Analysis of stress block parameters for high strength concrete

Brijesh Singh,Vikas Patel,P. N. Ojha,V. V. Arora 아시아콘크리트학회 2020 Journal of Asian Concrete Federation Vol.6 No.1

In Indian Standard code IS: 456-2000 for concrete of grades higher than M55, the design parameters given may not be applicable as structural behaviour of concrete changes as strength of concrete increases. Different international standards give different stress block parameters which can be reduced to these two basic factors. In this paper, stress block parameters K (strength reduction factor) and k2 (factor for the depth of resultant compressive force) were calculated from experimental strain values considering the stress-strain curve as parabolic for lower grades and as linear for higher grades. Also, the method and approach for the calculation of stress block parameters have been worked out. The method so proposed is compared with the model proposed in European design standard EC: 02-2004 by trans-forming the European stress block parameters to the basic parameters used. Also, the effect of the shape of the stress-strain curve and value of ultimate strain in concrete on stress block parameters and moment capacity of the members was analyzed by working on the representative section. The method or approach so proposed will be useful to understand and compare flexural design philosophies used in different international standards by reducing the stress block parameters to two basic factors.

Empirical equation and experimental validation of shear parameters for high strength concrete (HSC)

Brijesh Singh,Ojha P N,Patel Vikas,Trivedi Amit,Singh Abhishek 아시아콘크리트학회 2021 Journal of Asian Concrete Federation Vol.7 No.2

With many benefits of the high strength concrete (HSC) the more brittle behaviour that leads to sudden failure makes it important for proper understanding of its behaviour and safe and efficient estimation of capacities. Research on the behaviour of HSC has been extensively carried out since last decade. HSC has higher tensile strength hence a higher cracking shear can be expected. This paper analyzes the different international standards available for estimating concrete’s component of shear strength for reinforced cement concrete (RCC) beam. Different important factors mainly strength in compression, steel reinforcement (dowel action), ratio of shear span and depth, size effect i.e. depth along with the aggregate type (density of concrete) contributing to shear stress (Tc) of concrete has been also analyzed and thereafter, an equation has been proposed to compute or predict Tc value for concrete of both normal and higher grade or strength. The proposed equation has been validated by experimental results wherein 12 RCC beams (with and without reinforcement for shear) were cast and tested to fail in shear. The experimental results validated the proposed equation with considerable factor of safety keeping in view the sudden and brittle nature of failure in concrete in case of shear.

RESEARCH : Open Access ; Effect of misting and wallowing cooling systems on milk yield, blood and physiological variables during heat stress in lactating Murrah buffalo

( Brijesh Yadav ),( Vijay Pandey ),( Sarvajeet Yadav ),( Yajuvendra Singh ),( Vinod Kumar ),( Rajneesh Sirohi ) 한국동물자원과학회(구 한국축산학회) 2016 한국축산학회지 Vol.58 No.1

Background: Heat stress adversely affects the physiological and metabolic status, and the productive performance of buffalo. Methods: The present study was conducted to explicate the effect of misting and wallowing cooling strategies during heat stress in lactating Murrah buffalo. The study was conducted for three months (May.July) of which first two months were hot dry and last month was hot humid. Eighteen lactating buffaloes, offered the same basal diet, were blocked by days in milk, milk yield and parity, and then randomly allocated to three treatments: negative control (no cooling), cooling by misting, and cooling by wallowing. Results: The results showed higher (P < 0.05) milk yield in buffaloes of misting and wallowing group compared to control during the experimental period however wallowing was found more (P < 0.05) effective during July (hot humid period). Both the treatments resulted into significant (P < 0.05) reduction in rectal temperature (RT) and respiratory rate (RR) compared to control animals during study period whereas wallowing was found to be effective on pulse rate (PR) only during July. Both treatments were resulted in mitigating the heat stress mediated decrease in packed cell volume (PCV), lymphocytopnoea and neutrophilia whereas decrease in total erythrocyte count (TEC) and monocytes was only mitigated by wallowing. Heat load induced alteration in serum creatinine and sodium concentration was significantly (P < 0.05) ameliorated by misting and wallowing whereas aspartate aminotransferase, alkaline phosphatase and superoxide dismutase activity, and reactive oxygen species concentration could be normalized neither by misting nor by wallowing. The significant (P < 0.05) increment in serum cortisol and prolactin levels observed in June and July period in control animals was significantly (P < 0.05) prevented by misting and wallowing. Conclusions: It can be concluded that misting and wallowing were equally effective in May and June (hot dry period) whereas wallowing was more effective during hot humid period in preventing a decline in milk production and maintaining physiological, metabolic, endocrine and redox homeostasis.

