Showing 8 results for Ahamad
Volume 3, Issue 3 (summer 2021)
Abstract
Coronaviruses were discovered in the 1960s, and continued to be studied until the mid-1980s. The virus is naturally prevalent in mammals and birds, yet seven human-transmitted coronaviruses have been discovered so far; the most important of these, SARS Acute Respiratory Syndrome or acute respiratory syndrome, was a dangerous viral respiratory disease of genetic origin caused by coronavirus and from November 2002 to July 2003, the outbreak in Southern China caused 8098 cases. Possible disease and death of 774 people in 17 countries, and now since December 2019, another and more dangerous type called COVID-19 has spread with the human epidemic in Wuhan, China and in a short time has spread all over the world. China was the source of the virus, as well as the first country to stop it's spread to a large extent, but other countries failed to contain the virus despite their ability to contain it. Why? The answer is simple: "It is a matter of policy and approach, not power"! Another issue is "change"; as cities begin to recede and move toward recovery, the consequences of the epidemic will lead to new norms. In this article, we have tried to study the process of crisis management in several countries of the world is facing this virus and the extent of damages to the citizens of these countries until April 30, 2021.
Volume 4, Issue 1 ( winter 2021)
Abstract
Tensions between the Kurds and the Iraqi central government have continued throughout the country's contemporary history. The imposed geopolitics of the trans-regional powers in Iraq for more than half a century has led to violent ethnic resistance. To begin with, Iraq is an outcome of trans-regional geopolitical policy. Its leaders have always struggled to create an inclusive national identity and have used only violent means.
One of Iraq's problems for political stability and the creation of a coherent structure is the agreement with the Iraqi Kurdistan Federal Government on the disputed issues. Among these, one of the most contentious factors between the central government and the Kurds is the issues related to the disputed areas which its settlement is widely reflected in the Iraqi constitution and Security Council resolutions and a variety of solutions has been offered. This article uses a descriptive-analytical method to study and explain the territorial dispute between the Kurds and the central government of Iraq. The results of the research show that the settlement of territorial disputes is affected by geopolitical competition and the best solution to this crisis is to use a good governance model for the development and stability of those areas.
Volume 7, Issue 3 (Summer 2021)
Abstract
Backgrounds: This study aimed to describe the epidemiological and clinical characteristics of inactive HBV chronic carriers at the gastroenterology department of the university teaching hospital Yalgado Ouedraogo.
Materials & Methods: This descriptive cross-sectional study was conducted from January 1, 2007 to December 31, 2014 by employing a prospective data collection method. It was a census of all cases meeting the eligibility criteria. All patients with chronic viral hepatitis B (VHB) and ≥15 years of age and presenting the following signs were included in this study: positive result on hepatitis B surface antigen test for at least 6 months, normal levels of alanine amino-transferase for at least one year, positive anti-HBe antibodies, negative HBeAg, and viral DNA < 20,000 IU/mL.
Findings: The mean age of patients was 35 years, and the mean duration of HBsAg carriage was 6 years. The physical examination was normal in all participants. Ultrasound exam was normal in 150 (92.6%) participants and showed a fatty liver in 12 (7.4%) participants. Overall 4.4% of participants developed severe fibrosis, and no patient developed cirrhosis. The main indications for drug treatment included the existence of a family history of hepatocellular carcinoma (36.7%), the presence of active hepatitis (33.3%), and the progression of the fibrosis (30%).
Conclusion: This study confirms the importance of close follow up of HBV-infected patients to dramatically reduce the risk of developing complications such as cirrhosis or hepatocellular carcinoma.
Volume 10, Issue 4 (11-2021)
Abstract
Butterflies are flagship taxa and bio-indicator of terrestrial ecosystems. Studies of butterflies are performed in different regions of Nepal, but no detailed research has been carried out in Tanahun. Hence, this study was conducted to determine the species diversity and abundance of butterflies in Byas municipality-6 of the Tanahun, Nepal, from March to November 2020. The Pollard walk method was used for the data collection. A total of six transects of 500 m, two in each habitat type (forests, settlements, and agricultural lands), were laid out randomly. The study was performed in three seasons (9 months); Pre-Monsoon (March to May), Monsoon (June to September), and Post-Monsoon (October to November). Each transect was surveyed nine times (once a month) to record species in each month. Data were pooled and analyzed with SPSS. A total of 1,753 individuals of 149 butterfly species from 92 genera and six families were recorded during the study. The overall Shannon-Wiener and Margalef diversity indices were H = 4.17 and R = 19.95. Pielou’s Evenness was E = 0.83. Nymphalidae was the most diverse, richest species, and most abundant family (H = 3.33, R = 8.30, N = 851). Species evenness was maximum in the family Papilionidae (E = 0.88). The forests comprised the maximum number of species (115 species, 898 individuals). The maximum number of species was recorded in March (106 species), while the highest species abundance was in June (268 individuals). The result of this study could be the baseline for further researches on butterflies in the Tanahun district.
Volume 11, Issue 3 (Summer 2023)
Abstract
Aims: In this study, the response of individual trees and the stand structure to windstorm damage were investigated in a mixed broad-leaf forest stands located in Darabkola Forest, Sari, northern Iran. A field survey was conducted over an area of 2612 ha of the given stands.
