Straight Hook Research Articles

Analytic Investigation of Hooked Stirrups on Seismic Behavior of Reinforced Concrete 3D Frame Buildings

Ensuring the safety and stability of buildings during earthquakes is of utmost importance. This can be achieved by assessing the seismic performance of reinforced concrete structures with consideration of design details. This study focused on the seismic behavior of reinforced concrete buildings by comparing the effects of two different types of stirrups, namely those with a 135° angled end-hook shape and straight hooks, with variation of concrete strength. Pushover analysis of a sample building was performed to determine the effect of hook shape on stirrup reinforcement with a constant volumetric ratio for various concrete strength classes. The results of the analysis indicated significant differences in concrete strength and seismic behavior between the two stirrup configurations. The hooked stirrups demonstrated superior energy dissipation capability and ductility, which led to better seismic performance compared to unhooked stirrups across varying levels of concrete strength. To extend the investigation, the study compared the Mander et al., Kent–Scott–Park, and Kappos–Konstantinidis concrete models with different concrete classes (C50-C25-C20-C16-C10). The findings emphasized the importance of stirrup configuration in the design of earthquake-resistant structures. The study concluded that RC structural performance with the 135-degree hooked concrete members exhibited much better behavior of the 90-degree members for the various concrete strength. In this way, it has been revealed the arrangement and detailing of reinforcement in the construction beams and columns improves the governing effect on seismic structural performance.

Redescription of Illiosentis cetratus Van Cleave, 1945 (Acanthocephala: Illiosentidae) from Menticirrhus undulatus (Girard) in California, with notes on Illiosentis furcatus from Peru.

Illiosentis Van Cleave et Lincicome, 1939 initially included two species: Illiosentis furcatus Van Cleave et Lincicome, 1939 found in the West Atlantic from Cape Cod in Massachusetts, USA to northern Argentina and Illiosentis cetratus Van Cleave, 1945 with restricted distribution in the Pacific coast of southern California. We are reporting I. furcatus from Peru for the first time and describe a population of I. cetratus from the California corbina, Menticirrhus undulatus (Girard), from southern California. The proboscis hook formula was 14 longitudinal rows for I. furcatus of 18-23 hooks each compared to 16 rows of 19-24 hooks each reported by Van Cleave (1945). We complete the inadequate description of I. cetratus with new information on sexual differentiation in the length of the trunk, dorsal vs. ventral hooks, hook roots, trunk spines, two types of anterior recurved rooted hooks vs. posterior rootless straight hooks, measurements of dorsal and ventral hooks and spines, shape of hook roots, terminal position of the female gonopore, and of position of the cephalic ganglion at the anterior margin of the trunk. We also include new details of the reproductive system in both sexes including Saefftigen's pouch and cement gland ducts. We present new SEM and light microscope images. The Energy Dispersive X-ray analysis (EDXA) shows a high level of sulfur in anterior, middle and posterior hooks in various hook sites, as well as spectra of hook tips with a higher relative concentration of sulfur compared to other hook sites. For the placement of I. cetratus, phylogenetic analysis of sequences of three molecular markers, 18S, 28S rRNA and mitochondrial cox 1 genes, was performed with other related available sequences. The resulting analysis illustrated that I. cetratus was nested within a separate clade along with species of two genera, Dentitruncus truttae Sinzar, 1955 and Neotegorhynchus cyprini Lisitsyna, Xi, Orosová, Barčák et Oros, 2022 represented our species of Illiosentis separate from species of Tegorhynchus Van Cleave, 1921 (as also according to the morphology) with which the Illiosentis species were previously synonymised.

