglione, M; Berger, F H; Romano, L; Brunese, L

    2014-01-01

    Body packing represents the concealment of illegal substances in a person's body with the aim of smuggling. “Body packers” either swallow drug-filled packets or introduce drug-filled packets into their bodies rectally or vaginally with the purpose of concealing them. The three main smuggled drugs are cocaine, heroin and cannabis products. Body packing represents a serious risk of acute narcotic toxicity from drug exposure, intestinal obstruction owing to pellet impaction and bowel perforation with consequent abdominal sepsis. A suspected body packer is generally admitted to hospital to perform imaging investigations and confirm the presence of drugs in his/her body. Radiological imaging methods are essential to diagnose body packing and to detect potential complications. Increasing sophistication of traffickers and improvements in packaging add to the detection difficulty. Radiologists should be aware of the appearance of drug packets in a range of imaging modalities. This article informs physicians about the challenging aspects of body packing, its background and medicolegal issues, what imaging methods can be used and what criteria are necessary to perform a correct diagnosis. PMID:24472727

  17. 7 CFR 920.13 - Pack.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Pack. 920.13 Section 920.13 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE KIWIFRUIT GROWN IN CALIFORNIA...

  18. Close packing of rods on spherical surfaces.

    PubMed

    Smallenburg, Frank; Löwen, Hartmut

    2016-04-28

    We study the optimal packing of short, hard spherocylinders confined to lie tangential to a spherical surface, using simulated annealing and molecular dynamics simulations. For clusters of up to twelve particles, we map out the changes in the geometry of the closest-packed configuration as a function of the aspect ratio L/D, where L is the cylinder length and D the diameter of the rods. We find a rich variety of cluster structures. For larger clusters, we find that the best-packed configurations up to around 100 particles are highly dependent on the exact number of particles and aspect ratio. For even larger clusters, we find largely disordered clusters for very short rods (L/D = 0.25), while slightly longer rods (L/D = 0.5 or 1) prefer a global baseball-like geometry of smectic-like domains, similar to the behavior of large-scale nematic shells. Intriguingly, we observe that when compared to their optimal flat-plane packing, short rods adapt to the spherical geometry more efficiently than both spheres and longer rods. Our results provide predictions for experimentally realizable systems of colloidal rods trapped at the interface of emulsion droplets. PMID:27131565

  19. 7 CFR 989.9 - Packed raisins.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 8 2011-01-01 2011-01-01 false Packed raisins. 989.9 Section 989.9 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE RAISINS PRODUCED FROM GRAPES GROWN...

  20. 7 CFR 989.9 - Packed raisins.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 8 2014-01-01 2014-01-01 false Packed raisins. 989.9 Section 989.9 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE RAISINS PRODUCED FROM GRAPES GROWN...

  1. 7 CFR 989.9 - Packed raisins.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 8 2013-01-01 2013-01-01 false Packed raisins. 989.9 Section 989.9 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE RAISINS PRODUCED FROM GRAPES GROWN...

  2. 7 CFR 989.9 - Packed raisins.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 8 2012-01-01 2012-01-01 false Packed raisins. 989.9 Section 989.9 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE RAISINS PRODUCED FROM GRAPES GROWN...

  3. 7 CFR 989.9 - Packed raisins.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Packed raisins. 989.9 Section 989.9 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE RAISINS PRODUCED FROM GRAPES GROWN...

  4. The P.E.A.C.E. Pack: A Computerized Online Assessment of School Bullying

    ERIC Educational Resources Information Center

    Slee, Phillip T.; Mohyla, Jury

    2014-01-01

    School bullying is an international problem with harmful outcomes for those involved. This study describes the design and field testing of an innovative computer-based social learning tool for assessing student perceptions of bullying developed for an Australian intervention program called the P.E.A.C.E. Pack. Students rate their peer group…

  5. Third-order thermo-mechanical properties for packs of Platonic solids using statistical micromechanics

    PubMed Central

    Gillman, A.; Amadio, G.; Matouš, K.; Jackson, T. L.

    2015-01-01

    Obtaining an accurate higher order statistical description of heterogeneous materials and using this information to predict effective material behaviour with high fidelity has remained an outstanding problem for many years. In a recent letter, Gillman & Matouš (2014 Phys. Lett. A 378, 3070–3073. ()) accurately evaluated the three-point microstructural parameter that arises in third-order theories and predicted with high accuracy the effective thermal conductivity of highly packed material systems. Expanding this work here, we predict for the first time effective thermo-mechanical properties of granular Platonic solid packs using third-order statistical micromechanics. Systems of impenetrable and penetrable spheres are considered to verify adaptive methods for computing n-point probability functions directly from three-dimensional microstructures, and excellent agreement is shown with simulation. Moreover, a significant shape effect is discovered for the effective thermal conductivity of highly packed composites, whereas a moderate shape effect is exhibited for the elastic constants. PMID:27547103

  6. Multi-objective optimal design of lithium-ion battery packs based on evolutionary algorithms

    NASA Astrophysics Data System (ADS)

    Severino, Bernardo; Gana, Felipe; Palma-Behnke, Rodrigo; Estévez, Pablo A.; Calderón-Muñoz, Williams R.; Orchard, Marcos E.; Reyes, Jorge; Cortés, Marcelo

    2014-12-01

    Lithium-battery energy storage systems (LiBESS) are increasingly being used on electric mobility and stationary applications. Despite its increasing use and improvements of the technology there are still challenges associated with cost reduction, increasing lifetime and capacity, and higher safety. A correct battery thermal management system (BTMS) design is critical to achieve these goals. In this paper, a general framework for obtaining optimal BTMS designs is proposed. Due to the trade-off between the BTMS's design goals and the complex modeling of thermal response inside the battery pack, this paper proposes to solve this problem using a novel Multi-Objective Particle Swarm Optimization (MOPSO) approach. A theoretical case of a module with 6 cells and a real case of a pack used in a Solar Race Car are presented. The results show the capabilities of the proposal methodology, in which improved designs for battery packs are obtained.

  7. Fluid modelling of a packed bed dielectric barrier discharge plasma reactor

    NASA Astrophysics Data System (ADS)

    Van Laer, Koen; Bogaerts, Annemie

    2016-02-01

    A packed bed dielectric barrier discharge plasma reactor is computationally studied with a fluid model. Two different complementary axisymmetric 2D geometries are used to mimic the intrinsic 3D problem. It is found that a packing enhances the electric field strength and electron temperature at the contact points of the dielectric material due to polarization of the beads by the applied potential. As a result, these contact points prove to be of direct importance to initiate the plasma. At low applied potential, the discharge stays at the contact points, and shows the properties of a Townsend discharge. When a high enough potential is applied, the plasma will be able to travel through the gaps in between the beads from wall to wall, forming a kind of glow discharge. Therefore, the inclusion of a so-called ‘channel of voids’ is indispensable in any type of packed bed modelling.

  8. Body packing: from seizures to laparotomy.

    PubMed

    Janczak, Joanna M; Beutner, Ulrich; Hasler, Karin

    2015-01-01

    Body packing is a common method for illegal drug trafficking. Complications associated with body packing can be severe and even lead to rapid death. Thus, a timely diagnosis is warranted. As most body packers initially do not show any symptoms, making a correct diagnosis can be rather challenging. We describe a case of a 41-year-old male, who was admitted with an epileptic seizure and who turned out to be a cocaine intoxicated body packer. Due to neurological and cardiovascular deterioration an emergency surgery was performed. Four bags of cocaine could be removed. We discuss the current management regimen in symptomatic and asymptomatic body packers and highlight pearls and pitfalls with diagnosis and treatment. PMID:25883813

  9. Is incest common in gray wolf packs?

    USGS Publications Warehouse

    Smith, D.; Meier, T.; Geffen, E.; Mech, L.D.; Burch, J.W.; Adams, L.G.; Wayne, R.K.

    1997-01-01

    Wolf packs generally consist of a breeding pair and their maturing offspring that help provision and protect pack young. Because the reproductive tenure in wolves often is short, reproductively mature offspring might replace their parents, resulting in sibling or parent-offspring matings. To determine the extent of incestuous pairings, we measure relatedness based on variability in 20 microsatellite loci of mated pairs, parent-offspring pairs and siblings in two populations of gray wolves. Our 16 sampled mated pairs had values of relatedness not overlapping those of known parent-offspring or sibling dyads, which is consistent with their being unrelated or distantly related. These results suggest that full siblings or a parent and their offspring rarely mate and that incest avoidance is an important constraint on gray wolf behavioral ecology.

  10. 36 CFR 2.16 - Horses and pack animals.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 1 2013-07-01 2013-07-01 false Horses and pack animals. 2.16... RESOURCE PROTECTION, PUBLIC USE AND RECREATION § 2.16 Horses and pack animals. The following are prohibited: (a) The use of animals other than those designated as “pack animals” for purposes of...

  11. 36 CFR 34.10 - Saddle and pack animals.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 1 2014-07-01 2014-07-01 false Saddle and pack animals. 34... INTERIOR EL PORTAL ADMINISTRATIVE SITE REGULATIONS § 34.10 Saddle and pack animals. The use of saddle and pack animals is prohibited without a permit from the Superintendent....

  12. 36 CFR 34.10 - Saddle and pack animals.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false Saddle and pack animals. 34... INTERIOR EL PORTAL ADMINISTRATIVE SITE REGULATIONS § 34.10 Saddle and pack animals. The use of saddle and pack animals is prohibited without a permit from the Superintendent....

  13. 36 CFR 1002.16 - Horses and pack animals.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 3 2013-07-01 2012-07-01 true Horses and pack animals. 1002... AND RECREATION § 1002.16 Horses and pack animals. The following are prohibited: (a) The use of animals other than those designated as “pack animals” for purposes of transporting equipment. (b) The use...

  14. 36 CFR 2.16 - Horses and pack animals.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 1 2014-07-01 2014-07-01 false Horses and pack animals. 2.16... RESOURCE PROTECTION, PUBLIC USE AND RECREATION § 2.16 Horses and pack animals. The following are prohibited: (a) The use of animals other than those designated as “pack animals” for purposes of...

  15. 36 CFR 34.10 - Saddle and pack animals.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 1 2011-07-01 2011-07-01 false Saddle and pack animals. 34... INTERIOR EL PORTAL ADMINISTRATIVE SITE REGULATIONS § 34.10 Saddle and pack animals. The use of saddle and pack animals is prohibited without a permit from the Superintendent....

  16. 36 CFR 1002.16 - Horses and pack animals.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 3 2012-07-01 2012-07-01 false Horses and pack animals. 1002... AND RECREATION § 1002.16 Horses and pack animals. The following are prohibited: (a) The use of animals other than those designated as “pack animals” for purposes of transporting equipment. (b) The use...

  17. 36 CFR 1002.16 - Horses and pack animals.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 3 2014-07-01 2014-07-01 false Horses and pack animals. 1002... AND RECREATION § 1002.16 Horses and pack animals. The following are prohibited: (a) The use of animals other than those designated as “pack animals” for purposes of transporting equipment. (b) The use...

  18. 36 CFR 2.16 - Horses and pack animals.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 1 2011-07-01 2011-07-01 false Horses and pack animals. 2.16... RESOURCE PROTECTION, PUBLIC USE AND RECREATION § 2.16 Horses and pack animals. The following are prohibited: (a) The use of animals other than those designated as “pack animals” for purposes of...

  19. 36 CFR 2.16 - Horses and pack animals.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false Horses and pack animals. 2.16... RESOURCE PROTECTION, PUBLIC USE AND RECREATION § 2.16 Horses and pack animals. The following are prohibited: (a) The use of animals other than those designated as “pack animals” for purposes of...

  20. 36 CFR 34.10 - Saddle and pack animals.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 1 2013-07-01 2013-07-01 false Saddle and pack animals. 34... INTERIOR EL PORTAL ADMINISTRATIVE SITE REGULATIONS § 34.10 Saddle and pack animals. The use of saddle and pack animals is prohibited without a permit from the Superintendent....

  1. 36 CFR 1002.16 - Horses and pack animals.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 3 2011-07-01 2011-07-01 false Horses and pack animals. 1002... AND RECREATION § 1002.16 Horses and pack animals. The following are prohibited: (a) The use of animals other than those designated as “pack animals” for purposes of transporting equipment. (b) The use...

  2. 36 CFR 1002.16 - Horses and pack animals.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Horses and pack animals. 1002... AND RECREATION § 1002.16 Horses and pack animals. The following are prohibited: (a) The use of animals other than those designated as “pack animals” for purposes of transporting equipment. (b) The use...

  3. 36 CFR 2.16 - Horses and pack animals.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Horses and pack animals. 2.16... RESOURCE PROTECTION, PUBLIC USE AND RECREATION § 2.16 Horses and pack animals. The following are prohibited: (a) The use of animals other than those designated as “pack animals” for purposes of...

  4. 36 CFR 34.10 - Saddle and pack animals.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Saddle and pack animals. 34... INTERIOR EL PORTAL ADMINISTRATIVE SITE REGULATIONS § 34.10 Saddle and pack animals. The use of saddle and pack animals is prohibited without a permit from the Superintendent....

  5. 48 CFR 211.272 - Alternate preservation, packaging, and packing.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ..., packaging, and packing. 211.272 Section 211.272 Federal Acquisition Regulations System DEFENSE ACQUISITION... Requirements Documents 211.272 Alternate preservation, packaging, and packing. Use the provision at 252.211-7004, Alternate Preservation, Packaging, and Packing, in solicitations which include...

  6. 21 CFR 133.124 - Cold-pack cheese food.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 2 2014-04-01 2014-04-01 false Cold-pack cheese food. 133.124 Section 133.124 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD... Cheese and Related Products § 133.124 Cold-pack cheese food. (a)(1) Cold-pack cheese food is the...

  7. 7 CFR 319.37-9 - Approved packing material.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Plants for Planting 1 2 § 319.37-9 Approved... United States shall not be packed in a packing material unless the plants were packed in the...

  8. 7 CFR 319.37-9 - Approved packing material.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Plants for Planting 1, 2 § 319.37-9 Approved... United States shall not be packed in a packing material unless the plants were packed in the...

  9. 21 CFR 133.124 - Cold-pack cheese food.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Cold-pack cheese food. 133.124 Section 133.124 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD... Cheese and Related Products § 133.124 Cold-pack cheese food. (a)(1) Cold-pack cheese food is the...

  10. 21 CFR 133.124 - Cold-pack cheese food.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 2 2011-04-01 2011-04-01 false Cold-pack cheese food. 133.124 Section 133.124 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD... Cheese and Related Products § 133.124 Cold-pack cheese food. (a)(1) Cold-pack cheese food is the...

  11. 1. Contextual view looking west, showing packing house and Union ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Contextual view looking west, showing packing house and Union Ice building, which is located to the north of Packing House (right hand side in photo) - College Heights Lemon Packing House, 519-532 West First Street, Claremont, Los Angeles County, CA

  12. 48 CFR 211.272 - Alternate preservation, packaging, and packing.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ..., packaging, and packing. 211.272 Section 211.272 Federal Acquisition Regulations System DEFENSE ACQUISITION... Requirements Documents 211.272 Alternate preservation, packaging, and packing. Use the provision at 252.211-7004, Alternate Preservation, Packaging, and Packing, in solicitations which include...

  13. 48 CFR 552.211-87 - Export packing.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false Export packing. 552.211-87... FORMS SOLICITATION PROVISIONS AND CONTRACT CLAUSES Text of Provisions and Clauses 552.211-87 Export packing. As prescribed in 511.204(b)(7), insert the following clause: Export Packing (JAN 2010)...

  14. Breakup of Pack Ice, Antarctic Ice Shelf

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Breakup of Pack Ice along the periphery of the Antarctic Ice Shelf (53.5S, 3.0E) produced this mosaic of ice floes off the Antarctic Ice Shelf. Strong offshore winds, probably associated with strong katabatic downdrafts from the interior of the continent, are seen peeling off the edges of the ice shelf into long filamets of sea ice, icebergs, bergy bits and growlers to flow northward into the South Atlantic Ocean. 53.5S, 3.0E

  15. Probe with integrated heater and thermocouple pack

    DOEpatents

    McCulloch, Reginald W.; Dial, Ralph E.; Finnell, Wilber K. R.

    1988-01-01

    A probe for measuring heat includes an elongate rod fitted within a sheath, and a plurality of annular recesses are formed on the surface of the rod in a spaced-apart relationship to form annular chambers that are resistant to heat flow. A longitudinal bore extends axially into the rod and within the cylinders defined by the annular chambers, and an integrated heater and thermocouple pack is dimensioned to fit within the bore. In construction, the integrated pack includes a plurality of wires disposed in electrical insulation within a sheath and a heater cable. These wires include one common wire and a plurality of thermocouple wires. The common wire is constructed of one type of conductive material while the thermocouple wires are each constructed of two types of materials so that at least one thermocouple junction is formed therein. All of the wires extend the length of the integrated pack and are connected together at their ends. The thermocouple wires are constructed to form thermocouple junctions proximate to each annular chamber for producing electromotive forces corresponding to the temperature of the rod within the annular chambers relative to outside the chambers. In the preferred embodiment, each thermocouple wire forms two thermocouple junctions, one junction being disposed within an annular chamber and the second junction being disposed outside of, but proximate to, the same annular chamber. In one embodiment two thermocouple wires are configured to double the sensitivity of the probe in one region.

  16. Packing transition in alkali metallic clusters

    NASA Astrophysics Data System (ADS)

    Kawai, R.; Sung, Ming Wen; Weare, John H.

    1996-03-01

    Small metallic clusters form a local geometric configuration quite different from the bulk crystals. As the cluster size increases, several transitions in the local coordination take place before the bulk structure appears. These transitions involve change in the nature of chemical bonds. We have systematically investigated the structural transition of various alkali metal clusters including binary compounds using an ab initio molecular dynamics simulation. Among them, Li clusters exhibit unusual transition in their packing pattern. Small lithium clusters (N <= 21) form open structures based on a ``solvation shell''.(M. Sung, R. Kawai, and J. Weare, Phys. Rev. Lett. 73) (1994) 3552., which is quite different from other alkali metal clusters. The bonding of these small clusters is partially ionic. Above N=25, a close-packed structure is established. However, the local configuration still differ from that of the bulk crystal. As the size further increases, the ionic nature decreases and the system reaches another close-packed structure based on the Mackay icosahedron, which is similar to the bulk crystal structure.

  17. Symmetric scrolled packings of multilayered carbon nanoribbons

    NASA Astrophysics Data System (ADS)

    Savin, A. V.; Korznikova, E. A.; Lobzenko, I. P.; Baimova, Yu. A.; Dmitriev, S. V.

    2016-06-01

    Scrolled packings of single-layer and multilayer graphene can be used for the creation of supercapacitors, nanopumps, nanofilters, and other nanodevices. The full atomistic simulation of graphene scrolls is restricted to consideration of relatively small systems in small time intervals. To overcome this difficulty, a two-dimensional chain model making possible an efficient calculation of static and dynamic characteristics of nanoribbon scrolls with allowance for the longitudinal and bending stiffness of nanoribbons is proposed. The model is extended to the case of scrolls of multilayer graphene. Possible equilibrium states of symmetric scrolls of multilayer carbon nanotribbons rolled up so that all nanoribbons in the scroll are equivalent are found. Dependences of the number of coils, the inner and outer radii, lowest vibrational eigenfrequencies of rolled packages on the length L of nanoribbons are obtained. It is shown that the lowest vibrational eigenfrequency of a symmetric scroll decreases with a nanoribbon length proportionally to L -1. It is energetically unfavorable for too short nanoribbons to roll up, and their ground state is a stack of plane nanoribbons. With an increasing number k of layers, the nanoribbon length L necessary for creation of symmetric scrolls increases. For a sufficiently small number of layers k and a sufficiently large nanoribbon length L, the scrolled packing has the lowest energy as compared to that of stack of plane nanoribbons and folded structures. The results can be used for development of nanomaterials and nanodevices on the basis of graphene scrolled packings.

  18. Influence of fiber packing structure on permeability

    NASA Technical Reports Server (NTRS)

    Cai, Zhong; Berdichevsky, Alexander L.

    1993-01-01

    The study on the permeability of an aligned fiber bundle is the key building block in modeling the permeability of advanced woven and braided preforms. Available results on the permeability of fiber bundles in the literature show that a substantial difference exists between numerical and analytical calculations on idealized fiber packing structures, such as square and hexagonal packing, and experimental measurements on practical fiber bundles. The present study focuses on the variation of the permeability of a fiber bundle under practical process conditions. Fiber bundles are considered as containing openings and fiber clusters within the bundle. Numerical simulations on the influence of various openings on the permeability were conducted. Idealized packing structures are used, but with introduced openings distributed in different patterns. Both longitudinal and transverse flow are considered. The results show that openings within the fiber bundle have substantial effect on the permeability. In the longitudinal flow case, the openings become the dominant flow path. In the transverse flow case, the fiber clusters reduce the gap sizes among fibers. Therefore the permeability is greatly influenced by these openings and clusters, respectively. In addition to the porosity or fiber volume fraction, which is commonly used in the permeability expression, another fiber bundle status parameter, the ultimate fiber volume fraction, is introduced to capture the disturbance within a fiber bundle.

  19. Helix-packing motifs in membrane proteins.

    PubMed

    Walters, R F S; DeGrado, W F

    2006-09-12

    The fold of a helical membrane protein is largely determined by interactions between membrane-imbedded helices. To elucidate recurring helix-helix interaction motifs, we dissected the crystallographic structures of membrane proteins into a library of interacting helical pairs. The pairs were clustered according to their three-dimensional similarity (rmsd packing. Thus, the universe of common transmembrane helix-pairing motifs is relatively simple. The largest cluster, which comprises 29% of the library members, consists of an antiparallel motif with left-handed packing angles, and it is frequently stabilized by packing of small side chains occurring every seven residues in the sequence. Right-handed parallel and antiparallel structures show a similar tendency to segregate small residues to the helix-helix interface but spaced at four-residue intervals. Position-specific sequence propensities were derived for the most populated motifs. These structural and sequential motifs should be quite useful for the design and structural prediction of membrane proteins.

  20. Constellation choosing based on multi-dimensional sphere packing technique

    NASA Astrophysics Data System (ADS)

    Jinghe, Li; Guijun, Hu; Kashero, Enock; Zhaoxi, Li

    2016-09-01

    In this paper we address the sphere packing lattice points selection problem being used as constellation points in high-dimensional modulation. We propose a new type of points selection method based on threshold theory. Theoretically, this method improves the transmission performance of high-dimensional signal modulation systems. We find that the BER of a 4D modulation signal using the threshold value points selection method reduces. We also compared random and distant points selection methods in a BER of 10-3 and obtained a reduced SNR of about 2 db. At a 10-3 BER, a 8D modulation signal with points selected using the threshold selection methods obtained a reduced SNR of about 3 db. At a 10-3 BER, a 16D modulation signal with points selected using the threshold selection methods obtained a reduced SNR of about 3.5 db.

  1. Eating less from bigger packs: Preventing the pack size effect with diet primes.

    PubMed

    Versluis, Iris; Papies, Esther K

    2016-05-01

    An increase in the package size of food has been shown to lead to an increase in energy intake from this food, the so-called pack size effect. Previous research has shown that providing diet-concerned individuals with a reminder, or prime, of their dieting goal can help them control their consumption. Here, we investigated if providing such a prime is also effective for reducing the magnitude of the pack size effect. We conducted two experiments in which the cover of a dieting magazine (Experiment 1) and diet-related commercials (Experiment 2) served as diet goal primes. Both experiments had a 2 (pack size: small vs. large) × 2 (prime: diet vs. control) × 2 (dietary restraint: high vs. low) between participants design. We measured expected consumption of four snack foods in Experiment 1 (N = 477), and actual consumption of M&M's in Experiment 2 (N = 224). Results showed that the diet prime reduced the pack size effect for both restrained and unrestrained eaters in Experiment 1 and for restrained eaters only in Experiment 2. Although effect sizes were small, these findings suggest that a diet prime motivates restrained eaters to limit their consumption, and as a result the pack size has less influence on the amount consumed. We discuss limitations of this research as well as potential avenues for further research and theoretical and practical implications. PMID:26876911

  2. Highly efficient capillary columns packed with superficially porous particles via sequential column packing.

    PubMed

    Treadway, James W; Wyndham, Kevin D; Jorgenson, James W

    2015-11-27

    Highly efficient capillary columns packed with superficially porous particles were created for use in ultrahigh pressure liquid chromatography. Superficially porous particles around 1.5μm in diameter were packed into fused silica capillary columns with 30, 50, and 75μm internal diameters. To create the columns, several capillary columns were serially packed from the same slurry, with packing progress plots being generated to follow the packing of each column. Characterization of these columns using hydroquinone yielded calculated minimum reduced plate heights as low as 1.24 for the most efficient 30μm internal diameter column, corresponding to over 500,000plates/m. At least one highly efficient column (minimum reduced plate height less than 2) was created for all three of the investigated column inner diameters, with the smallest diameter columns having the highest efficiency. This study proves that highly efficient capillary columns can be created using superficially porous particles and shows the efficiency potential of these particles.

  3. Volatile species in halide-activated-diffusion coating packs

    NASA Technical Reports Server (NTRS)

    Bianco, Robert; Rapp, Robert A.; Jacobson, Nathan S.

    1992-01-01

    An atmospheric pressure sampling mass spectrometer was used to identify the vapor species generated in a halide-activated cementation pack. Pack powder mixtures containing a Cr-Al binary masteralloy powder, an NH4Cl activator salt, and either ZrO2 or Y2O3 (or neither) were analyzed at 1000 C. Both the equilibrium calculations for the pack and mass spectrometer results indicated that volatile AlCl(x) and CrCl(y) species were generated by the pack powder mixture; in packs containing the reactive element oxide, volatile ZrCl(z) and YCl(w) species were formed by the conversion of their oxide sources.

  4. Improved packing of protein side chains with parallel ant colonies

    PubMed Central

    2014-01-01

    Introduction The accurate packing of protein side chains is important for many computational biology problems, such as ab initio protein structure prediction, homology modelling, and protein design and ligand docking applications. Many of existing solutions are modelled as a computational optimisation problem. As well as the design of search algorithms, most solutions suffer from an inaccurate energy function for judging whether a prediction is good or bad. Even if the search has found the lowest energy, there is no certainty of obtaining the protein structures with correct side chains. Methods We present a side-chain modelling method, pacoPacker, which uses a parallel ant colony optimisation strategy based on sharing a single pheromone matrix. This parallel approach combines different sources of energy functions and generates protein side-chain conformations with the lowest energies jointly determined by the various energy functions. We further optimised the selected rotamers to construct subrotamer by rotamer minimisation, which reasonably improved the discreteness of the rotamer library. Results We focused on improving the accuracy of side-chain conformation prediction. For a testing set of 442 proteins, 87.19% of X1 and 77.11% of X12 angles were predicted correctly within 40° of the X-ray positions. We compared the accuracy of pacoPacker with state-of-the-art methods, such as CIS-RR and SCWRL4. We analysed the results from different perspectives, in terms of protein chain and individual residues. In this comprehensive benchmark testing, 51.5% of proteins within a length of 400 amino acids predicted by pacoPacker were superior to the results of CIS-RR and SCWRL4 simultaneously. Finally, we also showed the advantage of using the subrotamers strategy. All results confirmed that our parallel approach is competitive to state-of-the-art solutions for packing side chains. Conclusions This parallel approach combines various sources of searching intelligence and energy

  5. Structural characterization of the packings of granular regular polygons

    NASA Astrophysics Data System (ADS)

    Wang, Chuncheng; Dong, Kejun; Yu, Aibing

    2015-12-01

    By using a recently developed method for discrete modeling of nonspherical particles, we simulate the random packings of granular regular polygons with three to 11 edges under gravity. The effects of shape and friction on the packing structures are investigated by various structural parameters, including packing fraction, the radial distribution function, coordination number, Voronoi tessellation, and bond-orientational order. We find that packing fraction is generally higher for geometrically nonfrustrated regular polygons, and can be increased by the increase of edge number and decrease of friction. The changes of packing fraction are linked with those of the microstructures, such as the variations of the translational and orientational orders and local configurations. In particular, the free areas of Voronoi tessellations (which are related to local packing fractions) can be described by log-normal distributions for all polygons. The quantitative analyses establish a clearer picture for the packings of regular polygons.

