Simple Connection Research Articles

Elementary Slender Soft Robots Inspired by Skeleton Joint System of Animals.

In this article, we demonstrate elementary slender soft robots mimicking the skeleton joint system of animals with excellent locomotion performance and scalability. Inspired from bending characteristics of mammal joints, the soft joint, consisting of two Pneu-nets (PNs), one with three chambers and the other with two chambers, was developed. By using simple constraints and connections, the soft joint can be separately controlled by 180° bending and unbending, and exhibits large force output with limited volume and deformation. Then, a skeleton joint-like slender robot was proposed by including a different number of the soft joint and stiff skeleton for different functionalities. This robot exhibits excellent locomotion performance due to the skeleton joint design to achieve large deformation level and proper selection of gait to fully utilize the skeleton joint-like motion, that is, moving 0.5 body length per loading cycle and navigating both continuous terrains, such as a slope, and unprecedented terrains with "discrete" obstacles, such as a wall and stairs. Besides, the slender soft robot is scalable in joint and skeleton, and additional tuning joints can be introduced to achieve turning and spinning locomotion. The slender robot presented herein has not only the advantages of simple fabrication, light weight, good adaptability and scalability, and human-friendly interface but also provides insights for future development of mobile soft robots.

Beam-to-beam eccentric end plate connections - Experimental comparison to fin plate and partial-depth end plate connections

This paper presents a study of eccentric end plate (EEP) beam-to-beam connections as a non-standard detailed design presented in SCI P358 and commonly used for complex geometries where standard simple connections are not suitable. The rotational capacity of EEP connections is often questioned since it should theoretically be a nominally-pinned connection. In this study the rotational behaviour is investigated with a series of moment-rotation experiments and then compared with another two simple connections; a fin plate (FP) connection, and a partial-depth end plate (PDEP_ connection). It is concluded that the EEP connection is semi-rigid with a higher stiffness and strength than the FP and PDEP connections which are found to behave as nominally-pinned. The EEP connection imposed higher forces and thus more deformation was obtained on the supporting member in comparison with the FP or PDEP connections. The concluding recommendation is to only use EEP connections if the specific connection design has been verified to be nominally-pinned or by including the fixity in the frame analysis.

Optimal sustainable harvesting of populations in random environments

We study the optimal sustainable harvesting of a population that lives in a random environment. The novelty of our setting is that we maximize the asymptotic harvesting yield, both in an expected value and almost sure sense, for a large class of harvesting strategies and unstructured population models. We prove under relatively weak assumptions that there exists a unique optimal harvesting strategy characterized by an optimal threshold below which the population is maintained at all times by utilizing a local time push-type policy. We also discuss, through Abelian limits, how our results are related to the optimal harvesting strategies when one maximizes the expected cumulative present value of the harvesting yield and establish a simple connection and ordering between the values and optimal boundaries. Finally, we explicitly characterize the optimal harvesting strategies in two different cases, one of which is the celebrated stochastic Verhulst Pearl logistic model of population growth.

Complementary Resistive Switching Using Metal-Ferroelectric-Metal Tunnel Junctions.

Complementary resistive switching (CRS) devices are receiving attention because they can potentially solve the current-sneak and current-leakage problems of memory arrays based on resistive switching (RS) elements. It is shown here that a simple anti-serial connection of two ferroelectric tunnel junctions, based on BaTiO3 , with symmetric top metallic electrodes and a common, floating bottom nanometric film electrode, constitute a CRS memory element. It allows nonvolatile storage of binary states ("1" = "HRS+LRS" and "0" = "LRS+HRS"), where HRS (LRS) indicate the high (low) resistance state of each ferroelectric tunnel junction. Remarkably, these states have an identical and large resistance in the remanent state, characteristic of CRS. Here, protocols for writing information are reported and it is shown that non-destructive or destructive reading schemes can be chosen by selecting the appropriate reading voltage amplitude. Moreover, this dual-tunnel device has a significantly lower power consumption than a single ferroelectric tunnel junction to perform writing/reading functions, as is experimentally demonstrated. These findings illustrate that the recent impressive development of ferroelectric tunnel junctions can be further exploited to contribute to solving critical bottlenecks in data storage and logic functions implemented using RS elements.

Resection of an Intramedullary Glomus-type Arteriovenous Malformation of the Conus Medullaris: Technical Note and Step-by-step Surgical Video.

