Gain In Capacity Research Articles

Health care network for chronic conditions: an intervention and evaluation in the health system

Abstract Background Health assessments are necessary for the (re) formulation of effective public policies and to guarantee the quality of care offered. This study aim to evaluate the perception of health professionals concerning the institutional capacity of the health system to care for Chronic Conditions (CC) after intervention in a medium-sized municipality in Minas Gerais, Brazil. Methods It is a panel study with evaluation before, during and after an intervention in the health system with a focus on three CC, i.e., i) diabetes; ii) hypertension; and iii) pregnant women. Health care professionals from primary and specialized care units were interviewed using the Assessment of Chronic Illness Care (ACIC) scale, which was applied in nine focal groups organized by health care unit. Results A total of 240 professionals participated of this evaluation, being 94, 63 and 82 participants in 2013, 2015 and 2018 respectively. The ACIC scores showed an positive evolution in the capacity of the health system to care for CC over the years. In the first wave the global score was 5.40 (basic capacity), while in the third wave the score was 9.38 (optimal capacity), with a significant increase in the scores (p < 0.01). Conclusions An important gain in the institutional capacity of the municipality was evidenced for the care of chronic conditions after intervention in the health system. Such an enhancement of the health system to operate in the CC might be sustainable over the time. Furthermore, its impact may directly reflect on the health indicators of the population. Key messages The results showed a strengthening of the local health system. These findings can subsidize other municipalities with a similar reality in the organization of the health care network and, consequently improve the care provided to chronic conditions.

Golden Coded GFDM for 5G Communication

The 5th Generation (5G) of wireless communication will be heterogeneous to support various traffic types and applications. Generalized Frequency Division Multiplexing (GFDM) is a 5G non-orthogonal waveform contender that offers scalable and spectrally compliant air interface which addresses the needs of 5G requirements. To aid the demand of high-capacity and reliable transmission, multiple antenna techniques are relied upon. In this work, the 5G modulation scheme GFDM is combined with a full rate Space–Time Block Code (STBC) with nonvanishing determinant called Golden Codes to exploit the diversity to the fullest. The proposed work is implemented in a real-time SDR test-bed called Wireless Open Access Research Platform (WARP). The proposed work is compared with 4G OFDM modulation in both Golden Coded and Uncoded case. The performance is assessed in terms of BER and Capacity/Bandwidth resolution. From the investigations, it is seen that the BER performance of Golden Coded GFDM outperforms the Uncoded GFDM by 3 dB SNR gain and attains a near-equal performance as OFDM. Also, it is evident from the analysis that, there is a 3.5 bps/Hz gain in capacity when compared to OFDM.

Improvements in plate anchor capacity due to cyclic and maintained loads combined with consolidation

Plate anchor technology is an efficient solution for mooring offshore floating facilities for oil and gas or renewable energy projects. When used with a taut mooring, the anchor is typically subjected to a maintained load component and intermittent episodes of cyclic loading throughout the design life. These loads, and the associated shearing, remoulding and consolidation processes, cause changes in the anchor capacity, particularly in soft, fine-grained soils. The changing anchor capacity affects the mooring performance by changing the safety margin and also the overall system reliability. In this paper the changing anchor capacity in reconstituted, normally consolidated natural carbonate silt was assessed through a series of beam centrifuge tests on horizontally loaded circular plate anchors. The results demonstrate that full consolidation under a typical maintained load leads to a 50% gain in the anchor capacity, and subsequent cyclic loading and reconsolidation can triple this increase. An effective stress framework based on critical state concepts is employed to explain and support the experimental observations. This study shows that, when viewed from a whole-life reliability perspective, maintained and cyclic loading provide a long-term enhancement of anchor capacity in soft, fine-grained soils. This beneficial effect is currently overlooked in design practice, but can be predicted using the framework shown here, which can form the basis for a digital twin that monitors the through-life integrity of a plate anchor.