  6. Simple cloud chambers using gel ice packs

    NASA Astrophysics Data System (ADS)

    Kamata, Masahiro; Kubota, Miki

    2012-07-01

    Although cloud chambers are highly regarded as teaching aids for radiation education, school teachers have difficulty in using cloud chambers because they have to prepare dry ice or liquid nitrogen before the experiment. We developed a very simple and inexpensive cloud chamber that uses the contents of gel ice packs which can substitute for dry ice or liquid nitrogen. The gel can be frozen in normal domestic freezers, and can be used repeatedly by re-freezing. The tracks of alpha-ray particles can be observed continuously for about 20 min, and the operation is simple and easy.

  7. Packed fluidized bed blanket for fusion reactor

    DOEpatents

    Chi, John W. H.

    1984-01-01

    A packed fluidized bed blanket for a fusion reactor providing for efficient radiation absorption for energy recovery, efficient neutron absorption for nuclear transformations, ease of blanket removal, processing and replacement, and on-line fueling/refueling. The blanket of the reactor contains a bed of stationary particles during reactor operation, cooled by a radial flow of coolant. During fueling/refueling, an axial flow is introduced into the bed in stages at various axial locations to fluidize the bed. When desired, the fluidization flow can be used to remove particles from the blanket.

  8. The effect of nanoparticle packing on capacitive electrode performance.

    PubMed

    Lee, Younghee; Noh, Seonmyeong; Kim, Min-Sik; Kong, Hye Jeong; Im, Kyungun; Kwon, Oh Seok; Kim, Sungmin; Yoon, Hyeonseok

    2016-06-01

    Nanoparticles pack together to form macro-scale electrodes in various types of devices, and thus, optimization of the nanoparticle packing is a prerequisite for the realization of a desirable device performance. In this work, we provide in-depth insight into the effect of nanoparticle packing on the performance of nanoparticle-based electrodes by combining experimental and computational findings. As a model system, polypyrrole nanospheres of three different diameters were used to construct pseudocapacitive electrodes, and the performance of the electrodes was examined at various nanosphere diameter ratios and mixed weight fractions. Two numerical algorithms are proposed to simulate the random packing of the nanospheres on the electrode. The binary nanospheres exhibited diverse, complicated packing behaviors compared with the monophasic packing of each nanosphere species. The packing of the two nanosphere species with lower diameter ratios at an optimized composition could lead to more dense packing of the nanospheres, which in turn could contribute to better device performance. The dense packing of the nanospheres would provide more efficient transport pathways for ions because of the reduced inter-nanosphere pore size and enlarged surface area for charge storage. Ultimately, it is anticipated that our approach can be widely used to define the concept of "the best nanoparticle packing" for desirable device performance. PMID:27242155

  9. Structural characterization of submerged granular packings

    NASA Astrophysics Data System (ADS)

    Jakšić, Z. M.; Šćepanović, J. R.; Lončarević, I.; Budinski-Petković, Lj.; Vrhovac, S. B.; Belić, A.

    2014-12-01

    We consider the impact of the effective gravitational acceleration on microstructural properties of granular packings through experimental studies of spherical granular materials saturated within fluids of varying density. We characterize the local organization of spheres in terms of contact connectivity, distribution of the Delaunay free volumes, and the shape factor (parameter of nonsphericity) of the Voronoï polygons. The shape factor gives a clear physical picture of the competition between less and more ordered domains of particles in experimentally obtained packings. As the effective gravity increases, the probability distribution of the shape factor becomes narrower and more localized around the lowest values of the shape factor corresponding to regular hexagon. It is found that curves of the pore distributions are asymmetric with a long tail on the right-hand side, which progressively reduces while the effective gravity gets stronger for lower densities of interstitial fluid. We show that the distribution of local areas (Voronoï cells) broadens with decreasing value of the effective gravity due to the formation of lose structures such as large pores and chainlike structures (arches or bridges). Our results should be particularly helpful in testing the newly developed simulation techniques involving liquid-related forces associated with immersed granular particles.

  10. Packing material formulation for odorous emission biofiltration.

    PubMed

    Gaudin, François; Andres, Yves; Le Cloirec, Pierre

    2008-01-01

    In biological gas treatment, like biofiltration of volatile organic compounds or odorous substances, the microbial nutritional needs could be a key factor of the process. The aim of this work is to propose a new packing material able to provide the lacking nutrients. In the first part of this study, two kinds of material composed of calcium carbonate, an organic binder and two different nitrogen sources, ammonium phosphate and urea phosphate (UP), were compared. The new supports present bulk densities between 0.88 and 1.15g cm(-3), moisture retention capacities close to 50% and 70%, and water cohesion capacities greater than six months for the material with 20% binder. In the second part, oxygen consumption measurements in liquid experiments show that these packing materials could enhance bacterial growth compared to pine bark or pozzolan and have no inhibitory effect. The biodegradation of different substrates (sodium sulfide and ammonia) and the support colonization by the biomass were evaluated. Finally, UP 20 was chosen and tested in a hydrogen sulfide or ammoniac biofiltration process. This showed that, for H2S concentrations greater than 100mg m(-3), UP 20 has a real advantage over pine bark or pozzolan. PMID:17889256

  11. Effective Thermal Conductivity of Adsorbent Packed Beds

    NASA Astrophysics Data System (ADS)

    Mori, Hideo; Hamamoto, Yoshinori; Yoshida, Suguru

    The effective thermal conductivity of adsorbent packed beds of granular zeolite 13X and granular silica gel A in the presence of stagnant steam or air was measured under different conditions of the adsorbent bed temperature, particle size and filler-gas pressure. The measured effective thermal conductivity showed to become smaller with decreasing particle size or decreasing pressure, but it was nearly independent of the bed temperature. When steam was the filler-gas, the rise in the thermal conductivity of the adsorbent particles due to steam adsorption led to the increase in the effective thermal conductivity of the bed, and this effect was not negligible at high steam pressure for the bed of large particle size. It was found that both the predictions of the effective thermal conductivity by the Hayashi et al.'s model and the Bauer-Schlünder model generally agreed well with the measurements, by considering the particle thermal conductivity rise due to steam adsorption. The thermal conductivity of a consolidated bed of granular zeolite 13X was also measured, and it was found to be much larger than that of the packed bed especially at lower pressure. The above prediction models underestimated the effective thermal conductivity of the consolidated bed.

  12. Understanding shape entropy through local dense packing.

    PubMed

    van Anders, Greg; Klotsa, Daphne; Ahmed, N Khalid; Engel, Michael; Glotzer, Sharon C

    2014-11-11

    Entropy drives the phase behavior of colloids ranging from dense suspensions of hard spheres or rods to dilute suspensions of hard spheres and depletants. Entropic ordering of anisotropic shapes into complex crystals, liquid crystals, and even quasicrystals was demonstrated recently in computer simulations and experiments. The ordering of shapes appears to arise from the emergence of directional entropic forces (DEFs) that align neighboring particles, but these forces have been neither rigorously defined nor quantified in generic systems. Here, we show quantitatively that shape drives the phase behavior of systems of anisotropic particles upon crowding through DEFs. We define DEFs in generic systems and compute them for several hard particle systems. We show they are on the order of a few times the thermal energy ([Formula: see text]) at the onset of ordering, placing DEFs on par with traditional depletion, van der Waals, and other intrinsic interactions. In experimental systems with these other interactions, we provide direct quantitative evidence that entropic effects of shape also contribute to self-assembly. We use DEFs to draw a distinction between self-assembly and packing behavior. We show that the mechanism that generates directional entropic forces is the maximization of entropy by optimizing local particle packing. We show that this mechanism occurs in a wide class of systems and we treat, in a unified way, the entropy-driven phase behavior of arbitrary shapes, incorporating the well-known works of Kirkwood, Onsager, and Asakura and Oosawa.

  13. Immersion Calorimetry: Molecular Packing Effects in Micropores.

    PubMed

    Madani, S Hadi; Silvestre-Albero, Ana; Biggs, Mark J; Rodríguez-Reinoso, Francisco; Pendleton, Phillip

    2015-12-21

    Repeated and controlled immersion calorimetry experiments were performed to determine the specific surface area and pore-size distribution (PSD) of a well-characterized, microporous poly(furfuryl alcohol)-based activated carbon. The PSD derived from nitrogen gas adsorption indicated a narrow distribution centered at 0.57±0.05 nm. Immersion into liquids of increasing molecular sizes ranging from 0.33 nm (dichloromethane) to 0.70 nm (α-pinene) showed a decreasing enthalpy of immersion at a critical probe size (0.43-0.48 nm), followed by an increase at 0.48-0.56 nm, and a second decrease at 0.56-0.60 nm. This maximum has not been reported previously. After consideration of possible reasons for this new observation, it is concluded that the effect arises from molecular packing inside the micropores, interpreted in terms of 2D packing. The immersion enthalpy PSD was consistent with that from quenched solid density functional theory (QSDFT) analysis of the nitrogen adsorption isotherm.

  14. Immersion Calorimetry: Molecular Packing Effects in Micropores.

    PubMed

    Madani, S Hadi; Silvestre-Albero, Ana; Biggs, Mark J; Rodríguez-Reinoso, Francisco; Pendleton, Phillip

    2015-12-21

    Repeated and controlled immersion calorimetry experiments were performed to determine the specific surface area and pore-size distribution (PSD) of a well-characterized, microporous poly(furfuryl alcohol)-based activated carbon. The PSD derived from nitrogen gas adsorption indicated a narrow distribution centered at 0.57±0.05 nm. Immersion into liquids of increasing molecular sizes ranging from 0.33 nm (dichloromethane) to 0.70 nm (α-pinene) showed a decreasing enthalpy of immersion at a critical probe size (0.43-0.48 nm), followed by an increase at 0.48-0.56 nm, and a second decrease at 0.56-0.60 nm. This maximum has not been reported previously. After consideration of possible reasons for this new observation, it is concluded that the effect arises from molecular packing inside the micropores, interpreted in terms of 2D packing. The immersion enthalpy PSD was consistent with that from quenched solid density functional theory (QSDFT) analysis of the nitrogen adsorption isotherm. PMID:26394883

  15. Understanding shape entropy through local dense packing.

    PubMed

    van Anders, Greg; Klotsa, Daphne; Ahmed, N Khalid; Engel, Michael; Glotzer, Sharon C

    2014-11-11

    Entropy drives the phase behavior of colloids ranging from dense suspensions of hard spheres or rods to dilute suspensions of hard spheres and depletants. Entropic ordering of anisotropic shapes into complex crystals, liquid crystals, and even quasicrystals was demonstrated recently in computer simulations and experiments. The ordering of shapes appears to arise from the emergence of directional entropic forces (DEFs) that align neighboring particles, but these forces have been neither rigorously defined nor quantified in generic systems. Here, we show quantitatively that shape drives the phase behavior of systems of anisotropic particles upon crowding through DEFs. We define DEFs in generic systems and compute them for several hard particle systems. We show they are on the order of a few times the thermal energy ([Formula: see text]) at the onset of ordering, placing DEFs on par with traditional depletion, van der Waals, and other intrinsic interactions. In experimental systems with these other interactions, we provide direct quantitative evidence that entropic effects of shape also contribute to self-assembly. We use DEFs to draw a distinction between self-assembly and packing behavior. We show that the mechanism that generates directional entropic forces is the maximization of entropy by optimizing local particle packing. We show that this mechanism occurs in a wide class of systems and we treat, in a unified way, the entropy-driven phase behavior of arbitrary shapes, incorporating the well-known works of Kirkwood, Onsager, and Asakura and Oosawa. PMID:25344532

  16. A new approach to: (a) grid generation for numerical optimization, and (b) interconnect networks for beowulf clusters, leveraging n-dimensional sphere-packings

    NASA Astrophysics Data System (ADS)

    Bewley, Thomas; Cessna, Joseph; Belitz, Paul

    2008-11-01

    The abstract field of n-dimensional sphere packing theory is well developed (for a comprehensive review, see Sphere Packings, Lattices and Groups by Conway and Sloane). This theory forms the theoretical underpinning of the error-correcting codes used in both deep space communications and in computer memory. The present work extends this elegant theory to two important and immensely practical problems in computational fluid dynamics: (a) the generation of efficient grids for the coordination of grid-based derivative-free optimization algorithms in n dimensions, and (b) the effective n-dimensional interconnection of massively-parallel clusters of computational nodes. As we will illustrate and quantify, the first problem benefits tremendously from dense sphere packings with large kissing numbers >> 2n, whereas the latter problem benefits tremendously from rare sphere packings with kissing number = n+1.

  17. Aspects of column fabrication for packed capillary electrochromatography.

    PubMed

    Angus, P D; Demarest, C W; Catalano, T; Stobaugh, J F

    2000-07-28

    Various parameters have been evaluated to develop a process for optimization of column manufacture for packed capillary electrochromatography (CEC). Spherisorb ODS-1 was packed into 75 microm I.D. capillaries to establish a standard set of packing conditions to afford high-performance columns free of voids. Numerous silica-based packing materials including porous and non-porous reversed-phase and ion-exchange phases were employed to evaluate the applicability of the standard conditions. Success of column manufacture and performance demonstrate a relationship to the colligative properties of the packing materials under the applied conditions. Frequently encountered difficulties arising from inadequate column conditioning and void formation in the packed bed are identified and discussed.

  18. Howling at two Minnesota wolf pack summer homesites

    USGS Publications Warehouse

    Harrington, F.H.; Mech, L.D.

    1978-01-01

    Howling sessions were monitored at two Minnesota wolf pack homesites for 2255 h between 29 April and 3 August 1973. All sessions recorded occurred from dusk through early morning, with an evening peak for one pack. Within a night, multiple sessions were grouped temporally, most occurring within an hour of one another. Howling rates for both packs increased throughout the homesite season, with the larger pack howling twice as frequently. The role of howling in both intrapack and interpack contexts was considered. Much of the howling seemed to be involved in the coordination of pack activities. Further, the low frequency and clumped temporal distribution of sessions suggest that howling plays a secondary role in interpack contexts to other modes such as scent marking during the homesite season, but may increase in relative importance once homesites are abandoned and pack travel becomes nomadic.

  19. Simulation of abuse tolerance of lithium-ion battery packs

    NASA Astrophysics Data System (ADS)

    Spotnitz, Robert M.; Weaver, James; Yeduvaka, Gowri; Doughty, D. H.; Roth, E. P.

    A simple approach for using accelerating rate calorimetry data to simulate the thermal abuse resistance of battery packs is described. The thermal abuse tolerance of battery packs is estimated based on the exothermic behavior of a single cell and an energy balance than accounts for radiative, conductive, and convective heat transfer modes of the pack. For the specific example of a notebook computer pack containing eight 18650-size cells, the effects of cell position, heat of reaction, and heat-transfer coefficient are explored. Thermal runaway of the pack is more likely to be induced by thermal runaway of a single cell when that cell is in good contact with other cells and is close to the pack wall.

  20. Physics based modeling of a series parallel battery pack for asymmetry analysis, predictive control and life extension

    NASA Astrophysics Data System (ADS)

    Ganesan, Nandhini; Basu, Suman; Hariharan, Krishnan S.; Kolake, Subramanya Mayya; Song, Taewon; Yeo, Taejung; Sohn, Dong Kee; Doo, Seokgwang

    2016-08-01

    Lithium-Ion batteries used for electric vehicle applications are subject to large currents and various operation conditions, making battery pack design and life extension a challenging problem. With increase in complexity, modeling and simulation can lead to insights that ensure optimal performance and life extension. In this manuscript, an electrochemical-thermal (ECT) coupled model for a 6 series × 5 parallel pack is developed for Li ion cells with NCA/C electrodes and validated against experimental data. Contribution of the cathode to overall degradation at various operating conditions is assessed. Pack asymmetry is analyzed from a design and an operational perspective. Design based asymmetry leads to a new approach of obtaining the individual cell responses of the pack from an average ECT output. Operational asymmetry is demonstrated in terms of effects of thermal gradients on cycle life, and an efficient model predictive control technique is developed. Concept of reconfigurable battery pack is studied using detailed simulations that can be used for effective monitoring and extension of battery pack life.

  1. Monoclinic sphere packings. I. Invariant, univariant and bivariant lattice complexes.

    PubMed

    Sowa, Heidrun; Fischer, Werner

    2016-05-01

    All homogeneous sphere packings were derived that refer to the two invariant, the four univariant and the three bivariant lattice complexes belonging to the monoclinic crystal system. In total, sphere packings of 29 types have been found. Only for five types is the maximal inherent symmetry of their sphere packings monoclinic whereas the inherent symmetry is orthorhombic for nine types, tetragonal for five types, hexagonal for six types and cubic for four types. PMID:27126112

  2. Real-time image analysis for nondestructive detection of metal sliver in packed food

    NASA Astrophysics Data System (ADS)

    Chen, Xin; Jing, Hansong; Tao, Yang; Cheng, Xuemei

    2005-11-01

    Foreign materials such as metal slivers and stones in packed food are listed safety hazards, which could lead to severe health problems. In this paper, a real time X-ray imaging inspection method is investigated for foreign material detection in chili packages. A new image segmentation method combining edge detection and region growing was successfully applied to address the challenges due to the uneven thickness of chili package.

  3. Fixed Packed Bed Reactors in Reduced Gravity

    NASA Technical Reports Server (NTRS)

    Motil, Brian J.; Balakotaiah, Vemuri; Kamotani, Yasuhiro; McCready, Mark J.

    2004-01-01

    We present experimental data on flow pattern transitions, pressure drop and flow characteristics for cocurrent gas-liquid flow through packed columns in microgravity. The flow pattern transition data indicates that the pulse flow regime exists over a wider range of gas and liquid flow rates under microgravity conditions compared to 1-g and the widely used Talmor map in 1-g is not applicable for predicting the transition boundaries. A new transition criterion between bubble and pulse flow in microgravity is proposed and tested using the data. Since there is no static head in microgravity, the pressure drop measured is the true frictional pressure drop. The pressure drop data, which has much smaller scatter than most reported 1-g data clearly shows that capillary effects can enhance the pressure drop (especially in the bubble flow regime) as much as 200% compared to that predicted by the single phase Ergun equation. The pressure drop data are correlated in terms of a two-phase friction factor and its dependence on the gas and liquid Reynolds numbers and the Suratman number. The influence of gravity on the pulse amplitude and frequency is also discussed and compared to that under normal gravity conditions. Experimental work is planned to determine the gas-liquid mass transfer coefficients. Because of enhanced interfacial effects, we expect the gas-liquid transfer coefficients k(L)a and k(G)a (where a is the gas-liquid interfacial area) to be higher in microgravity than in normal gravity at the same flow conditions. This will be verified by gas absorption experiments, with and without reaction in the liquid phase, using oxygen, carbon dioxide, water and dilute aqueous amine solutions. The liquid-solid mass transfer coefficient will also be determined in the bubble as well as the pulse flow regimes using solid benzoic acid particles in the packing and measuring their rate of dissolution. The mass transfer coefficients in microgravity will be compared to those in normal

  4. Fixed Packed Bed Reactors in Reduced Gravity

    NASA Technical Reports Server (NTRS)

    Motil, Brian J.; Balakotaiah, Vemuri; Kamotani, Yasuhiro; McCready, Mark J.

    2004-01-01

    We present experimental data on flow pattern transitions, pressure drop and flow characteristics for cocurrent gas-liquid flow through packed columns in microgravity. The flow pattern transition data indicates that the pulse flow regime exists over a wider range of gas and liquid flow rates under microgravity conditions compared to 1-g and the widely used Talmor map in 1-g is not applicable for predicting the transition boundaries. A new transition criterion between bubble and pulse flow in microgravity is proposed and tested using the data. Since there is no static head in microgravity, the pressure drop measured is the true frictional pressure drop. The pressure drop data, which has much smaller scatter than most reported 1-g data clearly shows that capillary effects can enhance the pressure drop (especially in the bubble flow regime) as much as 200% compared to that predicted by the single phase Ergun equation. The pressure drop data are correlated in terms of a two-phase friction factor and its dependence on the gas and liquid Reynolds numbers and the Suratman number. The influence of gravity on the pulse amplitude and frequency is also discussed and compared to that under normal gravity conditions. Experimental work is planned to determine the gas-liquid and liquid-solid mass transfer coefficients. Because of enhanced interfacial effects, we expect the gas-liquid transfer coefficients kLa and kGa (where a is the gas-liquid interfacial area) to be higher in microgravity than in normal gravity at the same flow conditions. This will be verified by gas absorption experiments, with and without reaction in the liquid phase, using oxygen, carbon dioxide, water and dilute aqueous amine solutions. The liquid-solid mass transfer coefficient will also be determined in the bubble as well as the pulse flow regimes using solid benzoic acid particles in the packing and measuring their rate of dissolution. The mass transfer coefficients in microgravity will be compared to

  5. Packed bed carburization of tantalum and tantalum alloy

    DOEpatents

    Lopez, P.C.; Rodriguez, P.J.; Pereyra, R.A.

    1999-06-29

    Packed bed carburization of a tantalum or tantalum alloy object is disclosed. A method for producing corrosion-resistant tantalum or tantalum alloy objects is described. The method includes the steps of placing the object in contact with a carburizing pack, heating the packed object in vacuum furnace to a temperature whereby carbon from the pack diffuses into the object forming grains with tantalum carbide along the grain boundaries, and etching the surface of the carburized object. This latter step removes tantalum carbides from the surface of the carburized tantalum object while leaving the tantalum carbide along the grain boundaries. 4 figs.

  6. Packed bed carburization of tantalum and tantalum alloy

    DOEpatents

    Lopez, Peter C.; Rodriguez, Patrick J.; Pereyra, Ramiro A.

    1999-01-01

    Packed bed carburization of a tantalum or tantalum alloy object. A method for producing corrosion-resistant tantalum or tantalum alloy objects is described. The method includes the steps of placing the object in contact with a carburizing pack, heating the packed object in vacuum furnace to a temperature whereby carbon from the pack diffuses into the object forming grains with tantalum carbide along the grain boundaries, and etching the surface of the carburized object. This latter step removes tantalum carbides from the surface of the carburized tantalum object while leaving the tantalum carbide along the grain boundaries.

  7. An approach to defect inspection for packing presswork with virtual orientation points and threshold template image

    NASA Astrophysics Data System (ADS)

    Hao, Xiangyang; Liu, Songlin; Zhao, Fulai; Jiang, Lixing

    2015-05-01

    The packing presswork is an important factor of industrial product, especially for the luxury commodities such as cigarettes. In order to ensure the packing presswork to be qualified, the products should be inspected and unqualified one be picked out piece by piece with the vision-based inspection method, which has such advantages as no-touch inspection, high efficiency and automation. Vision-based inspection of packing presswork mainly consists of steps as image acquisition, image registration and defect inspection. The registration between inspected image and reference image is the foundation and premise of visual inspection. In order to realize rapid, reliable and accurate image registration, a registration method based on virtual orientation points is put forward. The precision of registration between inspected image and reference image can reach to sub pixels. Since defect is without fixed position, shape, size and color, three measures are taken to improve the inspection effect. Firstly, the concept of threshold template image is put forward to resolve the problem of variable threshold of intensity difference. Secondly, the color difference is calculated by comparing each pixel with the adjacent pixels of its correspondence on reference image to avoid false defect resulted from color registration error. Thirdly, the strategy of image pyramid is applied in the inspection algorithm to enhance the inspection efficiency. Experiments show that the related algorithm is effective to defect inspection and it takes 27.4 ms on average to inspect a piece of cigarette packing presswork.

  8. Pressure-flow relationships for packed beds of compressible chromatography media at laboratory and production scale.

    PubMed

    Stickel, J J; Fotopoulos, A

    2001-01-01

    Pressure drop across chromatography beds employing soft or semirigid media can be a significant problem in the operation of large-scale preparative chromatography columns. The shape or aspect ratio (length/diameter) of a packed bed has a significant effect on column pressure drop due to wall effects, which can result in unexpectedly high pressures in manufacturing. Two types of agarose-based media were packed in chromatography columns at various column aspect ratios, during which pressure drop, bed height, and flow rate were carefully monitored. Compression of the packed beds with increasing flow velocities was observed. An empirical model was developed to correlate pressure drop with the aspect ratio of the packed beds and the superficial velocity. Modeling employed the Blake-Kozeny equation in which empirical relationships were used to predict bed porosity as a function of aspect ratio and flow velocity. Model predictions were in good agreement with observed pressure drops of industrial scale chromatography columns. A protocol was developed to predict compression in industrial chromatography applications by a few laboratory experiments. The protocol is shown to be useful in the development of chromatographic methods and sizing of preparative columns.

  9. Probe with integrated heater and thermocouple pack

    SciTech Connect

    McCulloch, R.W.; Dial, R.E.; Finnell, W.R.

    1988-02-16

    A gamma thermometer probe for detecting heat produced within the thermometer probe is described comprising: an outer elongate thermometer sheath having a cylindrical cross-section, a length, an outer end and an inner end; an elongate rod having a cylindrical cross-section fitted within the elongate thermometer sheath, the rod being constructed of material that absorbs radiation and produces heat; annular recesses formed between the rod, and sheath and being spaced apart along the length of the rod, the recesses forming annular chambers that are resistive to heat flow; a longitudinal bore extending axially into the rod and being positioned to extend through the cylinders defined by the annular chambers; and an integrated thermocouple pack dimensioned to fit within the longitudinal bore and extending through the cylinders defined by the annular chambers.

  10. Volatile Components from Packing Matrials, Rev. 2

    SciTech Connect

    Smith, R. A.

    2006-03-01

    An outgassing study was conducted on five packing materials, comprising two experiments. These materials comprised 277-4 borated concrete, Borobond4 concrete, polyethylene bags, silica-filled silicone rubber seals, and silicone foam padding. The purpose was measure the volume of gases which diffuse from packaging materials when sealed in containers. Two heating profiles were used to study the offgassing quantities in a set of accelerated aging tests. It was determined that the concretes contain a large quantity of water. The plastic materials hold much less moisture, with the silicone materials even consuming water, possibly due to the presence of silica filler. Polyethylene tends to degrade as the temperature is elevated and the foam stiffens.

  11. Microextraction by packed sorbent (MEPS): a tutorial.

    PubMed

    Abdel-Rehim, Mohamed

    2011-09-01

    This tutorial provides an overview on a new technique for sample preparation, microextraction by packed sorbent (MEPS). Not only the automation process by MEPS is the advantage but also the much smaller volumes of the samples, solvents and dead volumes in the system. Other significant advantages such as the speed and the simplicity of the sample preparation process are provided. In this tutorial the main concepts of MEPS will be elucidated. Different practical aspects in MEPS are addressed. The factors affecting MEPS performance will be discussed. The application of MEPS in clinical and pre-clinical studies for quantification of drugs and metabolites in blood, plasma and urine will be provided. A comparison between MEPS and other extraction techniques such as SPE, LLE, SPME and SBSE will be discussed.