Adsorption of chlorhexidine digluconate on acid modified flyash : Kinetics, isotherms and influencing factors

Astha Singh,Sonalika Sonal,Rohit Kumar,Brijesh Kumar Mishra 대한환경공학회 2020 Environmental Engineering Research Vol.25 No.2

Chlorhexidine digluconate (CHD) in the aquatic environment causes irreversible change to microbes, making them resistant to biodegradation, which needs remediation other than biological process. Adsorption study was performed for the removal of CHD on fly ash (FA) as a function of pH and ionic strength. Experimental result has been validated by characterization using Scanning electron microscopy, Fourier Transform-Infrared Spectroscopy and Brunauer-Emmett-Teller. CHD adsorption with FA showed an increasing trend with an increase in pH. Variation in pH proved to be an influential parameter for the surface charge of adsorbent and the degree of ionization of the CHD molecules. The adsorption capacity of CHD decreased from 23.60 mg g-1 to 1.13 mg g-1, when ionic strength increased from to M. The adsorption isotherms were simulated well by the Freundlich isotherm model having R2 = 0.98. The Lagergren’s model was incorporated to predict the system kinetics, while the mechanistic study was better explained by pseudo-second order for FA. On the basis of operational conditions and cost-effectiveness FA was found to be more economical as an adsorbent for the adsorption of CHD.

Removal of chlorhexidine digluconate from aqueous solution by heterogenous photocatalysis using sunlight-driven Ni-doped TiO2 material

Astha Singh,Brijesh Kumar Mishra 대한환경공학회 2023 Environmental Engineering Research Vol.28 No.1

Photoactive Ni-TiO2 was synthesized through green hydrothermal method with preferential photocatalytic performance in visible and solar light for synthetic and formulated wastewater treatment. Incorporation of this transition metal into TiO2 was examined by XRD, FTIR, UV–visible DRS, XPS, SEM-EDS and HRTEM analysis. According to the Langmuir–Hinshelwood model, the photodegradation of the chlorhexidine digluconate under solar (R2=0.986) and simulated visible light (R2=0.982), follows a pseudo-first-order kinetics. The interaction of operational fractions, such as S/C ratio, irradiation time, and pH of the reaction mixture, were evaluated using the RSM. Although complete mineralization of CHD was not achieved using Ni-TiO2 under visible light, but the parent compound was mineralized to some extent, as demonstrated by TOC reduction (85.71%-synthetic wastewater and 61.17%-formulated wastewater), UV254 (89.91% synthetic wastewater and 55.39%-formulated wastewater) and UV280 (68.23%-synthetic wastewater and 68.23%-formulated wastewater) absorbance variations. Based on the identified transformed products, the possible degradation pathway was proposed and bacterial susceptibility test on Bacillus cereus DPAML065 was performed to evaluate the toxicity of oxidation intermediates. Comparative studies about energy consumption and removal efficiency during simulated visible light/Ni-TiO2 and sunlight/Ni-TiO2 mediated treatment system for formulated wastewater revealed that sunlight/Ni-TiO2 mediated treatment system was high energy efficient (1.67 kWhKg−1) system.

Removal of chlorhexidine digluconate from aqueous solution by heterogenous photocatalysis using sunlight-driven Ni-doped TiO₂ material

Astha Singh,Brijesh Kumar Mishra 대한환경공학회 2023 Environmental Engineering Research Vol.28 No.1

Photoactive Ni-TiO₂ was synthesized through green hydrothermal method with preferential photocatalytic performance in visible and solar light for synthetic and formulated wastewater treatment. Incorporation of this transition metal into TiO₂ was examined by XRD, FTIR, UV–visible DRS, XPS, SEM-EDS and HRTEM analysis. According to the Langmuir–Hinshelwood model, the photodegradation of the chlorhexidine digluconate under solar (R²=0.986) and simulated visible light (R²=0.982), follows a pseudo-first-order kinetics. The interaction of operational fractions, such as S/C ratio, irradiation time, and pH of the reaction mixture, were evaluated using the RSM. Although complete mineralization of CHD was not achieved using Ni-TiO₂ under visible light, but the parent compound was mineralized to some extent, as demonstrated by TOC reduction (85.71%-synthetic wastewater and 61.17%-formulated wastewater), UV<SUB>254</SUB> (89.91% synthetic wastewater and 55.39%-formulated wastewater) and UV<SUB>280</SUB> (68.23%-synthetic wastewater and 68.23%-formulated wastewater) absorbance variations. Based on the identified transformed products, the possible degradation pathway was proposed and bacterial susceptibility test on Bacillus cereus DPAML065 was performed to evaluate the toxicity of oxidation intermediates. Comparative studies about energy consumption and removal efficiency during simulated visible light/Ni-TiO₂ and sunlight/ Ni-TiO₂ mediated treatment system for formulated wastewater revealed that sunlight/ Ni-TiO₂ mediated treatment system was high energy efficient (1.67 kWhKg<SUP>-1</SUP>) system.