Experimental performance and energy efficiency investigation of composite superabsorbent polymer and potassium formate coated heat exchangers

The poor efficiency of vapor compression chillers emerges due to the simultaneous treatment of sensible and latent cooling loads. By employing desiccant coated heat exchangers (DCHEs) for removing latent loads, the energy efficiency is enhanced as the conventional cooling coil is used for high-temperature sensible cooling. Currently, DCHEs have limitations due to low sorption capacity, high regeneration temperature, short operating time, corrosion, and deliquescence of the desiccating material. To address these research gaps, we synthesized a composite polymer desiccant by combining a superabsorbent polymer and less corrosive potassium formate salt. Desiccant characterization experiments showed that the new desiccant exhibited 4–8 times gain in sorption capacity when compared to pure/composite silica gel. The dynamic performance studies showed that the cycle time could be extended up to 15 min and 40–50 °C was sufficient for regeneration in contrast to the previous constraint of 5 min and 60–80 °C, respectively. Further, the new composite desiccant removed 3 times higher cooling load than silica gel based DCHEs and recorded 2 times higher thermal efficiency. When integrated with conventional air-conditioners, DCHE could trim up to 50% of the electrical power, and short payback periods of less than 2 years were obtained.

Social Reliable D2D Relay for Trustworthy Paradigm in 5G Wireless Networks

5G wireless networks envision the usage of millimeter Wave (mmWave) frequencies for a manifold data rates and user capacity increase. However, the inherent line-of-sight (LoS) in mmWave communications raises significant challenges in providing seamless coverage across the dense 5G networks. Device-to-device (D2D) communications offer promising solutions for this LoS challenge by providing relay services. The selection of relay requires maintaining a certain level of trust and confidentiality of the devices. In this paper, we utilize social relationships among devices to form personal trust among different devices. Subsequently, we introduce distributed architecture for social relationships in D2D communications and we discuss new methods for a dynamic social relationship and trust management paradigm. Our analytical models not only show that the proposed scheme achieves 10% - 80% gain in device capacity, 30% - 200% increase in data rates, with approximately 50% less energy consumption over earlier methods, but also discuss co-existence with existing SINR based relay selection schemes. We present temporal dynamics of our social-communication graph using the random graph and Markov process. Our NS3 based 5G simulations demonstrate that our scheme obtains 3 - 5 times more throughput and 50 - 100m coverage extension, with relatively negligible additional delay.

Restoration of the shear capacity for RC beams with web openings using precast SHCC plates

Providing web opening in the shear-span zone of RC beams results in significant reduction in the shear capacity of such beams. Thus, an efficient restoration technique has to be found out and implemented in order to compensate the developed reduction. The main target of the current paper is to introduce and validate an innovative restoration technique for the new construction making use of the Strain-Hardening Cementitious Composites (SHCC) material. Accordingly, precast thin SHCC plates having the required opening were cast and cured for about 3 weeks to eliminate the volumetric change issues, and then placed inside the formwork at both sides before casting the RC beams included web openings. The chosen thickness of the SHCC plates was 20 mm in order to be easily accommodated in the concrete cover. For the considered openings, the opening depth was kept constant to be 0.30 of the beam effective depth, while the opening length was varied considering three values; 150, 300, and 450 mm. Besides, small amount of internal reinforcement in the form of steel wire mesh was provided inside some SHCC plates in order to enhance their shear strength and ductility. Experimental results showed that the provided SHCC layers enabled the strengthened beams to exhibit distinguished performance in terms of ultimate capacity, ductility and decreased shear crack width. In addition, the gain in shear capacity due to the SHCC plates is decreased with the increase of the opening width. Finally, comparisons between the obtained experimental results and the predicted shear capacities stipulated by the ACI 318-19 and JSCE codes were performed. The comparisons revealed that the estimated shear capacities are in satisfactory agreement with the experimental results, however, these estimations tend to be overestimated with the increase of the opening length.