  12. New Packing Structure of Concentration Solar Receiver

    SciTech Connect

    Tsai, Shang-Yu; Lee, Yueh-Mu; Shih, Zun-Hao; Hong, Hwen-Fen; Shin, Hwa-Yuh; Kuo, Cherng-Tsong

    2010-10-14

    This paper presents a solution to the temperature issue in High Concentration Photovoltaic (HCPV) module device by using different thermal conductive material and packing structure. In general, the open-circuited voltage of a device reduces with the increase of temperature and therefore degrades its efficiency. The thermal conductive material we use in this paper, silicon, has a high thermal conductive coefficient (149 W/m{center_dot}K) and steady semiconductor properties which are suitable for the application of solar receiver in HCPV module. Solar cell was soldered on a metal-plated Si substrate with a thicker SiO{sub 2} film which acts as an insulating layer. Then it was mounted on an Al-based plate to obtain a better heat dissipating result.

  13. COLLOIDS. Colloidal matter: Packing, geometry, and entropy.

    PubMed

    Manoharan, Vinothan N

    2015-08-28

    Colloidal particles with well-controlled shapes and interactions are an ideal experimental system for exploring how matter organizes itself. Like atoms and molecules, these particles form bulk phases such as liquids and crystals. But they are more than just crude analogs of atoms; they are a form of matter in their own right, with complex and interesting collective behavior not seen at the atomic scale. Their behavior is affected by geometrical or topological constraints, such as curved surfaces or the shapes of the particles. Because the interactions between the particles are often short-ranged, we can understand the effects of these constraints using geometrical concepts such as packing. The geometrical viewpoint gives us a window into how entropy affects not only the structure of matter, but also the dynamics of how it forms. PMID:26315444

  14. Hyperstaticity and loops in frictional granular packings

    NASA Astrophysics Data System (ADS)

    Tordesillas, Antoinette; Lam, Edward; Metzger, Philip T.

    2009-06-01

    The hyperstatic nature of granular packings of perfectly rigid disks is analyzed algebraically and through numerical simulation. The elementary loops of grains emerge as a fundamental element in addressing hyperstaticity. Loops consisting of an odd number of grains behave differently than those with an even number. For odd loops, the latent stresses are exterior and are characterized by the sum of frictional forces around each loop. For even loops, the latent stresses are interior and are characterized by the alternating sum of frictional forces around each loop. The statistics of these two types of loop sums are found to be Gibbsian with a "temperature" that is linear with the friction coefficient μ when μ<1.

  15. Optical anisotropy in packed isotropic spherical particles: indication of nanometer scale anisotropy in packing structure.

    PubMed

    Yamaguchi, Kohei; Inasawa, Susumu; Yamaguchi, Yukio

    2013-02-28

    We investigated the origin of birefringence in colloidal films of spherical silica particles. Although each particle is optically isotropic in shape, colloidal films formed by drop drying demonstrated birefringence. While periodic particle structures were observed in silica colloidal films, no regular pattern was found in blended films of silica and latex particles. However, since both films showed birefringence, regular film structure patterns were not required to exhibit birefringence. Instead, we propose that nanometer-scale film structure anisotropy causes birefringence. Due to capillary flow from the center to the edge of a cast suspension, particles are more tightly packed in the radial direction. Directional packing results in nanometer-scale anisotropy. The difference in the interparticle distance between radial and circumferential axes was estimated to be 10 nm at most. Nanometer-scale anisotropy in colloidal films and the subsequent optical properties are discussed.

  16. Sound Packing DNA: packing open circular DNA with low-intensity ultrasound

    NASA Astrophysics Data System (ADS)

    Park, Donghee; Jung, Bong-Kwang; Park, Hyunjin; Lee, Hyungbeen; Lee, Gyudo; Park, Jingam; Shin, Unchul; Won, Jong Ho; Jo, Yong Jun; Chang, Jin Woo; Lee, Sangwoo; Yoon, Daesung; Seo, Jongbum; Kim, Chul-Woo

    2015-04-01

    Supercoiling DNA (folding DNA into a more compact molecule) from open circular forms requires significant bending energy. The double helix is coiled into a higher order helix form; thus it occupies a smaller footprint. Compact packing of DNA is essential to improve the efficiency of gene delivery, which has broad implications in biology and pharmaceutical research. Here we show that low-intensity pulsed ultrasound can pack open circular DNA into supercoil form. Plasmid DNA subjected to 5.4 mW/cm2 intensity ultrasound showed significant (p-values <0.001) supercoiling compared to DNA without exposure to ultrasound. Radiation force induced from ultrasound and dragging force from the fluid are believed to be the main factors that cause supercoiling. This study provides the first evidence to show that low-intensity ultrasound can directly alter DNA topology. We anticipate our results to be a starting point for improved non-viral gene delivery.

  17. Softening of stressed granular packings with resonant sound waves.

    PubMed

    Reichhardt, C J Olson; Lopatina, L M; Jia, X; Johnson, P A

    2015-08-01

    We perform numerical simulations of a two-dimensional bidisperse granular packing subjected to both a static confining pressure and a sinusoidal dynamic forcing applied by a wall on one edge of the packing. We measure the response experienced by a wall on the opposite edge of the packing and obtain the resonant frequency of the packing as the static or dynamic pressures are varied. Under increasing static pressure, the resonant frequency increases, indicating a velocity increase of elastic waves propagating through the packing. In contrast, when the dynamic amplitude is increased for fixed static pressure, the resonant frequency decreases, indicating a decrease in the wave velocity. This occurs both for compressional and for shear dynamic forcing and is in agreement with experimental results. We find that the average contact number Zc at the resonant frequency decreases with increasing dynamic amplitude, indicating that the elastic softening of the packing is associated with a reduced number of grain-grain contacts through which the elastic waves can travel. We image the excitations created in the packing and show that there are localized disturbances or soft spots that become more prevalent with increasing dynamic amplitude. Our results are in agreement with experiments on glass bead packings and earth materials such as sandstone and granite and may be relevant to the decrease in elastic wave velocities that has been observed to occur near fault zones after strong earthquakes, in surficial sediments during strong ground motion, and in structures during earthquake excitation. PMID:26382390

  18. 14 CFR 1214.605 - Preflight packing and storing.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 5 2011-01-01 2010-01-01 true Preflight packing and storing. 1214.605 Section 1214.605 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION SPACE FLIGHT Mementos Aboard Space Shuttle Flights § 1214.605 Preflight packing and storing. (a) Items intended for...

  19. 14 CFR 1214.605 - Preflight packing and storing.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 5 2012-01-01 2012-01-01 false Preflight packing and storing. 1214.605 Section 1214.605 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION SPACE FLIGHT Mementos Aboard Space Shuttle Flights § 1214.605 Preflight packing and storing. (a) Items intended for...

  20. 14 CFR § 1214.605 - Preflight packing and storing.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 5 2014-01-01 2014-01-01 false Preflight packing and storing. § 1214.605 Section § 1214.605 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION SPACE FLIGHT Mementos Aboard Space Shuttle Flights § 1214.605 Preflight packing and storing. (a) Items intended...

  1. 14 CFR 1214.605 - Preflight packing and storing.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 5 2013-01-01 2013-01-01 false Preflight packing and storing. 1214.605 Section 1214.605 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION SPACE FLIGHT Mementos Aboard Space Shuttle Flights § 1214.605 Preflight packing and storing. (a) Items intended for...

  2. 14 CFR 1214.605 - Preflight packing and storing.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Preflight packing and storing. 1214.605 Section 1214.605 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION SPACE FLIGHT Mementos Aboard Space Shuttle Flights § 1214.605 Preflight packing and storing. (a) Items intended for...

  3. 7 CFR 51.2927 - Marking and packing requirements.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... (INSPECTION, CERTIFICATION, AND STANDARDS) United States Standards for Grades of Apricots Marking and Packing Requirements § 51.2927 Marking and packing requirements. The minimum size or numerical count of the apricots in... diameter of the smallest apricot in the package. It shall be stated in terms of whole and eighth inches,...

  4. 7 CFR 51.2927 - Marking and packing requirements.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... STANDARDS) United States Standards for Grades of Apricots Marking and Packing Requirements § 51.2927 Marking and packing requirements. The minimum size or numerical count of the apricots in any package shall be... apricot in the package. It shall be stated in terms of whole and eighth inches, as 11/2 inches min.,...

  5. 7 CFR 51.2927 - Marking and packing requirements.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... STANDARDS) United States Standards for Grades of Apricots Marking and Packing Requirements § 51.2927 Marking and packing requirements. The minimum size or numerical count of the apricots in any package shall be... apricot in the package. It shall be stated in terms of whole and eighth inches, as 11/2 inches min.,...

  6. 7 CFR 51.2927 - Marking and packing requirements.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... (INSPECTION, CERTIFICATION, AND STANDARDS) United States Standards for Grades of Apricots Marking and Packing Requirements § 51.2927 Marking and packing requirements. The minimum size or numerical count of the apricots in... diameter of the smallest apricot in the package. It shall be stated in terms of whole and eighth inches,...

  7. 7 CFR 51.2927 - Marking and packing requirements.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... STANDARDS) United States Standards for Grades of Apricots Marking and Packing Requirements § 51.2927 Marking and packing requirements. The minimum size or numerical count of the apricots in any package shall be... apricot in the package. It shall be stated in terms of whole and eighth inches, as 11/2 inches min.,...

  8. 27 CFR 24.308 - Bottled or packed wine record.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... record. A proprietor who bottles, packs, or receives bottled or packed beverage wine in bond shall maintain a record, by tax class, as follows: (a) The date, kind of wine, the number and size of bottle or... or destroyed, breakage, used for tasting. The volume recorded as bottled for bottle...

  9. 48 CFR 852.214-73 - Alternate packaging and packing.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Alternate packaging and....214-73 Alternate packaging and packing. As prescribed in 814.201-6(b)(3), insert the following provision: Alternate Packaging and Packing (JAN 2008) The bidder's offer must clearly indicate the...

  10. 48 CFR 552.211-75 - Preservation, Packaging and Packing.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false Preservation, Packaging....211-75 Preservation, Packaging and Packing. As prescribed in 511.204(b)(2), insert the following clause: Preservation, Packaging, and Packing (FEB 1996) Unless otherwise specified, all items shall...

  11. 21 CFR 133.124 - Cold-pack cheese food.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... is “cold-pack cheese food”. The full name of the food shall appear on the principal display panel of..., the full name of the food shall immediately and conspicuously precede or follow such word or statement... 21 Food and Drugs 2 2012-04-01 2012-04-01 false Cold-pack cheese food. 133.124 Section...

  12. 21 CFR 133.124 - Cold-pack cheese food.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... is “cold-pack cheese food”. The full name of the food shall appear on the principal display panel of..., the full name of the food shall immediately and conspicuously precede or follow such word or statement... 21 Food and Drugs 2 2013-04-01 2013-04-01 false Cold-pack cheese food. 133.124 Section...

  13. Packed bed reactor for photochemical .sup.196 Hg isotope separation

    DOEpatents

    Grossman, Mark W.; Speer, Richard

    1992-01-01

    Straight tubes and randomly oriented pieces of tubing having been employed in a photochemical mercury enrichment reactor and have been found to improve the enrichment factor (E) and utilization (U) compared to a non-packed reactor. One preferred embodiment of this system uses a moving bed (via gravity) for random packing.

  14. Complexity in Surfaces of Densest Packings for Families of Polyhedra

    NASA Astrophysics Data System (ADS)

    Chen, Elizabeth R.; Klotsa, Daphne; Engel, Michael; Damasceno, Pablo F.; Glotzer, Sharon C.

    2014-01-01

    Packings of hard polyhedra have been studied for centuries due to their mathematical aesthetic and more recently for their applications in fields such as nanoscience, granular and colloidal matter, and biology. In all these fields, particle shape is important for structure and properties, especially upon crowding. Here, we explore packing as a function of shape. By combining simulations and analytic calculations, we study three two-parameter families of hard polyhedra and report an extensive and systematic analysis of the densest known packings of more than 55 000 convex shapes. The three families have the symmetries of triangle groups (icosahedral, octahedral, tetrahedral) and interpolate between various symmetric solids (Platonic, Archimedean, Catalan). We find optimal (maximum) packing-density surfaces that reveal unexpected richness and complexity, containing as many as 132 different structures within a single family. Our results demonstrate the importance of thinking about shape not as a static property of an object, in the context of packings, but rather as but one point in a higher-dimensional shape space whose neighbors in that space may have identical or markedly different packings. Finally, we present and interpret our packing results in a consistent and generally applicable way by proposing a method to distinguish regions of packings and classify types of transitions between them.

  15. 7 CFR 319.37-9 - Approved packing material.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... material immediately prior to shipment; such packing material is free from sand, soil, or earth (except for sand designated below); has not been used previously as packing material or otherwise; and is listed below: Baked or expanded clay pellets. Buckwheat hulls. Coral sand from Bermuda, if the article...

  16. On the kinetics of the pack - Aluminization process

    NASA Technical Reports Server (NTRS)

    Sivakumar, R.; Seigle, L. L.

    1976-01-01

    An investigation has been made of the aluminization of unalloyed Ni in fluoride-activated packs of varying Al activity. In packs of low Al activity, in which the ratio of Al to Ni was less than 50 at. pct, the specimen surface quickly came to equilibrium with the pack and remained close to equilibrium for the duration of normal coating runs. In these packs the kinetics of aluminization was controlled by diffusion in the solid. In packs of higher Al activity the surface of the specimen did not come to equilibrium with the pack and the kinetics of the process was governed by a combination of solid and gas diffusion rates. Under most conditions however, the surface composition was time-invariant and a steady-state appeared to exist at the pack-coating interface. By combining Levine and Caves' model for gaseous diffusion in pure-Al packs with calculations of solid diffusion rates some success has been achieved in explaining the results.

  17. 75 FR 31283 - Clarification of Parachute Packing Authorization

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-03

    ... Federal Aviation Administration 14 CFR Part 65 RIN 2120-AJ08 Clarification of Parachute Packing...). SUMMARY: This action amends the requirements for individuals who pack, maintain, or alter main parachutes of a dual-parachute system--those with main and ``back up'' parachutes--to be used for...

  18. A relationship between maximum packing of particles and particle size

    NASA Technical Reports Server (NTRS)

    Fedors, R. F.

    1979-01-01

    Experimental data indicate that the volume fraction of particles in a packed bed (i.e. maximum packing) depends on particle size. One explanation for this is based on the idea that particle adhesion is the primary factor. In this paper, however, it is shown that entrainment and immobilization of liquid by the particles can also account for the facts.

  19. Paired Science: A Resource Pack for Parents and Children.

    ERIC Educational Resources Information Center

    Croft, Susan; Topping, Keith

    This pack of resource materials is designed for students in Scotland, ages 5-7, to be done with their parents at home or with another student in school. Forty-five activity sheets cover 7 different areas of science: Air, Magnets, Moving Things, Light, Heat, Myself and Water. The pack also includes a leaflet for parent or peer tutors, lists of…

  20. GENERAL VIEW OF SOUTH AND WEST FACADES OF PACKING AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    GENERAL VIEW OF SOUTH AND WEST FACADES OF PACKING AND JOB SHOP; BUILDING TO LEFT IS PRODUCTION FACILITY FOR ALCOA, SMALL BRICK BUILDING AT FAR RIGHT ON HIGHER GROUND IS THE FORMER ELECTRIC LIGHT PLANT FOR ALLEGHENY VALLEY LIGHT COMPANY - Alcoa-New Kensington Works, Packing & Job Shop, New Kensington, Westmoreland County, PA

  1. Softening of stressed granular packings with resonant sound waves.

    PubMed

    Reichhardt, C J Olson; Lopatina, L M; Jia, X; Johnson, P A

    2015-08-01

    We perform numerical simulations of a two-dimensional bidisperse granular packing subjected to both a static confining pressure and a sinusoidal dynamic forcing applied by a wall on one edge of the packing. We measure the response experienced by a wall on the opposite edge of the packing and obtain the resonant frequency of the packing as the static or dynamic pressures are varied. Under increasing static pressure, the resonant frequency increases, indicating a velocity increase of elastic waves propagating through the packing. In contrast, when the dynamic amplitude is increased for fixed static pressure, the resonant frequency decreases, indicating a decrease in the wave velocity. This occurs both for compressional and for shear dynamic forcing and is in agreement with experimental results. We find that the average contact number Zc at the resonant frequency decreases with increasing dynamic amplitude, indicating that the elastic softening of the packing is associated with a reduced number of grain-grain contacts through which the elastic waves can travel. We image the excitations created in the packing and show that there are localized disturbances or soft spots that become more prevalent with increasing dynamic amplitude. Our results are in agreement with experiments on glass bead packings and earth materials such as sandstone and granite and may be relevant to the decrease in elastic wave velocities that has been observed to occur near fault zones after strong earthquakes, in surficial sediments during strong ground motion, and in structures during earthquake excitation.

  2. 27 CFR 24.255 - Bottling or packing wine.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Bottling or packing wine. 24.255 Section 24.255 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS WINE Storage, Treatment and Finishing of Wine Bottling, Packing,...

  3. 27 CFR 24.255 - Bottling or packing wine.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Bottling or packing wine. 24.255 Section 24.255 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS WINE Storage, Treatment and Finishing of Wine Bottling, Packing,...

  4. 8. Photographic copy of photograph, Parachute Packing Room, ca. 1932, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. Photographic copy of photograph, Parachute Packing Room, ca. 1932, in possession of Selfridge Base Museum (Historic Photograph File; location of original negative), Mt. Clemens, Michigan. NORTHEAST VIEW, PACKING ROOM WITH PARACHUTES - Selfridge Field, Building No. 121, Wilbur Wright Avenue west of Ash Street, Mount Clemens, Macomb County, MI

  5. 21 CFR 890.5730 - Moist heat pack.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Moist heat pack. 890.5730 Section 890.5730 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5730 Moist heat pack....

  6. 21 CFR 890.5730 - Moist heat pack.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Moist heat pack. 890.5730 Section 890.5730 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5730 Moist heat pack....

  7. 21 CFR 890.5730 - Moist heat pack.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Moist heat pack. 890.5730 Section 890.5730 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5730 Moist heat pack....

  8. 46 CFR 160.043-6 - Marking and packing.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 6 2014-10-01 2014-10-01 false Marking and packing. 160.043-6 Section 160.043-6 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Jackknife (With Can Opener) for Merchant Vessels § 160.043-6 Marking and packing. (a)...

  9. 48 CFR 852.214-73 - Alternate packaging and packing.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 5 2011-10-01 2011-10-01 false Alternate packaging and....214-73 Alternate packaging and packing. As prescribed in 814.201-6(b)(3), insert the following provision: Alternate Packaging and Packing (JAN 2008) The bidder's offer must clearly indicate the...

  10. 48 CFR 552.211-75 - Preservation, Packaging and Packing.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 4 2011-10-01 2011-10-01 false Preservation, Packaging....211-75 Preservation, Packaging and Packing. As prescribed in 511.204(b)(2), insert the following clause: Preservation, Packaging, and Packing (FEB 1996) Unless otherwise specified, all items shall...

  11. Colonic perforation: a lethal consequence of cannabis body packing.

    PubMed

    Cawich, Shamir O; Downes, Ross; Martin, Allie C; Evans, Necia R; Mitchell, Derek I G; Williams, Eric

    2010-07-01

    Body packing is one method of smuggling cannabis across international borders. The practice is prevalent in Jamaica. There has been one reported death from this practice in medical literature. We report a second fatal case of cannabis body packing, reinforcing the dangerous nature of this practice.

  12. Packing fraction of particles with lognormal size distribution.

    PubMed

    Brouwers, H J H

    2014-05-01

    This paper addresses the packing and void fraction of polydisperse particles with a lognormal size distribution. It is demonstrated that a binomial particle size distribution can be transformed into a continuous particle-size distribution of the lognormal type. Furthermore, an original and exact expression is derived that predicts the packing fraction of mixtures of particles with a lognormal distribution, which is governed by the standard deviation, mode of packing, and particle shape only. For a number of particle shapes and their packing modes (close, loose) the applicable values are given. This closed-form analytical expression governing the packing fraction is thoroughly compared with empirical and computational data reported in the literature, and good agreement is found.

  13. Fully ordered to disordered granular sphere packings with random deposition

    NASA Astrophysics Data System (ADS)

    Kudrolli, Arshad; Panaitescu, Andreea

    2013-03-01

    Granular packings are typically obtained by pouring grains into a container in a gravitational field as when sugar is poured into a jar, or grains into a silo. We deconstruct this method and study the impact on packing by simply varying the pour rate and energy of particles dropped randomly but spatially uniformly in a large container whose substrate can act as a template. We find that fully disordered packings are observed when large number of particles are added all at once but an ordered fcc crystal is observed when particles are added sequentially at random locations and allowed to come to rest before adding the next layer. By scanning the packings obtained by 3D X-ray tomography, we identify the positions of all the particles and the growth of order and defects. We present an analysis of the structures formed and compare and contrast it with packings obtained using other protocols including by cyclic shear.

  14. Toward the jamming threshold of sphere packings: Tunneled crystals

    NASA Astrophysics Data System (ADS)

    Torquato, S.; Stillinger, F. H.

    2007-11-01

    We have discovered a family of three-dimensional crystal sphere packings that are strictly jammed (i.e., mechanically stable) and yet possess an anomalously low density. This family constitutes an uncountably infinite number of crystal packings that are subpackings of the densest crystal packings and are characterized by a high concentration of self-avoiding "tunnels" (chains of vacancies) that permeate the structures. The fundamental geometric characteristics of these tunneled crystals command interest in their own right and are described here in some detail. These include the lattice vectors (that specify the packing configurations), coordination structure, Voronoi cells, and density fluctuations. The tunneled crystals are not only candidate structures for achieving the jamming threshold (lowest-density rigid packing), but may have substantially broader significance for condensed matter physics and materials science.

  15. The effect of nanoparticle packing on capacitive electrode performance

    NASA Astrophysics Data System (ADS)

    Lee, Younghee; Noh, Seonmyeong; Kim, Min-Sik; Kong, Hye Jeong; Im, Kyungun; Kwon, Oh Seok; Kim, Sungmin; Yoon, Hyeonseok

    2016-06-01

    Nanoparticles pack together to form macro-scale electrodes in various types of devices, and thus, optimization of the nanoparticle packing is a prerequisite for the realization of a desirable device performance. In this work, we provide in-depth insight into the effect of nanoparticle packing on the performance of nanoparticle-based electrodes by combining experimental and computational findings. As a model system, polypyrrole nanospheres of three different diameters were used to construct pseudocapacitive electrodes, and the performance of the electrodes was examined at various nanosphere diameter ratios and mixed weight fractions. Two numerical algorithms are proposed to simulate the random packing of the nanospheres on the electrode. The binary nanospheres exhibited diverse, complicated packing behaviors compared with the monophasic packing of each nanosphere species. The packing of the two nanosphere species with lower diameter ratios at an optimized composition could lead to more dense packing of the nanospheres, which in turn could contribute to better device performance. The dense packing of the nanospheres would provide more efficient transport pathways for ions because of the reduced inter-nanosphere pore size and enlarged surface area for charge storage. Ultimately, it is anticipated that our approach can be widely used to define the concept of ``the best nanoparticle packing'' for desirable device performance.Nanoparticles pack together to form macro-scale electrodes in various types of devices, and thus, optimization of the nanoparticle packing is a prerequisite for the realization of a desirable device performance. In this work, we provide in-depth insight into the effect of nanoparticle packing on the performance of nanoparticle-based electrodes by combining experimental and computational findings. As a model system, polypyrrole nanospheres of three different diameters were used to construct pseudocapacitive electrodes, and the performance of the

  16. Effect of vacuum packing and temperature on survival and hatching of strongyle eggs in faecal samples.

    PubMed

    Sengupta, Mita E; Thapa, Sundar; Thamsborg, Stig M; Mejer, Helena

    2016-02-15

    Strongyle eggs of helminths of livestock usually hatch within a few hours or days after deposition with faeces. This poses a problem when faecal sampling is performed in the field. As oxygen is needed for embryonic development, it is recommended to reduce air supply during transport and refrigerate. The present study therefore investigated the combined effect of vacuum packing and temperature on survival of strongyle eggs and their subsequent ability to hatch and develop into L3. Fresh faecal samples were collected from calves infected with Cooperia oncophora, pigs infected with Oesophagostomum dentatum, and horses infected with Strongylus vulgaris and cyathostomins. The samples were allocated into four treatments: vacuum packing and storage at 5 °C or 20 °C (5 V and 20 V); normal packing in plastic gloves closed with a loose knot and storage at 5 °C or 20 °C (5 N and 20 N). The number of eggs per gram faeces (EPG) was estimated every fourth day until day 28 post set up (p.s.) by a concentration McMaster-method. Larval cultures were prepared on day 0, 12 and 28 p.s. and the larval yield determined. For C. oncophora, the EPG was significantly higher in vacuum packed samples after 28 days as compared to normal storage, regardless of temperature. However, O. dentatum EPG was significantly higher in samples kept at 5 °C as compared to 20 °C, irrespective of packing. For the horse strongyles, vacuum packed samples at 5 °C had a significantly higher EPG compared to the other treatments after 28 days. The highest larval yield of O. dentatum and horse strongyles were obtained from fresh faecal samples, however, if storage is necessary prior to setting up larval cultures O. dentatum should be kept at room temperature (aerobic or anaerobic). However, horse strongyle coprocultures should ideally be set up on the day of collection to ensure maximum yield. Eggs of C. oncophora should be kept vacuum packed at room temperature for the highest larval yield.

  17. On fully packed loop configurations with four sets of nested arches

    NASA Astrophysics Data System (ADS)

    Di Francesco, P.; Zuber, J.-B.

    2004-06-01

    The problem of counting the number of fully packed loop (FPL) configurations with four sets of a, b, c, d nested arches is addressed. It is shown that it may be expressed as the problem of enumeration of tilings of a domain of the triangular lattice with a conic singularity. After re-expression in terms of non-intersecting lines, the Lindström-Gessel-Viennot theorem leads to a formula as a sum of determinants. This is made quite explicit when min(a, b, c, d) = 1 or 2. We also find a compact determinant formula which generates the numbers of configurations with b = d.

  18. Too packed to change: side-chain packing and site-specific substitution rates in protein evolution.

    PubMed

    Marcos, María Laura; Echave, Julian

    2015-01-01

    In protein evolution, due to functional and biophysical constraints, the rates of amino acid substitution differ from site to site. Among the best predictors of site-specific rates are solvent accessibility and packing density. The packing density measure that best correlates with rates is the weighted contact number (WCN), the sum of inverse square distances between a site's C α and the C α of the other sites. According to a mechanistic stress model proposed recently, rates are determined by packing because mutating packed sites stresses and destabilizes the protein's active conformation. While WCN is a measure of C α packing, mutations replace side chains. Here, we consider whether a site's evolutionary divergence is constrained by main-chain packing or side-chain packing. To address this issue, we extended the stress theory to model side chains explicitly. The theory predicts that rates should depend solely on side-chain contact density. We tested this prediction on a data set of structurally and functionally diverse monomeric enzymes. We compared side-chain contact density with main-chain contact density measures and with relative solvent accessibility (RSA). We found that side-chain contact density is the best predictor of rate variation among sites (it explains 39.2% of the variation). Moreover, the independent contribution of main-chain contact density measures and RSA are negligible. Thus, as predicted by the stress theory, site-specific evolutionary rates are determined by side-chain packing.