Paraketa balıkçılığında kullanılan farklı yemlerin avcılık performansı ve olta iğnesinde kalma oranı

In this study, the catch performance and remaining ratio on fishing hooks of natural alive mud shrimp (Upogebia pusilla) (CCK), siliconized mud shrimp (SCK) and siliconized pellet (SP) were investigated in a longline. The trials were carried out monthly between May 2016 and April 2017 in Zeytinlikuyu district of Kıyıkislacik Village – Milas-Mugla province. The main body diameter has 0.70 mm, leader and snoods have 0.40 mm. The snood length and distance is 1.5 m and 4.0 m, respectively. 14 no straight hooks were used. Totally 150 hooks, 50 for each bait were used and each bait was replaced in 25 hooks. The individuals caught during the samplings were separated as CCK, SCK and SP, and each individual was measured as the precision of mm the total length (TL) and weighted of 0.01 g. Totally 191 individuals from seven families with 18 different species were caught. Gilthead sea bream (Sparus aurata) was the abundant species with 48.7% in all bait type, and the followed by common pandora (Pagellus erythrinus) with 10.5%, common two-banded sea bream (Diplodus vulgaris) with 9.4% and annular sea bream (Diplodus annularis) with 8.9%. Of the 191 individuals, 55% (105 individuals) were caught with CCK, 33.5% (64 individuals) with SCK and 11.5% (22 individuals) with SP. The results of the trial with 3 different bait types were shoved that that there are significant differences between the catch rates of gilthead sea bream, annular and common two-banded sea bream (χ2, P<0.05). In paired tests between bait groups (CCK-SCK, CCK-SP and SCK-SP), there were no clear differences between the sizes of the individuals (ANOVA, P>0.05). Catch per unit effort (CPUE) values of CCK, SCK and SP were calculated as 0.05 n/h, 0.03 n/h and 0.01 n/h, respectively. In the same order, yield per unit effort (YPUE) values were determined as 7.28 g/h, 4.35 g/h and 2.99 g/h. When the remaining rate of baits on the hooks were evaluated, CCK gave the lowest rate with 6.32%2.01. It is thought that SCK should be used as an alternative particularly when natural mud shrimp cannot be utilized as alive or unable to be supplied due to the cold weather conditions and time restrictions. On the other hand, it is thought that performing such studies with bait made with natural binders such as gelatine instead of silicone will be extremely important in terms of less harm to both fish and nature.

Living in a Foster Home: The Single Subpolar Flagellum Fla1 of Rhodobacter sphaeroides.

Rhodobacter sphaeroides is an α-proteobacterium that has the particularity of having two functional flagellar systems used for swimming. Under the growth conditions commonly used in the laboratory, a single subpolar flagellum that traverses the cell membrane, is assembled on the surface. This flagellum has been named Fla1. Phylogenetic analyses have suggested that this flagellar genetic system was acquired from an ancient γ-proteobacterium. It has been shown that this flagellum has components homologous to those present in other γ-proteobacteria such as the H-ring characteristic of the Vibrio species. Other features of this flagellum such as a straight hook, and a prominent HAP region have been studied and the molecular basis underlying these features has been revealed. It has also been shown that FliL, and the protein MotF, mainly found in several species of the family Rhodobacteraceae, contribute to remodel the amphipathic region of MotB, known as the plug, in order to allow flagellar rotation. In the absence of the plug region of MotB, FliL and MotF are dispensable. In this review we have covered the most relevant aspects of the Fla1 flagellum of this remarkable photosynthetic bacterium.

Size Effect on Mechanical Properties of Rock-Like Materials with Three Joints

In order to study the size effect, failure mode and damage evolution process of rock-like materials with three joints, two rock-like materials with different sizes of joints were prepared for uniaxial compression tests. The digital image correlation technique was used to record the change characteristics of the apparent strain field, and an acoustic emission device was applied to record the damage process. The results show that the peak compressive strength of samples with the same joint inclination decreases with the increase of size. The peak compressive strength of samples decreases obviously when the joint inclination ranges from 0°–45° and 75°–90°. When the joint inclination ranges from 45° to 75°, the peak compressive strength of samples decreases insignificantly. With the increase of joint inclination, the peak compressive strength of the sample decreases gradually. It reaches the minimum when the joint inclination angle is 60°, and then the peak compressive strength steadily increased. It is prone to failure when the joint inclination is 60°. According to the crack propagation model, the failure modes of jointed samples can be divided into five failure modes: tension failure, airfoil tension failure, tension-shear mixed failure, shear failure and integral splitting failure. According to the damage curve, the damage evolution process can be divided into inverted L type, spoon type, S type and straight hook type. Large size samples and samples with joint inclination of 0°, 90° and 60° are prone to brittle failure and step damage.

