Influence of miscibility phenomenon on crystalline polymorph transition in poly(vinylidene fluoride)/ acrylic rubber/clay nanocomposite hybrid

In this paper, intercalation of nanoclay in the miscible polymer blend of poly(vinylidene fluoride) (PVDF) and acrylic rubber(ACM) was studied. X-ray diffraction was used to investigate the formation of nanoscale polymer blend/clay hybrid. Infrared spectroscopy and X-ray analysis revealed the coexistence of b and c crystalline forms in PVDF/Clay nanocomposite while a crystalline form was found to be dominant in PVDF/ACM/Clay miscible hybrids. Flory-Huggins interaction parameter (B) was used to further explain the miscibility phenomenon observed. The B parameter was determined by combining the melting point depression and the binary interaction model. The estimated B values for the ternary PVDF/ACM/Clay and PVDF/ACM pairs were all negative, showing both proper intercalation of the polymer melt into the nanoclay galleries and the good miscibility of PVDF and ACM blend. The B value for the PVDF/ACM blend was almost the same as that measured for the PVDF/ACM/Clay hybrid, suggesting that PVDF chains in nanocomposite hybrids interact with ACM chains and that nanoclay in hybrid systems is wrapped by ACM molecules

Recreation Potential Assessment at Tamarix Forest Reserves: A Method Based on Multicriteria Evaluation Approach and Landscape Metrics

The purpose of this study was to develop new methods to describe outdoor recreation potential based on landscape indicators and systemic multicriteria evolution in the Tamarix forest reserves of Varamin city, a part of Iranian–Turanian forests of the Tehran province in Iran. First, in conducting a multicriteria evaluation, ecological factors that included slope, aspect, elevation, vegetation density, precipitation, temperature, and soil texture were mapped, classified, and coded according to the degree of desirability for outdoor recreation. All these maps were then intersected and the final map of recreational potential for three regions of the forest reserves was prepared. Results showed that the Shokrabad region had more recreation potential than the other two regions (Fakhrabad and Dolatabad) in terms of the sum of ecological factors potentially affecting tourism potential. Second, in conducting a landscape-based method, six of the most important indicators of the landscape that are effective in outdoor recreational potential were developed for each region. The combination of these landscape features determined the value of a place for recreational activities from a landscape perspective. The results showed that a large part of the Shokrabad region and a smaller number of places in the Fakhrabad and Dolatabad regions have high outdoor recreational potential. The area suitable for recreation in the output of the multicriteria evaluation method turned out to be greater than the area suggested by the landscape method, as more factors were examined in the multicriteria evaluation method. Of the set investigated, the topography and soil factors played an important role in the evaluation

Study of three common mitochondrial mutations in Arab patients with nonsyndromic hearing loss in Khuzestan province, I.R.Iran

زمینه و هدف : ناشنوایی یکی از شایع ترین اختلالات حسی –عصبی است که در هر 1000 تولد زنده رخ می دهد. بیشتر ناشنوایی ها منشا ژنتیکی داشته و حدود 2-0 موارد ناشنوایی مربوط به جهش در ژن های میتوکندریایی است. این مطالعه با هدف بررسی فراوانی سه جهش میتوکندریایی A1555G ، A3243G و A7445G در ناشنوایان غیر سندرمیک استان خوزستان انجام شده است. روش بررسی: در این مطالعه توصیفی 62 دانش آموز ناشنوای غیر سندرومیک با الگوی اتوزومی مغلوب عرب استان خوزستان به روش آسان انتخاب شدند. DNA با روش استاندارد فنل کلروفرم استخراج و جهش های احتمالی در سه ژن میتوکندریایی شامل A1555G ، G3243A و A7445G با روش چند شکلی طول قطعه محدود ( PCR-RFLP ) غربالگری شد. در نهایت جهش های احتمالی به روش توالی یابی مستقیم مورد بررسی و تائید قرار گرفتند. یافته ها: در این مطالعه هیچ یک از جهش های A1555G ، A3243G و A7445G یافت نشد، با این حال دو جهش G3316A و A7445C در دو بیمار مورد مطالعه یافت شد. نتیجه گیری: این مطالعه نشان می دهد که جهش های میتوکندریایی G3316A و A7445C مسئول تعداد کمی از ناشنوایی های قبل از زبان باز کردن در جمعیت استان خوزستان می باشند و جهش های A1555G ، A3243G و A7445G در ایجاد ناشنوایی در این جمعیت نقشی نداشته اند. مطالعه ی حاضر خواهد توانست مشاوران ژنتیک در استان خوزستان را در برنامه مشاوره ژنتیک ناشنوایی خانواده ی بیماران ناشنوا یاری کند

Assessing the Effect of Land use Changes on Groundwater Quality of Zarand Plain using Satellite Images and Geostatistical