  19. Polypeptide vesicles with densely packed multilayer membranes.

    PubMed

    Song, Ziyuan; Kim, Hojun; Ba, Xiaochu; Baumgartner, Ryan; Lee, Jung Seok; Tang, Haoyu; Leal, Cecilia; Cheng, Jianjun

    2015-05-28

    Multilamellar membranes are important building blocks for constructing self-assembled structures with improved barrier properties, such as multilamellar lipid vesicles. Polymeric vesicles (polymersomes) have attracted growing interest, but multilamellar polymersomes are much less explored. Here, we report the formation of polypeptide vesicles with unprecedented densely packed multilayer membrane structures with poly(ethylene glycol)-block-poly(γ-(4,5-dimethoxy-2-nitrobenzyl)-l-glutamate) (PEG-b-PL), an amphiphilic diblock rod-coil copolymer containing a short PEG block and a short hydrophobic rod-like polypeptide segment. The polypeptide rods undergo smectic ordering with PEG buried between the hydrophobic polypeptide layers. The size of both blocks and the rigidity of the hydrophobic polypeptide block are critical in determining the membrane structures. Increase of the PEG length in PEG-b-PL results in the formation of bilayer sheets, while using random-coil polypeptide block leads to the formation of large compound micelles. UV treatment causes ester bond cleavage of the polypeptide side chain, which induces helix-to-coil transition, change of copolymer amphiphilicity, and eventual disassembly of vesicles. These polypeptide vesicles with unique membrane structures provide a new insight into self-assembly structure control by precisely tuning the composition and conformation of polymeric amphiphiles.

  20. Fluid flow through packings of rotating obstacles

    NASA Astrophysics Data System (ADS)

    Oliveira, Rafael S.; Andrade, José S.; Andrade, Roberto F. S.

    2015-03-01

    We investigate through numerical simulation the nonstationary flow of a Newtonian fluid through a two-dimensional channel filled with an array of circular obstacles of distinct sizes. The disks may rotate around their respective centers, modeling a nonstationary, inhomogeneous porous medium. Obstacle sizes and positions are defined by the geometry of an Apollonian packing (AP). To allow for fluid flow, the radii of the disks are uniformly reduced by a factor 0.6 ≤s ≤0.8 for assemblies corresponding to the four first AP generations. The investigation is targeted to elucidate the main features of the rotating regime as compared to the fixed disk condition. It comprises the evaluation of the region of validity of Darcy's law as well as the study of the nonlinear hydraulic resistance as a function of the channel Reynolds number, the reduction factor s , and the AP generation. Depending on a combination of these factors, the resistance of rotating disks may be larger or smaller than that of the corresponding static case. We also analyze the flow redistribution in the interdisk channels as a result of the rotation pattern and characterize the angular velocity of the disks. Here, the striking feature is the emergence of a stable oscillatory behavior of the angular velocity for almost all disks that are inserted into the assemblies after the second generation.

  1. Conical wave propagation and diffraction in two-dimensional hexagonally packed granular lattices

    DOE PAGESBeta

    Chong, C.; Kevrekidis, P. G.; Ablowitz, M. J.; Ma, Yi-Ping

    2016-01-25

    We explore linear and nonlinear mechanisms for conical wave propagation in two-dimensional lattices in the realm of phononic crystals. As a prototypical example, a statically compressed granular lattice of spherical particles arranged in a hexagonal packing configuration is analyzed. Upon identifying the dispersion relation of the underlying linear problem, the resulting diffraction properties are considered. Analysis both via a heuristic argument for the linear propagation of a wave packet and via asymptotic analysis leading to the derivation of a Dirac system suggests the occurrence of conical diffraction. This analysis is valid for strong precompression, i.e., near the linear regime. Formore » weak precompression, conical wave propagation is still possible, but the resulting expanding circular wave front is of a nonoscillatory nature, resulting from the complex interplay among the discreteness, nonlinearity, and geometry of the packing. Lastly, the transition between these two types of propagation is explored.« less

  2. Conical wave propagation and diffraction in two-dimensional hexagonally packed granular lattices.

    PubMed

    Chong, C; Kevrekidis, P G; Ablowitz, M J; Ma, Yi-Ping

    2016-01-01

    Linear and nonlinear mechanisms for conical wave propagation in two-dimensional lattices are explored in the realm of phononic crystals. As a prototypical example, a statically compressed granular lattice of spherical particles arranged in a hexagonal packing configuration is analyzed. Upon identifying the dispersion relation of the underlying linear problem, the resulting diffraction properties are considered. Analysis both via a heuristic argument for the linear propagation of a wave packet and via asymptotic analysis leading to the derivation of a Dirac system suggests the occurrence of conical diffraction. This analysis is valid for strong precompression, i.e., near the linear regime. For weak precompression, conical wave propagation is still possible, but the resulting expanding circular wave front is of a nonoscillatory nature, resulting from the complex interplay among the discreteness, nonlinearity, and geometry of the packing. The transition between these two types of propagation is explored.

  3. Removal of polychlorinated phenols in sequential anaerobic-aerobic biofilm reactors packed with tire chips

    SciTech Connect

    Shin, H.S.; Yoo, K.S.; Park, J.K.

    1999-05-01

    Scrap vehicle tire chips were used as packing material for sequential anaerobic-aerobic biofilm reactors to remove persistent chlorinated hydrocarbons. Adsorption capacity of scrap tires was greater under acidic conditions than under basic conditions. However, it was only approximately 0.04 to 0.3% of that of activated carbon. The amount of biomass that attached to the surface of scrap tires was 3.16 and 3.72 mg volatile suspended solids/cm{sup 2} after 14 and 37 days, respectively. Two laboratory-scale, down-flow anaerobic-aerobic biofilm reactors packed with tire chips were operated to remove 2,4-dichlorophenol (DCP) and 4-chlorophenol (CP). More than 98% of DCP was dehalogenated to CP in the anaerobic reactor, 70 to 98% of which was subsequently degraded in the aerobic reactor. Scrap tires did not cause any operational problems when used as biofilter media.

  4. Evaluation of ceramic packed-rod regenerator matrices

    NASA Technical Reports Server (NTRS)

    Lawless, W. N.; Arenz, R. W.

    1981-01-01

    An extensive evaluation of a modified cryocooler with various regenerator matrices is reported. The matrices examined are 0.015 in. diam. Pb spheres and 0.008, 0.015, and 0.030 in. diam. rods of a 0.2% SnCl2 doped ceramic labelled LS-8A. Specific heat and thermal conductivity data on these rod materials are also reported. The chronic pulverization/dusting problem common to Pb spheres was investigated. During a 1000 hr life test with 0.0008 in. diam. rods there was no degradation of the refrigerator performance, and a subsequent examination of the rods themselves revealed no evidence of breakage or pulverization. The load temperature characteristics for the rod packed regenerators were inferior to that for the Pb spheres, the effect being to shift the Pb spheres load curve up in temperature. This temperature shift was 5.0, 7.4, and 11.6K for the 0.0008, 0.015, and 0.030 in. diam. rods, respectively.

  5. RGBA packing for fast cone beam reconstruction on the GPU

    NASA Astrophysics Data System (ADS)

    Ino, Fumihiko; Yoshida, Seiji; Hagihara, Kenichi

    2009-02-01

    This paper presents a fast cone beam reconstruction method accelerated on the graphics processing unit (GPU). We implement the Feldkamp, Davis, and Kress (FDK) algorithm on the OpenGL graphics pipeline, which allows us to exploit the full resources and capabilities available on the GPU. The proposed method differs from previous GPU-based methods in having an RGBA packing scheme capable of directly dealing with projections without rebinning. It also reduces the amount of computation by using a data reuse scheme, which is useful to save the memory bandwidth for this memory-intensive problem. Both schemes contribute to reduce the number of rendering passes, namely the number of kernel invocations on the GPU, realizing fast cone beam reconstruction. We show some experimental results obtained on a desktop PC with an nVIDIA GeForce 8800 GTX card. As a result, the proposed method takes 8.1 seconds to reconstruct a 5123-voxel volume from 360 5122-pixel projection images. This execution time is equivalent to a 15.6-fold speedup over a CPU implementation, showing 10% higher performance as compared with a previous OpenGL-based method that requires the single-slice rebinning of projections for acceleration. With respect to non-rebinned data, our method provides approximately three times higher performance than the previous method.

  6. PackBot: a versatile platform for military robotics

    NASA Astrophysics Data System (ADS)

    Yamauchi, Brian M.

    2004-09-01

    The iRobot PackBot is a combat-tested, man-portable UGV that has been deployed in Afghanistan and Iraq. The PackBot is also a versatile platform for mobile robotics research and development that supports a wide range of payloads suitable for many different mission types. In this paper, we describe four R&D projects that developed experimental payloads and software using the PackBot platform. CHARS was a rapid development project to develop a chemical/radiation sensor for the PackBot. We developed the CHARS payload in six weeks and deployed it to Iraq to search for chemical and nuclear weapons. Griffon was a research project to develop a flying PackBot that combined the capabilities of a UGV and a UAV. We developed a Griffon prototype equipped with a steerable parafoil and gasoline-powered motor, and we completed successful flight tests including remote-controlled launch, ascent, cruising, descent, and landing. Valkyrie is an ongoing research and development project to develop a PackBot payload that will assist medics in retrieving casualties from the battlefield. Wayfarer is an applied research project to develop autonomous urban navigation capabilities for the PackBot using laser, stereo vision, GPS, and INS sensors.

  7. Complexity in surfaces of densest packings for families of polyhedra

    NASA Astrophysics Data System (ADS)

    Klotsa, Daphne; Chen, Elizabeth R.; Engel, Michael; Damasceno, Pablo F.; Glotzer, Sharon C.

    2014-03-01

    Packings of hard polyhedra have been studied for centuries due to their mathematical aesthetic and more recently for their applications in fields such as nanoscience, colloidal matter, and biology. In all these fields, particle shape is important for structure and properties, especially upon crowding. In this talk, we explore packing as a function of shape. By combining simulations and analytic calculations, we study three 2-parameter families of hard polyhedra and report an extensive and systematic analysis of the densest known packings of more than 55,000 convex shapes. The three families have the symmetries of triangle groups (20-hedral, 8-hedral, 4-hedral) and interpolate between various symmetric solids (Platonic, Archimedean, Catalan). We find that maximum packing density surfaces reveal unexpected richness and complexity, containing as many as 130 different structures within a single family. Our results demonstrate the importance of thinking about shape not as a static property of an object, in the context of packings, but rather as but one point in a higher dimensional shape space whose neighbors in that space may have identical or markedly different packings. Finally, we propose a method to distinguish regions of packings and classify types of transitions between them.

  8. Epitaxial growth of ordered and disordered granular sphere packings.

    PubMed

    Panaitescu, Andreea; Kudrolli, Arshad

    2014-09-01

    We demonstrate that epitaxy can be used to obtain a wide range of ordered to disordered granular packings by simply changing the deposition flux. We show that a defect-free face-centered-cubic (fcc) monocrystal can be obtained by depositing athermal granular spheres randomly into a container with a templated surface in a gravitational field without direct manipulation. This packing corresponds to the maximum sphere packing fraction and is obtained when the substrate is templated corresponding to the (100) plane of a fcc crystal and the container side is an integer multiple of the sphere diameter. We find that the maximum sphere packing is obtained when the deposited grains come to rest, one at a time, without damaging the substrate. A transition to a disordered packing is observed when the flux is increased. Using micro x-ray computed tomography, we find that defects nucleate at the boundaries of the container in which the packing is grown as grains cooperatively come to rest above their local potential minimum. This leads to a transition from ordered to disordered loose packings that grow in the form of an inverted cone, with the apex located at the defect nucleation site. We capture the observed decrease in order using a minimal model in which a defect leads to growth of further defects in the neighboring sites in the layer above with a probability that increases with the deposition flux.

  9. The Effect of Nasal Packing Removal on Patients Anxiety

    PubMed Central

    Sahin, Caner; Aras, Hatice Imer

    2015-01-01

    Aim: We aimed to investigate the effect of removal of merocel nasal packings on patients anxiety after septoplasty using Hamilton Anxiety Scale. Material and methods: Total amount of 50 patients who had septoplasty operation in the Department of Ear, Nose and Throat Clinic of our hospital were enrolled to the study. Patients anxiety determined using Hamilton Anxiety Scale. The patients anxiety levels were measured before 24 hours before the operation (Group 1), 48 hours after operation before nasal packing removal (Group 2) and 60 minutes after nasal packing removal (Group 3). Results: Patients were evaluated according to the Hamilton Anxiety Scale; in Group 1 15.3 ± 7.2, 19.3 ± 7 in Group 2, 14.6 ± 6,5 in Group 3 was measured. Conclusion: There was no statistically significant difference between Groups 1 and 3. There is a statistically significant difference on patients anxiety levels 48 hours after operation before nasal packing removal (p<0.001). There is an statistically significant increase of patients anxiety before packing removal. We recommend using soluble packings or sewing techniques without nasal packings after septoplasty because of patient comfort after operation. PMID:26843732

  10. Do gray wolves (Canis lupus) support pack mates during aggressive inter-pack interactions?

    PubMed

    Cassidy, Kira A; McIntyre, Richard T

    2016-09-01

    For group-living mammals, social coordination increases success in everything from hunting and foraging (Crofoot and Wrangham in Mind the Gap, Springer, Berlin, 2010; Bailey et al. in Behav Ecol Sociobiol 67:1-17, 2013) to agonism (Mosser and Packer in Anim Behav 78:359-370, 2009; Wilson et al. in Anim Behav 83:277-291, 2012; Cassidy et al. in Behav Ecol 26:1352-1360, 2015). Cooperation is found in many species and, due to its low costs, likely is a determining factor in the evolution of living in social groups (Smith in Anim Behav 92:291-304, 2014). Beyond cooperation, many mammals perform costly behaviors for the benefit of group mates (e.g., parental care, food sharing, grooming). Altruism is considered the most extreme case of cooperation where the altruist increases the fitness of the recipient while decreasing its own fitness (Bell in Selection: the mechanism of evolution. Oxford University Press, Oxford 2008). Gray wolf life history requires intra-pack familiarity, communication, and cooperation in order to succeed in hunting (MacNulty et al. in Behav Ecol doi: 10.1093/beheco/arr159 2011) and protecting group resources (Stahler et al. in J Anim Ecol 82: 222-234, 2013; Cassidy et al. in Behav Ecol 26:1352-1360, 2015). Here, we report 121 territorial aggressive inter-pack interactions in Yellowstone National Park between 1 April 1995 and 1 April 2011 (>5300 days of observation) and examine each interaction where one wolf interferes when its pack mate is being attacked by a rival group. This behavior was recorded six times (17.6 % of interactions involving an attack) and often occurred between dyads of closely related individuals. We discuss this behavior as it relates to the evolution of cooperation, sociality, and altruism. PMID:27193460

  11. Enabling Microliquid Chromatography by Microbead Packing of Microchannels

    NASA Technical Reports Server (NTRS)

    Balvin, Manuel; Zheng, Yun

    2014-01-01

    The microbead packing is the critical element required in the success of on-chip microfabrication of critical microfluidic components for in-situ analysis and detection of chiral amino acids. In order for microliquid chromatography to occur, there must be a stationary phase medium within the microchannel that interacts with the analytes present within flowing fluid. The stationary phase media are the microbeads packed by the process discussed in this work. The purpose of the microliquid chromatography is to provide a lightweight, low-volume, and low-power element to separate amino acids and their chiral partners efficiently to understand better the origin of life. In order to densely pack microbeads into the microchannels, a liquid slurry of microbeads was created. Microbeads were extracted from a commercially available high-performance liquid chromatography column. The silica beads extracted were 5 microns in diameter, and had surface coating of phenyl-hexyl. These microbeads were mixed with a 200- proof ethanol solution to create a microbead slurry with the right viscosity for packing. A microfilter is placed at the outlet via of the microchannel and the slurry is injected, then withdrawn across a filter using modified syringes. After each injection, the channel is flushed with ethanol to enhance packing. This cycle is repeated numerous times to allow for a tightly packed channel of microbeads. Typical microbead packing occurs in the macroscale into tubes or channels by using highly pressurized systems. Moreover, these channels are typically long and straight without any turns or curves. On the other hand, this method of microbead packing is completed within a microchannel 75 micrometers in diameter. Moreover, the microbead packing is completed into a serpentine type microchannel, such that it maximizes microchannel length within a microchip. Doing so enhances the interactions of the analytes with the microbeads to separate efficiently amino acids and amino acid

  12. Enabling Microliquid Chromatography by Microbead Packing of Microchannels

    NASA Technical Reports Server (NTRS)

    Balvin, Manuel; Zheng, Yun

    2013-01-01

    The microbead packing is the critical element required in the success of on-chip microfabrication of critical microfluidic components for in-situ analysis and detection of chiral amino acids. In order for microliquid chromatography to occur, there must be a stationary phase medium within the microchannel that interacts with the analytes present within flowing fluid. The stationary phase media are the microbeads packed by the process discussed in this work. The purpose of the microliquid chromatography is to provide a lightweight, low-volume, and low-power element to separate amino acids and their chiral partners efficiently to understand better the origin of life. In order to densely pack microbeads into the microchannels, a liquid slurry of microbeads was created. Microbeads were extracted from a commercially available high-performance liquid chromatography column. The silica beads extracted were 5 microns in diameter, and had surface coating of phenyl-hexyl. These microbeads were mixed with a 200- proof ethanol solution to create a microbead slurry with the right viscosity for packing. A microfilter is placed at the outlet via of the microchannel and the slurry is injected, then withdrawn across a filter using modified syringes. After each injection, the channel is flushed with ethanol to enhance packing. This cycle is repeated numerous times to allow for a tightly packed channel of microbeads. Typical microbead packing occurs in the macroscale into tubes or channels by using highly pressurized systems. Moreover, these channels are typically long and straight without any turns or curves. On the other hand, this method of microbead packing is completed within a microchannel 75 micrometers in diameter. Moreover, the microbead packing is completed into a serpentine type microchannel, such that it maximizes microchannel length within a microchip. Doing so enhances the interactions of the analytes with the microbeads to separate efficiently amino acids and amino acid

  13. 50. INTERIOR VIEW OF PACKING LINE WHERE ALL THE NAIL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    50. INTERIOR VIEW OF PACKING LINE WHERE ALL THE NAIL BOXES ARE FORMED, FILLED WITH NAILS AND SEALED; NOTE THESE ARE FIFTY-POUND BOXES - LaBelle Iron Works, Thirtieth & Wood Streets, Wheeling, Ohio County, WV

  14. Structural Evolution of a Granular Pack under Manual Tapping

    NASA Astrophysics Data System (ADS)

    Iikawa, Naoki; Bandi, Mahesh M.; Katsuragi, Hiroaki

    2015-09-01

    We experimentally study a two-dimensional (2D) granular pack of photoelastic disks subject to vertical manual tapping. Using bright- and dark-field images, we employ gradient-based image analysis methods to analyze various structural quantities. These include the packing fraction (ϕ), force per disk (Fd), and force chain segment length (l) as functions of the tapping number (τ). The increase in the packing fraction with the tapping number is found to exponentially approach an asymptotic value. An exponential distribution is observed for the cumulative numbers of both the force per disk Fd:Ncum(Fd) = AFexp ( - Fd/F0), and the force chain segment length l:Ncum(l) = Alexp ( - l/l0). Whereas the coefficient AF varies with τ for Fd, l shows no dependence on τ. The τ dependences of Fd and ϕ allow us to posit a linear relationship between the total force of the granular pack Ftot*(τ ) and ϕ(τ).

  15. 8. HIGH POWER SPRAY IN MEN'S PACK ROOM. Hot ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. HIGH POWER SPRAY IN MEN'S PACK ROOM. - Hot Springs National Park Bathhouse Row, Maurice Bathhouse: Mechanical & Piping Systems, State Highway 7, 1 mile north of U.S. Highway 70, Hot Springs, Garland County, AR

  16. 9. NEEDLE SHOWER IN MEN'S PACK ROOM. Hot Springs ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. NEEDLE SHOWER IN MEN'S PACK ROOM. - Hot Springs National Park Bathhouse Row, Maurice Bathhouse: Mechanical & Piping Systems, State Highway 7, 1 mile north of U.S. Highway 70, Hot Springs, Garland County, AR

  17. Ice pack heat sink subsystem - phase 1, volume 2

    NASA Technical Reports Server (NTRS)

    Roebelen, G. J., Jr.

    1973-01-01

    The design, development, and test of a functional laboratory model ice pack heat sink subsystem are discussed. Operating instructions to include mechanical and electrical schematics, maintenance instructions, and equipment specifications are presented.

  18. Molecular structures and crystal packings of 2-styrylquinoxaline derivatives

    NASA Astrophysics Data System (ADS)

    Kuz'mina, L. G.; Sitin, A. G.; Gulakova, E. N.; Fedorova, O. A.; Lermontova, E. Kh.; Churakov, A. V.

    2012-01-01

    The crystal and molecular structures of 2-styrylquinoxaline derivatives with different substituents in the styryl fragment are determined. The degree of planarity of the molecules studied varies in a very wide range, from 1.7° to 33.5°. In the ethylene fragment, the double bond is essentially localized. The bicycle-pedal disordering of the ethylene fragment is found in the crystals of the methoxy and oxyacetyl derivatives of 2-styrylquinoxaline. None of the packings contains packing motifs favorable for the photocycloaddition (PCA) reaction with single crystal retention. The crystal packings of these compounds and that of 2-(4-methylstyryl)quinoxaline are characterized by a stacking motif of the head-to-head type, which eliminates the possibility of PCA taking place with single crystal retention but is suitable for this reaction in polycrystalline films. The crystal packing of 2-(3,4-dimethoxystyryl)quinoxaline does not contain elements with stacking interactions.

  19. Ice pack heat sink subsystem - Phase 1, Volume 1

    NASA Technical Reports Server (NTRS)

    Roebelen, G. J., Jr.

    1973-01-01

    The design, development, fabrication, and test at one-g of a functional laboratory model (non-flight) ice pack heat sink subsystem to be used eventually for astronaut cooling during manned space missions are discussed. In normal use, excess heat in the liquid cooling garment (LCG) coolant is transferred to a reusable/regenerable ice pack heat sink. For emergency operation, or for extension of extravehicular activity mission time after all the ice has melted, water from the ice pack is boiled to vacuum, thereby continuing to remove heat from the LCG coolant. This subsystem incorporates a quick connect/disconnect thermal interface between the ice pack heat sink and the subsystem heat exchanger.

  20. 15. STOCKHAM PACKED SMALL FITTINGS IN BARRELS AND, AS EARLY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. STOCKHAM PACKED SMALL FITTINGS IN BARRELS AND, AS EARLY AS 1919, TRANSPORTED THEM IN THEIR OWN PACKARD DELIVERY TRUCKS. - Stockham Pipe & Fittings Company, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  1. 48 CFR 552.211-87 - Export packing.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...) Offerors are requested to quote, in the pricelist accompanying their offer (or by separate attachment... specifications describing the packing to be furnished at the price quoted. (b) Ordering activities will not...

  2. 10. NEEDLE SHOWER IN WOMEN'S PACK ROOM. Hot Springs ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. NEEDLE SHOWER IN WOMEN'S PACK ROOM. - Hot Springs National Park, Bathhouse Row, Lamar Bathhouse: Mechanical & Piping Systems, State Highway 7, 1 mile north of U.S. Highway 70, Hot Springs, Garland County, AR

  3. 36. ORCHARD LINE, LOOKING SOUTH, SHOWING PACIFIC FRUIT PACKING HOUSE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    36. ORCHARD LINE, LOOKING SOUTH, SHOWING PACIFIC FRUIT PACKING HOUSE NEAR END OF LINE - Yakima Valley Transportation Company Interurban Railroad, Connecting towns of Yakima, Selah & Wiley City, Yakima, Yakima County, WA

  4. [Promising technologies of packed red blood cells production and storage].

    PubMed

    Maksimov, A G; Golota, A S; Krassiĭ, A B

    2013-10-01

    The current article is dedicated to promising technologies of packed red blood cells production and storage. The following new technical approaches are presented: (1) erythrocytes storage in strict anaerobic argon-hydrogen environment, (2) lyophilization of erythrocyte suspension by its atomization in nitrogen gas, (3) lyophilization of erythrocytes by directional freezing under the influence of radio frequency radiation, (4) automated pharming of antigen free packed red blood cells from progenitor cell directly at the battlefield.

  5. Nanostructure and nanomechanics of cement: polydisperse colloidal packing.

    PubMed

    Masoero, E; Del Gado, E; Pellenq, R J-M; Ulm, F-J; Yip, S

    2012-10-12

    Cement setting and cohesion are governed by the precipitation and growth of calcium-silicate-hydrate, through a complex evolution of microstructure. A colloidal model to describe nucleation, packing, and rigidity of calcium-silicate-hydrate aggregates is proposed. Polydispersity and particle size dependent cohesion strength combine to produce a spectrum of packing fractions and of corresponding elastic properties that can be tested against nanoindentation experiments. Implications regarding plastic deformations and reconciling current structural characterizations are discussed.

  6. [Promising technologies of packed red blood cells production and storage].

    PubMed

    Maksimov, A G; Golota, A S; Krassiĭ, A B

    2013-10-01

    The current article is dedicated to promising technologies of packed red blood cells production and storage. The following new technical approaches are presented: (1) erythrocytes storage in strict anaerobic argon-hydrogen environment, (2) lyophilization of erythrocyte suspension by its atomization in nitrogen gas, (3) lyophilization of erythrocytes by directional freezing under the influence of radio frequency radiation, (4) automated pharming of antigen free packed red blood cells from progenitor cell directly at the battlefield. PMID:24611298

  7. Model for surface packing and aeolian transport on sand ripples

    NASA Astrophysics Data System (ADS)

    Louge, M. Y.; Valance, A.; el-Moctar, A. Ould; Ahmedou, D. Ould; Dupont, P.

    2009-06-01

    Measurements indicate that the solid volume fraction on a sand ripple varies from random jammed packing at troughs to the minimum stable packing at crests. By relating variations of the solid volume fraction to those of the surface turbulent shear stress, a collisional model of reptation suggests a qualitative origin for these observations. Although the model overestimates the critical shear velocity at which reptation arises, it predicts the rate of aeolian transport on Earth and Mars.

  8. Packing Infinite Number of Cubes in a Finite Volume Box

    ERIC Educational Resources Information Center

    Yao, Haishen; Wajngurt, Clara

    2006-01-01

    Packing an infinite number of cubes into a box of finite volume is the focus of this article. The results and diagrams suggest two ways of packing these cubes. Specifically suppose an infinite number of cubes; the side length of the first one is 1; the side length of the second one is 1/2 , and the side length of the nth one is 1/n. Let n approach…

  9. Consideration of grain packing in granular iron treatability studies.

    PubMed

    Firdous, R; Devlin, J F

    2014-08-01

    Commercial granular iron (GI) is light steel that is used in Permeable Reactive Barriers (PRBs). Investigations into the reactivity of GI have focused on its chemical nature and relatively little direct work has been done to account for the effects of grain shape and packing. Both of these factors are expected to influence available grain surface area, which is known to correlate to reactivity. Commercial granular iron grains are platy and therefore pack in preferential orientations that could affect solution access to the surface. Three packing variations were investigated using Connelly Iron and trichloroethylene (TCE). Experimental kinetic data showed reaction rates 2-4 times higher when grains were packed with long axes preferentially parallel to flow (VP) compared to packings with long axes preferentially perpendicular to flow (HP) or randomly arranged (RP). The variations were found to be explainable by variations in reactive sorption capacities, i.e., sorption to sites where chemical transformations took place. The possibility that the different reactive sorption capacities were related to physical pore-scale differences was assessed by conducting an image analysis of the pore structure of sectioned columns. The analyses suggested that pore-scale factors - in particular the grain surface availability, reflected in the sorption capacity terms of the kinetic model used - could only account for a fraction of the observed reactivity differences between packing types. It is concluded that packing does affect observable reaction rates but that micro-scale features on the grain surfaces, rather than the pore scale characteristics, account for most of the apparent reactivity differences. This result suggests that treatability tests should consider the packing of columns carefully if they are to mimic field performance of PRBs to the greatest extent possible.