An embedding technique for smartcard-supported e-healthcare services

Generally, a smartcard contains the photograph of its owner. Few recent applications manage patient’s information by embedding them into that photograph. The historical records of a patient may increase gradually. The volume of raw data onto growing records could be unmanageable by a scheme. Therefore, an objective of this research is to encode every raw data by 1–3 bits owing to minimize the length of the embedding information. Prediction error-based reversible embedding schemes present higher embedding capacity and image quality. In the prediction error space, it is investigated that the frequency of − 2 is noticeably smaller than − 1, similarly, − 3 than − 2 and so on. The scenario is valid for positive-valued errors as well. For this, every single-layer embedding scheme implants bits in the errors of − 1 and 0 only. Another investigation reveals that secret data of a patient with chronic diseases may exceed the frequency of − 1 and 0 valued errors. Hence, another objective of this research is to implant bits in the errors of − 1 and 0 for multiple times. Considering these objectives, we have proposed a model that encodes raw data of patient’s history and embeds the encoded data in an image for multi-times. The encoding technique both minimizes the length of embedding information by 1/10th and enhances the security of the implanted data. The proposed model is verified by experimenting with MATLAB 7.0 on BOSS and CalTech 101 image datasets. Experimental results present a double gain in the embedding capacity for the proposed scheme. It will be a notable contribution to the field of medical applications.

Finite element modeling of non-conventional energy dissipating systems using metallic like-composite tubular structures

This work focused on a numerical modeling of innovative non-conventional energy dissipating systems developed and tested experimentally in [1] to enhance their energy absorption capacity. The basic concept utilized the axial plastic buckling of right-circular mild steel like-composite tubes with various case-hardened patterns. Such a heat treatment has been applied on 15% of the outer surface with a depth of 0.5 mm. In this work, a nonlinear finite element modeling was conducted describing the response of such tubes targeting particularly their behavior along the tube thickness. The S4R shell element of 1 mm size was used looking for an accurate mesh convergence. A contact with a dry friction penalty was highlighted by the contact between the tube surface-to-surface and the tube-to-rigid bodies. The mass scaling technique was also considered to increase the stability time. Four case-hardened patterns of 2, 3, 4 and 5 rings and two other vertical strip patterns of 2 and 3 strips were modeled, simulated and compared with the experimental data. Moreover, a numerical design platform with several new case-hardened patterns was proposed. Among the latter, two patterns (12C and 3R3V) showed better energy absorption capacities than the others even for those observed experimentally. Actually, they offered a gain in the energy absorption capacity of 42% compared to the conventional case.

Improving the hydrogenation properties of AZ31-Mg alloys with different carbonaceous additives by high energy ball milling (HEBM) and equal channel angular pressing (ECAP)

In this study, the hydrogen storage performance of commercial AZ31-Mg alloys combined with various allotropes of carbon was investigated and the microstructural modifications with respect to plastic deformation and high energy milling techniques investigated, with the aim of obtaining enhanced hydrogen storage efficiency. The hydrogen storage performance of alloys prepared with different weight ratios of carbonaceous materials as a catalyst was monitored in order to explore the effective improvement in hydrogen storage performance through microstructural modification. Additionally, the effects of different processing methods such as equal channel angular pressing (ECAP) and high energy ball milling (HEBM) were also observed. AZ31 Mg based composites with various carbon additives were produced through gravity resistance casting and their micrographic structures examined through optical Microscopy (OM), X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS). The average particle size distributions of the sample powders were also measured. The rate of hydrogenation kinetics was calculated by a Sievert's type apparatus. Significant enhancement of the hydrogenation performance was obtained with the addition of carbonaceous materials. Overall, the hydrogen storage performance after ECAP deformation of the AZ31-3CB (carbon Black) composite showed a gain in the maximum capacity of 6.72 ± 0.05 wt%. Similar, after milling of the AZ31-3G (Graphene) composite materials, a maximum potential capacity of 6.83 ± 0.04 wt% was attained within 792 ± 144.34 s, with desorption of the entire H2 content in 143.2 ± 26.09 s. The obtained results revealed significant improvement in the hydrogen storage capacity of AZ31-Mg alloys with the addition of carbon materials and with respect to plastic deformation and milling techniques.

