Comparative Atomic Charges on Na+-(H2O)n (n = 1–6) Clusters

Nizam Uddin,최철호 대한화학회 2015 Bulletin of the Korean Chemical Society Vol.36 No.3

The performance of our mean gradient charge (MGC) concept was systematically investigated by adopting Na+-(H2O)n (n = 1–6) model clusters. The Mulliken charges are sensitive to the choice of theories and basis sets, and ChelpG charges abnormally behave with the system size. MGC and “atoms-in-molecules” (AIM) show small mean standard deviations (~0.02) with the choice of the theory and the basis set. However, an unpredictable value was found in AIM predictions. Both natural population analysis (NPA) and MGC yielded smooth and monotonic curves as a function of the system size. Therefore, MGC appears to have desirable properties in the consistent and reliable predictions of atomic charges.

Hydrothermal carbonization of oil palm shell

Sabzoi Nizamuddin,Natesan Subramanian Jayakumar,Jaya Narayan Sahu,Poobalan Ganesan,Abdul Waheed Bhutto,Nabisab Mujawar Mubarak 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.9

Palm shell is one of the most plentiful wastes of the palm oil mill industry. This study identifies the capability of hydrothermal carbonization process (HTC) to convert palm shell into high energy hydrochar. The influence of reaction time and reaction temperature of the HTC process was investigated. The process parameters selected were temperature 200 oC to 240 oC, time 10 to 60min, and water to biomass ratio was fixed at 10 : 1 by weight %. Fourier transform infrared (FTIR), elemental, proximate, Burner Emmett and Teller (BET), thermo-gravimetric (TGA) analyses were performed to characterize the product and the feed. The heating value (HHV) was increased from 12.24 MJ/ kg (raw palm shell) to 22.11 MJ/kg (hydrochar produced at 240 oC and 60 min). The hydrochar yield exhibited a higher degree inverse proportionality with temperature and reaction time. Elemental analysis revealed an increase in carbon percentage and a proportional decrease in hydrogen and oxygen contents which caused higher value of HHV. The dehydration and decarboxylation reactions take place at higher temperatures during HTC resulting in the increase of carbon and decrease in oxygen values of hydrochar. The FESEM results reveal that the structure of raw palm shell was decomposed by HTC process. The pores on the surface of hydrochar increased as compared to the raw palm shell.

Flow Analyses Inside Jet Pumps Used for Oil Wells

Samad, Abdus,Nizamuddin, Mohammad Korean Society for Fluid machinery 2013 International journal of fluid machinery and syste Vol.6 No.1

Jet pump is one type of artificial lifts and is used when depth and deviation of producing wells increases and pressure depletion occurs. In the present study, numerical analysis has been carried out to analyze the flow behavior and find the performance of the jet pump. Reynolds-averaged Navier Stokes equations were solved and k-${\varepsilon}$ turbulence model was used for simulations. Water and light oil as primary fluids were used to pump water, light oil and heavy oil. The ratios of area and length to diameter of the mixing tube were considered as design parameters. The pump efficiency was considered to maximize for the downhole conditions. It was found that the increase in viscosity and density of the secondary fluid reduced efficiency of the system. Water as primary fluid produced better efficiency than the light oil. It was also found that the longer throat length increased efficiency upto 40% if light oil was used as primary fluid and secondary fluid viscosity was 350 cSt.

Design and Comparative Analysis of High Performance Carbon Nanotube-Based Operational Transconductance Amplifiers

Sajad A. Loan,M. Nizamuddin,Abdul R. Alamoud,Shuja A. Abbasi 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2015 NANO Vol.10 No.3

In this paper, novel carbon nanotube (CNT) based operational transconductance amplifiers (OTAs) have been designed and simulated. Three types of CNT-based OTAs have been designed at 45 nm technology node and have been compared with the conventional CMOS-based OTA. The comparative analysis of the key characteristics of all the devices has revealed that a significant improvement in performance is observed in the CNT-based OTAs, particularly in a pure CNT-OTA. In the pure CNT-OTA, DC gain has increased by 218%, slew rate has increased by 22.58%, the output resistance has increased by 55.2% and the power consumption is ~193 times less in comparison to the conventional CMOS-OTA. Further, common mode rejection ratio (CMRR) and power supply rejection ratio positive (PSRRþ) has increased by 31.87% and 136.3%, respectively in pure CNT-OTA. The performance of CNT-based OTAs has also been studied thoroughly by varying the number of CNTs (N), CNT pitch (S) and the diameter of CNTs (DCNT) at 0.9 V. It has been observed that their performance can be improved further by using optimized values of CNT number; inter CNT-pitch and diameter. The stability analysis has shown that the pure CNT-OTA is highly stable. A 16.7% and 4% increase in phase and gain margins is achieved in the pure CNT-OTA in comparison to the bulk CMOS OTA. Finally, band and high pass filters have been realized by using the proposed CNT-based OTAs.