Arteriovenous malformations (AVMs) of the spine include a broad spectrum of lesions that vary from a simple arteriovenous fistulous connection to a more complex net of abnormal vessels involving multiple spinal levels. These entities are poorly studied and understood because of their rarity and are often either managed conservatively with observation if the lesion is complex, or treated surgically or interventionally in the presence of an accessible and distinct fistulous connection. Most surgeons avoid intervening on more intricate lesions until they become symptomatic with progressive neurological decline.We describe the case of a 38-year-old man who presented with severe sharp back pain after an appendectomy procedure. A magnetic resonance angiogram (MRA) revealed an arteriovenous malformation of the conus medullaris, with a compact glomus-type nidus and arterial feeders originating from an enlarged artery of Adamkiewicz. The malformation was resected through a posterior midline approach, and the patient was neurologically intact at his discharge on postoperative Day 2. Follow-up angiography showed complete obliteration of the lesion. Our operative video is meant to serve as a step-by-step and systematic guide to the approach and management of conus arteriovenous spinal lesions, which can be difficult to treat.We provide a pre- and postoperative radiological description of the anomaly as well as a technical guide to the resection of a spinal vascular lesion. This video could serve as an operative guide and reference to neurosurgeons—both established and in training—when confronting similar disease processes in the future.

Experimental investigation on the pull-out force of modified purlin to rafter connections

In Malaysia, almost all houses in rural area are non-engineered structures. The roof of these houses is susceptible to failure and many types if roofing failure can be expected. This study examines the pull-out capacity of several simple connections meant for tying the timber purlin to rafter. The types of connections are single nail, double nail, nail plus metal strap and nail plus rope. The tests were conducted on timber type Damar Minyak (Araucariaceae), commonly used for the purlin and rafter assembly of rural houses. The wind load was applied in the form of pull-out force generated via in-house frame and Universal Testing Machine. The results from the pull-out force versus nail displacement exhibited unique features for each type of connection. In the case of a single nail connection, the graph showed two phases. When the single nail is combined with another nail or metal strap or rope, the responses exhibited in three distinct phases. The first phase for every type of connections showed linear relationship. The failure pattern for nail only (single and double) showed gentle degradation of the connection strength. However, for nail and metal strap connection, the strength degradation was abrupt due to the yielding of the metal strap. On the other hand, for nail and rope connection, the failure phase was cascaded due to the progressive snapping of the jute fibre. The highest the pull-out resistance based on the maximum pull-out force was shown by the nail and metal strap connection.

Dual frequency comb photon echo spectroscopy

Dual frequency comb (DFC) nonlinear spectroscopy is an emerging technique that can be used to study a variety of molecular nonlinear responses by exploiting the automatic pulse-to-pulse time delay scanning and fast data acquisition characteristics of the DFC techniques. Here, we propose a DFC-based photon echo spectroscopy (DFC-PES), where two optical frequency comb lasers have slightly different repetition rates and are also allowed to have different carrier frequencies. We first demonstrate our theoretical approach for DFC linear spectroscopy. Then, the signals expected from the proposed DFC-PES are theoretically calculated. The slight offset in the pulse repetition rates enables asynchronous optical sampling and automatic scanning of the time intervals between different field–matter interaction events, making frequency tuning unnecessary. Analytic expression of the third-order photon echo signal is demonstrated in two frequency dimensions for a simple two-level model system. The signal has a well-defined and simple connection to the underlying third-order response function and exhibits the expected down-conversion features from the optical frequency into the radio frequency region with a down-conversion factor that is experimentally controllable.

Single Image Super Resolution Model Using Learnable Weight Factor in Residual Skip Connection

In single image super-resolution problems, the recent feed forward deep learning architectures use residual connections in order to preserve local features and carry them through the next layer. In a simple residual skip connection, all the features of the earlier layer are concatenated with the features of the current layer. A simple concatenation of the features does not exploit the fact that some features may be more useful than other features and vice versa. To overcome this limitation, we propose an extended architecture (baby neural network) which will have input as the features learned from the previous layer and output a multiplication factor. This multiplication factor will give importance to the given feature and thus help in training the current layer’s features more accurately. The proposed model clearly outperforms the existing works.