Exploring the use of EMImFSI ionic liquid as additive or co-solvent for room temperature sodium ion battery electrolytes

Sodium ion batteries (SIB) market is limited by their gravimetric and volumetric energies and therefore, search of high voltage redox couples combined with suitable electrolytes is nowadays mandatory. Ionic liquids can bring advantageous properties to SIB, particularly from a safe point of view, but are still quite expensive. In this pioneering work, we explore the use of small amounts of 1-ethyl-3-methylimidazolium bis(fluoromethanesulfonyl)imide (EMImFSI) ionic liquid in the electrolyte formulation, either as an additive (2% in weight ratio to a binary mixture of ethylene carbonate (EC)/propylene carbonate (PC)) or as co-solvent (10% in weight ratio). Results are compared to electrolytes containing classical SIB additive fluoro-ethylenecarbonate (FEC). Physicochemical properties of the electrolytes prepared with NaClO4, NaPF6 and NaFSI are differently influenced by the EMImFSI additive, which contributes with ionic species to the electrolyte ionic conductivity but increases its viscosity. Extension of the sodium plating/stripping is higher for more dissociated salt in un-doped electrolytes. Introduction of EMImFSI results in the occurrence of a SEI that hinders the plating except for the 10% EMImFSI-NaFSI based electrolyte. Electrochemical cycling of a hard carbon electrode reveals that FSI− anion, mainly coming from the added ionic liquid, can introduce new peaks in the cyclic voltammetry or new steps in the galvanostatic discharge. The products of such degradation create an electrode/electrolyte interface which determines the cycling properties. The complex picture of the interplay between sodium salt anion and EMImFSI presence and amount is not completely described in this work. However, it is clear that EMImFSI introduces initially a larger polarization in the discharge/charge curves and that only added to the NaPF6 system helps to stabilize the coulombic efficiency and gain in capacity (+50%). EMImFSI has not beneficial effect on the NaClO4-based formulations and the initial positive effect on the sodium half cells cycled in NaFSI-based electrolytes is cancelled after 25 cycles. Microscopy examinations on cycled electrodes reveal that coulombic efficiency and thus capacity retention are associated to a protective film completely recovering the hard carbon particles without modifying their pristine shape. This is the case for electrodes tested with un-doped NaClO4 and EMImFSI-NaPF6 electrolytes. Our results also show that compared with EMImFSI, FEC added in 2% weight ratio content provides much better or similar electrochemical performances at a lower price.

Improvement of bearing capacity of soil by using natural geotextile

An experimental study has been carried out to improve the bearing capacity of soils by using geotextile. In the present study geojute (gunny bags) is used as geotextile, whereas sand is used as soil media. This research presents the results of laboratory load tests on model square footings supported on reinforced sand beds. A total of 32 load tests are conducted to evaluate the effects of single layer reinforcement placed below square model footings. Parameters of testing programme of the research are the depth of reinforcement, the plan area of reinforcement and the footing size. The test results indicated that the maximum gain in ultimate bearing capacity (UBC) of footings on reinforced soil (by using geojute) is found to be increased by a factor of 3.37 as compared to soil without geojute. Also, the optimum size of reinforcement is found to be 3.5B × 3.5B irrespective of the type of reinforcing materials used. The optimum placement position of geotextile is found to be 0.5B from the base of the footing. At low settlement rates, the study on the values of BCR reveals almost the same results with regard to optimum depth and size of reinforcement mentioned above. It is found that with increase in the settlement rate, BCR increases. Also, the improvement in bearing capacity is found to increase with increase in footing size.

