Critical Impact Energy for Spalling, Tunnelling and Penetration of Concrete Slab impacted with Hard Projectile

Qadir Bux alias Imran Latif,Ismail Abdul Rahman,Ahmad Mujahid Ahmad Zaidi,Kamran Latif 대한토목학회 2015 KSCE JOURNAL OF CIVIL ENGINEERING Vol.19 No.1

Penetration is the basic element of designing protective concrete structure against the local impact damage of hard missile. Impactenergy is the dominant cause of damage in moving accidents. When hard projectile collides with concrete target, it is the impactenergy of the projectile that makes concrete target to deform. Therefore, it is vital to study critical impact energy required to causespenetration. An analytical model is developed to predict the required critical impact energy for maximum penetration without reareffects in concrete slabs when it is impacted with hard projectile. The nose shape factor Ni also has been introduced with inclusion ofempirical friction factor Nf, as modification in Chen & Li nose shape factor for ogive nose hard projectile. The newly developedanalytical model and nose shape factor Ni is examined for CRH = 2.0, CRH = 3.0, and CRH = 4.25. It was found that the predictedresults from analytical model with nose shape Ni are in close relation with experimental data in all cases as compared to predictedresults with traditional Li and Chen nose shape N*. In, General, the analytical model generates encouraging prediction which isconsistent and follows a general trend of experimental results.

Influence of Organomodified Nanoclay on the Mechanical and Flammability behavior of Jute Fabric/Vinyl Ester Nanocomposites

Latif, M.,Prabhakar, M.N.,Nam, Gi-Beop,Lee, Dong-Woo,Song, Jung-Il The Korean Society for Composite Materials 2017 Composites research Vol.30 No.5

Organo-montmorillonite (OMMT) has attracted much attention for fiber-reinforced polymer composites as a filler material due to high aspect ratio and low charge density. The present study focused on the fabrication of nanocomposites using Vinyl ester and Jute fabric as matrix and reinforcement respectively. The OMMT was uniformly dispersed in vinyl ester resin at 1, 2 and 3 wt%, loading through high speed mechanical stirrer at room temperature and further nanocomposites were manufactured through vacuum assisted resin infusion (VARI) technique. Effects of OMMT on the mechanical properties of vinyl ester/Jute composites were carefully investigated through tensile, bending and Izod impact tests, which revealed significant improvement in mechanical properties. The morphology of the nanocomposites after tensile test was investigated by SEM which affirmed that OMMT filled nanocomposites has improved interactions with the host matrix than the pure composites. Based on the nature and flame retardancy mechanism, the OMMT slightly improved the flammability property which was clearly explained by horizontal burning test.

Federated Learning for Cellular Networks: Joint User Association and Resource Allocation

Latif U. Khan,Umer Majeed,Choong Seon Hong 한국통신학회 2020 한국통신학회 APNOMS Vol.2020 No.09

Recent years have shown a remarkable interest in federated learning from researchers to make several Internet of Things applications smart. Although, federated learning offers users’ privacy preservation, it has communication resources optimization challenge. In this paper, we consider federated learning for cellular networks. We formulate an optimization problem to jointly minimizes latency and effect of loss in federated learning model accuracy due to channel uncertainties. We decompose the main optimization problem into two sub-problems: resource allocation and device association sub-problems, due to the NP-hard nature of the main optimization problem. To solve these sub-problems, we propose an iterative approach which further uses efficient heuristic algorithms for resource blocks allocation and device association. Finally, we provide numerical results for the validation of our proposed scheme.