Optimization of Cúk Voltage Regulator Parameters for Better Performance and Better Efficiency

This paper discusses the harmonic distortion and voltage-current ripple minimization of a Cúk regulator based on the design optimization of its parameters using multichannel connection with uncoupled smoothing filters. The main attention is focused on the analysis and simulation of the fundamental and two-phase parallel connection of Cúk regulator with uncoupled smoothing filters. A detailed analysis has been done to show the benefits of uncoupled smoothing filters and their positive impact on balancing the energy compensation between the capacitors and inductors of the double-phase Cúk regulator as compared to conventional one. As a result of that the dc source current values do not go from positive to negative and vice versa as in the case of a fundamental connection which does not cause any saturation problem for the regulator. In general, multichannel parallel connection of Cúk regulators with uncoupled smoothing filters has ingrained benefits such as eminent current distribution characteristics, sacredness to component tolerance, reduction of parasitic effects and relief in current control complexity. Specifically, by employing double-phase connection with uncoupled smoothing filters for these regulators, overall current fluctuation can be effectively reduced by more than 25% after introducing the double-phase connection, compared to that of simple connection. Moreover, it is proved that the output voltage ripple of the double-phase connection is also reduced by more than 25% from that of the fundamental connection. Computer simulations using Simplorer 7 or Matlab and Excel have been done to validate the concepts.

CONTRIBUTION of GRAVITY FRAMES TO SEISMIC PERFORMANCE OF STEEL MOMENT RESISTING FRAMES

Traditionally, lateral stiffness and strength of the gravity frames in steel buildings are neglected in structural analysis. During the past earthquakes, such as Northridge, USA, 1994 and Kobe, Japan, 1995, unexpected failures were detected at beam-to-column connections of steel moment resisting frames (MRFs). In the aftermath of these earthquakes, extensive research has been carried out to reveal the causes of these failures. Based on the detailed observations, it is likely that the reserve capacity provided by the gravity frames prevented the highly damaged steel buildings from collapsing, since majority of the moment-resisting connections failed prematurely during the Northridge earthquake (1994). Even though the influence of gravity frames (GFs) on structural behavior can be substantial, little attention is paid to evaluate its impact on structural response. With this paper, the contribution of interior GFs in seismic performance of special moment resisting steel frames (SMRFs) is evaluated. For this purpose, 4- and 9-story SMRFs were designed in accordance with the requirements of Draft Turkish Seismic Code (2016). The frames are, then, subjected to incremental dynamic analysis. To evaluate the contribution of the interior GFs on the overall seismic performance of structural system, inelastic behavior of shear tab (simple) connections at beam-to-gravity-only columns were idealized as semi-rigid joints. A general purpose structural analysis software, ETABS, is utilized for the analyses. The results of the study are presented in terms of story drifts, base shear vs. roof displacement.

Seismic behavior of coupled steel plate shear walls with simple boundary frame connections

SummaryThe coupled steel plate shear wall (C‐SPSW) configuration has been investigated by researchers as a means of improving the overturning stiffness and architectural flexibility of SPSW structures. While C‐SPSWs have been shown to exhibit excellent seismic performance, the fabrication cost associated with the high number of moment‐resisting connections used in such systems is a potential detraction to their use as an economical solution. Past research has shown that the hysteresis response of SPSWs with simple frame connections is significantly pinched, and as such, most seismic codes prohibit their use in high seismic areas. However, when used in the C‐SPSW configuration, a dual system is formed in which the coupling beams not only improve resistance to overturning but also provide substantial lateral strength and energy dissipation capacity. This paper presents an exploration of the potential to improve the economy of C‐SPSWs by using the simple boundary frame connections. First, employing the principles of plastic analysis, an attempt is made to quantify the contribution of the coupling beams to the overall lateral load resistance of the system. Then, to evaluate the seismic performance of such C‐SPSW systems and allow for the comparison with that of the C‐SPSWs with rigid frames, several prototypes are designed and analyzed using a series of nonlinear response history and pushover analyses. The results indicated that the C‐SPSWs with simple boundary frames exhibited satisfactory seismic performance comparable with that of the C‐SPSWs with rigid frames under both the 10/50 and 2/50 hazard levels, while allowing for reduced fabrication costs.

Benefits of multiple rocking segments for CLT and LVL Pres-Lam wall systems

Press-Lam mass timber wall system is an adaptation of the Precast Seismic Structural System used for concrete and steel buildings to resist earthquakes. Single rocking segment systems with rigid connections between panels result in a dynamic amplification of the forces in the upper storeys. The objectives of this research were to compare through analytical studies the design requirements for Pres-Lam wall systems made of laminated veneer lumber (LVL) and cross-laminated timber (CLT) panels and to demonstrate through numerical modeling that the dynamic amplification can be reduced by introducing simple connections allowing a gap opening at construction joints. Results of the study demonstrated that the CLT walls needed approximately 20% wider panels and 10–30% less initial pre-stress in the post-tensioning bars to obtain the same moment-rotation behavior as in the LVL walls. Time history analyses on multiple rocking segment models showed that the shear and bending moment envelopes were reduced nearly 45% in comparison with the equivalent single rocking segment systems.