Lattice Parameter Hysteresis in Li- and Mn-Rich Layered Oxides and Its Dependence on State of Charge and Open Circuit Voltage

Li- and Mn-rich layered oxides, also known as high energy NCM (HE-NCM, Li1+x[NiCoMn]1-xO2 with typically 0.1 < x < 0.2), are promising next-generation cathode active materials (CAMs) for Li-ion batteries, since they contain intrinsically more lithium ions than regular NCM materials (x < 0.05). The gain in capacity is accompanied by the drawbacks of voltage hysteresis (between charge and discharge) and voltage fade (during long-term cycling).1 The voltage hysteresis is a unique property of over-lithiated layered oxides, which does not only manifest itself in the voltage profile, but also in the cathode resistance,2 the redox activity of transition metals (TM) and oxygen,2 and the bond distances.3 Figure 1 shows our results of an in-situ X-ray diffraction (XRD) experiment during the initial cycles of a Li-rich NCM material. As seen in Figure 1a and b, the state of charge (SOC, equivalent to total xLi) dependence of the bulk lattice parameters a and c after the first activation cycle is characterized by a pronounced hysteresis between charge and discharge. Here, the hysteresis loop of the lattice parameter a is clearly different from that of c. Furthermore, the hysteresis of the lattice parameter a vanishes when it is correlated to the open circuit voltage (OCV) of the respective SOC (see Figure 1c), but c maintains the shifted maxima during charge and discharge (see Figure 1d). Based on the literature, these observations could be either explained by a path dependency of the reversible TM migration between TM and Li layer,4 the oxygen redox,2 or a combination of both.5 In addition to in-situ XRD data, we will show co-refined X-ray and neutron diffraction data of selected ex-situ samples, which have either the same SOC or OCV. By means of diffraction techniques, it is our goal to elucidate the lattice parameter variations in Li-rich CAMs and to clarify the often described contribution of TM migration to the hysteresis effects. Figure 1: In-situ XRD measurement of HE-NCM during the first 3 cycles. The pouch cell was cycled at a rate of C/10 between 2.0-4.8 V against metallic lithium with intermediate OCV steps to collect XRD patterns (at a laboratory diffractometer with Mo-Kα1 radiation). Using the trigonal model (space group R-3m), the lattice parameters a and c are shown as a function of SOC (a,b) and OCV (c,d), respectively. Acknowledgements: We want to acknowledge BASF SE for the support within the frame of its scientific network on electrochemistry and batteries and the BMBF (Federal Ministry of Education and Research, Germany) for its financial support within the ExZellTUM II project (grant number 03XP0081). We also thank the research neutron source FRM II for access to the instrument SPODI.

MICROSTRUCTURE-BASED SIMULATIONS OF QUASISTATIC DEFORMATION USING AN EXPLICIT DYNAMIC APPROACH

Microstructure-based simulations of the deformation processes require substantial computational resources due to the necessity of using detailed meshes with a large number of elements. An approach that considerably reduces the computational costs implies simulation of quasistatic deformation within a dynamic approach involving a solution of the motion equations rather than the equilibrium equations. It enables a transition from implicit to explicit time integration providing a significant gain in the computational capacity. In this paper, we show that the explicit dynamic approach can be successfully used in the microstructure-based simulations of quasistatic deformation, considerably reducing the computational costs without losing the information and solution accuracy. The following conditions have to be met to ensure a close agreement between the dynamic and static solutions: (i) the load velocity in the dynamic calculations must be smoothly increased to its amplitude value and then kept constant to minimize the acceleration term appearing in the equation of motion and (ii) the constitutive model employed must describe a quasi-rate-independent response. An examination of the mesh convergence and the strain-rate dependence for a polycrystalline aluminum model has supported this conclusion.

