Elastic properties of mono- and polydisperse two-dimensional crystals of hard--core repulsive Yukawa particles

Monte Carlo simulations of mono-- and polydisperse two--dimensional crystals are reported. The particles in the studied system, interacting through hard--core repulsive Yukawa potential, form a solid phase of hexagonal lattice. The elastic properties of crystalline Yukawa systems are determined in the $NpT$ ensemble with variable shape of the periodic box. Effects of the Debye screening length ($\kappa^{-1}$), contact value of the potential ($\epsilon$), and the size polydispersity of particles on elastic properties of the system are studied. The simulations show that the polydispersity of particles strongly influences the elastic properties of the studied system, especially on the shear modulus. It is also found that the elastic moduli increase with density and their growth rate depends on the screening length. Shorter screening length leads to faster increase of elastic moduli with density and decrease of the Poisson's ratio. In contrast to its three-dimensional version, the studied system is non-auxetic, i.e. shows positive Poisson's ratio

No Clamp Robotic Assembly with Use of Point Cloud Data from Low-Cost Triangulation Scanner

The paper shows the clamp-less assembly idea as a very important one in the modern assembly. Assembly equipment such as clamps represent a significant group of industrial equipment in manufacturing plants whose number can be effectively reduced. The article presents the concept of using industrial robot equipped with a triangulation scanner in the assembly process in order to minimize the number of clamps that hold the units in a particular position in space. It also shows how the system searches for objects in the point cloud based on multi-step processing algorithm proposed in this work, then picks them up, transports and positions them in the right assembly locations with the use of industrial robot manipulator. The accuracy of the positioning of parts was also examined as well as the impact of the number of iterations of the algorithm searching the models in the point cloud on the accuracy of determining the position of the objects. The tests show that presented system is suitable for assembly of various items as plastic packaging and palletizing of products. Such kind of system is the basis for modern, fully flexible assembly systems

Flexible rod design for educational wind balance

This is a copy of the author 's preprint version of an article published in the journal Experimental techniques. The final publication is available at Springer via http://dx.doi.org/10.1007/s40799-016-0017-9This article provides a technical description of a flexible hinge for wind tunnel rigs. For academic purposes, the device was integrated into several rod flexures to build a home-made external wind balance system. The cylindrical elastic element incorporates several notches, and the flexure linkage is able to transmit force in the main axial direction without hindering perpendicular movement. The flexural element described here is simple and easily manufactured, and can also be used with other types of wind balance. The flexure described in this article has similar functionality to those mentioned in the reference section, but has a more compact element. The project's effectiveness was demonstrated in a series of experimental comparisons of forces and moments measured on a wing using the N.A.C.A. Clark-Y airfoil profile.Preprin

Epidermoid cysts of the cerebellopontine angle: Clinical features and treatment outcomes

Objective To report clinical characteristics, treatment outcomes and risk of recurrence in patients with surgically treated cerebellopontine angle epidermoids. Methods In 1994–2013, we operated 17 patients, including 7 with tumor limited to the cerebellopontine angle, 7 with cerebellopontine angle tumor penetrating supratentorially, and 3 with cerebellopontine angle tumor extending along skull base to contralateral cerebellopontine angle. All patients were followed-up for the mean duration of 126 months. Results On admission cranial nerve symptoms predominated. Total tumor removal was achieved in 5 patients, and incomplete removal (with small tumor remnants left on vessels, nerves, or brainstem) in 12 patients. Postoperatively, preoperative deficits worsened in 2 and new postoperative deficits occurred in 10 patients. The extent of tumor expansion had no effect on postoperative morbidity and risk of recurrence. During long-term follow-up, improvement or resolution of preoperative deficits was seen in 11 of 17 patients, and new postoperative deficits in 8 of 10 patients. Symptomatic recurrences after an average of more than 9 years were noted in 5 patients, 3 of whom were reoperated. Recurrences occurred in some younger patients and always in area of primary tumor. No effect of extent of tumor removal on risk of recurrence was found. Conclusions The extent of tumor removal had no effect on the risk of recurrence, and thus it may be acceptable to leave tumor capsule fragments adhering closely to nerves, vessels, or brainstem. During long-term follow-up, resolution or improvement of present preoperatively and new postoperative neurological deficits may be expected in most patients

Oral appliances for the treatment of obstructive sleep apnea and snoring – a literature review

According to the American Academy of Sleep Medicine, obstructive sleep apnea (OSA) is a sleep-related breathing disorder that involves a decrease or complete halt in the airflow of the upper airways despite an ongoing effort to breathe. Treatments for obstructive sleep apnea may include therapies with Continuous Positive Airway Pressure (CPAP), Oral Appliances (OA) or surgeries. OA are best suited for mild to moderate Obstructive Sleep Apnea, but are also an alternative for severe cases when a patient cannot tolerate Continuous Positive Airway Pressure (CPAP) treatment. They are also suitable for situations when there is no power for a CPAP machine such as camping and travelling. The appliances modify the upper airway by changing the posture of the mandible and tongue. The study was undertaken to review the available types of oral devices. The article also discusses the side effects, complications from appliance therapies and comparison with CPAP therapies or surgeries

Czynniki środowiskowe w analizie ESG

Socially Responsible Investing has been one of the major investment trends in the financial industry over the last years. Climate and environmental issues play an important role in it. There is some empirical evidence showing a link between a company's envi-ronmental responsibility and its financial results. The research suggests that companies standing out with respect to environmental performance achieve, on average, better and more stable financial results than competition that ignores this aspect. It is worth assuming that the Polish capital market will be, or already is, affected by this global trend. This implies that environmental factors will have a material impact on companies' operations, investors' interest and cost of capital. Our analysis points out that our market scores poorly in environmental issues compared to its counterparts, at least according to leading ESG rating agencies.(original abstract)Inwestowanie odpowiedzialne jest jednym z silniejszych trendów ostatnich lat na światowych rynkach finansowych. Kwestie klimatyczne i środowiskowe zajmują w tym obszarze istotne miejsce, jako element szerszej debaty o zmianach klimatu. Są empiryczne dowody na to, że istnieje zależność pomiędzy środowiskową odpowiedzialnością spółek a ich wynikami finansowymi. Badania sugerują, że spółki wyróżniające się pod kątem środowiskowym są w stanie osiągać średnio lepsze i bardziej stabilne wyniki finansowe niż konkurencja, która ignoruje te aspekty. Wydaje się, że jednym z kluczowych czynników, który ma na to wpływ, jest niższy koszt kapitału. Należy oczekiwać, że polski rynek finansowy nie pozostanie odporny na globalne trendy, a czynniki środowiskowe będą wywierały wymierny wpływ nie tylko na działalność operacyjną spółek, ale też zainteresowanie inwestorów i koszt dostarczanego kapitału. Niestety nasza analiza wskazuje, że czołowe instytucje oceniające spółki w obszarze środowiskowym przyznają rodzimym spółkom niskie oceny w tym obszarze, przynajmniej na tle innych rynków wschodzących.(abstrakt oryginalny