Early-life-history profiles, seasonal abundance, and distribution of four species of Clupeid larvae from the northern Gulf of Mexico, 1982 and 1983

We present data on ichthyoplankton distribution, abundance, and seasonality and supporting environmental information for four species of coastal pelagics from the family Clupeidae: round herring Etrumeus teres, scaled sardine Harengula jaguana, Atlantic thread herring Opisthonema oglinum, and Spanish sardine Sardinella aurita. Data are from 1982 and 1983 cruises across the northern Gulf of Mexico sponsored by the Southeastern Area Monitoring and Assessment Program (SEAMAP). This is the first such examination for these species on a multiyear and gulfwide scale. Bioproflles on reproductive biology, early life history, meristics, adult distribution, and fisheries characteristics are also presented for these species. During the summer, larval Atlantic thread herring and scaled and Spanish sardines were abundant on the inner shelf <40 m depth), but were rare or absent in deeper waters. Scaled sardine and thread herring were found virtually everywhere inner-shelf waters were sampled, but Spanish sardines were rare in the north-central Gulf. During 1982, larval Atlantic thread herring were the most abundant of the four target c1upeid species, whereas Spanish sardine were the most abundant during 1983. On the west Florida shelf, Spanish sardine dominated larval c1upeid populations both years. Scaled sardine larvae were the least abundant of the four species both years, but were still captured in 25% of inner-shelf bongo net collections. Round herring larvae, collected February-early June (primarily March-April), were abundant on the outer shelf (40-182 m depth) and especially off Louisiana. Over the 2-year period, outer-shelf mean abundance for round herring was 40.2 larvae/10 m2; inner-shelf mean abundances for scaled sardine, Atlantic thread herring, and Spanish sardine were 14.9, 39.2, and 41.9 larvae/l0 m2, respectively. (PDF file contains 66 pages.

Real-time depth sectioning: Isolating the effect of stress on structure development in pressure-driven flow

Transient structure development at a specific distance from the channel wall in a pressure-driven flow is obtained from a set of real-time measurements that integrate contributions throughout the thickness of a rectangular channel. This “depth sectioning method” retains the advantages of pressure-driven flow while revealing flow-induced structures as a function of stress. The method is illustrated by applying it to isothermal shear-induced crystallization of an isotactic polypropylene using both synchrotron x-ray scattering and optical retardance. Real-time, depth-resolved information about the development of oriented precursors reveals features that cannot be extracted from ex-situ observation of the final morphology and that are obscured in the depth-averaged in-situ measurements. For example, at 137 °C and at the highest shear stress examined (65 kPa), oriented thread-like nuclei formed rapidly, saturated within the first 7 s of flow, developed significant crystalline overgrowth during flow and did not relax after cessation of shear. At lower stresses, threads formed later and increased at a slower rate. The depth sectioning method can be applied to the flow-induced structure development in diverse complex fluids, including block copolymers, colloidal systems, and liquid-crystalline polymers

Design characteristics, primary stability and risk of fracture of orthodontic mini-implants: pilot scan electron microscope and mechanical studies

Objectives: Orthodontic mini-implants (OMIs) are increasingly used in orthodontics but can fail for various reasons. This study investigates the effects of OMI design characteristics on the mechanical properties in artificial bone. Material and Methods: Twelve self-drilling OMIs (2 small, 6 medium, 4 large) from 8 manufacturers were tested for their primary stability in simulated medium-high cancellous bone and the risk to fracture in high-density methacrylate blocks. For the assessments of the maximum insertion torque (IT) and torsional fracture (TF) 5 of each OMI were used and for the pull-out strength (POS) 10. The OMIs were inserted with a torque screwdriver (12 sec/360°) until the bottom at 8 mm depth was reached. OMI designs were analyzed with a scan electron mi - croscope (SEM). Results: SEM images revealed a great variation in product refinement. In the whole sample, a cylindrical OMI shape was associated with higher POS (p<0.001) but lower IT (p=0.002) values. The outer and inner OMI di - ameters were design characteristics well correlated with POS, IT and TF values (ranging from 0.601 to 0.961). Greater thread depth was related to greater POS values (r= 0.628), although OMIs with similar POS values may have different IT values. Thread depth and pitch had some impact on POS. TF depended mainly on the OMI inner (r= 0.961) and outer diameters (r=0.892). A thread depth to outer diameter ratio close to 40% increased TF risk. Conclusions: Although at the same insertion depth the OMI outer and inner diameters are the most important fac - tors for primary stability, other OMI design characteristics (cylindrical vs. conical, thread design) may significantly affect primary stability and torsional fracture. This needs to be considered when selecting the appropriate OMI for the desired orthodontic procedures

Дослідження міцності роз'ємного різьбового з'єднання з великим кроком в деталях з армованих композиційних матеріалів