Energy Budget Based Multiple Attribute Decision Making (EB-MADM) Algorithm for Cooperative Clustering in Wireless Body Area Networks

Amit Choudhary,M. Nizamuddin,Manish Kumar Singh,Vibhav Kumar Sachan 대한전기학회 2019 Journal of Electrical Engineering & Technology Vol.14 No.1

A wireless network of biosensor nodes, attached to different parts of the patient body, is termed as Wireless Body Area Network (WBAN). WBANs offer a real-time data monitoring platform for biological health parameters like blood pressure, heart rate, and glucose level etc. Low-power consumption is an essential WBAN design requirement due to limited power resources of biosensor nodes. Present work proposes the design of low power, clustering based data routing protocol for WBANs. Proposed protocol incorporates a novel “Energy Budget based Multiple Attributes Decision Making Algorithm (EB-MADM)” for dynamic cluster head selection. The algorithm selects an optimum node as cluster head which has the higher residual energy level and performs data routing at the cost of least network residual energy loss. EB-MADM selects a new cluster head for each transmission round and distributes cluster head load evenly among cluster nodes. It results in enhanced network lifetime. Proposed protocol incorporates another low power technique termed as “Cooperative effort of cluster nodes”. This technique saves node transmission energy by prohibiting redundant data from transmission. The proposed protocol is simulated using MATLAB tool and the performance results are compared with existing WBAN protocols. Proposed protocol shows better performance in terms of network lifetime, stability period, throughput, and propagation delay.

Flow Analyses Inside Jet Pumps Used for Oil Wells

Abdus Samad,Mohammad Nizamuddin 한국유체기계학회 2013 International journal of fluid machinery and syste Vol.6 No.1

Jet pump is one type of artificial lifts and is used when depth and deviation of producing wells increases and pressure depletion occurs. In the present study, numerical analysis has been carried out to analyze the flow behavior and find the performance of the jet pump. Reynolds-averaged Navier Stokes equations were solved and k-ε turbulence model was used for simulations. Water and light oil as primary fluids were used to pump water, light oil and heavy oil. The ratios of area and length to diameter of the mixing tube were considered as design parameters. The pump efficiency was considered to maximize for the downhole conditions. It was found that the increase in viscosity and density of the secondary fluid reduced efficiency of the system. Water as primary fluid produced better efficiency than the light oil. It was also found that the longer throat length increased efficiency upto 40% if light oil was used as primary fluid and secondary fluid viscosity was 350 cSt.

TAS2R38 bitter taste perception in the Koṅkaṇī Sārasvata Brahmin population

Sequeira Jaison Jeevan,Nizamuddin Sheikh,van Driem George,Mustak Mohammed S. 한국유전학회 2023 Genes & Genomics Vol.45 No.11

Background The TAS2R38 gene carries markers for phenylthiocarbamide (PTC) sensitivity. Various studies have investigated the genotype–phenotype association pattern for bitter tasting ability and other factors in different populations. However, a paucity of such information for endogamous Indian populations is the reason behind this study. Objective To study the association of phenylthiocarbamide (PTC) sensitivity with TAS2R38 gene variations in Koṅkaṇī Sārasvata Brahmin population. Methods We studied the association of the alleles rs714598, rs1726866, rs10246939 with PTC sensitivity and other factors in the Koṅkaṇī Sārasvata Brahmin population. DNA was extracted from 114 individuals belonging to the Koṅkaṇī Sārasvata Brahmin community. The TAS2R38 gene was sequenced to find the genotype distribution pattern. The association between genotype and phenotype was checked using the Chi-Square test and multifactorial logistical regression. Results We observed a 58.8% frequency of the AVI haplotype, which is the most prevalent in European populations. A higher number of non-taster haplotypes and diplotypes were observed in Koṅkaṇī Sārasvata Brahmins, with the allele rs10246939 showing a significant association with PTC bitter taste sensitivity in both allelic (p = 8.6 × 10–4; Allele-G, OR = 3.57 [95% CI = 1.66–7.69]) and genotype-based (p = 6.9 × 10–4; genotype-AG, OR = 3.11 [95% CI = 0.73–13.20]; genotype-GG, OR = 40 [95% CI = 3.58–447.03]) tests. Conclusion Our results are in line with earlier studies, which report an association between PTC sensitivity and the TAS2R38 gene in different populations. In the global context, Koṅkaṇī Sārasvata Brahmins, who are mostly distributed along the southwestern coast of India, show a PTC sensitivity pattern slightly similar to that of West Eurasian populations. Our findings suggest ancestry specific selection in TAS2R38 gene variations for taste sensitivity at global level.