  10. Longitudinal dispersion coefficient depending on superficial velocity of hydrogen isotopes flowing in column packed with zeolite pellets at 77.4 K

    SciTech Connect

    Kotoh, K.; Kubo, K.; Takashima, S.; Moriyama, S.T.; Tanaka, M.; Sugiyama, T.

    2015-03-15

    Authors have been developing a cryogenic pressure swing adsorption system for hydrogen isotope separation. In the problem of its design and operation, it is necessary to predict the concentration profiles developing in packed beds of adsorbent pellets. The profiling is affected by the longitudinal dispersion of gas flowing in packed beds, in addition to the mass transfer resistance in porous media of adsorbent pellets. In this work, an equation is derived for estimating the packed-bed dispersion coefficient of hydrogen isotopes, by analyzing the breakthrough curves of trace D{sub 2} or HD replacing H{sub 2} adsorbed in synthetic zeolite particles packed columns at the liquefied nitrogen temperature 77.4 K. Since specialized for hydrogen isotopes, this equation can be considered to estimate the dispersion coefficients more reliable for the cryogenic hydrogen isotope adsorption process, than the existing equations. (authors)

  11. Blister packing of copper hydroxide and titania nanoparticles on graphene and its recycling.

    PubMed

    Sridhar, Vadahanambi; Gangaraju, Deepa; Chun, Ho-Hwan; Park, Hyun

    2013-12-11

    Metal nanoparticles anchored on a graphene substrate find many applications such as sensors, catalysts, lithium ion batteries, etc. However, to date, graphene-metal nanohybrids have been synthesized by either covalent or ionic interactions between the graphene substrate and the metal nanoparticles. In this manuscript, we report a green and facile method to "bubble pack" metal nanoparticles on a graphene substrate by a simple process utilizing eco-friendly ionic liquids in conjunction with microwave heating. Copper nanoparticles bubble packed on graphene showed enhanced glucose sensing when compared to covalently bonded copper/graphene hybrids. Titania nanoparticles bubble packed on graphene when applied as anode materials in lithium ion batteries exhibited two times more lithium ion retention when compared to covalently bonded titania/graphene hybrids. "End of life" disposal of nanomaterials into the environment is a growing area of concern in recent days. One way of dealing with this problem is to extend the life cycle of nanomaterials by reusing the nanomaterials in multiple applications. In this report, we also show the recyclability of our novel bubble packaging material, by etching out the metal nanoparticles resulting in a unique 3D hierarchical graphene nanocup decorated graphene. The applicability of this recycled material in super capacitors is also reported. PMID:24256137

  12. A direct mixed-body boundary element method for packed silencers.

    PubMed

    Wu, T W; Cheng, C Y R; Zhang, P

    2002-06-01

    Bulk-reacting sound absorbing materials are often used in packed silencers to reduce broadband noise. A bulk-reacting material is characterized by a complex mean density and a complex speed of sound. These two material properties can be measured by the two-cavity method or calculated by empirical formulas. Modeling the entire silencer domain with a bulk-reacting lining will involve two different acoustic media, air and the bulk-reacting material. Traditionally, the interior silencer domain is divided into different zones and a multi-domain boundary element method (BEM) may be applied to solve the problem. However, defining different zones and matching the elements along each interface is tedious, especially when the zones are intricately connected. In this paper, a direct mixed-body boundary element method is used to model a packed silencer without subdividing it into different zones. This is achieved by summing up all the integral equations in different zones and then adding the hypersingular integral equations at interfaces. Several test cases, including a packed expansion chamber with and without an absorbing center bullet, and a parallel baffle silencer, are studied. Numerical results for the prediction of transmission loss (TL) are compared to experimental data.

  13. A direct mixed-body boundary element method for packed silencers

    NASA Astrophysics Data System (ADS)

    Wu, T. W.; Cheng, C. Y. R.; Zhang, P.

    2002-06-01

    Bulk-reacting sound absorbing materials are often used in packed silencers to reduce broadband noise. A bulk-reacting material is characterized by a complex mean density and a complex speed of sound. These two material properties can be measured by the two-cavity method or calculated by empirical formulas. Modeling the entire silencer domain with a bulk-reacting lining will involve two different acoustic media, air and the bulk-reacting material. Traditionally, the interior silencer domain is divided into different zones and a multi-domain boundary element method (BEM) may be applied to solve the problem. However, defining different zones and matching the elements along each interface is tedious, especially when the zones are intricately connected. In this paper, a direct mixed-body boundary element method is used to model a packed silencer without subdividing it into different zones. This is achieved by summing up all the integral equations in different zones and then adding the hypersingular integral equations at interfaces. Several test cases, including a packed expansion chamber with and without an absorbing center bullet, and a parallel baffle silencer, are studied. Numerical results for the prediction of transmission loss (TL) are compared to experimental data. copyright 2002 Acoustical Society of America.

  14. Analysis and migration of phthalates in infant food packed in recycled paperboard.

    PubMed

    Gärtner, Sonja; Balski, Matthias; Koch, Matthias; Nehls, Irene

    2009-11-25

    The contamination of infant food with substances from its packaging due to migration processes is still a problem. Most recently, great attention was paid to the migration of epoxidized soybean oil (ESBO) and phthalates from twist-off closures into baby food packed in glass jars. Besides, packaging made of recycled fiber materials such as paper and paperboard were found to be the source of contaminants in dry and powdery foodstuffs such as sugar, rice, and maize flour. In this study 20 infant food samples packed in recycled paperboard containers were tested for phthalates and diisopropyl naphthalenes (DIPN), known incorporated substances in recycled paper. Furthermore, the barrier function of different secondary packaging materials (paper and aluminum-coated foil) was investigated. The highest contents of phthalates (mainly diisobutyl phthalate, DiBP) and DIPN in infant food samples were found for those foods packed in inner bags made of paper. Migration experiments were performed under authentic conditions to evaluate possible transfer mechanism (gas phase, direct contact) of phthalate esters into foodstuff. It is shown that paper does not provide an appropriate barrier against migration of semipolar compounds such as phthalates. The air space itself otherwise effectively prevents migration of the less volatile phthalates under the applied conditions.

  15. Granular flow through an aperture: influence of the packing fraction.

    PubMed

    Aguirre, M A; De Schant, R; Géminard, J-C

    2014-07-01

    For the last 50 years, the flow of a granular material through an aperture has been intensely studied in gravity-driven vertical systems (e.g., silos and hoppers). Nevertheless, in many industrial applications, grains are horizontally transported at constant velocity, lying on conveyor belts or floating on the surface of flowing liquids. Unlike fluid flows, that are controlled by the pressure, granular flow is not sensitive to the local pressure but rather to the local velocity of the grains at the outlet. We can also expect the flow rate to depend on the local density of the grains. Indeed, vertical systems are packed in dense configurations by gravity, but, in contrast, in horizontal systems the density can take a large range of values, potentially very small, which may significantly alter the flow rate. In the present article, we study, for different initial packing fractions, the discharge through an orifice of monodisperse grains driven at constant velocity by a horizontal conveyor belt. We report how, during the discharge, the packing fraction is modified by the presence of the outlet, and we analyze how changes in the packing fraction induce variations in the flow rate. We observe that variations of packing fraction do not affect the velocity of the grains at the outlet, and, therefore, we establish that flow-rate variations are directly related to changes in the packing fraction. PMID:25122295

  16. Spectral action models of gravity on packed swiss cheese cosmology

    NASA Astrophysics Data System (ADS)

    Ball, Adam; Marcolli, Matilde

    2016-06-01

    We present a model of (modified) gravity on spacetimes with fractal structure based on packing of spheres, which are (Euclidean) variants of the packed swiss cheese cosmology models. As the action functional for gravity we consider the spectral action of noncommutative geometry, and we compute its expansion on a space obtained as an Apollonian packing of three-dimensional spheres inside a four-dimensional ball. Using information from the zeta function of the Dirac operator of the spectral triple, we compute the leading terms in the asymptotic expansion of the spectral action. They consist of a zeta regularization of the divergent sum of the leading terms of the spectral actions of the individual spheres in the packing. This accounts for the contribution of points 1 and 3 in the dimension spectrum (as in the case of a 3-sphere). There is an additional term coming from the residue at the additional point in the real dimension spectrum that corresponds to the packing constant, as well as a series of fluctuations coming from log-periodic oscillations, created by the points of the dimension spectrum that are off the real line. These terms detect the fractality of the residue set of the sphere packing. We show that the presence of fractality influences the shape of the slow-roll potential for inflation, obtained from the spectral action. We also discuss the effect of truncating the fractal structure at a certain scale related to the energy scale in the spectral action.

  17. Use of bauxite as packing material in steam injection wells

    SciTech Connect

    Scoglio, J.; Joubert, G.; Gallardo, B.

    1995-12-31

    Cyclic steam injection, also known as steam soak, has proven to be the most efficient method for producing heavy crude oil and bitumen from unconsolidated sands. The application of steam injection may, however, generate sand production, causing, among other things, a decrease in production. The gravel pack technique is the most efficient way to prevent fines production from cold producing wells. But, once they are steam stimulated, a dissolution of quartz containing gravel material takes place reducing greatly the packing permeability and eventually sand production. Different types of packing material have been used to avoid sand production after cyclic steam injection, such as gravel, ceramics, bauxite, coated resin, and American sand. This paper presents the results of field test, using sinterized bauxite as a packing material, carried out in Venezuela`s heavy oil operations as a part of a comprehensive program aimed at increasing the packing durability and reducing sand production. This paper also verify the results of laboratory tests in which Bauxite was found to be less soluble than other packing material when steam injected.

  18. Granular flow through an aperture: influence of the packing fraction.

    PubMed

    Aguirre, M A; De Schant, R; Géminard, J-C

    2014-07-01

    For the last 50 years, the flow of a granular material through an aperture has been intensely studied in gravity-driven vertical systems (e.g., silos and hoppers). Nevertheless, in many industrial applications, grains are horizontally transported at constant velocity, lying on conveyor belts or floating on the surface of flowing liquids. Unlike fluid flows, that are controlled by the pressure, granular flow is not sensitive to the local pressure but rather to the local velocity of the grains at the outlet. We can also expect the flow rate to depend on the local density of the grains. Indeed, vertical systems are packed in dense configurations by gravity, but, in contrast, in horizontal systems the density can take a large range of values, potentially very small, which may significantly alter the flow rate. In the present article, we study, for different initial packing fractions, the discharge through an orifice of monodisperse grains driven at constant velocity by a horizontal conveyor belt. We report how, during the discharge, the packing fraction is modified by the presence of the outlet, and we analyze how changes in the packing fraction induce variations in the flow rate. We observe that variations of packing fraction do not affect the velocity of the grains at the outlet, and, therefore, we establish that flow-rate variations are directly related to changes in the packing fraction.

  19. Densest packings of hard spheres in a cylinder

    NASA Astrophysics Data System (ADS)

    Fu, Lin; Steinhardt, William; Zhao, Hao; Socolar, Joshua; Charbonneau, Patrick

    Densely packing hard spheres (HS) within a cylinder is remarkably complex. Little is known about the densest achievable packings when the cylinder diameter, D, is larger than 2.85 times the sphere diameter, s. Here, we extend the identification of the densest packings up to D = 4.00s by adapting Torquato-Jiao's adaptive-shrinking-cell formulation and sequential-linear-programming technique to this geometry. We identify 17 new structures, almost all of them chiral. Beyond D, approx2.85s , most of the structures consist of an outer shell and of an inner core that compete for being close packed. In some cases the shell adopts a periodic configuration that is optimal and the stacking of core spheres within it is quasiperiodic, while in other cases a direct interplay between the two layers is observed. For some packings the very distinction between the core and shell vanishes, which results in exotic geometries, including some that are a three-dimensional extension of packing hard disks in a circle. In order to connect our results with experiments on comparable systems, we also consider the ease with which these structures assemble. Using kinetic Monte Carlo simulations, we find that some of the structures promtply assemble while others simply do not.

  20. Non-universal Voronoi cell shapes in amorphous ellipsoid packs

    NASA Astrophysics Data System (ADS)

    Schaller, Fabian M.; Kapfer, Sebastian C.; Hilton, James E.; Cleary, Paul W.; Mecke, Klaus; De Michele, Cristiano; Schilling, Tanja; Saadatfar, Mohammad; Schröter, Matthias; Delaney, Gary W.; Schröder-Turk, Gerd E.

    2015-07-01

    In particulate systems with short-range interactions, such as granular matter or simple fluids, local structure determines the macroscopic physical properties. We analyse local structure metrics derived from the Voronoi diagram of oblate ellipsoids, for various aspect ratios α and global packing fractions φ\\text{g} . We focus on jammed static configurations of frictional ellipsoids, obtained by tomographic imaging and by discrete element method simulations. The rescaled distribution of local packing fractions φ\\text{l} , defined as the ratio of particle volume and its Voronoi cell volume, is found to be independent of the particle aspect ratio, and coincide with results for sphere packs. By contrast, the typical Voronoi cell shape, quantified by the Minkowski tensor anisotropy index β=β_02,0 , points towards a difference between random packings of spheres and those of oblate ellipsoids. While the average cell shape β of all cells with a given value of φ\\text{l} is similar in dense and loose jammed sphere packings, the structure of dense and loose ellipsoid packings differs substantially such that this does not hold true.

  1. Pack aluminization of nickel anode for molten carbonate fuel cells

    NASA Astrophysics Data System (ADS)

    Chun, H. S.; Park, G. P.; Lim, J. H.; Kim, K.; Lee, J. K.; Moon, K. H.; Youn, J. H.

    1994-04-01

    The aluminum pack cementation (pack aluminization) process on a porous nickel anode for molten carbonate fuel cells has been studied to improve anode creep resistance. The porous nickel substrates used in this study were fabricated by doctor blade equipment followed by sintering (850 C). Packs surrounding the Ni anode were made by mixing Al2O3 powder, Al powder, and NaCl as activator. The pack aluminization was performed at 700 to 850 C for 0.5-5.0 h. After pack aluminization, the principal Ni-Al intermetallic compounds detected were Ni3Al at 700 C, NiAl at 750 C and Ni3Al2 at 800 C. The aluminum content in the aluminized Ni anode was proportional to the square root of pack aluminizing time. With increasing the Al content in the anode, the creep of the anode decreased. It was nearly constant (2.0%) when the Al content was above 5.0%. Although the exchange current density (24 mA/sq cm) for the aluminized (2.5 wt.%) Ni anode was somewhat lower than that of the pure Ni anode (40 mA/sq cm), the performance of a single cell using an aluminized Ni anode was similar to that of the one with pure Ni anode.

  2. Setting Up a Small School: Information Pack.

    ERIC Educational Resources Information Center

    Carnie, Fiona

    A growing number of families are looking for alternative ways to educate their children, as discontent with mainstream schooling rises. Human Scale Education sees the problem with the education system in the United Kingdom as one of size and believes that most schools and classes are too large for children to be known individually by their…

  3. Think Safety When Picking, Packing School Backpacks

    MedlinePlus

    ... lead to muscle and joint injury, neck and shoulder pain, as well as posture problems, child health experts warn. The American Academy of Pediatrics (AAP) suggests that: parents and kids choose a lightweight backpack with wide, padded shoulders; two shoulder straps; a padded back; and a ...

  4. Straight Privilege: Unpacking the (Still) Invisible Knapsack

    ERIC Educational Resources Information Center

    Tollefson, Kaia

    2010-01-01

    Several unearned benefits attending straight privilege are listed, prefaced by two main arguments. First, it is argued that the rampant heterosexism in the U.S. is largely attributable to many Americans' framing of heterosexism as a matter of religious freedom rather than as a form of bigotry. It is further argued that educators' elimination of…

  5. Generation of Random Particle Packings for Discrete Element Models

    NASA Astrophysics Data System (ADS)

    Abe, S.; Weatherley, D.; Ayton, T.

    2012-04-01

    An important step in the setup process of Discrete Element Model (DEM) simulations is the generation of a suitable particle packing. There are quite a number of properties such a granular material specimen should ideally have, such as high coordination number, isotropy, the ability to fill arbitrary bounding volumes and the absence of locked-in stresses. An algorithm which is able to produce specimens fulfilling these requirements is the insertion based sphere packing algorithm originally proposed by Place and Mora, 2001 [2] and extended in this work. The algorithm works in two stages. First a number of "seed" spheres are inserted into the bounding volume. In the second stage the gaps between the "seed" spheres are filled by inserting new spheres in a way so they have D+1 (i.e. 3 in 2D, 4 in 3D) touching contacts with either other spheres or the boundaries of the enclosing volume. Here we present an implementation of the algorithm and a systematic statistical analysis of the generated sphere packings. The analysis of the particle radius distribution shows that they follow a power-law with an exponent ≈ D (i.e. ≈3 for a 3D packing and ≈2 for 2D). Although the algorithm intrinsically guarantees coordination numbers of at least 4 in 3D and 3 in 2D, the coordination numbers realized in the generated packings can be significantly higher, reaching beyond 50 if the range of particle radii is sufficiently large. Even for relatively small ranges of particle sizes (e.g. Rmin = 0.5Rmax) the maximum coordination number may exceed 10. The degree of isotropy of the generated sphere packing is also analysed in both 2D and 3D, by measuring the distribution of orientations of vectors joining the centres of adjacent particles. If the range of particle sizes is small, the packing algorithm yields moderate anisotropy approaching that expected for a face-centred cubic packing of equal-sized particles. However, once Rmin < 0.3Rmax a very high degree of isotropy is demonstrated in

  6. OVERCOMING THE METER BARRIER AND THE FORMATION OF SYSTEMS WITH TIGHTLY PACKED INNER PLANETS (STIPs)

    SciTech Connect

    Boley, A. C.; Morris, M. A.; Ford, E. B.

    2014-09-10

    We present a solution to the long outstanding meter barrier problem in planet formation theory. As solids spiral inward due to aerodynamic drag, they will enter disk regions that are characterized by high temperatures, densities, and pressures. High partial pressures of rock vapor can suppress solid evaporation, and promote collisions between partially molten solids, allowing rapid growth. This process should be ubiquitous in planet-forming disks, which may be evidenced by the abundant class of Systems with Tightly packed Inner Planets discovered by the NASA Kepler Mission.

  7. 7 CFR 51.691 - Standard pack for oranges except Temple variety.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false Standard pack for oranges except Temple variety. 51... Grades of Oranges (Texas and States Other Than Florida, California, and Arizona) Standard Pack § 51.691 Standard pack for oranges except Temple variety. (a) Fruit shall be fairly uniform in size. When packed...

  8. 7 CFR 51.691 - Standard pack for oranges except Temple variety.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false Standard pack for oranges except Temple variety. 51... Grades of Oranges (Texas and States Other Than Florida, California, and Arizona) Standard Pack § 51.691 Standard pack for oranges except Temple variety. (a) Fruit shall be fairly uniform in size. When packed...

  9. Mixed-integer programming methods for transportation and power generation problems

    NASA Astrophysics Data System (ADS)

    Damci Kurt, Pelin

    This dissertation conducts theoretical and computational research to solve challenging problems in application areas such as supply chain and power systems. The first part of the dissertation studies a transportation problem with market choice (TPMC) which is a variant of the classical transportation problem in which suppliers with limited capacities have a choice of which demands (markets) to satisfy. We show that TPMC is strongly NP-complete. We consider a version of the problem with a service level constraint on the maximum number of markets that can be rejected and show that if the original problem is polynomial, its cardinality-constrained version is also polynomial. We propose valid inequalities for mixed-integer cover and knapsack sets with variable upper bound constraints, which appear as substructures of TPMC and use them in a branch-and-cut algorithm to solve this problem. The second part of this dissertation studies a unit commitment (UC) problem in which the goal is to minimize the operational cost of power generators over a time period subject to physical constraints while satisfying demand. We provide several exponential classes of multi-period ramping and multi-period variable upper bound inequalities. We prove the strength of these inequalities and describe polynomial-time separation algorithms. Computational results show the effectiveness of the proposed inequalities when used as cuts in a branch-and-cut algorithm to solve the UC problem. The last part of this dissertation investigates the effects of uncertain wind power on the UC problem. A two-stage robust model and a three-stage stochastic program are compared.

  10. Thermodynamics and kinetics of pack aluminide coating formation on IN-100

    NASA Technical Reports Server (NTRS)

    Levine, S. R.; Caves, R. M.

    1973-01-01

    An investigation of the effects of pack variables on the formation of aluminide coatings on nickel-base superalloy IN-100 was conducted. Also, the thermodynamics and kinetics of coating formation were analyzed. Observed coating weights were in good agreement with predictions made from the analysis. Pack temperature rather than pack aluminum activity controls the principal coating phase formed. In 1 weight percent aluminum packs, aluminum weight gains were related to the halide pack activator. Solid-state nickel diffusion controlled coating formation from sodium fluoride and chloride and ammonium fluoride activated packs. In other ammonium and sodium halide activated 1 weight percent aluminum packs, gaseous diffusion controlled coating formation.

  11. Characterization of the structure of heterogeneous materials and particle packings

    NASA Astrophysics Data System (ADS)

    Jiao, Yang

    In this dissertation, we present a combination of computational and theoretical results concerning the characterization of the microstructure of heterogeneous materials and hard-particle packings. An overview of the dissertation is provided in Chapter 1. In Part I of this dissertation, we focus on the characterization of multi-phase heterogeneous materials. In Chapter 2, we present a detailed discussion of the correlation functions that statistically characterize the microstructure of a heterogeneous material. Examples of such materials include composites, colloids, foams and biological media. In Chapter 3, we introduce a microstructure reconstruction/construction procedure developed by Yeong and Torquato and devise a powerful universal sampling scheme, called the lattice-point scheme, that enables one to incorporate the widest class of lower-order correlation functions known to date into the Yeong-Torquato procedure, which opens the door to many fruitful applications. In Chapter 4, we present two major applications of our lattice-point scheme including modelling heterogeneous materials via two-point correlation functions and identifying superior microstructure descriptors of random media. These developments suggest novel approach for material design and more accurate rigorous structure-property relations; they also have ramifications in atomic and molecular systems. In Part II of this dissertation, we focus on quantitatively describing the structure of hard-particle packings, which have been employed to model a wide spectrum of condensed matters such as simple liquid, disordered/crystalline solids and granular media as well as biological systems. In Chapter 5, we present two major numerical packing protocols, namely the Donev-Torquato-Stillinger (DTS) event-driven molecular dynamics (MD) algorithm for smooth convex particles and the adaptive-shrinking-cell (ASC) scheme for hard polyhedral particles. In Chapter 6, the DTS event-driven MD algorithm is employed to

  12. Bernal's road to random packing and the structure of liquids

    NASA Astrophysics Data System (ADS)

    Finney, John L.

    2013-11-01

    Until the 1960s, liquids were generally regarded as either dense gases or disordered solids, and theoretical attempts at understanding their structures and properties were largely based on those concepts. Bernal, himself a crystallographer, was unhappy with either approach, preferring to regard simple liquids as 'homogeneous, coherent and essentially irregular assemblages of molecules containing no crystalline regions'. He set about realizing this conceptual model through a detailed examination of the structures and properties of random packings of spheres. In order to test the relevance of the model to real liquids, ways had to be found to realize and characterize random packings. This was at a time when computing was slow and in its infancy, so he and his collaborators set about building models in the laboratory, and examining aspects of their structures in order to characterize them in ways which would enable comparison with the properties of real liquids. Some of the imaginative - often time consuming and frustrating - routes followed are described, as well the comparisons made with the properties of simple liquids. With the increase of the power of computers in the 1960s, computational approaches became increasingly exploited in random packing studies. This enabled the use of packing concepts, and the tools developed to characterize them, in understanding systems as diverse as metallic glasses, crystal-liquid interfaces, protein structures, enzyme-substrate interactions and the distribution of galaxies, as well as their exploitation in, for example, oil extraction, understanding chromatographic separation columns, and packed beds in industrial processes.

  13. A Geometric-Structure Theory for Maximally Random Jammed Packings

    NASA Astrophysics Data System (ADS)

    Tian, Jianxiang; Xu, Yaopengxiao; Jiao, Yang; Torquato, Salvatore

    2015-11-01

    Maximally random jammed (MRJ) particle packings can be viewed as prototypical glasses in that they are maximally disordered while simultaneously being mechanically rigid. The prediction of the MRJ packing density ϕMRJ, among other packing properties of frictionless particles, still poses many theoretical challenges, even for congruent spheres or disks. Using the geometric-structure approach, we derive for the first time a highly accurate formula for MRJ densities for a very wide class of two-dimensional frictionless packings, namely, binary convex superdisks, with shapes that continuously interpolate between circles and squares. By incorporating specific attributes of MRJ states and a novel organizing principle, our formula yields predictions of ϕMRJ that are in excellent agreement with corresponding computer-simulation estimates in almost the entire α-x plane with semi-axis ratio α and small-particle relative number concentration x. Importantly, in the monodisperse circle limit, the predicted ϕMRJ = 0.834 agrees very well with the very recently numerically discovered MRJ density of 0.827, which distinguishes it from high-density “random-close packing” polycrystalline states and hence provides a stringent test on the theory. Similarly, for non-circular monodisperse superdisks, we predict MRJ states with densities that are appreciably smaller than is conventionally thought to be achievable by standard packing protocols.

  14. A Geometric-Structure Theory for Maximally Random Jammed Packings

    PubMed Central

    Tian, Jianxiang; Xu, Yaopengxiao; Jiao, Yang; Torquato, Salvatore

    2015-01-01

    Maximally random jammed (MRJ) particle packings can be viewed as prototypical glasses in that they are maximally disordered while simultaneously being mechanically rigid. The prediction of the MRJ packing density ϕMRJ, among other packing properties of frictionless particles, still poses many theoretical challenges, even for congruent spheres or disks. Using the geometric-structure approach, we derive for the first time a highly accurate formula for MRJ densities for a very wide class of two-dimensional frictionless packings, namely, binary convex superdisks, with shapes that continuously interpolate between circles and squares. By incorporating specific attributes of MRJ states and a novel organizing principle, our formula yields predictions of ϕMRJ that are in excellent agreement with corresponding computer-simulation estimates in almost the entire α-x plane with semi-axis ratio α and small-particle relative number concentration x. Importantly, in the monodisperse circle limit, the predicted ϕMRJ = 0.834 agrees very well with the very recently numerically discovered MRJ density of 0.827, which distinguishes it from high-density “random-close packing” polycrystalline states and hence provides a stringent test on the theory. Similarly, for non-circular monodisperse superdisks, we predict MRJ states with densities that are appreciably smaller than is conventionally thought to be achievable by standard packing protocols. PMID:26568437

  15. Iron supplementation, maternal packed cell volume, and fetal growth.

    PubMed Central

    Hemminki, E; Rimpelä, U

    1991-01-01

    Previous studies have found that there is a correlation between mothers' haemoglobin concentration or packed cell volume and infants' birth weight, and that iron supplementation increases mothers' haemoglobin concentration. The purpose of this study, using the data of a large randomised trial on iron prophylaxis during pregnancy, was to find out whether iron supplementation causes fetal growth to deteriorate. At their first antenatal visit, 2912 pregnant women were randomised into non-routine iron and routine iron supplementation. The mean length of gestation was shorter in the non-routine group. Birth weight did not differ between the groups, but due to longer gestations boys in the group receiving routine iron were taller than in the non-routine group. In both groups, whether studied by various values of packed cell volume or correlation coefficients, the lower the packed cell volume, the heavier and taller the infant and heavier the placenta. These negative correlations could be seen even with a packed cell volume measured early in pregnancy. Standardising for blood pressure did not influence the correlation coefficients. The correlation between a high ratio for packed cell volume and poor fetal growth thus may not be caused by iron supplementation, nor mediated by blood pressure, but by some other mechanism. PMID:2025036

  16. How proteins pack into crystals: nuclei achieve translation symmetries by growing.

    PubMed

    Feng, Dan; Zeng, Zong-Hao

    2004-07-01

    How protein molecules pack into a crystal remains problematic. Packing units are direct materials for packing into crystals. The group generator method is introduced for automatically identifying the packing unit. By introducing deviations into the nucleation stage of crystallization, we proved that these deviations diminish in further packing. This process illustrates how translation symmetries are achieved by the growing of nuclei. Two effects, the size effect and the close up effect, are found to behave differently in this process.