Thermal Properties of Non-Volatile Phase Change Memories at Device Length Scale

Chalcogenide materials such as Ge2Sb2Te5 (GST) which undergo structural transition between amorphous and crystalline phases with applied thermal load, have emerged as potential material candidates for new memory technologies due to prospective gain in speed, device lifetime, and capacity. In these devices, each memory cell is composed of various components with different material compositions and functionalities. Therefore, a solid understanding of how heat transfers between each component is pivotal in the enhancement of performance and minimization of power consumption. In this study using time-domain thermoreflectance, we measure thermal properties relevant to device operation, at material length scales (< 40 nm) similar to those used in actual devices, such as sound speed, thermal conductivity and thermal boundary conductance (TBC) for a temperature range from 25 °C to 400 °C. According to acoustic echoes obtained from picosecond acoustic measurements, the speed of sound in GST is calculated to be around 2,900 m/s. Moreover, we report the thermal boundary resistance (TBR) when different spacer compositions (W, SiO2, SiNx) are introduced to separate GST from the other components where SiNx/GST interface showed the highest TBR compared to both W and SiO2 interlayers. Additionally, the temperature dependent results indicate that the GST change phase from amorphous to cubic structure at 150 C and again from cubic to hexagonal at approximately 340 C. The thermal conductivity of GST experiences a significant jump at the transition temperature of 150 from 0.15 W/m/K to 0.30 W/m/K and continue to linearly increase by raising the temperature until its crystal structure completely transforms into the hexagonal where the thermal conductivity flattens out to the value of 1.4 W/m/K.

Evaluating the impact of connected and autonomous vehicles on traffic safety

This study aims to analyze the impact of connected and autonomous vehicles (CAVs) on traffic safety under various penetration rates. Based on a recently proposed heterogeneous flow model, the mixed traffic flow with both conventional vehicles and CAVs was simulated and studied. The frequency of dangerous situations and value of time-to-collision in the mixed traffic flow under different CAV penetration rates was calculated and used as indicators of CAV’s impact on traffic safety. Acceleration rate and velocity difference distribution of the mixed traffic flow was presented to show the evolution of mixed traffic flow dynamics with the increase in CAV penetration rates within the mixed flow. Results show that the condition of traffic safety is greatly improved with the increase in the CAV penetration rate. More cautious car-following strategy of the CAV would contribute to a greater benefit on traffic safety, though less gain in capacity. With the increase in CAV penetration rate, the portion of smooth driving is increased. Velocity difference between vehicles is decreased and traffic flow is greatly smoothed. Stop-and-go traffic will be greatly eased.

Enhancement of bearing capacity from consolidation: due to changing strength or failure mechanism?

Bearing capacity of shallow foundations is higher following preload (or self-weight)-induced consolidation because the soil strength changes, and perhaps because the failure mechanism changes. Previous studies have illustrated this effect by plotting or predicting changes in either bearing capacity factor or strength. In this study, the relative contribution of these two effects is explored. This is achieved by formalising a definition of bearing capacity factor, which is described in terms of the average strength mobilised in the deformation mechanism at failure. Using the alternative definition of bearing capacity factor, the gain in foundation capacity is shown to be almost entirely due to changes in soil strength, rather than bearing capacity factor, which remains largely unaffected by the strength gains. This observation should encourage future studies into consolidated bearing capacity to present gains in capacity in terms of changes in mobilised strength rather than changes in bearing capacity factors, and supports the use of prediction methods that focus on defining the change in soil strength.

A Survey on Handover Management: From LTE to NR

To satisfy the high data demands in future cellular networks, an ultra-densification approach is introduced to shrink the coverage of base station (BS) and improve the frequency reuse. The gain in capacity is expected but at the expense of increased interference, frequent handovers (HOs), increased HO failure (HOF) rates, increased HO delays, increase in ping pong rate, high energy consumption, increased overheads due to frequent HO, high packet losses and bad user experience mostly in high-speed user equipment (UE) scenarios. This paper presents the general concepts of radio access mobility in cellular networks with possible challenges and current research focus. In this article, we provide an overview of HO management in long-term evolution (LTE) and 5G new radio (NR) to highlight the main differences in basic HO scenarios. A detailed literature survey on radio access mobility in LTE, heterogeneous networks (HetNets) and NR is provided. In addition, this paper suggests HO management challenges and enhancing techniques with a discussion on the key points that need to be considered in formulating an efficient HO scheme.

