Evaluation of Light Falling Weight Deflectometer for In Situ Measurement of Secondary Deformation Modulus of Various Forest Road Pavements

Roads in forests are necessary for proper forest management and active protection of the natural environment. They facilitate tourism and recreation and have a very important function in firefighting. The cost of building roads in forest areas is considerable, even when relatively cheap materials such as aggregates of natural or anthropogenic origin are used. Therefore, any road investment must be well prepared and executed. Bearing capacity and compaction are among the most important and frequently used geotechnical parameters in road construction. The aim of this study was to determine the possibility of predicting the value of the secondary deformation modulus E2 (obtained from measurements with a static plate load test – PLT) based on measurements with a light falling weight deflectometer (LFWD) Zorn, type ZFG 3000 GPS with a drop weight of 10 kg. The regression analysis included 245 results of bearing capacity measurements carried out on 46 forest road sections with various road pavements. Different regression models were tested: linear, logarithmic, polynomial, exponential and power models, excluding polynomials of fourth and higher degree. Prediction of E2 (PLT) values from dynamic deformation modulus Evd (LFWD) values is possible. However, the reported unsatisfactory strength of the relationship between the two parameters is associated with a high risk of error (r=0.73, R2=0.54, Se=80.37 MN·m-2). Neither the use of more complex non-linear regression models nor the use of multiple regression by introducing an additional estimator in the form of the s/v ratio significantly improved the estimation results. The quality of the prediction of E2 values is not constant. It varies depending on the type of forest road pavements, the use of geosynthetic pavement reinforcements and the type of road subgrade. The study also found that the quality of E2 prediction can be improved by limiting the range of tested Evd values upwards. It is advisable to continue this type of research, as the results obtained could be the basis for developing national standards for the application of LFWD to control the bearing capacity and compaction of forest road surfaces in the future

Bearing Capacity Standards for Forest Roads Constructed Using Various Technologies from Mechanically and Chemically Stabilised Aggregate

Forest roads are essential for adequate forest management and environmental protection. They enable tourism and recreation activity, while at the same time playing a very important role in fire protection. When open to the local traffic, they significantly supplement the public traffic networks. Costs of constructing permanent roads in forested areas are considerable, because they need to have adequate bearing capacity. Forest roads are predominantly constructed using natural or anthropogenic aggregate stabilised mechanically and chemically. A tangible parameter verifying the proper construction of road structure is provided by its bearing capacity, i.e. the capacity of the pavement to carry loads generated by traffic without excessive strains hindering normal use of the pavement or reducing its durability. Some forest road networks are also constructed as temporary roads composed of cheaper aggregates. It seems reasonable to assume different bearing capacity standards for such roads than for permanent roads. The aim of the studies presented in this paper was to develop bearing capacity standards for forest roads constructed using various technologies. The adopted research hypothesis assumes that each of the analysed technologies is characterised by a different bearing capacity required during road construction inspections. An example of such a structure may be provided by the so-called geotextile mattress and crushed stone constructed on wetland soils. When developing the standards, the analyses included the predicted traffic intensity, assumed operation time before rehabilitation is required, soil conditions and the type of construction material. Bearing capacity of the testing road sections was assessed based on values of strain moduli calculated from the static plate load tests (VSS). As a result, bearing capacity standards were obtained for structures constructed using aggregates and chemical stabilisers as well as geotextiles potentially facilitating reduction of the layer thickness without deterioration of road durability

Leveraging 3D printing to enhance mass spectrometry:A review

The use of 3D printing in the chemical and analytical sciences has gained a lot of momentum in recent years. Some of the earliest publications detailed 3D-printed interfaces for mass spectrometry, which is an evolving family of powerful detection techniques. Since then, the application of 3D printing for enhancing mass spectrometry has significantly diversified, with important reasons for its application including flexible integration of different parts or devices, fast customization of setups, additional functionality, portability, cost-effectiveness, and user-friendliness. Moreover, computer-aided design (CAD) and 3D printing enables the rapid and wide distribution of scientific and engineering knowledge. 3D printers allow fast prototyping with constantly increasing resolution in a broad range of materials using different fabrication principles. Moreover, 3D printing has proven its value in the development of novel technologies for multiple analytical applications such as online and offline sample preparation, ionization, ion transport, and developing interfaces for the mass spectrometer. Additionally, 3D-printed devices are often used for the protection of more fragile elements of a sample preparation system in a customized fashion, and allow the embedding of external components into an integrated system for mass spectrometric analysis. This review comprehensively addresses these developments, since their introduction in 2013. Moreover, the challenges and choices with respect to the selection of the most appropriate printing process in combination with an appropriate material for a mass spectrometric application are addressed; special attention is paid to chemical compatibility, ease of production, and cost. In this review, we critically discuss these developments and assess their impact on mass spectrometry