  17. 6-PACK programme to decrease fall injuries in acute hospitals: cluster randomised controlled trial

    PubMed Central

    Morello, Renata T; Wolfe, Rory; Brand, Caroline A; Haines, Terry P; Hill, Keith D; Brauer, Sandra G; Botti, Mari; Cumming, Robert G; Livingston, Patricia M; Sherrington, Catherine; Zavarsek, Silva; Lindley, Richard I; Kamar, Jeannette

    2016-01-01

    Objective To evaluate the effect of the 6-PACK programme on falls and fall injuries in acute wards. Design Cluster randomised controlled trial. Setting Six Australian hospitals. Participants All patients admitted to 24 acute wards during the trial period. Interventions Participating wards were randomly assigned to receive either the nurse led 6-PACK programme or usual care over 12 months. The 6-PACK programme included a fall risk tool and individualised use of one or more of six interventions: “falls alert” sign, supervision of patients in the bathroom, ensuring patients’ walking aids are within reach, a toileting regimen, use of a low-low bed, and use of a bed/chair alarm. Main outcome measures The co-primary outcomes were falls and fall injuries per 1000 occupied bed days. Results During the trial, 46 245 admissions to 16 medical and eight surgical wards occurred. As many people were admitted more than once, this represented 31 411 individual patients. Patients’ characteristics and length of stay were similar for intervention and control wards. Use of 6-PACK programme components was higher on intervention wards than on control wards (incidence rate ratio 3.05, 95% confidence interval 2.14 to 4.34; P<0.001). In all, 1831 falls and 613 fall injuries occurred, and the rates of falls (incidence rate ratio 1.04, 0.78 to 1.37; P=0.796) and fall injuries (0.96, 0.72 to 1.27; P=0.766) were similar in intervention and control wards. Conclusions Positive changes in falls prevention practice occurred following the introduction of the 6-PACK programme. However, no difference was seen in falls or fall injuries between groups. High quality evidence showing the effectiveness of falls prevention interventions in acute wards remains absent. Novel solutions to the problem of in-hospital falls are urgently needed. Trial registration Australian New Zealand Clinical Trials Registry ACTRN12611000332921. PMID:26813674

  18. Lightweight, Flexible, Thin, Integrated Solar-Power Packs

    NASA Technical Reports Server (NTRS)

    Hanson, Robert R.

    2004-01-01

    Lightweight, flexible, thin, one-piece, solar-power packs are undergoing development. Each power pack of this type is a complete, modular, integrated power-supply system comprising three power subsystems that, in conventional practice, have been constructed as separate units and connected to each other by wires. These power packs are amenable to a variety of uses: For example, they could be laminated to the tops of tents and other shelters to provide or augment power for portable electronic equipment in the field, and they could be used as power sources for such small portable electronic systems as radio transceivers (including data relays and cellular telephones), laptop computers, video camcorders, and Global Positioning System receivers.

  19. How much biomass do plant communities pack per unit volume?

    PubMed Central

    Rheault, Guillaume; Bonin, Laurianne; Roca, Irene Torrecilla; Martin, Charles A.; Desrochers, Louis; Seiferling, Ian

    2015-01-01

    Aboveground production in terrestrial plant communities is commonly expressed in amount of carbon, or biomass, per unit surface. Alternatively, expressing production per unit volume allows the comparison of communities by their fundamental capacities in packing carbon. In this work we reanalyzed published data from more than 900 plant communities across nine ecosystems to show that standing dry biomass per unit volume (biomass packing) consistently averages around 1 kg/m3 and rarely exceeds 5 kg/m3 across ecosystem types. Furthermore, we examined how empirical relationships between aboveground production and plant species richness are modified when standing biomass is expressed per unit volume rather than surface. We propose that biomass packing emphasizes species coexistence mechanisms and may be an indicator of resource use efficiency in plant communities. PMID:25802814

  20. Hydrogen gettering packing material, and process for making same

    DOEpatents

    LeMay, James D.; Thompson, Lisa M.; Smith, Henry Michael; Schicker, James R.

    2001-01-01

    A hydrogen gettering system for a sealed container is disclosed comprising packing material for use within the sealed container, and a coating film containing hydrogen gettering material on at least a portion of the surface of such packing material. The coating film containing the hydrogen gettering material comprises a mixture of one or more organic materials capable of reacting with hydrogen and one or more catalysts capable of catalyzing the reaction of hydrogen with such one or more organic materials. The mixture of one or more organic materials capable of reacting with hydrogen and the one or more catalysts is dispersed in a suitable carrier which preferably is a curable film-forming material. In a preferred embodiment, the packing material comprises a foam material which is compatible with the coating film containing hydrogen gettering material thereon.

  1. Structural evolution in the packing of uniform spheres.

    PubMed

    Tian, Z A; Dong, K J; Yu, A B

    2014-03-01

    Structural analysis is very important to understanding the physics of atomic or particle systems of various types. However, properly characterizing the structures at different packing fraction ρ is still a challenge. Here we analyze the local structure, in terms of the so-called common-neighbor-subcluster (CNS), of sphere packings with ρ ∈ (0.2, 0.74). We show that although complicated in structure, there are totally 39 kinds of CNSs of which 12 are dominant. The evolution of these CNSs with the increase of ρ is quantified, and the rules governing the evolution are explored. The results are found to be useful in constructing a comprehensive picture about the critical states and their transition in sphere packing.

  2. Hydrogen gettering packing material and process for making same

    SciTech Connect

    LeMay, James D.; Thompson, Lisa M.; Smith, Henry Michael; Schicker, James R.

    1999-09-09

    A hydrogen gettering system for a sealed container is disclosed comprising packing material for use within the sealed container, and a coating film containing hydrogen gettering material on at least a portion of the surface of such packing material. The coating film containing the hydrogen gettering material comprises a mixture of one or more organic materials capable of reacting with hydrogen and one or more catalysts capable of catalyzing the reaction of hydrogen with such one or more organic materials. The mixture of one or more organic materials capable of reacting with hydrogen and the one or more catalysts is dispersed in a suitable carrier which preferably is a curable film-forming material. In a preferred embodiment, the packing material comprises a foam material which is compatible with the coating film containing hydrogen gettering material thereon.

  3. FY-87 packing fabrication techniques (commercial waste form) results

    SciTech Connect

    Werry, E.V.; Gates, T.E.; Cabbage, K.S.; Eklund, J.D.

    1988-04-01

    This report covers the investigation of fabrication techniques associated with the development of suitable materials and methods to provide a prefabricated packing for waste packages for the Basalt Waste Isolation Project (BWIP). The principal functions of the packing are to minimize container corrosion during the 300 to 1000 years following repository closure and provide long-term control of the release of radionuclides from the waste package. The investigative work, discussed in this report, was specifically conceived to develop the design criteria for production of full-scale prototypical packing rings. The investigative work included the preparation of procedures, the preparation of fabrication materials, physical properties, and the determination of the engineering properties. The principal activities were the preparation of the materials and the determination of the physical properties. 21 refs., 20 figs., 14 tabs.

  4. Photovoltaic dryer with dual packed beds for drying medical herb

    SciTech Connect

    Abdel-Rehim, Z.S.; Fahmy, F.H.

    1998-03-01

    This work presents design and optimization of a cylindrical photovoltaic dryer with dual packed beds thermal energy storage for drying medical herb. The dryer is provided with electrical heater where the electrical energy is generated by using photovoltaic system. The electrical heater is designed and sized to realize continuous drying (day and night) to minimize the drying time. Two packed beds are used to fix the drying temperature in dryer during day and night. The main packed bed thermal energy storage is charged during the sunlight hours directly, to realize continued drying after sunset. An efficient PV dryer is devised to work under forced air created by air blower and heated by the electrical coils.

  5. Structure of marginally jammed polydisperse packings of frictionless spheres.

    PubMed

    Zhang, Chi; O'Donovan, Cathal B; Corwin, Eric I; Cardinaux, Frédéric; Mason, Thomas G; Möbius, Matthias E; Scheffold, Frank

    2015-03-01

    We model the packing structure of a marginally jammed bulk ensemble of polydisperse spheres. To this end we expand on the granocentric model [Clusel et al., Nature (London) 460, 611 (2009)], explicitly taking into account rattlers. This leads to a relationship between the characteristic parameters of the packing, such as the mean number of neighbors and the fraction of rattlers, and the radial distribution function g(r). We find excellent agreement between the model predictions for g(r) and packing simulations, as well as experiments on jammed emulsion droplets. The observed quantitative agreement opens the path towards a full structural characterization of jammed particle systems for imaging and scattering experiments. PMID:25871105

  6. Packing entropy of extended, hard, rigid objects on a lattice

    NASA Astrophysics Data System (ADS)

    Li, Wenshuo; Freed, Karl F.; Nemirovsky, Adolfo M.

    1993-06-01

    We present a systematic method of evaluating the packing entropy for a set of mutually avoiding extended, hard, rigid objects on a lattice. The method generalizes a simple algebraic representation of the lattice cluster theory developed by Freed and co-workers for systems composed of flexible objects. The theory provides a power series expansion in z-1 for the corrections to the zeroth order mean field approximation partition function, where z is the lattice coordination number. We illustrate the general theory by calculating the packing entropy of four-unit rigid ``square'' objects on a hypercubic lattice as a function of the volume fraction of the squares. As a particular limiting case, we also evaluate for the packing entropy of two, three, and four squares on a two-dimensional square lattice and find agreement with the cluster expansion.

  7. Pack-Mutator-like transposable elements (Pack-MULEs) induce directional modification of genes through biased insertion and DNA acquisition.

    PubMed

    Jiang, Ning; Ferguson, Ann A; Slotkin, R Keith; Lisch, Damon

    2011-01-25

    In monocots, many genes demonstrate a significant negative GC gradient, meaning that the GC content declines along the orientation of transcription. Such a gradient is not observed in the genes of the dicot plant Arabidopsis. In addition, a lack of homology is often observed when comparing the 5' end of the coding region of orthologous genes in rice and Arabidopsis. The reasons for these differences have been enigmatic. The presence of GC-rich sequences at the 5' end of genes may influence the conformation of chromatin, the expression level of genes, as well as the recombination rate. Here we show that Pack-Mutator-like transposable elements (Pack-MULEs) that carry gene fragments specifically acquire GC-rich fragments and preferentially insert into the 5' end of genes. The resulting Pack-MULEs form independent, GC-rich transcripts with a negative GC gradient. Alternatively, the Pack-MULEs evolve into additional exons at the 5' end of existing genes, thus altering the GC content in those regions. We demonstrate that Pack-MULEs modify the 5' end of genes and are at least partially responsible for the negative GC gradient of genes in grasses. Such a unique and global impact on gene composition and gene structure has not been observed for any other transposable elements.

  8. Characterization of maximally random jammed sphere packings: Voronoi correlation functions

    NASA Astrophysics Data System (ADS)

    Klatt, Michael A.; Torquato, Salvatore

    2014-11-01

    We characterize the structure of maximally random jammed (MRJ) sphere packings by computing the Minkowski functionals (volume, surface area, and integrated mean curvature) of their associated Voronoi cells. The probability distribution functions of these functionals of Voronoi cells in MRJ sphere packings are qualitatively similar to those of an equilibrium hard-sphere liquid and partly even to the uncorrelated Poisson point process, implying that such local statistics are relatively structurally insensitive. This is not surprising because the Minkowski functionals of a single Voronoi cell incorporate only local information and are insensitive to global structural information. To improve upon this, we introduce descriptors that incorporate nonlocal information via the correlation functions of the Minkowski functionals of two cells at a given distance as well as certain cell-cell probability density functions. We evaluate these higher-order functions for our MRJ packings as well as equilibrium hard spheres and the Poisson point process. It is shown that these Minkowski correlation and density functions contain visibly more information than the corresponding standard pair-correlation functions. We find strong anticorrelations in the Voronoi volumes for the hyperuniform MRJ packings, consistent with previous findings for other pair correlations [A. Donev et al., Phys. Rev. Lett. 95, 090604 (2005), 10.1103/PhysRevLett.95.090604], indicating that large-scale volume fluctuations are suppressed by accompanying large Voronoi cells with small cells, and vice versa. In contrast to the aforementioned local Voronoi statistics, the correlation functions of the Voronoi cells qualitatively distinguish the structure of MRJ sphere packings (prototypical glasses) from that of not only the Poisson point process but also the correlated equilibrium hard-sphere liquids. Moreover, while we did not find any perfect icosahedra (the locally densest possible structure in which a central

  9. A model for evaluating the ballistic resistance of stratified packs

    NASA Astrophysics Data System (ADS)

    Pirvu, C.; Georgescu, C.; Badea, S.; Deleanu, L.

    2016-08-01

    Models for evaluating the ballistic performance of stratified packs are useful in reducing the time for laboratory tests, understanding the failure process and identifying key factors to improve the architecture of the packs. The authors present the results of simulating the bullet impact on a packs made of 24 layers, taking into consideration the friction between layers (μ = 0.4) and the friction between bullet and layers (μ = 0.3). The aim of this study is to obtain a number of layers that allows for the bullet arrest in the packs and to have several layers undamaged in order to offer a high level of safety for this kind of packs that could be included in individual armors. The model takes into account the yield and fracture limits of the two materials the bullet is made of and those for one layer, here considered as an orthotropic material, having maximum equivalent plastic strain of 0.06. All materials are considered to have bilinear isotropic hardening behavior. After documentation, the model was designed as isothermal because thermal influence of the impact is considered low for these impact velocities. The model was developed with the help of Ansys 14.5. Each layer has 200 mm × 200 × 0.35 mm. The bullet velocity just before impact was 400 m/s, a velocity characterizing the average values obtained in close range with a ballistic barrel and the bullet model is following the shape and dimensions of the 9 mm FMJ (full metal jacket). The model and the results concerning the number of broken layers were validated by experiments, as the number of broken layers for the actual pack (made of 24 layers of LFT SB1) were also seven...eight. The models for ballistic impact are useful when they are particularly formulated for resembling to the actual system projectile - target.

  10. Volatile compounds and odor preferences of ground beef added with garlic and red wine, and irradiated with charcoal pack

    NASA Astrophysics Data System (ADS)

    Lee, Kyung Haeng; Yun, Hyejeong; Lee, Ju Woon; Ahn, Dong Uk; Lee, Eun Joo; Jo, Cheorun

    2012-08-01

    Irradiation is the most efficient non-thermal technology for improving hygienic quality and extending the shelf-life of food products. One of the adverse effects of food irradiation, however, is off-flavor production, which significantly affects the sensory preferences for certain foods. In this study, garlic (5%, w/w) and red wine (1:1, w/w) were added to ground beef to increase the radiation sensitivity of pathogens and improve meat odor/flavor. Samples were irradiated at 0 or 5 kGy in the presence of charcoal pack. SPME-GC-MS analysis was performed to measure the changes in the volatile compounds and sensory characteristics of the samples. The amount of total volatile compounds produced from ground beef was greater when the sample was irradiated. When garlic and red wine were added to the ground beef, the amount of volatile compounds significantly increased, and the amount of volatile compounds increased even further after irradiation. However, when the samples were irradiated with charcoal pack, the amount of volatile compounds decreased significantly. Sensory evaluation indicated that charcoal pack significantly increased the odor preferences for both irradiated and non-irradiated ground beef added with garlic. These results indicated that addition of charcoal pack to ground beef could reduce off-odor problems induced by irradiation, and this effect was consistent even when certain additives such as garlic and red wine were added.

  11. [Removal of Mixed Waste Gases by a Biotrickling Filter Packed with a Novel Combined Packing Material].

    PubMed

    Mei, Yu; Cheng, Zhuo-wei; Wang, Jia-de; Lu, Yin

    2015-12-01

    A pilot biotrickling filter (BTF) was set up for removal of a mixed waste gas containing toluene and ethanol. The packing material was composed of polyhedral sphere and polyhedral hollow column previously designed by our group. The results showed this BTF could successfully start up within only 8 d and the average eliminate capacities for toluene and ethanol were 97.14 and 113.10 g · (m³ · h)⁻¹, respectively. Empty bed residence time (EBRT) and the inlet concentration had effects on the removal of toluene. The maximum elimination capacity of toluene and ethanol was 123.34 and 206.36 g (m³ · h)⁻¹ under EBRT of 21.11 s, respectively. However, the effect of spray liquid density was not obvious, and the optimal value of solution and gas ratio was 6.82 L · m⁻³. The influence of unstable processing condition on its performance was also investigated. NaOH solution could effectively reduce the plugging of the filler layer, and the removal capability of pollutant could be recovered within 3 days. After the running was stopped for 10 d, the removal performance of this BTF could be quickly recovered.

  12. [Removal of Mixed Waste Gases by a Biotrickling Filter Packed with a Novel Combined Packing Material].

    PubMed

    Mei, Yu; Cheng, Zhuo-wei; Wang, Jia-de; Lu, Yin

    2015-12-01

    A pilot biotrickling filter (BTF) was set up for removal of a mixed waste gas containing toluene and ethanol. The packing material was composed of polyhedral sphere and polyhedral hollow column previously designed by our group. The results showed this BTF could successfully start up within only 8 d and the average eliminate capacities for toluene and ethanol were 97.14 and 113.10 g · (m³ · h)⁻¹, respectively. Empty bed residence time (EBRT) and the inlet concentration had effects on the removal of toluene. The maximum elimination capacity of toluene and ethanol was 123.34 and 206.36 g (m³ · h)⁻¹ under EBRT of 21.11 s, respectively. However, the effect of spray liquid density was not obvious, and the optimal value of solution and gas ratio was 6.82 L · m⁻³. The influence of unstable processing condition on its performance was also investigated. NaOH solution could effectively reduce the plugging of the filler layer, and the removal capability of pollutant could be recovered within 3 days. After the running was stopped for 10 d, the removal performance of this BTF could be quickly recovered. PMID:27011972

  13. Packing confined hard spheres denser with adaptive prism phases.

    PubMed

    Oğuz, Erdal C; Marechal, Matthieu; Ramiro-Manzano, Fernando; Rodriguez, Isabelle; Messina, René; Meseguer, Francisco J; Löwen, Hartmut

    2012-11-21

    We show that hard spheres confined between two parallel hard plates pack denser with periodic adaptive prismatic structures which are composed of alternating prisms of spheres. The internal structure of the prisms adapts to the slit height which results in close packings for a range of plate separations, just above the distance where three intersecting square layers fit exactly between the plates. The adaptive prism phases are also observed in real-space experiments on confined sterically stabilized colloids and in Monte Carlo simulations at finite pressure.

  14. Wire-packed heat exchangers for dilution refrigerators.

    PubMed

    Polturak, E; Rappaport, M; Rosenbaum, R

    1978-03-01

    Very simple wire-packed step heat exchangers for dilution refrigerators are described. No sintering is used in fabrication. Flow impedances and thermal resistance between the liquid and the copper wires are low. A refrigerator with five wire-packed heat exchangers in addition to a countercurrent heat exchanger attains a temperature of 11.4 mK with a single mixing chamber and 6.1 mK with two mixing chambers. High cooling power is achieved at modest (3)He circulation rates. PMID:18699084

  15. Effect of packing density on strain estimation by Fry method

    NASA Astrophysics Data System (ADS)

    Srivastava, Deepak; Ojha, Arun

    2015-04-01

    Fry method is a graphical technique that uses relative movement of material points, typically the grain centres or centroids, and yields the finite strain ellipse as the central vacancy of a point distribution. Application of the Fry method assumes an anticlustered and isotropic grain centre distribution in undistorted samples. This assumption is, however, difficult to test in practice. As an alternative, the sedimentological degree of sorting is routinely used as an approximation for the degree of clustering and anisotropy. The effect of the sorting on the Fry method has already been explored by earlier workers. This study tests the effect of the tightness of packing, the packing density%, which equals to the ratio% of the area occupied by all the grains and the total area of the sample. A practical advantage of using the degree of sorting or the packing density% is that these parameters, unlike the degree of clustering or anisotropy, do not vary during a constant volume homogeneous distortion. Using the computer graphics simulations and the programming, we approach the issue of packing density in four steps; (i) generation of several sets of random point distributions such that each set has same degree of sorting but differs from the other sets with respect to the packing density%, (ii) two-dimensional homogeneous distortion of each point set by various known strain ratios and orientation, (iii) estimation of strain in each distorted point set by the Fry method, and, (iv) error estimation by comparing the known strain and those given by the Fry method. Both the absolute errors and the relative root mean squared errors give consistent results. For a given degree of sorting, the Fry method gives better results in the samples having greater than 30% packing density. This is because the grain centre distributions show stronger clustering and a greater degree of anisotropy with the decrease in the packing density. As compared to the degree of sorting alone, a

  16. Balance Problems

    MedlinePlus

    ... often, it could be a sign of a balance problem. Balance problems can make you feel unsteady or as ... fall-related injuries, such as hip fracture. Some balance problems are due to problems in the inner ...

  17. Comparison of the biological NH3 removal characteristics among four inorganic packing materials.

    PubMed

    Hirai, M; Kamamoto, M; Yani, M; Shoda, M

    2001-01-01

    Four inorganic packing materials were evaluated in terms of their availability as a packing material of a packed tower deodorization apparatus (biofilter) from the viewpoints of biological NH3 removal characteristics and some physical properties. Porous ceramics (A), calcinated cristobalite (B), calcinated and formed obsidian (C), granulated and calculated soil (D) were used. The superiority of these packing materials determined based on the values of non-biological removal per unit weight or unit volume of packing material, complete removal capacity of NH3 per unit weight of packing material per day or unit volume of packing material per day and pressure drop of the packed bed was in the order of A approximately = C > B > or = D. Packing materials A and C with high porosity, maximum water content, and suitable mean pore diameter showed excellent removal capacity. PMID:16233018

  18. Comparison of the biological NH3 removal characteristics among four inorganic packing materials.

    PubMed

    Hirai, M; Kamamoto, M; Yani, M; Shoda, M

    2001-01-01

    Four inorganic packing materials were evaluated in terms of their availability as a packing material of a packed tower deodorization apparatus (biofilter) from the viewpoints of biological NH3 removal characteristics and some physical properties. Porous ceramics (A), calcinated cristobalite (B), calcinated and formed obsidian (C), granulated and calculated soil (D) were used. The superiority of these packing materials determined based on the values of non-biological removal per unit weight or unit volume of packing material, complete removal capacity of NH3 per unit weight of packing material per day or unit volume of packing material per day and pressure drop of the packed bed was in the order of A approximately = C > B > or = D. Packing materials A and C with high porosity, maximum water content, and suitable mean pore diameter showed excellent removal capacity.

  19. Involvement of Clostridium gasigenes and C. algidicarnis in 'blown pack' spoilage of Brazilian vacuum-packed beef.

    PubMed

    Silva, Alessandra R; Paulo, Ezio N; Sant'Ana, Anderson S; Chaves, Rafael D; Massaguer, Pilar R

    2011-08-15

    The objectives of this study were to isolate psychrotrophic clostridia from Brazilian vacuum-packed beef cuts (spoiled or not) and to identify the isolates by using 16S rRNA gene sequencing. Anaerobic psychrotrophic microorganisms were also enumerated and samples were collected to verify the incidence of psychrotrophic clostridia in the abattoir environment. Vacuum-packed beef cuts (n=8 grossly distended and n=5 non-spoiled) and environmental samples were obtained from a beef packing plant located in the state of São Paulo, Brazil. Each sample was divided in three subsamples (exudate, beef surface and beef core) that were analyzed for vegetative forms, total spore-forming, and sulfide reducing spore-forming, both activated by alcohol and heat. Biochemical profiles of the isolates were obtained using API20A, with further identification using 16S rRNA gene sequencing. The growth temperature and the pH range were also assessed. Populations of psychrotrophic anaerobic vegetative microorganisms of up to 10(10)CFU/(g, mL or 100 cm(2)) were found in 'blown pack' samples, while in non-spoiled samples populations of 10(5)CFU/(g, CFU/mL or CFU/100 cm(2)) was found. Overall, a higher population of total spores and sulfide reducing spores activated by heat in spoiled samples was found. Clostridium gasigenes (n=10) and C. algidicarnis (n=2) were identified using 16S rRNA gene sequencing. Among the ten C. gasigenes isolates, six were from spoiled samples (C1, C2 and C9), two were isolated from non-spoiled samples (C4 and C5) and two were isolated from the hide and the abattoir corridor/beef cut conveyor belt. C. algidicarnis was recovered from spoiled beef packs (C2). Although some samples (C3, C7, C10 and C14) presented signs of 'blown pack' spoilage, Clostridium was not recovered. C. algidicarnis (n=1) and C. gasigenes (n=9) isolates have shown a psychrotrophic behavior, grew in the range 6.2-8.2. This is the first report on the isolation of psychrotrophic Clostridium (C

  20. Precipitation of sparingly soluble salts in packed sandbeds

    NASA Astrophysics Data System (ADS)

    Pavlakou, Efstathia I.; Sygouni, Varvara; Paraskeva, Christakis A.

    2015-04-01

    One of the main problems encountered by the oil extraction industry, is the reduction of the local permeability of the rock formation near the extraction wells because of salt deposition in the pores of the rocks during the injection of brine water to displace the trapped oil ganglia within the oil formations. This phenomenon makes the oil recovery less efficient and under extreme cases the well is abandoned with a large amount of oil entrapped. Several detailed studies have been conducted in the past concerning sand bed consolidation using sparingly soluble salts for varying conditions (e.g. temperature, grain size, sand type, salt concentrations etc) and various salts [1]. Nevertheless, salt precipitation in the rock formation pores under the presence of other miscible or immiscible substances with water has not been investigated in details yet. In the present study, salt (CaCO3) precipitation experiments were performed in small beds packed with sea sand mixed with a low amount of CaCO3 seed grains. The experiments were performed using pure solutions (NaHCO3, CaCl2.2H2O) and solutions mixed with Ethylene Glycol in sand beds. Additionally, precipitation experiments were performed using pure solutions in sand beds saturated with oil phase (n-dodecane) for a wide range of solution supersaturation. During the experiments the ionic strength was kept constant. pH and concentration values of calcium ion of the effluent were measured and the precipitated salt crystals were identified using X-ray Diffraction (XRD) method. At the end of each experiment Scanning Electron Microscope (SEM) was conducted using a sample of the precipitated sand to identify the morphology of the precipitated crystals and their cohesion with sand grains. Acknowledgments This research was partially funded by the European Union (European Social Fund-ESF) and Greek National Funds through the Operational program "Education and Lifelong Learning" under the action Aristeia II (Code No 4420). References

  1. From belt picking to bin packing

    NASA Astrophysics Data System (ADS)

    Balslev, Ivar; Eriksen, René D.