Rehabilitation in Simple Steel Connections against Progressive Collapse due to Column Removal

Strengthening of the structures against progressive collapse is very essential. Structural frames with simple connections are of highest potential in progressive collapse; therefore, rehabilitation of such structural system for both existing and new structures is vital. The available simple connections consist of double web angles and one seat angle which are assessed numerically, leading to the proposal of some effective techniques in order to reduce destruction due to this phenomenon. The proposed methods do not increase hardness and rigidity of the connections, and they hardly change the size or type of the loads of the other members, but, they are very beneficial in existing strategic structures. Eight models with both bolted and welded connections are considered in this study. The effect of damper in control of this phenomenon is assessed. The obtained results indicate that applying tendons in details improve performance of the models to considerable extent, because the proposed techniques reduce the vertical displacement of the connection up to 70%. Applying of damper in some of the models leads to a 20% reduction in vertical displacement.

Aspects of simple connectives in Ikwere

This work on aspects of simple connectives in Ikwere, an Igboid language spoken in Rivers State was undertaken because the subject matter of connectives in Ikwere has received very little attention. This study was thus carried out to investigate the structure of simple connectives in Ikwere, ascertain the syntactic relevance of connectives in Ikwere and determine the semantic import of these connectives. The work is based on the Ò̟muanwa dialect of Ikwere Data for the work were obtained through unstructured elicitation interviews with competent language consultants of Ikwere and through participant observation. Data gathered were analyzed using the descriptive method of interlinear morpheme-to-morpheme glossing. Simple connectives in Ikwere were divided into Simple coordinators and Simple Subordinators. Simple coordinators in Ikwere were semantically split into additive, adversative and alternative while simple subordinators were functionally divided into subordinators in noun, relative and adverbial clauses. Our findings revealed that some simple connectives (simple adversatives) in Ikwere are optional as contrastive clauses are better linked without such connectives while some others are homophonous.Keywords: conjunctions, connectives, coordinators, subordinators

Investigation of the rigidity of welded shear tab connections

Shear tab connections are among the economical connections that are usually designed as a simple connection. The shear tab connection sustains some bending moment as the beam end rotates and therefore it may be classified as semi-rigid connections, based on the geometry of the connection. In this research, the end rotation of steel girders with shear tab connection, which is both welded to the supporting member and to the beam’s web, is investigated. 317 finite element models with different beam sizes and shear tab plates are used to investigate their effect on the connection rigidity and classification, under service loads. The results show that the main source of the connection rotation was the plastic deformations in the shear tab and the plastic modulus of the shear tab section plays an important role in the determination of the welded shear tab connection rotational rigidity. It also concluded that the gap between the beam and the connection face has negligible effect on the rigidity of the connection. Increasing the shear tab height leads to the increase of the shear tab section plastic modulus, which results in the increase of the connection rigidity. In addition, based on the results, a simple equation is introduced to predict the rigidity of the shear tab connections.

BPS operators in mathcal{N}=4 SO(N) super Yang-Mills theory: plethysms, dominoes and words

Permutations and associated algebras allow the construction of half and quarter BPS operators in maximally supersymmetric Yang Mills theory with U(N), SO(N) and Sp(N) gauge groups. The construction leads to bases for the operators, labelled by Young diagrams and associated group theory data, which have been shown to be orthogonal under the inner product defined by the free field two-point functions. In this paper, we study in detail the orientifold projection map between the Young diagram basis for U(N) theories and the Young diagram basis for SO(N) (and Sp(N)) half-BPS operators. We find a simple connection between this map and the plethystic refinement of the Littlewood Richardson coefficients which couple triples of Young diagrams where two of them are identical. This plethystic refinement is known to be computable using an algorithm based on domino tilings of Young diagrams. We discuss the domino combinatorics of the orientifold projection map in terms of giant graviton branes. The permutation construction of SO(N) operators is used to find large N generating functions for both the half and quarter BPS sectors. The structure of these generating functions is elucidated using the combinatorics of words, organised according to the number of periods. Aperiodic words in the U(N) theory are Lyndon words and an SO(N ) analogue of Lyndon words is defined using a minimally periodic condition. We calculate the normalization factor for the orthogonal basis of Young diagram operators in the baryonic sector of SO(N).

