Influence of pozzolans on properties of cementitious materials: A review

Garg, Rishav,Garg, Rajni,Eddy, Nnabuk Okon Techno-Press 2021 Advances in nano research Vol.11 No.4

Use of additives/supplementary materials in partial substitution of cement is gaining widespread attention across the world due to the sustainability issue with production of cement. With their pozzolanic activity & filler effect, use of nano-pozzolans such as nano-silica has been proved as quite promising & cost-effective for use as supplementary cementitious materials. This study is aimed at highlighting the effect of partial substitution of cement/addition of various nano-pozzolans on the hydration, strength and microstructure of the cementitious materials. Further, the effect of incorporation of other pozzolans has also been discussed. Comparative account of pozzolanic activity of different pozzolans has also been critically analyzed. It has been found that the cement matrix gets improved in terms of its microstructure by partial substitution of cement/addition of pozzolan in appropriate amount resulting in enhancement of the bulk properties by consumption of portlandite. The improved compressive strength of cementitious materials not only results in enhancement of the durability but also the service life of the construction structures and results in reduction of the cost incurred in maintenance and repair. Thus, the cement demand can be decreased by the partial substitution of cement/addition of such materials. It will result in an ultimate reduction of the greenhouse effect and lead to sustainable development.

Experimental Investigation of Electrochemical Corrosion and Chloride Penetration of Concrete Incorporating Colloidal Nanosilica and Silica Fume

Garg, Rishav,Garg, Rajni,Singla, Sandeep The Korean Electrochemical Society 2021 Journal of electrochemical science and technology Vol.12 No.4

Enhancement of durability and reduction of maintenance cost of concrete, with the implementation of various approaches, has always been a matter of concern to researchers. The integration of pozzolans as a substitute for cement into the concrete is one of the most desirable technique. Silica fume (SF) and colloidal nanosilica (CS) have received a great deal of interest from researchers with their significant performance in improving the durability of concrete. The synergistic role of the micro and nano-silica particles in improving the main characteristics of cemented materials needs to be investigated. This work aims to examine the utility of partial substitution of cement by SF and CS in binary and ternary blends in the improvement of the durability characteristics linked to resistance for electrochemical corrosion using electrical resistivity and half-cell potential analysis and chloride penetration trough rapid chloride penetration test. Furthermore, the effects of this silica mixture on the compressive strength of concrete under normal and aggressive environment have also been investigated. Based on the maximum compression strength of the concrete, the optimal cement substituent ratios have been obtained as 12% SF and 1.5% CS for binary blends. The optimal CS and SF combination mixing ratios has been obtained as 1.0% and 12% respectively for ternary blends. The ternary blends with substitution of cement by optimal percentage of CS and SF exhibited decreased rate for electrochemical corrosion. The strength and durability studies were found in consistence with the microstructural analysis signifying the beneficiary role of CS and SF in upgrading the performance of concrete.

Manganese(II) and Dioxomolybdenum(VI) Complexes with Monobasic Bidentate Schiff Bases : Synthesis, Characterization and Biological Investigation

Garg, Rekha,Kumari, Anita,Joshi, S.C.,Fahmi, Nighat Korean Chemical Society 2013 Bulletin of the Korean Chemical Society Vol.34 No.8

A new series of Mn(II) and Mo(VI) complexes containing the Schiff bases hydrazinecarbothioamide and hydrazinecarboxamide of 5,6-dimethyl-1H-indol-2,3-dione have been synthesized. The nature of bonding and the stereochemistry of the complexes have been deduced from elemental analyses, molecular weight determinations and spectral studies viz. electronic IR, ESR, $^1H$ NMR and $^{13}C$ NMR and X-ray diffraction spectral studies. The magnetic moment values of the manganese(II) complexes are in the range of 5.80-6.15 B.M. suggesting a high spin state of manganese in these complexes. The spectral data are consistent with a tetrahedral geometry around Mn(II) and an octahedral geometry for Mo(VI), in which the ligands act as bidentate chelating agents, coordinated through the nitrogen and sulfur/oxygen atoms. The ligands and their metal complexes have been tested against a number of pathogenic fungi and bacteria at different concentrations and were found to possess sufficient fungicidal and bactericidal properties. Further, the complexes were also tested for their antifertility activity in male albino rats and the results were indeed positive.