    2002-10-01

    We face the problem of computer-vision aided robot grasping of objects with more or less random positions. This field is of vital importance in the further progress in flexible automation of industrial processes, since conventional methods using fixtures and/or vibration bowls are expensive and inflexible. We study various types of disorder: A) visually isolated objects lying in distinct resting modes on a flat homogenous conveyer belt, B) partially occluded objects lying in distinct resting modes on a flat homogenous conveyer belt, C) visually separated objects, unrestricted object-camera pose, and fully surrounded by background, D) partially occluded objects, unrestricted relative orientation, but with a sizeable fraction of their contour detectable using foreground-background separation, E) partially occluded objects with unrestricted pose and no help from foreground-background separation. The cases A), B), and - to some extend - D) are encountered in belt picking, while case E) is true bin picking. Since physical storage of products and components in industry is based on deep containers with many layers of somewhat disordered objects, the belt-picking concept is only the first step for achieving flexible, unsupervised parts feeding. We have developed and tested a generic, fast, and easily trainable system for the cases A) and B). The system is unique because it handles the perspective effects exactly so there is no restriction concerning object dimensions relative to the distance to the camera. We report on a strategy to be used in treating case C) using the principles developed for the cases A-B). We discuss possible strategies to be employed when going all the way to cases of D) and E).

  2. 4. PACK TRAIN WAITING TO BE UNLOADED AT FOOT OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. PACK TRAIN WAITING TO BE UNLOADED AT FOOT OF YAKI TRAIL. APPROXIMATELY TWO-AND-ONE-HALF TONS OF STEEL ON ANIMALS SHOWN. NOTE COIL OF 1-1/2' WIND CABLE IN FOREGROUND. - Kaibab Trail Suspension Bridge, Spanning Colorado River, Grand Canyon, Coconino County, AZ

  3. Destabilization of confined granular packings due to fluid flow

    NASA Astrophysics Data System (ADS)

    Monloubou, Martin; Sandnes, Bjørnar

    2016-04-01

    Fluid flow through granular materials can cause fluidization when fluid drag exceeds the frictional stress within the packing. Fluid driven failure of granular packings is observed in both natural and engineered settings, e.g. soil liquefaction and flowback of proppants during hydraulic fracturing operations. We study experimentally the destabilization and flow of an unconsolidated granular packing subjected to a point source fluid withdrawal using a model system consisting of a vertical Hele-Shaw cell containing a water-grain mixture. The fluid is withdrawn from the cell at a constant rate, and the emerging flow patterns are imaged in time-lapse mode. Using Particle Image Velocimetry (PIV), we show that the granular flow gets localized in a narrow channel down the center of the cell, and adopts a Gaussian velocity profile similar to those observed in dry grain flows in silos. We investigate the effects of the experimental parameters (flow rate, grain size, grain shape, fluid viscosity) on the packing destabilization, and identify the physical mechanisms responsible for the observed complex flow behaviour.

  4. Packed bed heat storage: Continuum mechanics model and validation

    NASA Astrophysics Data System (ADS)

    Knödler, Philipp; Dreißigacker, Volker; Zunft, Stefan

    2016-05-01

    Thermal energy storage (TES) systems are key elements for various types of new power plant concepts. As possible cost-effective storage inventory option, packed beds of miscellaneous material come into consideration. However, high technical risks arise due to thermal expansion and shrinking of the packed bed's particles during cyclic thermal operation, possibly leading to material failure. Therefore, suitable tools for designing the heat storage system are mandatory. While particle discrete models offer detailed simulation results, the computing time for large scale applications is inefficient. In contrast, continuous models offer time-efficient simulation results but are in need of effective packed bed parameters. This work focuses on providing insight into some basic methods and tools on how to obtain such parameters and on how they are implemented into a continuum model. In this context, a particle discrete model as well as a test rig for carrying out uniaxial compression tests (UCT) is introduced. Performing of experimental validation tests indicate good agreement with simulated UCT results. In this process, effective parameters required for a continuous packed bed model were identified and used for continuum simulation. This approach is validated by comparing the simulated results with experimental data from another test rig. The presented method significantly simplifies subsequent design studies.

  5. Supramolecular Packing Controls H₂ Photocatalysis in Chromophore Amphiphile Hydrogels.

    PubMed

    Weingarten, Adam S; Kazantsev, Roman V; Palmer, Liam C; Fairfield, Daniel J; Koltonow, Andrew R; Stupp, Samuel I

    2015-12-01

    Light harvesting supramolecular assemblies are potentially useful structures as components of solar-to-fuel conversion materials. The development of these functional constructs requires an understanding of optimal packing modes for chromophores. We investigated here assembly in water and the photocatalytic function of perylene monoimide chromophore amphiphiles with different alkyl linker lengths separating their hydrophobic core and the hydrophilic carboxylate headgroup. We found that these chromophore amphiphiles (CAs) self-assemble into charged nanostructures of increasing aspect ratio as the linker length is increased. The addition of salt to screen the charged nanostructures induced the formation of hydrogels and led to internal crystallization within some of the nanostructures. For linker lengths up to seven methylenes, the CAs were found to pack into 2D crystalline unit cells within ribbon-shaped nanostructures, whereas the nine methylene CAs assembled into long nanofibers without crystalline molecular packing. At the same time, the different molecular packing arrangements after charge screening led to different absorbance spectra, despite the identical electronic properties of all PMI amphiphiles. While the crystalline CAs formed electronically coupled H-aggregates, only CAs with intermediate linker lengths showed evidence of high intermolecular orbital overlap. Photocatalytic hydrogen production using a nickel-based catalyst was observed in all hydrogels, with the highest turnovers observed for CA gels having intermediate linker lengths. We conclude that the improved photocatalytic performance of the hydrogels formed by supramolecular assemblies of the intermediate linker CA molecules likely arises from improved exciton splitting efficiencies due to their higher orbital overlap. PMID:26593389

  6. 7 CFR 51.2840 - Export packing requirements.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Export packing requirements. 51.2840 Section 51.2840 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE REGULATIONS AND STANDARDS UNDER THE...

  7. Learning To Change. A WEA Equal Opportunities Training Pack.

    ERIC Educational Resources Information Center

    Workers Educational Association, London (England).

    This training pack contains materials to help embed the principles of equal opportunities into the practice of part-time tutors and voluntary members of the Workers' Educational Association (WEA), a national voluntary organization dedicated to giving adults in the United Kingdom access to organized learning. Part 1 describes the rationale for the…

  8. 48 CFR 452.247-72 - Packing for Domestic Shipment.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 4 2011-10-01 2011-10-01 false Packing for Domestic Shipment. 452.247-72 Section 452.247-72 Federal Acquisition Regulations System DEPARTMENT OF AGRICULTURE CLAUSES AND FORMS SOLICITATION PROVISIONS AND CONTRACT CLAUSES Texts of Provisions and Clauses...

  9. 48 CFR 452.247-73 - Packing for Overseas Shipment.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 4 2011-10-01 2011-10-01 false Packing for Overseas Shipment. 452.247-73 Section 452.247-73 Federal Acquisition Regulations System DEPARTMENT OF AGRICULTURE CLAUSES AND FORMS SOLICITATION PROVISIONS AND CONTRACT CLAUSES Texts of Provisions and Clauses...

  10. 48 CFR 852.214-73 - Alternate packaging and packing.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false Alternate packaging and packing. 852.214-73 Section 852.214-73 Federal Acquisition Regulations System DEPARTMENT OF VETERANS AFFAIRS CLAUSES AND FORMS SOLICITATION PROVISIONS AND CONTRACT CLAUSES Texts of Provisions and Clauses...

  11. Disk Density Tuning of a Maximal Random Packing

    PubMed Central

    Ebeida, Mohamed S.; Rushdi, Ahmad A.; Awad, Muhammad A.; Mahmoud, Ahmed H.; Yan, Dong-Ming; English, Shawn A.; Owens, John D.; Bajaj, Chandrajit L.; Mitchell, Scott A.

    2016-01-01

    We introduce an algorithmic framework for tuning the spatial density of disks in a maximal random packing, without changing the sizing function or radii of disks. Starting from any maximal random packing such as a Maximal Poisson-disk Sampling (MPS), we iteratively relocate, inject (add), or eject (remove) disks, using a set of three successively more-aggressive local operations. We may achieve a user-defined density, either more dense or more sparse, almost up to the theoretical structured limits. The tuned samples are conflict-free, retain coverage maximality, and, except in the extremes, retain the blue noise randomness properties of the input. We change the density of the packing one disk at a time, maintaining the minimum disk separation distance and the maximum domain coverage distance required of any maximal packing. These properties are local, and we can handle spatially-varying sizing functions. Using fewer points to satisfy a sizing function improves the efficiency of some applications. We apply the framework to improve the quality of meshes, removing non-obtuse angles; and to more accurately model fiber reinforced polymers for elastic and failure simulations. PMID:27563162

  12. 7 CFR 319.37-9 - Approved packing material.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 5 2011-01-01 2011-01-01 false Approved packing material. 319.37-9 Section 319.37-9 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Nursery Stock, Plants, Roots, Bulbs,...

  13. 7 CFR 319.37-9 - Approved packing material.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 5 2010-01-01 2010-01-01 false Approved packing material. 319.37-9 Section 319.37-9 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Nursery Stock, Plants, Roots, Bulbs,...

  14. Hydrodynamics of Packed Bed Reactor in Low Gravity

    NASA Technical Reports Server (NTRS)

    Motil, Brian J.; Nahra, Henry K.; Balakotaiah, Vemuri

    2005-01-01

    Packed bed reactors are well known for their vast and diverse applications in the chemical industry; from gas absorption, to stripping, to catalytic conversion. Use of this type of reactor in terrestrial applications has been rather extensive because of its simplicity and relative ease of operation. Developing similar reactors for use in microgravity is critical to many space-based advanced life support systems. However, the hydrodynamics of two-phase flow packed bed reactors in this new environment and the effects of one physiochemical process on another has not been adequately assessed. Surface tension or capillary forces play a much greater role which results in a shifting in flow regime transitions and pressure drop. Results from low gravity experiments related to flow regimes and two-phase pressure drop models are presented in this paper along with a description of plans for a flight experiment on the International Space Station (ISS). Understanding the packed bed hydrodynamics and its effects on mass transfer processes in microgravity is crucial for the design of packed bed chemical or biological reactors to be used for water reclamation and other life support processes involving water purification.

  15. Optimizing packing fraction in granular media composed of overlapping spheres.

    PubMed

    Roth, Leah K; Jaeger, Heinrich M

    2016-01-28

    What particle shape will generate the highest packing fraction when randomly poured into a container? In order to explore and navigate the enormous search space efficiently, we pair molecular dynamics simulations with artificial evolution. Arbitrary particle shape is represented by a set of overlapping spheres of varying diameter, enabling us to approximate smooth surfaces with a resolution proportional to the number of spheres included. We discover a family of planar triangular particles, whose packing fraction of ϕ ∼ 0.73 is among the highest experimental results for disordered packings of frictionless particles. We investigate how ϕ depends on the arrangement of spheres comprising an individual particle and on the smoothness of the surface. We validate the simulations with experiments using 3D-printed copies of the simplest member of the family, a planar particle consisting of three overlapping spheres with identical radius. Direct experimental comparison with 3D-printed aspherical ellipsoids demonstrates that the triangular particles pack exceedingly well not only in the limit of large system size but also when confined to small containers.

  16. Particle shape effects on the stress response of granular packings.

    PubMed

    Athanassiadis, Athanasios G; Miskin, Marc Z; Kaplan, Paul; Rodenberg, Nicholas; Lee, Seung Hwan; Merritt, Jason; Brown, Eric; Amend, John; Lipson, Hod; Jaeger, Heinrich M

    2014-01-01

    We present measurements of the stress response of packings formed from a wide range of particle shapes. Besides spheres these include convex shapes such as the Platonic solids, truncated tetrahedra, and triangular bipyramids, as well as more complex, non-convex geometries such as hexapods with various arm lengths, dolos, and tetrahedral frames. All particles were 3D-printed in hard resin. Well-defined initial packing states were established through preconditioning by cyclic loading under given confinement pressure. Starting from such initial states, stress-strain relationships for axial compression were obtained at four different confining pressures for each particle type. While confining pressure has the largest overall effect on the mechanical response, we find that particle shape controls the details of the stress-strain curves and can be used to tune packing stiffness and yielding. By correlating the experimentally measured values for the effective Young's modulus under compression, yield stress and energy loss during cyclic loading, we identify trends among the various shapes that allow for designing a packing's aggregate behavior.

  17. Social Interactions Sparked by Pictorial Warnings on Cigarette Packs.

    PubMed

    Hall, Marissa G; Peebles, Kathryn; Bach, Laura E; Noar, Seth M; Ribisl, Kurt M; Brewer, Noel T

    2015-10-01

    The Message Impact Framework suggests that social interactions may offer smokers the opportunity to process pictorial warnings on cigarette packs more deeply. We aimed to describe adult smokers' social interactions about pictorial cigarette pack warnings in two longitudinal pilot studies. In Pilot Study 1, 30 smokers used cigarette packs with one of nine pictorial warnings for two weeks. In Pilot Study 2, 46 smokers used cigarette packs with one of five pictorial warnings for four weeks. Nearly all smokers (97%/96% in Pilot Study 1/2) talked about the warnings with other people, with the most common people being friends (67%/87%) and spouses/significant others (34%/42%). Pilot Study 2 found that 26% of smokers talked about the warnings with strangers. Discussions about the health effects of smoking and quitting smoking were more frequent during the first week of exposure to pictorial warnings than in the week prior to beginning the study (both p < 0.05). Pictorial warnings sparked social interactions about the warnings, the health effects of smoking, and quitting smoking, indicating that pictorial warnings may act as a social intervention reaching beyond the individual. Future research should examine social interactions as a potential mediator of the impact of pictorial warnings on smoking behavior. PMID:26506363

  18. Ruptured renal artery aneurysm: coil packing with GDCs.

    PubMed

    Takeuchi, Misako; Nakata, Manabu; Kawai, Akira; Suzuki, Kazumi; Morita, Tatsuo; Sugimoto, Hideharu

    2012-06-01

    Renal artery aneurysm (RAA) is a relatively uncommon occurrence, but it can be life-threatening when rupture (although rare) occurs. We present the successful endovascular treatment of a ruptured RAA, which was achieved by packing the aneurysm using Guglielmi and interlocking detachable coils.

  19. Frac packs maximize well productivity in sand control developments

    SciTech Connect

    Park, E.I.

    1995-08-01

    Historically, the installation of sand control hardware and treatments resulted in wells that did not achieve full production potential. Flow efficiencies of 25% or less were common and accepted as an unavoidable consequence of sand control. The production penalty paid for implementing sand control measures adversely affected the economic viability of many promising fields. A testament to the acceptance and utility of frac pack completions is evidenced by the numerous re-completions and re-activations of zones and fields that were not economic when evaluated with conventional sand control technology. BP`s current frac pack design and execution philosophies have evolved over 4 years of application in the Gulf of Mexico. The optimization efforts that have elevated frac packing to a mature, viable technology will be discussed. BP has executed more than 70 frac packs in new field developments, re-completions and workovers. Case studies from the Pompano, Amberjack and Ewing Bank 826 fields will demonstrate the range of applicability of the technique.

  20. Making One World: An Education Pack on Development and Environment.

    ERIC Educational Resources Information Center

    1992

    This pack contains activities aimed at 10-14 year-olds to help raise awareness of issues surrounding the environment and development and the concept of sustainable development. The Teachers' Notes outline the seven units of student activity sheets: (A) lifestyles (links between consumption, development, and the environment); (B) identifying the…

  1. Modeling water movement in beef cattle bedded manure pack

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bedded manure is a valuable fertilizer source because it contains essential macronutrients (nitrogen (N), phosphorus (P), and potassium (K)) for crop production. Previous research with beef cattle bedded manure packs demonstrated that water-soluble macronutrients accumulated toward the bottom of the...

  2. Interior view of the trimming and packing tables, ginaca machines ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Interior view of the trimming and packing tables, ginaca machines deliver pineapples from the left to the tables, view facing east - Kahului Cannery, Plant No. 28, Cannery Building and Dryer House/Feed Storage Building, 120 Kane Street, Kahului, Maui County, HI

  3. Packing and stability of geometrically cohesive granular media

    NASA Astrophysics Data System (ADS)

    Gravish, Nick; Franklin, Scott V.; Hu, David L.; Goldman, Daniel I.

    2011-11-01

    Granular particles with concave shapes may entangle with neighboring particles creating an effective cohesion controlled by particle geometry. We study the packing and stability of vertical columns formed from geometrically cohesive u-shaped particles (staples) of varying barb length, l. We prepare cohesive columns by packing particles in a confining cylindrical tube under vertical vibration at fixed frequency of f = 30 Hz and peak acceleration (in units of g) of Γ = 2 . The initial and final volume fraction vary with l and volume fraction increases for decreasing l. Once packed, the tube is removed and columns are subjected to vertical vibration at fixed f and variable Γ. We monitor column height, h (t) , during collapse and find that h (t) is described by a stretched exponential h (t) /h0 = exp [ -(t/τ)β ] . The characteristic collapse time, τ, is governed by an Arrhenius law with τ =τ0 exp (Γ0 / Γ) where Γ0 is a measure of the column's resistance to collapse. We find that Γ0 is a non-monotonic function of l and exhibits a maximum at intermediate l. We explain this effect through a model considering packing and entanglement.

  4. Packing bunkers and piles to maximize forage preservation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Forage is a valuable commodity stored on dairy farms. Bunker and pile silos have increased in use due to increasing herd size. Losses in feed value in bunker and pile silos are frequently higher than they should be because producers are not packing them sufficiently to exclude oxygen during the stor...

  5. Packing Bunker and Pile Silos to Minimize Porosity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This article discusses the issue of porosity (i.e., the portion of volume filled with gas) in silages. As porosity increases, the silage is subject to greater losses. Porosity can be reduced by adequately packing the crop at ensiling. To keep porosity below 40% a minimum bulk density of 44 lbs./cu. ...

  6. Flat pack interconnection structure simplifies modular electronic assemblies

    NASA Technical Reports Server (NTRS)

    Katzin, L.

    1967-01-01

    Flat pack interconnection structure composed of stick modules simplifies modular electronic assemblies by allowing a single axis mother board. Two of the wiring planes are located in the stick module, which is the lower level of assembly, with the third wiring plane in the mother board.

  7. Frac-and-pack stimulation: Application, design, and field experience

    SciTech Connect

    Roodhart, L.P.; Fokker, P.A.; Davies, D.R.; Shlyapobersky, J.; Wong, G.K.

    1994-03-01

    This paper discusses the criteria for selecting wells to be frac-and-packed. The authors show how systematic study of the inflow performance can be used to assess the potential of frac-and-packed wells, to identify the controlling factors, and to optimize design parameters. They also show that fracture conductivity is often the key to successful treatment. This conductivity depends largely on proppant size; formation permeability damage around the created fracture has less effect. Appropriate allowance needs to be made for flow restrictions caused by the presence of the perforations, partial penetration, and non-Darcy effects. They describe the application of the overpressure-calibrated hydraulic fracture model in frac-and-pack treatment design, and discuss some operational considerations with reference to field examples. The full potential of this promising new completion method can be achieved only if the design is tailored to the individual well. This demands high-quality input data, which can be obtained only from a calibration test. This paper presents their strategy for frac-and-pack design, drawing on examples from field experience. They also point out several areas that the industry needs to address, such as the sizing of proppant in soft formations and the interaction between fracturing fluids and resin in resin-coated proppant.

  8. Rapidly falling costs of battery packs for electric vehicles

    NASA Astrophysics Data System (ADS)

    Nykvist, Björn; Nilsson, Måns

    2015-04-01

    To properly evaluate the prospects for commercially competitive battery electric vehicles (BEV) one must have accurate information on current and predicted cost of battery packs. The literature reveals that costs are coming down, but with large uncertainties on past, current and future costs of the dominating Li-ion technology. This paper presents an original systematic review, analysing over 80 different estimates reported 2007-2014 to systematically trace the costs of Li-ion battery packs for BEV manufacturers. We show that industry-wide cost estimates declined by approximately 14% annually between 2007 and 2014, from above US$1,000 per kWh to around US$410 per kWh, and that the cost of battery packs used by market-leading BEV manufacturers are even lower, at US$300 per kWh, and has declined by 8% annually. Learning rate, the cost reduction following a cumulative doubling of production, is found to be between 6 and 9%, in line with earlier studies on vehicle battery technology. We reveal that the costs of Li-ion battery packs continue to decline and that the costs among market leaders are much lower than previously reported. This has significant implications for the assumptions used when modelling future energy and transport systems and permits an optimistic outlook for BEVs contributing to low-carbon transport.

  9. The Assignment Pack. Materials for Flexible and Open Learning.

    ERIC Educational Resources Information Center

    Adult Literacy and Basic Skills Unit, London (England).

    This assignment pack is designed for students and tutors working in open, flexible, or distance learning in Britain. Each of the six sections contains the following: (1) a detailed contents page that identifies the assignment under an activity heading, an individual title, and indication of the relationship to the City and Guilds of London…

  10. 21 CFR 890.5710 - Hot or cold disposable pack.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Hot or cold disposable pack. 890.5710 Section 890.5710 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5710 Hot or...

  11. 21 CFR 890.5710 - Hot or cold disposable pack.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Hot or cold disposable pack. 890.5710 Section 890.5710 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5710 Hot or...

  12. 21 CFR 890.5710 - Hot or cold disposable pack.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hot or cold disposable pack. 890.5710 Section 890.5710 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5710 Hot or...

  13. 21 CFR 890.5710 - Hot or cold disposable pack.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Hot or cold disposable pack. 890.5710 Section 890.5710 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5710 Hot or...

  14. 21 CFR 890.5710 - Hot or cold disposable pack.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Hot or cold disposable pack. 890.5710 Section 890.5710 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5710 Hot or...

  15. 48 CFR 1846.672-6 - Packing list instructions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Packing list instructions. 1846.672-6 Section 1846.672-6 Federal Acquisition Regulations System NATIONAL AERONAUTICS AND SPACE ADMINISTRATION CONTRACT MANAGEMENT QUALITY ASSURANCE Material Inspection and Receiving Reports 1846.672-6...

  16. Packed rod neutron shield for fast nuclear reactors

    DOEpatents

    Eck, John E.; Kasberg, Alvin H.

    1978-01-01

    A fast neutron nuclear reactor including a core and a plurality of vertically oriented neutron shield assemblies surrounding the core. Each assembly includes closely packed cylindrical rods within a polygonal metallic duct. The shield assemblies are less susceptible to thermal stresses and are less massive than solid shield assemblies, and are cooled by liquid coolant flow through interstices among the rods and duct.

  17. Social Interactions Sparked by Pictorial Warnings on Cigarette Packs

    PubMed Central

    Hall, Marissa G.; Peebles, Kathryn; Bach, Laura E.; Noar, Seth M.; Ribisl, Kurt M.; Brewer, Noel T.

    2015-01-01

    The Message Impact Framework suggests that social interactions may offer smokers the opportunity to process pictorial warnings on cigarette packs more deeply. We aimed to describe adult smokers’ social interactions about pictorial cigarette pack warnings in two longitudinal pilot studies. In Pilot Study 1, 30 smokers used cigarette packs with one of nine pictorial warnings for two weeks. In Pilot Study 2, 46 smokers used cigarette packs with one of five pictorial warnings for four weeks. Nearly all smokers (97%/96% in Pilot Study 1/2) talked about the warnings with other people, with the most common people being friends (67%/87%) and spouses/significant others (34%/42%). Pilot Study 2 found that 26% of smokers talked about the warnings with strangers. Discussions about the health effects of smoking and quitting smoking were more frequent during the first week of exposure to pictorial warnings than in the week prior to beginning the study (both p < 0.05). Pictorial warnings sparked social interactions about the warnings, the health effects of smoking, and quitting smoking, indicating that pictorial warnings may act as a social intervention reaching beyond the individual. Future research should examine social interactions as a potential mediator of the impact of pictorial warnings on smoking behavior. PMID:26506363

  18. 7 CFR 905.10 - Carton or standard packed carton.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 8 2012-01-01 2012-01-01 false Carton or standard packed carton. 905.10 Section 905.10 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE...

  19. 7 CFR 905.10 - Carton or standard packed carton.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 8 2011-01-01 2011-01-01 false Carton or standard packed carton. 905.10 Section 905.10 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE...

  20. 7 CFR 905.10 - Carton or standard packed carton.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Carton or standard packed carton. 905.10 Section 905.10 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE...

  1. 7 CFR 905.10 - Carton or standard packed carton.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 8 2014-01-01 2014-01-01 false Carton or standard packed carton. 905.10 Section 905.10 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE...

  2. 7 CFR 905.10 - Carton or standard packed carton.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 8 2013-01-01 2013-01-01 false Carton or standard packed carton. 905.10 Section 905.10 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE...

  3. Marginal stability in jammed packings: Quasicontacts and weak contacts

    NASA Astrophysics Data System (ADS)

    Kallus, Yoav; Torquato, Salvatore

    2014-08-01

    Maximally random jammed (MRJ) sphere packing is a prototypical example of a system naturally poised at the margin between underconstraint and overconstraint. This marginal stability has traditionally been understood in terms of isostaticity, the equality of the number of mechanical contacts and the number of degrees of freedom. Quasicontacts, pairs of spheres on the verge of coming in contact, are irrelevant for static stability, but they come into play when considering dynamic stability, as does the distribution of contact forces. We show that the effects of marginal dynamic stability, as manifested in the distributions of quasicontacts and weak contacts, are consequential and nontrivial. We study these ideas first in the context of MRJ packing of d-dimensional spheres, where we show that the abundance of quasicontacts grows at a faster rate than that of contacts. We reexamine a calculation of Jin et al. [Phys. Rev. E 82, 051126 (2010), 10.1103/PhysRevE.82.051126], where quasicontacts were originally neglected, and we explore the effect of their inclusion in the calculation. This analysis yields an estimate of the asymptotic behavior of the packing density in high dimensions. We argue that this estimate should be reinterpreted as a lower bound. The latter part of the paper is devoted to Bravais lattice packings that possess the minimum number of contacts to maintain mechanical stability. We show that quasicontacts play an even more important role in these packings. We also show that jammed lattices are a useful setting for studying the Edwards ensemble, which weights each mechanically stable configuration equally and does not account for dynamics. This ansatz fails to predict the power-law distribution of near-zero contact forces, P(f )˜fθ.