Assessment of kinetics behavior of electrocoagulation process for the removal of suspended solids and metals from synthetic water

Hariraj Singh,Brijesh Kumar Mishra 대한환경공학회 2017 Environmental Engineering Research Vol.22 No.2

Globalization, industrialization, mining, and uncontrolled population growth have fostered a shortage of potable water. Therefore, it has become imperative to understand an effective and reasonable water purification technique. A renewed interest in electrocoagulation (EC) has been spurred by the search for reliable, cost-effective, water-treatment processes. This paper has elucidated a technical approach for getting rid of heavy metals and total suspended solids (TSS) from synthetic water using an aluminum electrode. The effect of operational parameters, such as current density, inter-electrode distance, operating time, and pH, were studied and evaluated for maximum efficiency. This study corroborates the correlation between current density and removal efficiency. Neutral pH and a low electrode gap have been found to aid the efficacy of the EC setup. The outcome indicates that a maximum TSS removal efficiency of 76.6% occurred at a current density of 5.3 mA/cm² during a contact time of 30 min. In the case of heavy metals remediation, 40 min of process time exhibited extremely reduced rates of 99%, 59.2%, and 82.1%, for Cu, Cr, and Zn, respectively. Moreover, kinetic study has also demonstrated that pollutants removal follows first-and second-order model with current density and EC time being dependent.

Effect of Simulated Heat Stress on Digestibility, Methane Emission and Metabolic Adaptability in Crossbred Cattle

Yadav, Brijesh,Singh, Gyanendra,Wankar, Alok,Dutta, N.,Chaturvedi, V.B.,Verma, Med Ram Asian Australasian Association of Animal Productio 2016 Animal Bioscience Vol.29 No.11

The present experiment was conducted to evaluate the effect of simulated heat stress on digestibility and methane ($CH_4$) emission. Four non-lactating crossbred cattle were exposed to $25^{\circ}C$, $30^{\circ}C$, $35^{\circ}C$, and $40^{\circ}C$ temperature with a relative humidity of 40% to 50% in a climatic chamber from 10:00 hours to 15:00 hours every day for 27 days. The physiological responses were recorded at 15:00 hours every day. The blood samples were collected at 15:00 hours on 1st, 6th, 11th, 16th, and 21st days and serum was collected for biochemical analysis. After 21 days, fecal and feed samples were collected continuously for six days for the estimation of digestibility. In the last 48 hours gas samples were collected continuously to estimate $CH_4$ emission. Heat stress in experimental animals at $35^{\circ}C$ and $40^{\circ}C$ was evident from an alteration (p<0.05) in rectal temperature, respiratory rate, pulse rate, water intake and serum thyroxin levels. The serum lactate dehydrogenase, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase activity and protein, urea, creatinine and triglyceride concentration changed (p<0.05), and body weight of the animals decreased (p<0.05) after temperature exposure at $40^{\circ}C$. The dry matter intake (DMI) was lower (p<0.05) at $40^{\circ}C$ exposure. The dry matter and neutral detergent fibre digestibilities were higher (p<0.05) at $35^{\circ}C$ compared to $25^{\circ}C$ and $30^{\circ}C$ exposure whereas, organic matter (OM) and acid detergent fibre digestibilities were higher (p<0.05) at $35^{\circ}C$ than $40^{\circ}C$ thermal exposure. The $CH_4$ emission/kg DMI and organic matter intake (OMI) declined (p<0.05) with increase in exposure temperature and reached its lowest levels at $40^{\circ}C$. It can be concluded from the present study that the digestibility and $CH_4$ emission were affected by intensity of heat stress. Further studies are necessary with respect to ruminal microbial changes to justify the variation in the digestibility and $CH_4$ emission during differential heat stress.

ID- Based Authentication for WiMAX

Pushpi Rani1,Brijesh Kumar Chaurasia,Geetam Singh Tomar 보안공학연구지원센터 2016 International Journal of Future Generation Communi Vol.9 No.2

WiMAX is broadband wireless system being used for long range wireless networking, which makes this system vulnerable to security breaches. In this paperwe present authentication scheme using ID-based signature scheme for WiMAX, which offers a certificate-less public key verification. The proposed scheme has also increased message processing throughput as it has used elliptic curve cryptosystem, sigencryption and identity based cryptography.

Token Based Trust Computation in VANET

Kapil Sharma,Brijesh Kumar Chaurasia,Shekhar Verma,Geetam Singh Tomar 보안공학연구지원센터 2016 International Journal of Grid and Distributed Comp Vol.9 No.5

In vehicular ad hoc network or VANET, the safety related messages broadcast by vehicles is used by other vehicles to make critical decisions. This may trap a vehicle taking wrong decision with dire consequences and authenticated vehicles or malicious vehicles may also broadcast wrong messages. This necessitates those messages of vehicles to be trusted after authentication process of vehicles, especially in the absence of centralized authority. In this paper, token based trust computation based on network connectivity duration of vehicles in VANET is proposed. The proposed technique is based on travelling time association among vehicles or network connectivity of vehicle at the time of driving on the road. We present simulations of the proposed technique that verify its correctness and reliability in the presence of infrastructure and absence of infrastructure. Results show that the efficacy of the proposed scheme and makes it viable for secure and lightweight trusted communication in a VANET.