Characterization of harmonic response of human middle ear using finite element approach

Human middle ear (ME) is an important organ of the auditory system. Sound energy stimulates the cochlear fluids present in the inner ear. Ossicular chain, a part of human middle ear consists of Tympanic membrane (TM), ossicles, ligaments and muscles. Hearing loss is reported when the ossicles in the chain gets degraded. Surgical intervention is one of the approaches to overcome the situation. The possibility of replacement of damaged ossicles with normal biocompatible biomaterials is explored in the current study. To study the sound transfer function, a FE model is developed using μCT (Computed Tomography) scan data imported in MIMICS Research 19.0 (Materialise Interactive Medical Image Control System) modeling software. The harmonic response at the stapes footplate and umbo is examined with the assumption that sound pressure is incident from lateral side of eardrum. Pathological conditions are analysed to determine the gain or loss in hearing capacity for Cholesteatoma, Partial mallear fixation and variations of material properties in Tympanic membrane (TM). The human audible sound pressure levels (SPLs) of 60, 80, 100 and 120 dB are applied on eardrum within frequency range of 100 Hz–10,000 Hz. The results are compared with healthy ear to investigate gain or loss in hearing capacity for these pathologies.

Behaviour of RC beams strengthened in shear using near surface embedded FRCM

This paper presents an experimental study on the efficacy of a lately introduced “near surface embedded” technique (NSE) for fabric reinforced cementitious matrix (FRCM) for the strengthening of reinforced concrete (RC) beams in shear; considering two test variables: (a) fabric type (glass and carbon) and (b) strengthening configuration (intermittent versus full). For this purpose, five (5) simply supported medium-scale RC rectangular beams have been tested under displacement controlled monotonic three-point loading. The experimental results showed that the FRCM system is effective in strengthening of shear deficient RC beams. An average of 62% gain in the shear capacity has been achieved due to the FRCM strengthening system. Carbon FRCM owning the higher axial rigidity showed better performance than that of glass FRCM. The average gain in the shear capacity for carbon FRCM strengthened beams was 22.5% higher than that for glass FRCM strengthened beams. Moreover, full strengthening configuration showed better performance than that for the intermittent configuration counterparts confirming the significance of the FRCM continuity and its quantity in enhancing the shear capacity of the strengthened beams.

Reduction in Lateral Displacement of Cohesionless Soil at Box Tunnel Face Using Nails in Overburden

The construction of shallow box tunnel underpass below rail/road traffic using jack pushing has become a quite common technique these days to create an uninterrupted flow of traffic in metropolitan cities. During the driving of shallow box tunnel underpass, the overburden cohesionless soil experiences large stresses and excessive lateral displacements at the box tunnel face, which sometime causes an accident leading to loss of lives. In order to overcome this problem, a laboratory model study has been conducted. A steel tank of size 450 mm × 300 mm × 300 mm, filled with cohesionless soil was used, in which a square steel box tunnel of size 34 mm × 34 mm (inner) with 1 mm wall thickness was moved through jacks. This tunnel was slowly pushed into the soil mass with the help of jack. Three vertical offsets from top of soil surface as well as three horizontal offsets from center of loading. To restrict the excessive lateral displacement, the overburden soil above the box tunnel was reinforced with 8 mm diameter tor steel nails prior to pushing of box tunnel. The lateral displacement of soil at tunnel face was found reduced from 6.92 mm in case of ‘without nailed’ to 0.23 mm in case of ‘with nailed’ overburden soil. Further, there was also a gain in load carrying capacity of soil in case of reinforced overburden soil. The study shows that if, overburden soil is reinforced with nails prior to the driving of box tunnel, the chances of collapse or lateral displacement at box tunnel face soil can be minimized for construction of shallow underpass.