جستجوی مقالات مرتبط با کلیدواژه « suspension » در نشریات گروه « جغرافیا »

Land use change is one of the important factors in changing the hydrological flow, basin erosion and biodiversity destruction. Therefore, knowing the effect of land use change on discharge and suspended load is an inevitable necessity. The main purpose of this study is the efficiency test of the model and its usability as a simulation of the process of land use change on discharge and sediment is from the soil and water assessment model (SWAT) and SUFI2 program. Model simulation was performed for 29 years from 1987 to 2015, the first 5 years of which were selected for model calibration and the last 5 years for model results validation. Four statistical indices, r_factor, P_factor Nash-Sutcliffe (NS) and coefficient of determination (R2), the ratio of squared root-to-standard deviation (RSR) and the percentage of skewness (PBIAS) were selected monthly to evaluate the model. The accuracy of monthly simulation using NS evaluation index in the calibration and validation stage for flow and suspended load is equal to 0.65 and 0.49, respectively. The results of the study were considered acceptable according to the interpretive domains used in previous studies and indicate the satisfactory efficiency of the SWAT model in simulating the components of the impact of land use change on sediment and discharge in the Ojan Chay Bostanabad watershed. The results showed that the height of surface runoff increased by 1.15 mm and the sediment concentration increased by 1.5 tons per hectare per year.

Physical properties are one of the most important soil properties that affect other aspects of soil such as erosion and water infiltration into the soil. One way to improve soil properties is to use modifiers. Biochar is one of the modifiers based on organic matter that can play an important role in soil properties and the results of research studies have shown the effect of biochar on the physical and chemical properties of soil. Therefore, the purpose of this study was to investigate the effect of Shrimp and eggplant waste biochar suspension on some soil structure stability indices.

 In this study, the effect of Shrimp and eggplant waste biochar suspension on soil structure stability indices was investigated and for this purpose sandy soil was selected. The studied soil was sampled from agricultural lands around Bandar Abbas intact areas with polyethylene columns with a height of 25 and a diameter of 20 cm. The experiment was performed in a completely randomized design with 9 treatments and 3 replications. The studied treatments included biochar of eggplant and shrimp wastes suspension separately with concentrations of 0, 4, and 8 g/l which were added to the soil inside the columns according to the weight percentage. They were incubated for 100 days at moisture ranging from field capacity (FC) to 50 % FC in greenhouse conditions. Then some soil physical properties including mean weight diameter of wet sieving (MWDwet), dry sieving (MWDdry) aggregates, percentage of aggregate destruction (PAD), and saturated hydraulic conductivity (Ks) were measured. The analysis of variance for a completely randomized design was performed in order to evaluate the significance of shrimp and eggplant biochar rates on soil physical parameters by using the SPSS16 statistical software. The estimated Means were compared using Duncan’s test with a P<0.05 level of significance.

The results showed that the addition of shrimp and eggplant waste biochar suspension had a significant (p<0.01) effect on the measured parameters. In addition, the addition of both shrimp and eggplant waste biochar suspension to the soil increased MWDwet and MWDdry and decreased PAD, BD, and Ks, significantly. The maximum values of MWDwet and MWDdry were obtained by application of 8 and 4 g/l eggplant waste biochar suspension, respectively, which showed a significant difference (p<0.05) with the control treatment. The minimum percentage of aggregate destruction (PAD) was obtained by application of 8 g/l eggplant biochar suspension (21.7%), and the minimum of Ks was obtained by application of 4 g/l Shrimp waste biochar suspension (3.7 cm/h).

 The results showed that the addition of different levels of shrimp and eggplant biochar due to the presence of organic nuclei in it can act like cement, causing the mineral particles to stick to the soil and leading to the formation of stable aggregates. Organic biochar carbon in the soil with chemical bonds and the formation of bridges between soil particles as a bonding agent increased the stable bond between soil particles, increased aggregation and the formation of stable aggregates and also increased MWDwet and MWDdry. Therefore, by improving the soil properties by biochar, the percentage of aggregate destruction (PAD) can be reduced. Furthermore, the application of different levels of Shrimp and eggplant waste biochar suspension has reduced bulk density (BD) of sandy soil. It seems that the increase in bio-waste of shrimp and eggplant waste biochar, as an organic compound, has affected the amount and distribution of micropores and soil porosity with a sandy texture, therefore, reducing the bulk density of the soil. The application of different concentration levels of shrimp and eggplant waste biochar has reduced the hydraulic conductivity in the studied sandy soil. It seems that the addition of both types of eggplant and shrimp biochar by increasing more stable aggregates in dry and wet conditions and bulk density changes the pore distribution, reduces the number of macropores and increases the micropores in the sandy textures. It can also significantly reduce the saturated hydraulic conductivity compared to the control treatment that lacked any modifiers. According to the results of this research, the application of shrimp and eggplant waste biochar improved the physical properties of soil and reduced the percentage of soil degradation, hydraulic conductivity, and bulk density.