  4. Marginal stability in jammed packings: quasicontacts and weak contacts.

    PubMed

    Kallus, Yoav; Torquato, Salvatore

    2014-08-01

    Maximally random jammed (MRJ) sphere packing is a prototypical example of a system naturally poised at the margin between underconstraint and overconstraint. This marginal stability has traditionally been understood in terms of isostaticity, the equality of the number of mechanical contacts and the number of degrees of freedom. Quasicontacts, pairs of spheres on the verge of coming in contact, are irrelevant for static stability, but they come into play when considering dynamic stability, as does the distribution of contact forces. We show that the effects of marginal dynamic stability, as manifested in the distributions of quasicontacts and weak contacts, are consequential and nontrivial. We study these ideas first in the context of MRJ packing of d-dimensional spheres, where we show that the abundance of quasicontacts grows at a faster rate than that of contacts. We reexamine a calculation of Jin et al. [Phys. Rev. E 82, 051126 (2010)], where quasicontacts were originally neglected, and we explore the effect of their inclusion in the calculation. This analysis yields an estimate of the asymptotic behavior of the packing density in high dimensions. We argue that this estimate should be reinterpreted as a lower bound. The latter part of the paper is devoted to Bravais lattice packings that possess the minimum number of contacts to maintain mechanical stability. We show that quasicontacts play an even more important role in these packings. We also show that jammed lattices are a useful setting for studying the Edwards ensemble, which weights each mechanically stable configuration equally and does not account for dynamics. This ansatz fails to predict the power-law distribution of near-zero contact forces, P(f)∼f(θ).

  5. Consumer preferences for front-of-pack calories labelling

    PubMed Central

    van Kleef, Ellen; van Trijp, Hans; Paeps, Frederic; Fernández-Celemín, Laura

    2008-01-01

    Objective In light of the emerging obesity pandemic, front-of-pack calories labels may be an important tool to assist consumers in making informed healthier food choices. However, there is little prior research to guide key decisions on whether caloric content should be expressed in absolute terms or relative to recommended daily intake, whether it should be expressed in per serving or per 100 g and whether the information should be further brought alive for consumers in terms of what the extra calorie intake implies in relation to activity levels. The present study aimed at providing more insight into consumers’ appreciation of front-of-pack labelling of caloric content of food products and their specific preferences for alternative execution formats for such information in Europe. Design For this purpose, eight executions of front-of-pack calorie flags were designed and their appeal and information value were extensively discussed with consumers through qualitative research in four different countries (Germany, The Netherlands, France and the UK). Results The results show that calories are well-understood and that participants were generally positive about front-of-pack flags, particularly when flags are uniform across products. The most liked flags are the simpler flags depicting only the number of calories per serving or per 100 g, while more complex flags including references to daily needs or exercise and the flag including a phrase referring to balanced lifestyle were least preferred. Some relevant differences between countries were observed. Although participants seem to be familiar with the notion of calories, they do not seem to fully understand how to apply them. Conclusion From the results, managerial implications for the design and implementation of front-of-pack calorie labelling as well as important directions for future research are discussed. PMID:17601362

  6. High performance liquid chromatography column packings with deliberately broadened particle size distribution: relation between column performance and packing structure.

    PubMed

    Liekens, Anuschka; Billen, Jeroen; Sherant, Ron; Ritchie, Harald; Denayer, Joeri; Desmet, Gert

    2011-09-23

    The effect of the addition of 25%, 50% and 75% (weight percent, wt%) of larger particles (resp. 3 and 5 μm) to a commercial batch of 1.9 μm particles has been investigated as an academic exercise to study the effects of particle size distribution on the kinetic performance of packed bed columns in a magnified way. Comparing the performance of the different mixtures in a kinetic plot, it could be irrefutably shown that the addition of larger particles to a commercial batch of small particles cannot be expected to lead to an improved kinetic performance. Whereas the addition of 25 wt% of larger particles still only has a minor negative effect, a significantly deteriorated performance is obtained when 50 or 75 wt% of larger particles are added. In this case, separation impedance number increases up to 200% were observed. Studying the packing structure through computational packing simulations, together with the experimental determination of the external porosity, helped in understanding the obtained results. This showed that small particles tend to settle in the flow-through pores surrounding the larger particles, leading to very high packing densities (external porosities as low as 32% were observed) and also negatively influencing the column permeability as well as the band broadening (because of the broadened flow-through pore size range).

  7. Balance Problems

    MedlinePlus

    ... version of this page please turn Javascript on. Balance Problems About Balance Problems Have you ever felt dizzy, lightheaded, or ... dizziness problem during the past year. Why Good Balance is Important Having good balance means being able ...

  8. Packing, Scheduling and Covering Problems in a Game-Theoretic Perspective

    NASA Astrophysics Data System (ADS)

    Karlstrom, Leif

    Magma transport pathways through Earth's crust span 12--15 orders of magnitude in time and space, with unsteadiness at all scales. However emergent organization of this system is widespread, recorded by spatial loci of volcanism at the surface and large-scale, rapid outpourings of magma throughout the geologic record. This thesis explores several mechanisms for the organization and time evolution of magma transport, from the deep crust to the surface. A primary focus (Chapters 2--5) is the filling, stability and drainage of magma chambers, structures which function both as reservoirs feeding individual volcanic eruptions and as stalling points in the crust where magma accumulates and differentiation occurs. We show that magma chambers may dictate the spatio-temporal organization of magma rising through crust (Chapters 2--3), control the surface eruptive progression of extreme mantle melting events (Chapter 4), and actively set the size of calderas that form during shallow, crystal rich eruptions (Chapter 5). Each of these chapters explores variations on a hypothesis: interactions between magma chamber stresses and the rheology of surrounding crustal materials evolve during magma transport and this unsteady process helps determine the magnitude, location, and timing of surface eruptions. The last part of this thesis (Chapters 6--7) focuses on surface transport processes, the meandering of melt channels on the surface of glaciers and lava flows. We show that the meandering instability is a generic feature of flow over an erodable substrate, despite significantly different fluid characteristics and erosion mechanics.

  9. Solving the Problems of Designing and Teaching a Packed English for Specific Purposes Course

    ERIC Educational Resources Information Center

    Ho, Belinda

    2011-01-01

    Background: In an English for Specific Purposes (ESP) course offered to a department in a university in Hong Kong preparing the students for their internship, students were expected to learn to write and engage in spoken activities related to a number of documents over a period of 13 weeks. Having to achieve so many learning outcomes within so…

  10. A model for solving the prescribed burn planning problem.

    PubMed

    Rachmawati, Ramya; Ozlen, Melih; Reinke, Karin J; Hearne, John W

    2015-01-01

    The increasing frequency of destructive wildfires, with a consequent loss of life and property, has led to fire and land management agencies initiating extensive fuel management programs. This involves long-term planning of fuel reduction activities such as prescribed burning or mechanical clearing. In this paper, we propose a mixed integer programming (MIP) model that determines when and where fuel reduction activities should take place. The model takes into account multiple vegetation types in the landscape, their tolerance to frequency of fire events, and keeps track of the age of each vegetation class in each treatment unit. The objective is to minimise fuel load over the planning horizon. The complexity of scheduling fuel reduction activities has led to the introduction of sophisticated mathematical optimisation methods. While these approaches can provide optimum solutions, they can be computationally expensive, particularly for fuel management planning which extends across the landscape and spans long term planning horizons. This raises the question of how much better do exact modelling approaches compare to simpler heuristic approaches in their solutions. To answer this question, the proposed model is run using an exact MIP (using commercial MIP solver) and two heuristic approaches that decompose the problem into multiple single-period sub problems. The Knapsack Problem (KP), which is the first heuristic approach, solves the single period problems, using an exact MIP approach. The second heuristic approach solves the single period sub problem using a greedy heuristic approach. The three methods are compared in term of model tractability, computational time and the objective values. The model was tested using randomised data from 711 treatment units in the Barwon-Otway district of Victoria, Australia. Solutions for the exact MIP could be obtained for up to a 15-year planning only using a standard implementation of CPLEX. Both heuristic approaches can solve

  11. Pseudo-fivefold diffraction symmetries in tetrahedral packing.

    PubMed

    Lee, Stephen; Henderson, Ryan; Kaminsky, Corey; Nelson, Zachary; Nguyen, Jeffers; Settje, Nick F; Schmidt, Joshua Teal; Feng, Ji

    2013-07-29

    We review the way in which atomic tetrahedra composed of metallic elements pack naturally into fused icosahedra. Orthorhombic, hexagonal, and cubic intermetallic crystals based on this packing are all shown to be united in having pseudo-fivefold rotational diffraction symmetry. A unified geometric model involving the 600-cell is presented: the model accounts for the observed pseudo-fivefold symmetries among the different Bravais lattice types. The model accounts for vertex-, edge-, polygon-, and cell-centered fused-icosahedral clusters. Vertex-centered and edge-centered types correspond to the well-known pseudo-fivefold symmetries in Ih and D5h quasicrystalline approximants. The concept of a tetrahedrally-packed reciprocal space cluster is introduced, the vectors between sites in this cluster corresponding to the principal diffraction peaks of fused-icosahedrally-packed crystals. This reciprocal-space cluster is a direct result of the pseudosymmetry and, just as the real-space clusters, can be rationalized by the 600-cell. The reciprocal space cluster provides insights for the Jones model of metal stability. For tetrahedrally-packed crystals, Jones zone faces prove to be pseudosymmetric with one another. Lower and upper electron per atom bounds calculated for this pseudosymmetry-based Jones model are shown to accord with the observed electron counts for a variety of Group 10-12 tetrahedrally-packed structures, among which are the four known Cu/Cd intermetallic compounds: CdCu2, Cd3Cu4, Cu5Cd8, and Cu3Cd10. The rationale behind the Jones lower and upper bounds is reviewed. The crystal structure of Zn11Au15Cd23, an example of a 1:1 MacKay cubic quasicrystalline approximant based solely on Groups 10-12 elements is presented. This compound crystallizes in Im3 (space group no. 204) with a = 13.842(2) Å. The structure was solved with R1 = 3.53 %, I > 2σ; = 5.33 %, all data with 1282/0/38 data/restraints/parameters.

  12. 48 CFR 252.211-7004 - Alternate preservation, packaging, and packing.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... package gross weight and dimensions; (x) Packing; and (xi) Packing gross weight and dimensions; and (4) Item characteristics, to include— (i) Material and finish; (ii) Net weight; (iii) Net dimensions;...

  13. Comparison of the biological H2S removal characteristics among four inorganic packing materials.

    PubMed

    Hirai, M; Kamamoto, M; Yani, M; Shoda, M

    2001-01-01

    Four inorganic packing materials were evaluated in terms of their availability as packing materials of a packed tower deodorization apparatus (biofilter) from the viewpoints of biological H2S removal characteristics and some physical properties. Among porous ceramics (A), calcinated cristobalite (B), calcinated and formed obsidian (C), granulated and calcinated soil (D), the superiority of these packing materials determined based on the values of non-biological removal per unit weight or unit volume of packing material, complete removal capacity of H2S per unit weight of packing material per day or unit volume of packing material per day and pressure drop of the packed bed was in the order of A approximately equal to C > D approximately equal to B, which is correlated with the maximum water content, porosity, and mean pore diameter. PMID:16233011

  14. Comparison of the biological H2S removal characteristics among four inorganic packing materials.

    PubMed

    Hirai, M; Kamamoto, M; Yani, M; Shoda, M

    2001-01-01

    Four inorganic packing materials were evaluated in terms of their availability as packing materials of a packed tower deodorization apparatus (biofilter) from the viewpoints of biological H2S removal characteristics and some physical properties. Among porous ceramics (A), calcinated cristobalite (B), calcinated and formed obsidian (C), granulated and calcinated soil (D), the superiority of these packing materials determined based on the values of non-biological removal per unit weight or unit volume of packing material, complete removal capacity of H2S per unit weight of packing material per day or unit volume of packing material per day and pressure drop of the packed bed was in the order of A approximately equal to C > D approximately equal to B, which is correlated with the maximum water content, porosity, and mean pore diameter.

  15. CTEPP STANDARD OPERATING PROCEDURE FOR PACKING AND SHIPPING STUDY SAMPLES (SOP-3.11)

    EPA Science Inventory

    This SOP describes the methods for packing and shipping study samples. These methods are for packing and shipping biological and environmental samples. The methods have been tested and used in the previous pilot studies.

  16. Back pack injuries in Indian school children: risk factors and clinical presentations.

    PubMed

    Sharan, Deepak; Ajeesh, P S; Jose, Jerrish A; Debnath, Sukrit; Manjula, M

    2012-01-01

    The use of backpack increased substantially among the school children. Studies have shown that carrying a backpack cause to develop different symptoms of musculoskeletal disorders among the carrier of the backpack. In India there are fewer studies available in literature which explains the musculoskeletal discomfort among the school children. This study aimed at to find out the prevalence of different musculoskeletal problems among the school children. In a retrospective study data were collected for twenty two students. The main diagnostic criteria were pressure mark (redness or swelling) over neck and shoulder corresponding to the straps of the backpack, stooping posture while carrying the back pack, pain or stiffness in the neck, upper back and shoulders predominantly while carrying the back pack and absence of these symptoms during school holidays. Results revealed that pain in the upper back (40%), neck (27%) and shoulder (20%) were most prevalent body regions followed by forearm and wrist pain (7%) and low back (6%). Results further revealed that all the students participated in this study have a pressure mark over shoulder. 54.55% of the children were diagnosed with myofascial pain and rest with thoracic outlet syndrome. PMID:22316840

  17. Magnetic resonance velocity imaging of liquid and gas two-phase flow in packed beds.

    PubMed

    Sankey, M H; Holland, D J; Sederman, A J; Gladden, L F

    2009-02-01

    Single-phase liquid flow in porous media such as bead packs and model fixed bed reactors has been well studied by MRI. To some extent this early work represents the necessary preliminary research to address the more challenging problem of two-phase flow of gas and liquid within these systems. In this paper, we present images of both the gas and liquid velocities during stable liquid-gas flow of water and SF(6) within a packing of 5mm spheres contained within columns of diameter 40 and 27 mm; images being acquired using (1)H and (19)F observation for the water and SF(6), respectively. Liquid and gas flow rates calculated from the velocity images are in agreement with macroscopic flow rate measurements to within 7% and 5%, respectively. In addition to the information obtained directly from these images, the ability to measure liquid and gas flow fields within the same sample environment will enable us to explore the validity of assumptions used in numerical modelling of two-phase flows. PMID:19059796

  18. Calcium alginate fibre (Kaltostat 2) for nasal packing after trimming of turbinates--a pilot study.

    PubMed

    Sirimanna, K S

    1989-11-01

    Following surgical trimming of the inferior turbinates, 32 nostrils were packed with Calcium alginate fibre (Kaltostat 2 gramme fibre packs 80:20 per cent calcium:sodium) for 36-48 hours to achieve haemostasis. There was no bleeding while the packs were in place or after they were removed. These results were compared with two retrospective groups of patients who had undergone the same surgical procedure but the nostrils had been packed with alternative materials.

  19. Endoscopic removal of throat-packing gauze swallowed during general anesthesia.

    PubMed

    Iwai, Toshinori; Goto, Takahisa; Matsui, Yoshiro; Tohnai, Iwai

    2012-09-01

    Throat packing is commonly placed in the pharynx before starting oral and maxillofacial surgery under general anesthesia to protect the airway from aspiration of blood and surgical debris. Complications such as airway obstruction may arise if any of the throat packing is retained after extubation, and less commonly, swallowing of the throat packing has been reported. We report endoscopic removal of throat packing gauze swallowed during general anesthesia.

  20. Mobility of icy sand packs, with application to Martian permafrost

    USGS Publications Warehouse

    Durham, W.B.; Pathare, A.V.; Stern, L.A.; Lenferink, H.J.

    2009-01-01

    [1] The physical state of water on Mars has fundamental ramifications for both climatology and astrobiology. The widespread presence of "softened" Martian landforms (such as impact craters) can be attributed to viscous creep of subsurface ground ice. We present laboratory experiments designed to determine the minimum amount of ice necessary to mobilize topography within Martian permafrost. Our results show that the jammed-to-mobile transition of icy sand packs neither occurs at fixed ice content nor is dependent on temperature or stress, but instead correlates strongly with the maximum dry packing density of the sand component. Viscosity also changes rapidly near the mobility transition. The results suggest a potentially lower minimum volatile inventory for the impact-pulverized megaregolith of Mars. Furthermore, the long-term preservation of partially relaxed craters implies that the ice content of Martian permafrost has remained close to that at the mobility transition throughout Martian history. Copyright 2009 by the American Geophysical Union.

  1. Close-packed array of light emitting devices

    DOEpatents

    Ivanov, Ilia N.; Simpson, John T.

    2013-04-09

    A close-packed array of light emitting diodes includes a nonconductive substrate having a plurality of elongate channels extending therethrough from a first side to a second side, where each of the elongate channels in at least a portion of the substrate includes a conductive rod therein. The conductive rods have a density over the substrate of at least about 1,000 rods per square centimeter and include first conductive rods and second conductive rods. The close-packed array further includes a plurality of light emitting diodes on the first side of the substrate, where each light emitting diode is in physical contact with at least one first conductive rod and in electrical contact with at least one second conductive rod.

  2. Accumulation of BSA in Packed-bed Microfluidics

    NASA Astrophysics Data System (ADS)

    Summers, Samantha; Hu, Chuntian; Hartman, Ryan

    2012-11-01

    Alzheimers and Parkinsons are two diseases that are associated with protein deposition in the brain, causing loss of either cognitive or muscle functioning. Protein deposition diseases are considered progressive diseases since the continual aggregation of protein causes the patient's symptoms to slowly worsen over time. There are currently no known means of treatment for protein deposition diseases. Our goal is to understand the potential for packed-bed microfluidics to study protein accumulation. Measurement of the resistance to flow through micro-scale packed-beds is critical to understanding the process of protein accumulation. Aggregation in bulk is fundamentally different from accumulation on surfaces. Our study attempts to distinguish between either mechanism. The results from our experiments involving protein injection through a microfluidic system will be presented and discussed. Funding received by NSF REU Grant 1062611.

  3. An unusual case of predation: dog pack or cougar attack?

    PubMed

    Fonseca, Gabriel M; Palacios, Rocío

    2013-01-01

    Injuries produced by animals are capable of leaving severe patterns and in some cases may result in the death of the attacked individual. Law enforcement authorities may come to erroneous conclusions about the source of the bites based on their awareness of animals present and similarities of the injuries to the untrained eye, with dreadful consequences. Expertise of a carnivore biologist and an odontologist that indentifies the particularities of bite marks may be useful for identifying the attacking species. We present the investigation of a fatal dog pack attack involving a 43-year-old man in Bell Ville (Argentina) where the evidence provided by a forensic dentist and a biologist was categorical for establishing the animal species involved. Because of the unusual characteristics of the wounds and the initial hypothesis made by local authorities of a cougar attack, habits and specific patterns of both dog pack and cougar predation on humans are discussed. PMID:22971181

  4. Operation of Packed-Bed Reactors Studied in Microgravity

    NASA Technical Reports Server (NTRS)

    Motil, Brian J.; Balakotaiah, Vemuri

    2004-01-01

    The operation of a packed bed reactor (PBR) involves gas and liquid flowing simultaneously through a fixed-bed of solid particles. Depending on the application, the particles can be various shapes and sizes but are generally designed to force the two fluid phases through a tortuous route of narrow channels connecting the interstitial space. The PBR is the most common type of reactor in industry because it provides for intimate contact and high rates of transport between the phases needed to sustain chemical or biological reactions. The packing may also serve as either a catalyst or as a support for growing biological material. Furthermore, this type of reactor is relatively compact and requires minimal power to operate. This makes it an excellent candidate for unit operations in support of long-duration human space activities.

  5. Activated chemoreceptor arrays remain intact and hexagonally packed

    PubMed Central

    Briegel, Ariane; Beeby, Morgan; Thanbichler, Martin; Jensen, Grant J.

    2013-01-01

    Summary Bacterial chemoreceptors cluster into exquisitively sensitive, tunable, highly ordered, polar arrays. While these arrays serve as paradigms of cell signalling in general, it remains unclear what conformational changes transduce signals from the periplasmic tips, where attractants and repellents bind, to the cytoplasmic signalling domains. Conflicting reports support and contest the hypothesis that activation causes large changes in the packing arrangement of the arrays, up to and including their complete disassembly. Using electron cryotomography, here we show that in Caulobacter crescentus, chemoreceptor arrays in cells grown in different media and immediately after exposure to the attractant galactose all exhibit the same 12 nm hexagonal packing arrangement, array size and other structural parameters. ΔcheB and ΔcheR mutants mimicking attractant- or repellent-bound states prior to adaptation also show the same lattice structure. We conclude that signal transduction and amplification must be accomplished through only small, nanoscale conformational changes. PMID:21992450

  6. Anisotropy in Packing Structure and Elasticity of Sintered Spherical Particles

    NASA Astrophysics Data System (ADS)

    Kato, Hiroshi; Matsunaga, Chikako; Kurashige, Michio; Imai, Kazuwo

    By computer simulation, we estimated macroscopic elastic moduli of sintered equal-sized spherical particles. The simulation is composed of sequential accumulation of spheres and structural analysis of a “random network of 6-degree-freedom springs”, which is a mechanical model of “sintered particles”. From the examination of statistical characteristics of the random packings of spheres, we discovered that their packing structure is affected by gravity; more precisely, line segments connecting the centers of spheres in contact lie more frequently around the direction of 45° from the vertical (gravity) line, although they are uniformly distributed about the vertical line. This non-uniform zenithal frequency-distribution of segments makes, in turn, the sintered aggregates transversely isotropic in elasticity: Young's modulus in the vertical direction is roughly 17% larger than that in the horizontal direction. Our additional experiments using sintered glass-beads saturated with water support the simulated anisotropy.

  7. When do jammed sphere packings have a valid linear regime?

    NASA Astrophysics Data System (ADS)

    Goodrich, Carl; Liu, Andrea; Nagel, Sidney

    2014-03-01

    The physics of jamming can be studied in its purest form in packings of soft spheres at zero temperature. One of the successes of this approach is that bulk material properties, such as the elastic moduli or density of normal modes, can be predicted solely from the distance of the system to the jamming transition. Such properties are both defined and measured in the linear-response regime. It is thus tacitly assumed that the harmonic approximation to the local energy landscape can capture the meaningful physics, and it is therefore essential to delineate when this assumption is valid. We will examine the regime of validity of the harmonic approximation in jammed sphere packings as a function of system size and density. We will also discuss the crossover from linear response of the zero-temperature jammed solid to thermal behavior at nonzero temperatures.

  8. Molecular packing in bone collagen fibrils prior to mineralization

    NASA Astrophysics Data System (ADS)

    Hsiao, Benjamin; Zhou, Hong-Wen; Burger, Christian; Chu, Benjamin; Glimcher, Melvin J.

    2012-02-01

    The three-dimensional packing of collagen molecules in bone collagen fibrils has been largely unknown because even in moderately mineralized bone tissues, the organic matrix structure is severely perturbed by the deposition of mineral crystals. During the past decades, the structure of tendon collagen (e.g. rat tail) --- a tissue that cannot mineralize in vivo, has been assumed to be representative for bone collagen fibrils. Small-angle X-ray diffraction analysis of the native, uncalcified intramuscular fish bone has revealed a new molecular packing scheme, significantly different from the quasi-hexagonal arrangement often found in tendons. The deduced structure in bone collagen fibrils indicates the presence of spatially discrete microfibrils, and an arrangement of intrafibrillar space to form ``channels'', which could accommodate crystals with dimensions typically found in bone apatite.

  9. 21 CFR 161.173 - Canned wet pack shrimp in transparent or nontransparent containers.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 2 2011-04-01 2011-04-01 false Canned wet pack shrimp in transparent or... Specific Standardized Fish and Shellfish § 161.173 Canned wet pack shrimp in transparent or nontransparent containers. (a) Identity. (1) Canned wet pack shrimp is the food consisting of the processed meat of...

  10. 21 CFR 161.173 - Canned wet pack shrimp in transparent or nontransparent containers.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 2 2014-04-01 2014-04-01 false Canned wet pack shrimp in transparent or... Specific Standardized Fish and Shellfish § 161.173 Canned wet pack shrimp in transparent or nontransparent containers. (a) Identity. (1) Canned wet pack shrimp is the food consisting of the processed meat of...

  11. 21 CFR 161.173 - Canned wet pack shrimp in transparent or nontransparent containers.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 2 2013-04-01 2013-04-01 false Canned wet pack shrimp in transparent or... Specific Standardized Fish and Shellfish § 161.173 Canned wet pack shrimp in transparent or nontransparent containers. (a) Identity. (1) Canned wet pack shrimp is the food consisting of the processed meat of...

  12. 21 CFR 161.173 - Canned wet pack shrimp in transparent or nontransparent containers.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Canned wet pack shrimp in transparent or... Specific Standardized Fish and Shellfish § 161.173 Canned wet pack shrimp in transparent or nontransparent containers. (a) Identity. (1) Canned wet pack shrimp is the food consisting of the processed meat of...

  13. 21 CFR 161.173 - Canned wet pack shrimp in transparent or nontransparent containers.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 2 2012-04-01 2012-04-01 false Canned wet pack shrimp in transparent or... Specific Standardized Fish and Shellfish § 161.173 Canned wet pack shrimp in transparent or nontransparent containers. (a) Identity. (1) Canned wet pack shrimp is the food consisting of the processed meat of...

  14. 48 CFR 252.211-7004 - Alternate preservation, packaging, and packing.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ..., packaging, and packing. 252.211-7004 Section 252.211-7004 Federal Acquisition Regulations System DEFENSE... CLAUSES Text of Provisions And Clauses 252.211-7004 Alternate preservation, packaging, and packing. As prescribed in 211.272, use the following provision: Alternate Preservation, Packaging, and Packing (DEC...

  15. Stored grain pack factors for wheat: comparison of three methods to field measurements

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Storing grain in bulk storage units results in grain packing from overbearing pressure, which increases grain bulk density and storage-unit capacity. This study compared pack factors of hard red winter (HRW) wheat in vertical storage bins using different methods: the existing packing model (WPACKING...

  16. 48 CFR 252.211-7004 - Alternate preservation, packaging, and packing.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 3 2014-10-01 2014-10-01 false Alternate preservation, packaging, and packing. 252.211-7004 Section 252.211-7004 Federal Acquisition Regulations System DEFENSE... package gross weight and dimensions; (x) Packing; and (xi) Packing gross weight and dimensions; and...

  17. 49 CFR 173.129 - Class 5, Division 5.2-Assignment of packing group.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Class 5, Division 5.2-Assignment of packing group... Assignments and Exceptions for Hazardous Materials Other Than Class 1 and Class 7 § 173.129 Class 5, Division 5.2—Assignment of packing group. All Division 5.2 materials are assigned to Packing Group II...

  18. 21 CFR 133.125 - Cold-pack cheese food with fruits, vegetables, or meats.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 2 2011-04-01 2011-04-01 false Cold-pack cheese food with fruits, vegetables, or... for Specific Standardized Cheese and Related Products § 133.125 Cold-pack cheese food with fruits, vegetables, or meats. (a) Cold-pack cheese food with fruits, vegetables, or meats or mixtures of these is...

  19. 21 CFR 133.125 - Cold-pack cheese food with fruits, vegetables, or meats.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Cold-pack cheese food with fruits, vegetables, or... for Specific Standardized Cheese and Related Products § 133.125 Cold-pack cheese food with fruits, vegetables, or meats. (a) Cold-pack cheese food with fruits, vegetables, or meats or mixtures of these is...

  20. 21 CFR 133.125 - Cold-pack cheese food with fruits, vegetables, or meats.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 2 2012-04-01 2012-04-01 false Cold-pack cheese food with fruits, vegetables, or... for Specific Standardized Cheese and Related Products § 133.125 Cold-pack cheese food with fruits, vegetables, or meats. (a) Cold-pack cheese food with fruits, vegetables, or meats or mixtures of these is...