Neuro-Evolution Assisted Wireless Sensor Network Data Reconstruction

Latif U. Khan,Saeed Ullah,Choong Seon Hong 한국정보과학회 2018 한국정보과학회 학술발표논문집 Vol.2018 No.6

Industrial Internet of Things Based Efficient and Reliable Data Dissemination Solution for Vehicular Ad Hoc Networks

Latif, Shahid,Mahfooz, Saeed,Ahmad, Naveed,Jan, Bilal,Farman, Haleem,Khan, Murad,Han, Kijun WILEY INTERSCIENCE 2018 WIRELESS COMMUNICATIONS AND MOBILE COMPUTING Vol.2018 No.-

<P>Industrial Internet of Things (IIoT) is the other name of industrial Internet. It integrates a variety of existing industrial automation technologies with computing, machine learning, and communication technologies. Vehicular ad hoc network, an application of IIoT, is a self-organized network of vehicles which tends to provide improved road safety, diminished traffic congestion, and ultimate comfort to the travellers. In VANETs, vehicles exchange data with each other directly or through roadside units (RSUs). Data dissemination in VANETs experiences numerous challenging issues including broadcast storm, network partitions, intermittent connectivity between vehicles, and limited bandwidth. In literature, various data dissemination schemes are proposed. However, most of these schemes are designed for either urban or highway VANET scenarios and evaluated under sparse or dense traffic conditions. Moreover, these schemes do not effectively overcome the aforementioned issues simultaneously. In this paper, we present a new data dissemination protocol for VANETs, which disseminates the emergency messages in different scenarios under varying traffic conditions. During dense traffic conditions, DDP4V employs the segmentation of transmission region of a vehicle in order to select the most appropriate next forwarding vehicle (NFV). Accordingly, it divides the transmission region of a vehicle in three distinct segments and selects vehicle(s) inside the highest priority segment to forward the message to all neighbour vehicles, whereas it also uses implicit acknowledgements for guaranteed message delivery during sparse traffic Conditions. Simulation results show that DDP4V protocol outperforms the other existing related protocols in terms of coverage, network overhead, collision, and end-to-end delay.</P>

Development of Hybrid Composites with Improved Mechanical and Self-healing Properties

Latif, Muhammad,Kumar, C. Naga,Prabhakar, M.N.,Song, Jung-il 한국섬유공학회 2019 Fibers and polymers Vol.20 No.2

Multivariate design estimations under copulas constructions. Stage-1: Parametrical density constructions for defining flood marginals for the Kelantan River basin, Malaysia

Latif, Shahid,Mustafa, Firuza Techno-Press 2019 Ocean systems engineering Vol.9 No.3

Comprehensive understanding of the flood risk assessments via frequency analysis often demands multivariate designs under the different notations of return periods. Flood is a tri-variate random consequence, which often pointing the unreliability of univariate return period and demands for the joint dependency construction by accounting its multiple intercorrelated flood vectors i.e., flood peak, volume & durations. Selecting the most parsimonious probability functions for demonstrating univariate flood marginals distributions is often a mandatory pre-processing desire before the establishment of joint dependency. Especially under copulas methodology, which often allows the practitioner to model univariate marginals separately from their joint constructions. Parametric density approximations often hypothesized that the random samples must follow some specific or predefine probability density functions, which usually defines different estimates especially in the tail of distributions. Concentrations of the upper tail often seem interesting during flood modelling also, no evidence exhibited in favours of any fixed distributions, which often characterized through the trial and error procedure based on goodness-of-fit measures. On another side, model performance evaluations and selections of best-fitted distributions often demand precise investigations via comparing the relative sample reproducing capabilities otherwise, inconsistencies might reveal uncertainty. Also, the strength & weakness of different fitness statistics usually vary and having different extent during demonstrating gaps and dispensary among fitted distributions. In this literature, selections efforts of marginal distributions of flood variables are incorporated by employing an interactive set of parametric functions for event-based (or Block annual maxima) samples over the 50-years continuously-distributed streamflow characteristics for the Kelantan River basin at Gulliemard Bridge, Malaysia. Model fitness criteria are examined based on the degree of agreements between cumulative empirical and theoretical probabilities. Both the analytical as well as graphically visual inspections are undertaken to strengthen much decisive evidence in favour of best-fitted probability density.