Hook formation and joint strength in friction stir spot welding of Al alloy and Al–Si-coated hot-press forming steel

In the automotive industry, the demand for ultra-high-strength steel is increasing due to the CO2 emission and safety regulations. Hot-press forming (HPF) steels are a type of boron-alloyed high-strength steel fabricated via hot-press forming, which enables both high strength and elongation. Because HPF is conducted at high temperatures (900–950 °C) for a few minutes, its surface is coated with Al–Si or Zn to prevent surface oxidation and decarburizing. However, the coating layer often influences the properties of the welds. In this study, friction stir spot welding (FSSW) is used to weld dissimilar metals, i.e., an Al alloy and Al–Si-coated HPF steel. The effects of Al–Si coating on the mechanical and metallurgical properties of the hook formation on the weld are investigated. The shape of the hook, which is formed during FSSW, changes from bent to straight shape due to the presence of Al–Si and the HPF process. The joint strength of the straight hook-shaped specimens is demonstrated to be lower than that of the bent hook-shaped specimens. This difference in strength is because the hard Fe–Al–Si intermetallic (IMC) layer on the outer surface of the hook disturbs the bending of the hook during the welding. On the outer surface of the hook, a Fe–Al–Si IMC layer of chemical composition similar to that of the coating layer formed during HPF is observed. This formation is different from the inner surface of the hook, wherein a thin Fe–Al IMC layer is reconstructed between aluminum and steel. Thus, the hard Fe–Al–Si intermetallic layer transformed during the HPF process is the primary cause of the straight hook shape.

A triangular loop of domain D1 of FlgE is essential for hook assembly but not for the mechanical function

The bacterial flagellar hook is a short, curved tubular structure made of FlgE. The hook connects the basal body as a rotary motor and the filament as a helical propeller and functions as a universal joint to smoothly transmit torque produced by the motor to the filament. Salmonella FlgE consists of D0, Dc, D1 and D2 domains. Axial interactions between a triangular loop of domain D1 (D1-loop) and domain D2 are postulated to be responsible for hook supercoiling. In contrast, Bacillus FlgE lacks the D1-loop and domain D2. Here, to clarify the roles of the D1-loop and domain D2 in the mechanical function, we carried out deletion analysis of Salmonella FlgE. A deletion of the D1-loop conferred a loss-of-function phenotype whereas that of domain D2 did not. The D1-loop deletion inhibited hook polymerization. Suppressor mutations of the D1-loop deletion was located within FlgD, which acts as the hook cap to promote hook assembly. This suggests a possible interaction between the D1-loop of FlgE and FlgD. Suppressor mutant cells produced straight hooks, but retained the ability to form a flagellar bundle behind a cell body, suggesting that the loop deletion does not affect the bending flexibility of the Salmonella hook.

长挡板结构型式对竖缝式鱼道鱼池流速影响研究

大坝和堤堰等水工建筑物的修建截断了河流，使河流中鱼类的栖息地及洄游路线受到极为严重的干扰。为了解决鱼类的洄游问题，修建鱼道是广泛采用的工程措施，其中，以竖缝式鱼道的数量居多。本文从竖缝式鱼道的长挡板细部构造入手，通过模型实验的手段，对比分析了三种方案对竖缝式鱼道鱼池流速的影响。通过研究，推荐竖缝式鱼道的长挡板结构型式为“直钩”型。 The construction of dam and burrock blocks the river basin, and affects the migratory route of fishes. Fishways are widely used as engineering measures to guarantee the migration of fish. The vertical slot fishway is the most common type. This paper presents the results of an experimental work with three different long baffle schemes on the vertical slot fishway. The values of velocity are indicated by the results. Above all three schemes, “straight hook” type is recommended as the type for long baffle structure of the vertical slot fishway.