CERTAIN INTEGRAL RELATIONS INVOLVING H-FUNCTION OF TWO VARIABLES

Garg, Om Prakash Department of Mathematics 1976 Kyungpook mathematical journal Vol.16 No.2

Blunt Trauma Pancreas in Children: Is Non-Operative Management Appropriate for All Grades?

Garg, Ravi Kumar,Mahajan, Jai Kumar The Korean Society of Pediatric Gastroenterology 2017 Pediatric gastroenterology, hepatology & nutrition Vol.20 No.4

Purpose: Blunt trauma of pancreas in children is uncommon and its management varies from observational to early operative intervention. We analysed the feasibility and outcome of non-operative management in all grades of paediatric pancreatic injuries. Methods: A total of 15 patients of pancreatic trauma seen in a Paediatric Surgery Unit were retrospectively analyzed. Results: Age of the patients ranged from 3-11 years (mean, 7.7 years). The mode of injury was local trauma in 9 children. Only 3 patients had associated injuries and all were haemodynamically stable. Serum amylase levels were raised in 12 patients at admission which ranged from 400-1,000 IU. Computed tomography scan made a correct diagnosis in 14 patients. Grades of the injury varied from grade I-V (1, 3, 6, 4, 1 patients respectively). Fourteen patients were managed conservatively. One patient underwent laparotomy for suspected superior mesenteric hematoma. The average duration of enteral feeds was 3.7 days and of hospital stay was 9.4 days. Six patients formed pancreatic pseudocysts; two were managed conservatively while the other four underwent cystogastrostomy. The patients were followed up for a period of 1-12 years. All remained asymptomatic and none had exocrine or endocrine deficiencies. Conclusion: Non-operative treatment for isolated blunt trauma of pancreas in children may be safely followed for all the grades of injury; if associated injuries requiring surgical intervention are ruled out with a good quality imaging and the patients are hemodynamically stable. It did not increase the hospital stay and morbidity and avoided operative intervention on acutely injured pancreas.

RECURRENCES FOR THE H-FUNCTION OF TWO VARIABLES

Garg, O.P.,Rastogi, V.K. Department of Mathematics 1982 Kyungpook mathematical journal Vol.22 No.1

EFFECT OF SUPPLEMENTING UREA MOLASSES MINERAL BLOCK LICKS ON BACTERIAL PRODUCTION RATE IN THE RUMEN OF CROSSBRED CALVES

Garg, M.R.,Gupta, B.N. Asian Australasian Association of Animal Productio 1992 Animal Bioscience Vol.5 No.3

Sixteen crossbred (Sahiwal $\times$ Holstein) male rumen fistulated calves of 18 to 24 months of age were randomly divided into four groups of four animal, each. Animals in all the groups were fed wheat straw ad lib as basal roughage. However, the animals in group I were fed concentrate mixture at maintenance level, whereas, the animals in groups II, III and IV had free access to existing, modified (A) and modified (B) urea molasses mineral block licks respectively. Daily wheat straw intake (kg) was significantly (p<0.01) higher in groups II ($4.20{\pm}0.13$), III ($4.07{\pm}0.16$) and IV ($4.22{\pm}0.20$) as compared to group I ($3.21{\pm}0.14$). Total N and TCA precistrained rumen liquor) was significantly higher in groups II ($22.36{\pm}0.25$), III ($21.63{\pm}0.25$) and IV ($21.77{\pm}0.55$) as compared to group I ($18.31{\pm}0.41$). Bacterial production rate (g/day and g/kg digestible organic matter intake) were non-significantly different amongst groups I ($214.4{\pm}13.28;\;85.38{\pm}3.69$); II ($198.7{\pm}5.70;\;86.17{\pm}3.53$); III ($214.4{\pm}8.19;\;96.15{\pm}2.16$) and IV ($218.2{\pm}10.62;\;94.44{\pm}5.52$). Similarly, percent efficiency of N incorporation into bacterial protein was not found significantly different amongst groups I, II, III and IV. These studies indicate that when concentrate mixture (upto maintenance level) in the diet of ruminants was replaced with UMMB licks, various N fraction in SRL and efficiency of bacterial production rates in the rumen were not affected.