З метою дослідження міцності, запропонованого роз’ємного з’єднання для деталей з армованих композиційних матеріалів (АКМ), були проведені дослідження зі зміною основних параметрів що найбільше впливають на працездатність з’єднання. Для запропонованого з’єднання, круглої різьби з великим кроком, змінювалися такі основі параметри я крок різьби р та глибина профілю різьби t. Отримані значення сили, дозволили встановити, що запропоноване роз’ємне з’єднання за характеристиками міцності, при всіх встановлених параметрах наближається, за показниками міцності, до з’єднання з аналогічними параметрами виконаному в металі. За рахунок виконання повного факторного експерименту за класичною схемою його виконання, були встановлені основні параметри при яких показники міцності будуть найкращими, для нашого випадку значення кроку різьби складатиме р = 4 мм, а значення глибини профілю різьби t = 0.9 мм.With the purpose of research of durability, offered sectional connection for details from the reinforced composition materials (RCМ), there were undertaken studies with the change of basic parameters that most influence on the capacity of connection. For the offered connection, round screw-thread with a stride, such parameters as step of screw-thread of р and depth of profile of screw-thread of t changed. These basic parameters varied within the following limits step of screw-thread p in the range from 1 to 4 mm, and depth of profile of screw-thread t is from 0.5 to 1 mm. Mechanical processing of this connection was carried out on the newly developed technology, the detailed processing technology described in [1]. For processing, a CNC milling machine was used. Experimental strength tests were carried out using special equipment, a universal rupture machine P20. The threaded connection was made in a plate of 190x107x16 mm, the material from which the specified plate was made of fiberglass (0.5 to 0.5 mm gratings) 0.2 mm thick and EPOXY-520 epoxy resin. Got values of force, allowed to set that sectional connection on descriptions of durability, at all set parameters approached, on the indexes of durability, to connection, with analogical parameters executed in a metal. Due to implementation of complete factor experiment on the classic chart of his implementation, basic parameters were set at that indexes of durability will be the best, for our case a step of screw-thread will be р = 4 mm, and value of depth of profile of screw-thread of t = 0.9 mm

Research into strength of the thread detached connection with a large pitch of thread in designs made of reinforced composite material

З метою дослідження міцності, запропонованого роз’ємного з’єднання для деталей з армованих композиційних матеріалів (АКМ), були проведені дослідження зі зміною основних параметрів що найбільше впливають на працездатність з’єднання. Для запропонованого з’єднання, круглої різьби з великим кроком, змінювалися такі основі параметри я крок різьби р та глибина профілю різьби t. Отримані значення сили, дозволили встановити, що запропоноване роз’ємне з’єднання за характеристиками міцності, при всіх встановлених параметрах наближається, за показниками міцності, до з’єднання з аналогічними параметрами виконаному в металі. За рахунок виконання повного факторного експерименту за класичною схемою його виконання, були встановлені основні параметри при яких показники міцності будуть найкращими, для нашого випадку значення кроку різьби складатиме р = 4 мм, а значення глибини профілю різьби t = 0.9 мм.With the purpose of research of durability, offered sectional connection for details from the reinforced composition materials (RCМ), there were undertaken studies with the change of basic parameters that most influence on the capacity of connection. For the offered connection, round screw-thread with a stride, such parameters as step of screw-thread of р and depth of profile of screw-thread of t changed. These basic parameters varied within the following limits step of screw-thread p in the range from 1 to 4 mm, and depth of profile of screw-thread t is from 0.5 to 1 mm. Mechanical processing of this connection was carried out on the newly developed technology, the detailed processing technology described in [1]. For processing, a CNC milling machine was used. Experimental strength tests were carried out using special equipment, a universal rupture machine P20. The threaded connection was made in a plate of 190x107x16 mm, the material from which the specified plate was made of fiberglass (0.5 to 0.5 mm gratings) 0.2 mm thick and EPOXY-520 epoxy resin. Got values of force, allowed to set that sectional connection on descriptions of durability, at all set parameters approached, on the indexes of durability, to connection, with analogical parameters executed in a metal. Due to implementation of complete factor experiment on the classic chart of his implementation, basic parameters were set at that indexes of durability will be the best, for our case a step of screw-thread will be р = 4 mm, and value of depth of profile of screw-thread of t = 0.9 mm

Experimental analysis of the fatigue life of threaded pipe connections under cyclic bending

When subjected to cyclic loads, fatigue cracks can cause failure of pipe systems joined by threaded pipe connections. In this study, the effect of contact conditions and coupling geometry is investigated experimentally. Fatigue tests under cyclic bending are carried out on three different threaded connection configurations. The resulting fatigue lives are compared and fracture surfaces are investigated. The fatigue cracks are found to initiate at the last engaged thread of the pin and fatigue life can be increased by applying PTFE tape or changing the coupling geometry

Parallel Wavelet Tree Construction

We present parallel algorithms for wavelet tree construction with polylogarithmic depth, improving upon the linear depth of the recent parallel algorithms by Fuentes-Sepulveda et al. We experimentally show on a 40-core machine with two-way hyper-threading that we outperform the existing parallel algorithms by 1.3--5.6x and achieve up to 27x speedup over the sequential algorithm on a variety of real-world and artificial inputs. Our algorithms show good scalability with increasing thread count, input size and alphabet size. We also discuss extensions to variants of the standard wavelet tree.Comment: This is a longer version of the paper that appears in the Proceedings of the IEEE Data Compression Conference, 201

Transmission protocols for instruction streams

Threads as considered in thread algebra model behaviours to be controlled by some execution environment: upon each action performed by a thread, a reply from its execution environment -- which takes the action as an instruction to be processed -- determines how the thread proceeds. In this paper, we are concerned with the case where the execution environment is remote: we describe and analyse some transmission protocols for passing instructions from a thread to a remote execution environment.Comment: 13 page