Design Issues about the Bar Lay-Out at the Dapped Ends of Simply-Supported One-Way R/C Slabs

Directly-or indirectly-supported R/C slabs are frequently used in the covers of small-to-medium underground facilities, where the service loads are often rather limited, but very severe loads cannot be ruled out in accidental situations.To have fresh information on the structural performance and cracking of R/C slabs simply supported along their short sides via corbels (dapped ends), four rectangular slabs subjected to transversely distributed or concentrated loads have been recently tested in Milan (b x L = 1.30 x 2.20 m; simply-supported span = 2.10 m; thickness = 15 cm). The load was applied either at mid-span (in the bending tests, not presented in this paper), or at 1/10 of the span (in the shear tests).Two bar arrangements were investigated with straight or bent-up bars in the main body, and straight bars or hooks in the corbels.In the D zones of the slabs tested in shear, the concentrated load induces a rather complex 3-D crack pattern, with a limited reduction in the bearing capacity, compared with the cross-wise distributed load.Rather simple strut-and-tie models applied to the slabs with bent-up bars and hooks, and the equations provided by European and North-American codes for the beams devoid of transverse reinforcement are shown to yield realistic predictions for the bearing capacity at the ultimate limit state. In the former case, however, modelling the bond along the tension reinforcement of the corbel requires some care, because of bond local and global effects. Last but not least, refining bar layout confirms – once more – that slab performance can be markedly improved with little extra effort.

Experimental failure study of friction stir spot welded similar and dissimilar aluminum alloys

In this paper, it has been presented that with macroscopic study of nugget and using “effective distance” (ED) index, the reason of different strength of joints, which are welded with different parameters and from different materials, can be explained. Welds that have longer ED carry more static lodes compared to others. ED is the linear distance of Hook tip, i.e., the separation point of two overlapped sheets in partially bounded region which is crack initiation point, and keyhole. It has presented that Hook tip geometry also is an important factor that affects joint strength. The zig-zag Hook tip type is present at high strength welds while straight Hook tip can be seen for low strength joints. Lower tool rotational speed and higher tool plunge rate result longer ED and higher shear strength. ED is shorter for joints that are welded from dissimilar alloys compared to similar ones and joint strength differs similarly. The highest shear strength was 3050 N which was obtained with specimen that was welded from similar 6063-T3 aluminum sheets with tool rotational speed of 800 rpm and tool plunge rate of 80 mm/min. For this specimen, effective distance was 2025 μm.

FliA expression analysis and influence of the regulatory proteins RpoN, FleQ and FliA on virulence and in vivo fitness in Legionella pneumophila

In Legionella pneumophila, the regulation of the flagellum and the expression of virulence traits are linked. FleQ, RpoN and FliA are the major regulators of the flagellar regulon. We demonstrated here that all three regulatory proteins mentioned (FleQ, RpoN and FliA) are necessary for full in vivo fitness of L. pneumophila strains Corby and Paris. In this study, we clarified the role of FleQ for fliA expression from the level of mRNA toward protein translation. FleQ enhanced fliA expression, but FleQ and RpoN were not necessary for basal expression. In addition, we identified the initiation site of fliA in L. pneumophila and found a putative σ(70) promoter element localized upstream. The initiation site was not influenced in the ΔfleQ or ΔrpoN mutant strain. We demonstrated that there is no significant difference in the regulation of fliA between strains Corby and Paris, but the FleQ-dependent induction of fliA transcription in the exponential phase is stronger in strain Paris than in strain Corby. In addition, we showed for the first time the presence of a straight hook at the pole of the non-flagellated ΔfliA and ΔfliD mutant strains by electron microscopy, indicating the presence of an intact basal body in these strains.