Giant Duplication Cyst Presenting as a Discharging Umbilicus

Garg, Ravi Kumar,Bawa, Monika,Rao, Katragadda Lakshmi Narasimha The Korean Society of Pediatric Gastroenterology 2017 Pediatric gastroenterology, hepatology & nutrition Vol.20 No.3

Alimentary tract duplication cysts are rare congenital anomalies, most commonly located in the ileum, but may present anywhere from mouth to anus.Clinically, they may be asymptomatic, incidentally diagnosed or may present with obstruction, volvulus, intussusception or gastrointestinal bleed. Here we report a case of a one year old male child presenting in gasping state and shock. Despite the initial strong suspicion of Meckel's diverticulum and tubercular abdomen, the final diagnosis remained elusive till exploratory laparotomy was performed which revealed a duplication cyst of ileum with perforation into the umbilicus. Duplication cyst should always be kept as a differential diagnosis so that early intervention can help in better management.

NUTRIENT UTILIZATION, GROWTH RATE AND BODY COMPOSITION OF CROSSBRED CALVES SUPPLEMENTED WITH UREA MOLASSES MINERAL BLOCK LICKS

Garg, M.R.,Gupta, B.N. Asian Australasian Association of Animal Productio 1993 Animal Bioscience Vol.6 No.3

Twenty male crossbred ($Sahiwal{\times}HF$) calves of about 6-9 months of age were divided into four groups of five animals each. All the animals were offered wheat straw ad lib. As the basal feed. However, animals in group I were fed concentrate mixture while the animals in groups II, III and IV had free access to urea molasses mineral block (UMMB) lick (I), (II) and (III) respectively as a partial substitute of concentrate mixture. The average concentrate offered (kg/day) to the animals was significantly (p<0.01) higher in group I ($2.69{\pm}0.18$) compared to groups II ($1.76{\pm}0.15$), III ($1.70{\pm}0.06$) and IV ($1.65{\pm}0.12$). The UMMB lick consumed was non-significantly different amongst groups I ($535.40{\pm}38.14$), II ($525.60{\pm}31.82$), III ($551.00{\pm}38.49$) and IV ($548.80{\pm}45.46$). Except ether extract, the digestibility coefficients of CP, ADF and NDF were non-significantly different in different groups. Similarly, N balance (g/day) and percent N retention of intake was not affected in different groups on supplementation of UMMB lick. Body composition of animals was similar in different groups supplemented with either concentrate mixture or concentrate mixture and UMMB licks. It may be concluded from these studies that UMMB lick can partially replace the concentrate mixture in the diet of growing calves without affecting the growth rate, nutrient utilization and body composition. The UMMB lick, thus, can form a part of the ration economically in the diet of growing ruminants especially in developing countries.

Role of Bypass Protein in Feeding Ruminants on Crop Residue Based Diet - Review -

Garg, Manget Ram Asian Australasian Association of Animal Productio 1998 Animal Bioscience Vol.11 No.2

Measurement of DCP is considered inadequate and unsatisfactory means of assessing the protein value of the diet as no distinction is made between the digestion in ferestomach and in the small intestine. Protein meals should be classified on the basis of rumen degradable protein (RDP) and rumen undegradable protein (UDP). Usually, protein meals naturally available with high level of UDP or bypass protein value should be preferred for incorporation in the diet of lactating and growing animals. However, if such resources are non-available or are expensive, protein meals having high degradability can be carefully subjected to heat or formaldehyde treatment to achieve desired level of rumen bypassability. Various studies conducted the world over have revealed that bypass protein feeding to ruminants, especially when animals are fed on crop residue based basal diet, help increasing feed conversion efficiency in growing and lactating ruminants.