Phenomenology is one of the dominant philosophical schools that gradually entered the western philosophy in the late 19th century, and then attention has been paid to different scientific domains particularly in humanities, geography and human geography. Phenomenology is the study or recognition of phenomena and the phenomena consists of everything that appears to the mind. In other words, phenomenology is direct perception and intuition, without the intermediary of objects and phenomena. The purpose of the mediator in knowing everything is the conventional philosophical and scientific hypotheses, theories, categories and templates, and particular pre-assumptions of the reader. Knowing anything without using conventional formats will be possible only through direct intuition of nature. So this approach seeks direct intuition of objects and phenomena, and in this regard refuses the hypotheses, categories and pre-assumptions, therefore, phenomenology is considered a realistic but experimental approach toward realities. Thus, seemingly this traditional philosophy of science must be classified under the realistic viewpoint. Nevertheless, due to some typical esoterism, and particularly suspending the realities of external world, and even eliminating it as a mind-independent character and full emphasis on phenomenological character of realities, meaning subjective character of objects and phenomena, and eventually due to the phenomenological tradition relying on the intuitive experience approach, against some realistic attributes, this traditional philosophy of science must be classified under the realistic viewpoint. Nevertheless, regardless of positive aspect of this approach, meaning immediate experience of objects and phenomena, the approach mentioned above has some basic and epistemological insufficiency which will encounter serious hardships utilizing it as a scientific approach in the geography domain, and thus, it lacks the efficiency and required capabilities to be utilized in the study fields related to social science, and particularly geography, as a “scientific” approach and methodology. The main objective of this paper, which has been written with a realistic approach and critical rationalism attitude, is to analyze this issue from the viewpoint of logical and epistemological analyses.

The present study due to the nature of philosophy and own logical, is among the fundamental and theoretical research. This study is based on descriptive and analytical method (logical) and its analysis is done based on logical reasoning and arguments. Therefore, discussions and matters from this series of documentaries and library are considered.

Across the last few decades, the Philosophy of phenomenology has been one of the main and dominant schools in the field of western thought, which gradually from the second half of the 20th century, has contributed to the formation of intellectual foundations of western scholars and has influenced many fields particularly humanities domain especially geography. In human geography, across the last decades, we see an evolving tendency among geographers in the field of urban studies, urban design and planning, rural planning, social geography, economic geography, political geography, cultural geography, and some other subcategories are directed towards a kind of human geography that have been influenced by philosophy and methodology of phenomenology, or its derivatives, such as existentialism and interpretive and hermeneutic methods. The question is to see what methodology and principles the inspired geography is based on and what is its ultimate goal? Phenomenological geography refers to geographic studies in which geographic phenomena and subjects are studied by researchers without any intermediaries, regardless of formal and abstract templates, and without reliance on pre-assumptions, theories and customary prejudice in scientific studies and merely as a phenomenology. Thus, in this regard, phenomenological geography has the following characters:1. Immediate experience of objects and phenomena 2. Review of place identity individually and uniquely (monography) 3. Intuitive and interpretive method in recognizing and understanding the phenomena 4. Recognition of phenomena in the form of common sense 5. Utilizing descriptions instead of explanation in identifying the phenomena 6. Refusing pre-assumptions and categories and theories in identifying the phenomena.Meanwhile, the presence and close participation of the researcher in the study of subjects and environmental phenomena and the description and explanation of phenomena and their real descriptions are considered as a positive character of this approach, however refusing the hypotheses and pre-assumptions (which are actually impossible) and the focus on awareness and subjective cognitions and suspension of external world (Epoché) in the process of recognizing phenomena actually turns it into an idealistic approach, and unique cognitions of phenomena also lead to the lack of validation independent of the researcher, and ultimately confronts this approach with relativism, and thus making phenomenology inefficient as a scientific method in geographic studies.

a general sense, since philosophy and phenomenological methodology in different sciences, particularly in the field of humanities and social sciences, especially geography, merely refer to the participation of the researcher in the study of subjects and environmental phenomena and consider remote description and explanation of the phenomena inefficient and emphasizes on their real and deep description through direct and immediate intuition, and particularly suggests direct descriptions and real experiences in the field of researches related to practical plans for geographic places, it is worthwhile and important, and this aspect of phenomenology approach is considered a positive and strong point. Nevertheless, regardless of this positive aspect, the approach mentioned above has some basic and epistemological insufficiency, such as: refusing hypotheses and pre-assumptions, idealistic attitude and subjectivism, nomothetic approach in reviewing the phenomena which leads to the lack of true and false criteria or a lack of validation independent of the researcher’s mind; and in other words, leads to the lack of objectivity and, eventually; historicity and relativism. These issues encounter serious hardships utilizing it as a scientific approach in the geography domain, and thus, it lacks the efficiency and required capabilities to be utilized in the study fields related to social science, and particularly geography, as a “scientific” approach and methodology.