The effects of flagellar hook compliance on motility of monotrichous bacteria: A modeling study

A crucial structure in the motility of flagellated bacteria is the hook, which connects the flagellum filament to the motor in the cell body. Early mathematical models of swimming bacteria assume that the helically shaped flagellum rotates rigidly about its axis, which coincides with the axis of the cell body. Motivated by evidence that the hook is much more flexible than the rest of the flagellum, we develop a new model that allows a naturally straight hook to bend. Hook dynamics are based on the Kirchhoff rod model, which is combined with a boundary element method for solving viscous interactions between the bacterium and the surrounding fluid. For swimming in unbounded fluid, we find good support for using a rigid model since the hook reaches an equilibrium configuration within several revolutions of the motor. However, for effective swimming, there are constraints on the hook stiffness relative to the scale set by the product of the motor torque with the hook length. When the hook is too flexible, its shape cannot be maintained and large deformations and stresses build up. When the hook is too rigid, the flagellum does not align with the cell body axis and the cell “wobbles” with little net forward motion. We also examine the attraction of swimmers to no-slip surfaces and find that the tendency to swim steadily close to a surface can be very sensitive to the combination of the hook rigidity and the precise shape of the cell and flagellum.

A new species of the genus Polyrhanis Rivalier, 1963 (Coleoptera: Cicindelidae) from Papua (New Guinea, Indonesia)

A new tiger beetles species, Polyrhanis dabraensis sp. nov., is described from Dabra (Foja mountains region, Papua, New Guinea, Indonesia). Its elytral markings are similar to those of Polyrhanis funerata and P. barbata, but it is much smaller and its anteapical spot is more expanded on the disc and is connected with the apical lunule. The aedeagus has a thin straight hook (spur) directed perpendicularly on the dorsal side, like that of P. io, P. innocentior, P. excisilabris, P. olthofi, and P. vannideki. It is easily recognized by its distinctive elytral markings and small body size.

Failure Analysis and Design Improvements of MEMS Explosive Interrupter

Due to deformation of the cantilever and lock, the MEMS explosion interrupter used in fuze often cannot move properly. An explosion interrupter with improved strength is proposed. The caudal shape of the cantilever is improved and its structure is changing from the straight hook to the bend hook. The thickness and the patulous angle of the lock is enhanced. Simulation results show that the improved caudal shape of the cantilever is not stuck by the baseplate boss and the improved lock could enter into the locker successfully. The explosion interrupter moves in-position under centrifugal force and be locked.

The Effect of Circle Hooks and Straight (J) Hooks on the Catch Rates and Numbers of White Marlin and Blue Marlin Released Alive by the U.S. Pelagic Longline Fleet in the Gulf of Mexico

AbstractThe effect of circle and straight (J) hooks on the catch rates of white marlin Kajikia albida (formerly Tetrapturus albidus) and blue marlin Makaira nigricans and the proportions released alive by the U.S. pelagic longline fleet targeting yellowfin tuna Thunnus albacares in the Gulf of Mexico was assessed with data collected by scientific observers aboard commercial vessels between 1992 and 2004. Catch rates were lower with circle hooks than with straight hooks, but the differences were not significant; while the catch rates of the targeted species, yellowfin tuna, were the same for both hook types. However, a significantly higher proportion of marlins was released alive from circle hooks than from J hooks.

The hook gene (flgE) is expressed from the flgBCDEF operon in Rhodobacter sphaeroides: study of an flgE mutant.

In this work we identified the flgE gene encoding the flagellar hook protein from Rhodobacter sphaeroides. Our results show that this gene is part of a flagellar cluster that includes the genes flgB, flgC, flgD, flgE, and flgF. Two different types of mutants in the flgE gene were isolated, and both showed a Fla(-) phenotype, indicating the functionality of this sequence. Complementation studies of these mutant strains suggest that flgE is included in a single transcriptional unit that starts in flgB and ends in flgF. In agreement with this possibility, a specific transcript of approximately 3.5 kb was identified by Northern blot. This mRNA is large enough to represent the complete flgBCDEF operon. FlgE showed a relatively high proline content; in particular, a region of 12 amino acids near the N terminus, in which four prolines were identified. Cells expressing a mutant FlgE protein lacking this region showed abnormal swimming behavior, and their hooks were curved. These results suggest that this region is involved in the characteristic quaternary structure of the hook of R. sphaeroides and also imply that a straight hook, or perhaps the rigidity associated with this feature, is important for an efficient swimming behavior in this bacterium.