Population enhancement and consequently increasing of land use changes and excessive exploitation of ground water resources, not only has reduced the quantity of groundwater resources but also has degraded the quality of these resources. The study and investigation of groundwater resources quality can lead to the correct management of these resources. So the purpose of this study was investigation of the effect of land use changes process on groundwater resources quality and also comparison of different Geostatistical methods for water quality zoning in terms of EC and SAR parameters for agriculture and irrigation using Wilcox method. For this aim Landsat satellite images of the TM 2000 and OLI 2014 sensors using Maximum Likelihood Method was used. Wilcox method was used for determining the quality of groundwater resources in terms of EC and SAR parameters. Also, RMSE and R criteria were used in order to compare symmetry of fitted models to data. The results showed that Simple Kriging method with Circular Variogram Model and the amount of RMSE equal to 1782.19 and R equal to 0.81232 was the best method for EC and Ordinary Kriging Method with Gaussian Variogram Model and the amount of RMSE equal to 3.29534 and R equal to 0.79791 was the best method for SAR in terms of groundwater quality zoning. The conclusion showed that an increase of the area of urban and agricultural uses and also 13% increase in groundwater destruction have happened in study area which the most important causes were excessive exploitation and using organic fertilizer. Generally, due to the increasing of the area of urban and agricultural uses, an increase of 2% of pollution in terms of EC and an increase of 5.5% of pollution in terms of SAR has occurred in groundwater resources

Hierarchical cluster analysis to identify the homogeneous desertification management units.

Since in most mapping models geometric mean of different criteria are used to determine the desertification intensity, one of the most important issues in desertification studies is understanding the similar areas, which require similar management after determining the desertification intensity map. Two similar classes of desertification intensity may require different management due to differences in the criteria that affect its desertification severity. Therefore, after determining the geomorphological facies as the working units in Sistan plain, we used hierarchical cluster analysis to identify the homogeneous environmental management units (HEMUs) based on indices of MEDALUS model. According to the MEDALUS model, the studied area was divided into two categories namely medium and high desertification classes. Working units (geomorphological facies) are classified into five clusters according to HEMUs analysis based on climate, soil, vegetation, and wind erosion criteria. The first cluster (C11) include six facies with moderate and severe desertification; in all of these units the main effective factor was wind erosion, so they need the same management decisions controlling wind erosion. Two working units (1 and 4) with the same desertification severity were placed in two different clusters due to the main factors affecting each other. The results of the Mann-Whitney test showed that the value of the test statistics was 79. Also, the value of Asymp.Sig was obtained to be 0.018, which is less than 0.025 (two-tailed test), and it can be concluded that the classification of work units in the two models, clustering and desertification, is not equal (P<0.05). So It seems that using cluster analysis to identify the same units, which need the same management decision after preparing the desertification intensity, is necessary

Influence of processing conditions on polymorphic behavior, crystallinity, and morphology of electrospun poly(VInylidene fluoride) nanofibers

The polymorphism and crystallinity of poly(vinylidene fluoride) (PVDF) membranes, made from electrospinning of the PVDF in pure N,N-dimethylformamide (DMF) and DMF/acetone mixture solutions are studied. Influence of the processing and solution parameters such as flow rate, applied voltage, solvent system, and mixture ratio, on nanofiber morphology, total crystallinity, and crystal phase content of the nanofibers are investigated using scanning electron microscopy, wide-angle X-ray scattering, differential scanning calorimetric, and Fourier transform infrared spectroscopy. The results show that solutions of 20% w/w PVDF in two solvent systems of DMF and DMF/acetone (with volume ratios of 3/1 and 1/1) are electrospinnable; however, using DMF/acetone volume ratio of 1/3 led to blockage of the needle and spinning process was stopped. Very high fraction of &beta;-phase (&sim;79%-85%) was obtained for investigated nanofiber, while degree of crystallinity increased to 59% which is quite high due to the strong influence of electrospinning on ordering the microstructure. Interestingly, ultrafine fibers with the diameter of 12 and 15 nm were obtained in this work. Uniform and bead free nanofiber was formed when a certain amount of acetone was added in to the electrospinning solution

POM images of (A) PVDF, (B) PVDF20/ACM80 blend, (C) NPVDF, and (D) N20/80 samples.

<p>Samples were isothermally crystalized at 150°C for one hour.</p

Plot of vs. .

<p>Plot of vs. .</p

(A) WAXD pattern of neat PVDF and nanocomposite hybrids showed α polymorph characteristic peak while PVDF nanocomposite demonstrated β and γ phase (B) FTIR spectrum of samples showed the same results as WAXD.

<p>(A) WAXD pattern of neat PVDF and nanocomposite hybrids showed α polymorph characteristic peak while PVDF nanocomposite demonstrated β and γ phase (B) FTIR spectrum of samples showed the same results as WAXD.</p

Schematic representation of nanocomposite hybrids demonstrating ACM chains are scattered between PVDF crystals and clay platelets.

<p>Schematic representation of nanocomposite hybrids demonstrating ACM chains are scattered between PVDF crystals and clay platelets.</p