Parameters of Ensiled Maize With Biological and Chemical Additives

The amount of maize grown in Poland has increased rapidly. Nowadays it takes about 600,000 ha, 40% of which is used as silage. Changing climate in Poland, with dry summer followed by wet autumn with ground frost causes extensive moulds contamination and high presence of the fusarium toxins in the maize during the harvest. The norms accepted in the EU concerning the acceptable level of deoxynivalenol (DON) and zearalenol (ZON) in feedstuffs for cattle require detailed examination of this problem as it decides on the health quality and production results. The aim of the study was to evaluate the effects of ensiling forage maize with microbiological additive and chemical preservative on the DON and ZON amount. The effects of the secondary fermentation after the silos were open (stability evaluation) were also examined

Parameters of Ensiled Maize With Biological and Chemical Additives

The amount of maize grown in Poland has increased rapidly. Nowadays it takes about 600,000 ha, 40% of which is used as silage. Changing climate in Poland, with dry summer followed by wet autumn with ground frost causes extensive moulds contamination and high presence of the fusarium toxins in the maize during the harvest. The norms accepted in the EU concerning the acceptable level of deoxynivalenol (DON) and zearalenol (ZON) in feedstuffs for cattle require detailed examination of this problem as it decides on the health quality and production results. The aim of the study was to evaluate the effects of ensiling forage maize with microbiological additive and chemical preservative on the DON and ZON amount. The effects of the secondary fermentation after the silos were open (stability evaluation) were also examined

Hygienic Value and Mycotoxins Level of Grass Silage in Bales for Horses

Mycotoxins are secondary metabolites of moulds which have adverse effects on humans, animals, and crops and result in illnesses and economic losses. The toxins may occur in storage under conditions favourable for the growth of the toxin-producing fungus or fungi. The highest forage concentration of toxins was found in horizontal storage methods such as bunker silos and feed piles, which were left open to oxygen. In any fermentation storage system, temperature and the presence of moisture is sufficient for toxin production. In a plastic covered storage system, oxygen penetration is slowed but not eliminated. The longer silage is stored, the greater the opportunity for significant fungus growth and toxin contamination. Although the effects of mycotoxins on horses are not well documented in scientific literature, in many situations mycotoxin problems appear to be significant e.g. colic, neurological disorders, paralysis and brain lesions. The aim of this study was to determine the level of mycotoxins in grass silage prepared in bales for horses

Perceived Stress Levels in Adult Patients With Uveitis

Background: The aim of this study was to examine perceived stress levels in adult patients with uveitis. Patients and Methods: One hundred seventy-three adult consecutive uveitis patients (age range 18 to 85 years) were analyzed in a cross-sectional design for their perceived stress, according to the Perceived Stress Questionnaire (PSQ). Stress levels were classified into normal stress, moderate stress, and high stress. Results: In the majority of uveitis patients a normal stress level (82%) within the last 2 years was detected. In a subgroup analysis, perceived stress of the patients with active uveitis compared with patients with non-active uveitis was significantly higher within the last 2 years (n=80 active/n = 45 non-active; p = 0.005). Conclusions: Overall 18% of the uveitis patient had raised perceived stress, similar to the general population but patients with active uveitis were significantly more stressed. Therefore, consideration of stress levels may be important in the therapy of uveitis patients

An Immunologically Privileged Retinal Antigen Elicits Tolerance: Major Role for Central Selection Mechanisms

Immunologically privileged retinal antigens can serve as targets of experimental autoimmune uveitis (EAU), a model for human uveitis. The tolerance status of susceptible strains, whose target antigen is not expressed in the thymus at detectable levels, is unclear. Here, we address this issue directly by analyzing the consequences of genetic deficiency versus sufficiency of a uveitogenic retinal antigen, interphotoreceptor retinoid-binding protein (IRBP). IRBP-knockout (KO) and wild-type (WT) mice on a highly EAU-susceptible background were challenged with IRBP. The KO mice had greatly elevated responses to IRBP, an altered recognition of IRBP epitopes, and their primed T cells induced exacerbated disease in WT recipients. Ultrasensitive immunohistochemical staining visualized sparse IRBP-positive cells, undetectable by conventional assays, in thymi of WT (but not of KO) mice. IRBP message was PCR amplified from these cells after microdissection. Thymus transplantation between KO and WT hosts demonstrated that this level of expression is functionally relevant and sets the threshold of immune (and autoimmune) reactivity. Namely, KO recipients of WT thymi generated reduced IRBP-specific responses, and WT recipients of KO thymi developed enhanced responses and a highly exacerbated disease. Repertoire culling and thymus-dependent CD25+ T cells were implicated in this effect. Thus, uveitis-susceptible individuals display a detectable and functionally significant tolerance to their target antigen, in which central mechanisms play a prominent role

'Leader, you first': The everyday production of hierarchical space in a Chinese bureaucracy

Recent studies highlight how organizational power relations are materialized in space. However, relatively little is known about how these spatialized power relations are reproduced on a day-to-day basis. Drawing on a ten-month ethnographic study of a large government office in China, we find that hierarchical space is produced through three intertwined processes. It proliferates as employees actively seek out signs of hierarchy in the organization’s space; it becomes familiarized as employees fabricate and circulate fanciful narratives about their spatial environs; and it is ritualized by employees acting out hierarchical relations across the organization’s space. These processes resulted in a hardening of the hierarchical relations of power. The study extends the existing literature by showing how hierarchical organizational space is not just something that is imposed on employees; it is also imposed by the employees themselves