Vertebral Endplate Changes Correlate with Presence of Cartilaginous Endplate in the Herniated Disc Tissue: Factor Predicting Failure of Conservative Treatment

Latif Rabia,Imran Sumera,Ahmad Ijaz,Ilyas Muhammad Saad,Aziz Amer,Zehra Uruj 대한척추외과학회 2022 Asian Spine Journal Vol.16 No.2

Study Design: Cross-sectional comparative. Purpose: To characterize the scores of disc degeneration, inflammation, and nerve density in herniated disc samples and associate findings with the presence of vertebral endplate (VEP) changes on magnetic resonance imaging (MRI). Overview of Literature: Considering the role of disc composition in spontaneous regression and persistence of pain during conservative management, it is important to identify the influencing factors. VEP changes are highly associated with disc degeneration, but their correlation with herniated disc composition has not yet been reported. Methods: Fifty-one discs were obtained from patients undergoing surgery for herniated disc. Their ages ranged from 19-65 years, and 31/51 were male. Pre-surgical T1 and T2 weighted lumbar-spine MRIs were analyzed to observe Pfirrmann grade, VEP defects, herniation type, Modic changes, and high-intensity zones (HIZ) at the affected level. Five-micron thick sections were stained with hematoxylin and eosin, Alcian blue periodic acid–Schiff stain; examined for histological degeneration scores (HDS; 0–15), inflammation (0 [absence]–3 [severe]), and presence of cartilaginous endplate (CEP). Three-micron thick sections were stained with protein-gene-product 9.5 and expression was counted/mm2. Data was analyzed, and p<0.05 was considered to indicate statistical significance. Results: VEP defects, Modic changes, and HIZ were respectively observed in 30/51, 16/51, and 6/51 of the samples. CEP was observed in 26/51 samples and in 23/51 with endplate defects. Discs with adjacent VEP defects showed increased HDS (p<0.001) and inflammation (p<0.001). Discs with adjacent Modic changes also revealed increased HDS (p=0.01). Histological sections with CEP showed increased HDS (p<0.001) and inflammation (p<0.001), and nerve density was significantly positively correlated with HDS (r=0.27, p=0.02). Conclusions: VEP changes can modulate degeneration and inflammation of herniated discs. Presence of these changes is highly predictive of the occurrence of CEP in herniated discs, which leads to slow resorption and persistent clinical symptoms.

Synthesis and Biological Evaluation of Tetrapeptide Ketones as Reversible 20S Proteasome Inhibitors

Latif, Muhammad,Jung, Myoung Eun,Lee, Kwangho,Choi, Gildon Korean Chemical Society 2014 Bulletin of the Korean Chemical Society Vol.35 No.12

Proteasome, a multicatalytic protease complex, has been validated as a promising therapeutic target in oncology. Carfilzomib (Kyprolis$^{(R)}$), a tetrapeptide epoxyketone, irreversibly inhibits the chymotrypsin-like (CT-L) activity of the proteasome and has been recently approved for multiple myeloma treatment by FDA. A chemistry effort was initiated to discover the compounds that are reversibly inhibit the proteasome by replacing the epoxyketone moiety of carfilzomib with a variety of ketones as reversible and covalent warheads at the C-terminus. The newly synthesized compounds exhibited significant inhibitory activity against CT-L activity of the human 20S proteasome. When the compounds were tested for cancer cell viability, 14-8 was found to be most potent in inhibiting Molt-4 acute lymphoblastic leukemia cell line with a $GI_{50}$ of $4.4{\mu}M$. Cytotoxic effects of 14-8 were further evaluated by cell cycle analysis and Western blotting, demonstrating activation of apoptotic pathways.

Stereoselective Construction of 2,6-<i>cis</i>-Disubstituted Tetrahydropyrans via Intramolecular Amide Enolate Alkylation: Total Synthesis of (−)-Centrolobine

Latif, Muhammad,Yun, Jeong In,Seshadri, Kalapati,Kim, Hyoung Rae,Park, Chi Hoon,Park, Haeil,Kim, Hyoungsu,Lee, Jongkook American Chemical Society 2015 Journal of organic chemistry Vol.80 No.6

<P>A highly stereoselective construction of 2,6-cis-disubstituted tetrahydropyrans was achieved by using an intramolecular amide enolate alkylation with KHMDS. The efficiency and practicality of this methodology was successfully demonstrated in the total synthesis of (-)-centrolobine (1).</P>