Material & Methods: A full inventory was performed for all trees with diameter at breast height≥ 10cm and all damaged (i.e., snapped, snags, branch loss, broken trunk or uprooted) trees were identified within the study area. Tree height was measured using Laser Distance Meter for trees more than 10 m high and a Clinometer for all trees <10m. The percentage of trees damaged was the dependent variable; but, independent variables included number, mean height (m), total basal area (m2) and volume trees (m3). Independent t-test was performed to compare the mean of trees based on diameter classes. Also, the affection of height on susceptibility to windstorm effects was tested by comparing mean trees height within each class.
Findings: The number of the damaged trees varied with species, ranging from 0.04 % (2 individuals) in Tilia begonifolia Stev to 53.7 % (2709 individuals) in Fagus orientalis L. Among the damaged trees 5054 recorded, 2231 (44.20 %) had been snapped and 787 (15.6 %) uprooted, and 2028 (40.20 %) were snags. Among the species, Fagus orientalis L. (47.7 %), Alnus subcordata C. A. Mey. (19.7 %) and Carpinus betulus L. (18.8 %) were most susceptible to uprooting, whereas Populus caspica Bornm, Quercus castaneifolia C. A. Mey. and Ulmus glabra Huds. were the least susceptible to uprooting. The species differed significantly in their susceptibility to snapping. Trees ≥60cm dbh were more likely to be snapped (78 %) or snags (69 %), whereas trees <60 cm dbh were more presumably to be uprooted (50 %). Also, about one third (33 %) of total trees larger than 60 cm (D.B.H) have showed distinct effects and individual trees >20 m were more commonly uprooted. The number of snapped trees, snags and uprooted trees had a sharp increase in trees taller than 20m.
Conclusion: Our finding showed that Oriental beech and Common hornbeam to be species that were most susceptible to both being snapped and snagged, whereas Caucasian alder had the most uprooting damage among the other species. Overall, features like species, D.B.H, height and height to diameter ratio (H/D.B.H), were intensively related with the type and severity of windstorm damage. The findings showed that windstorms cause substantial structural effects in mixed stands of beech and hornbeam.
Volume 16, Issue 11 (1-2017)
Abstract
Residual stresses and distortion are of the main disadvantages of welding process which determining the amount and distribution of them have great importance in the design of structures, especially in the space industry. In this study, a finite element method is used to analyze the thermo- mechanical behavior of a spherical shell due to TIG welding. The spherical shell is made of titanium alloy (Ti-6Al-4V) with 2 mm thickness. The modeling of welding process is based on an uncoupled thermo- mechanical coupling. TIG welding is examined for six cases based on current intensity and welding progress speed setting the voltage on 12 V in all cases. Distribution of temperature and residual stresses caused by TIG welding of the titanium spherical shell have been extracted and compared among the six different cases. The effects of current intensity and welding progress speed on shell distortion and residual stress have been investigated. The results showed that increasing the current intensity and decreasing the welding progress speed have the most effects on longitudinal residual stresses which the amount of this increasing reached to %44 for decreasing the welding progress speed. Welding distortion increases to maximum %132 by increasing current and decreasing welding progress speed.
Volume 21, Issue 12 (December 2021)
Abstract
The increasing consumption of non-renewable energy sources such as oil and gas and reducing their reserves make it more necessary to pay attention to clean and renewable resources. In this situation, wind energy is known as one of the safest options for generating electrical energy. In this study, with the aim of evaluating the impact of climate change on the economic and environmental characteristics of wind turbines, numerical modeling was developed in MATLAB software. In order to evaluate the effects of the mentioned parameters as a case study, this numerical modeling for the parameters expressed in 4 cities of Iran, including Rasht, Tehran, Abadan, and Sanandaj, as the representatives of the main climates of Iran has been analyzed. According to the results of the economic point of view, which represents the Levelized cost of the energy production unit, Abadan was recognized as the most economical case with a Levelized cost of 1.04 $ per kilowatt-hour of energy. Also, the environmental aspect of the analysis, which is based on the life cycle assessment method, considering the amount of carbon dioxide produced during the system life cycle and its pricing based on penalty policies, Rasht with a mild climate and emissions of 156 kg. Carbon dioxide per year and the lowest fine cost (annual cost $ 2.26) showed the most suitable option among other cities.
S. Ahamad,
Volume 23, Issue 1 (1-2021)
Abstract
Among the various biotic constraints, stripe rust is known to cause significant losses in grain yield and quality of wheat. In this study, out of 20 varieties evaluated, WH-1105, WH-1121, WH-1124, WH-1142, VL-804, VL-907, HS-240 were found to be resistant; RSP-561, Raj-3765, PBW-664, PBW-590 were moderately resistant; Raj-3077, PBW-373, PBW-175, PBW-527, PBW-621, HS-490 were moderately susceptible, and PBW-343, PBW-550,HD-2967 were susceptible. Rust progressive curve had the highest value of 2,377.42 during 2014/2015 due to conducive environmental conditions, while in 2015/2016, it was 2459.4.The disease severity ranged from 1.0 to 15.30% at 10thof February in 2014/2015, while this range in 2015/2016 was 1.0 to 13.39%. The highest yield (44.95 q ha-1) was found in the plot treated with two sprays of Tilt @ 0.1% followed by two sprays of Folicur (43.47 q ha-1) and Bayleton @0.01% (43.2 q ha-1), respectively. Two sprays of Tilt (0.01 %) at 15 days interval gave minimum disease severity i.e. 4.03% followed by Folicur (5.29%) and Bayleton @ 0.01% (8.90%). The yield increased up to 34.60% when treated with two sprays of Tilt (0.01%) at 15 days interval.