Reasons for Patient's Delay in Diagnosis of Breast Carcinoma in Pakistan

Memon, Zahid Ali,Shaikh, Anum Nizamuddin,Rizwan, Sundus,Sardar, Maimoona Batool Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.12

Background: Delay in diagnosis of breast cancer is associated with a poorer survival and a pivotal contribution to this delayed diagnosis comes from patient delay in presenting at a clinic. Reasons involved must be evaluated in order to decrease this reducible delay. Objectives: i) To evaluate the reasons for patient delay in diagnosis of breast cancer; ii) to investigate any association with other variables. Materials and Methods: A 6 month cross sectional study (from July 2012 to Dec 2012), was carried out in Surgical and Oncology Units of Civil Hospital, Karachi. A total of 100 females diagnosed with breast cancer of any histological type were interviewed after informed consent and relevant data were collected. Due ethical clearance was obtained. Results: Mean age was $47.5{\pm}12.1$ years with a range from 25-77 years. Mean duration of delay was $5.13{\pm}4.8$ months, from shortest 1 month to longest 36 months. Duration of delay was observed to be no delay (<1 month) in 28%, short delay (1-3 months) in 30% and long delay (>3 months) in 42% of patients. Considering the symptoms as "harmless" (39%) was the most frequent reason of delay followed by "temporary" (20%) and the "use of traditional methods" (12%). Most common reason for later approaches was an increase in the size of the lump (41%). Statistically significant association (p-value <0.05) of longer patient delay was obtained with being single, being illiterate, painless breast lump as the first symptom, negative family history of breast cancer and vague attribution of the symptoms. Conclusions: Significant delay in approach to health care facility was observed in our study due to variable reasons given by women. Sufficient awareness regarding breast cancer, its symptoms and favorable effects of a timely diagnosis on prognosis must be imparted to our general population.

Recent trends in the synthesis of graphene and graphene oxide based nanomaterials for removal of heavy metals — A review

Jihn Yih Lim,N.M. Mubarak,E.C. Abdullah,Sabzoi Nizamuddin,Mohammad Khalid,Inamuddin 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.66 No.-

The advanced synthesis and development of raw graphene based on various significant functionalization has been outstanding in the wastewater treatment compared to the other alternatives such as carbon nanotubes and other carbon nanomaterials. Nano size graphene is known to possess large surface area and some promising properties in terms of mechanical, electrical, chemical and magnetism. Besides, the graphene can be generated via both Top-down and Bottom-up methods such as chemical exfoliation, chemical vapour deposition and other techniques so that it can be further functionalized to form graphene oxide-based nanomaterials. Hence, graphene oxide-based nanomaterials are discovered to be useful in the application of heavy metal removal from wastewater. In short, this paper critically reviewed on the synthesis method of graphene and application of graphene oxide-based nanomaterials in the term of heavy metal removal. The advantages, drawbacks, comparison of the data efficiencies, and research requirements are further highlighted, elaborated and discussed detailly. Lastly, the future challenges of graphene are elaborated. Therefore, it can be guaranteed that the wastewater discharged should be detected with the minimum or none of the heavy metals so that minimum effects on the ecosystem is discovered.

Parametric study of pyrolysis and steam gasification of rice straw in presence of K2CO3

Humair Ahmed Baloch,Abdul Waheed Bhutto,Tianhua Yang,Haipeng Sun,Jie Li,Sabzoi Nizamuddin,Rundong Li,Zhanguo Kou,Yang Sun 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.9

A parametric study of pyrolysis and steam gasification of rice straw (RS) was performed to investigate the effect of the presence of K2CO3 on the behavior of gas evolution, gas component distribution, pyrolysis/gasification reactivity, the quality and volume of synthetic gas. During pyrolysis, with the increase in K2CO3 content in RS (i) the instantaneous CO2 concentration was increased while CO concentration was relatively stable; (ii) the yield of CO2 and H2 increased on the cost of CH4. During steam gasification of RS, with the increase in K2CO3 content in RS (i) the instantaneous concentration of CO2 and H2 increased while instantaneous concentration of CO and CH4 decreased; (ii) the yield of CO2 and H2 production and total yield increased; and (iii) yield of CO and CH4 production followed the order: 9% K2CO3 RS<6% K2CO3 RS<raw RS<3% K2CO3 RS<water-leached RS. Water-leached RS showed the highest pyrolysis reactivity, while stream gasification reactivity was proportional to K2CO3 content in RS. The results of this study reveal that the presence of K2CO3 during pyrolysis and steam gasification of RS effectively improves production of H2 rich gas.