Design and Implementation of Robust, Secure, Simple Bluetooth Pairing using Physical Vibration

Short-range wireless communications technology is increasingly employed for communication among electronic devices. As a result, the demand for simple and secure connections between remote devices is also growing. In general, pairing is the establishment of an authentication key for agreement to secure communications between two devices over a wireless channel. In this paper, we propose a novel, secure, simple Bluetooth Low Energy pairing technology using physical vibration. We describe contact communications using physical vibration and two additional optimizations (8b/10b encoding and single error correction) to improve robustness while maintaining the data transmission rate. The data rate of vibration communication is enhanced by more than 40% with the optimizations. We also present a prototype implementation of the proposed Bluetooth pairing, which employs a mobile phone and a vibration sensor using a piezo-resistive strain gauge. Finally, we discuss the security and usability of our proposed Bluetooth pairing technique for electronic devices, compared with previous methods.

Apparent motion as hyperacuity phenomenon under low two-point spatial resolution

This work presents numerical simulations and experimental validation aimed at optimizing the design of large size flat-plate solar collectors (has a profile area of 10.04 m2). The large size collector with the advantages of high land use efficiency, compact structure, better thermal insulation and simple connection, are widely used in large scale heating systems (like seasonal storage system). Consequently, the study and optimization (thermal and antifreeze performance) of the large size collector are essential for the further application of the large size collector. However, unlike the conventional small collector, the large size collector has high flow and temperature ununiformity. The study of the large size collector should be treated differently with the conventional small collector. Meanwhile, the thermal stress induced by the temperature inhomogeneity should be studied. In this paper, we propose a numerical model of a double-glazed large size collector to evaluate the influence of the design parameters (type of absorber strips, aspect ratio, airgap thickness, number of pipes) on its thermal performance and antifreeze performance. A water-heating system with a large size solar collector is built and tested to validate the simulation model. A mechanical model is present to evaluate the thermal stress of the large solar collector and factors influencing the thermal stress of the large size collector are studied.

Iot Based Smart Jar For Connected Devices Using Machinelearning

The smart jar enables us to keep track of the medicines stocks with the help of an android app easily accessible anywhere with a simple internet connection. The jar contains an ultra-sonic sound waves emitter and sensor which uses the reflected ultra-sonic waves to find out what level the jar is filled to and how much empty space remains in jar yet to be filled. This sensor is also connected to the internet and interfaced with the application so that as soon as the level of content in the jar changes the data is updated to us in the application without any delay. This helps us in monitoring the stocks and prepare for restocking from anywhere,additionally it also provides important data such as the expiry date and the manufactured data of the content in the jar. .

Left Ventricular Function After Repair of Totally Anomalous Pulmonary Venous Connection

Poor left ventricular (LV) growth and diastolic dysfunction long after simple total anomalous pulmonary venous connection (TAPVC) repair has been well documented and is believed to originate from insufficient preoperative volume preload. The objective of the study was to confirm these findings. Of 61 patients undergoing simple TAPVC repair between 1996 and 2016, 42 patients undergoing postoperative catheter examinations were enrolled. The mean age at the time of repair was 39 ± 117 days. Postoperative catheter examinations were conducted at a mean duration of 1.1 years after the repair. LV end-diastolic volume (LVEDV) was calculated by biplane cineangiography with the use of Simpson's method as a Graham modification. LV ejection fraction, LV end-diastolic pressure (LVEDP), and cardiac index were 72% ± 5%, 10.3 ± 2.7 mm Hg, and 4.0 ± 0.7 L •·min-1 • m-2, respectively. LVEDV was 102% ± 16% of the predictive normal value, and it strongly correlated with the predictive normal value of LV end-diastolic diameter (LVEDd) calculated by two-dimensional echocardiography (R2= 0.29, p= 0.005). LVEDd maintained a normal range thereafter during the entire follow-up period. LVEDP correlated linearly with age at the time of TAPVC repair (R2= 0.18, p= 0.007) but not with LVEDV (p= 0.67). LV size maintained a normal range after the repair of simple TAPVC. High LVEDP was frequently observed a year after repair; it did not correlate with LV size but had a strong negative correlation with age at the time of repair.