Tag Archives: lifehack

Bending polycarbonate glasses

Polycarbonate glasses (sunglasses, safety goggles) can be bent to better fit one’s head by heating the thermoplastic polymer with a lighter, gas stove or other heat source. Example photos are below. Polycarbonate is not flammable and tolerates repeated heating and cooling. The only problem is that the paint discolours when heated and the plastic buckles and wrinkles when bent, so the lenses should not be heated, lest they become unusable. However, for the handles, a better fit outweighs cosmetic appearance in many applications.

Asking questions of yourself

To make better decisions, ask about all your activities “Am I doing this right? Is there a better way?” I would have benefited from considering such questions about many everyday tasks. For example, I brushed my teeth wrong (sawing at the roots) until late teens, brushed my teeth at the wrong time (right after a meal when the enamel is soft) until my 30s. I only learned to cut my own hair in my mid-20s, and this was the highest-return investment I ever made, because a hair clipper costs as much as a haircut, so pays for itself with the first use.

Peeling a kiwi with a spoon is far easier than slicing with a knife. All it took to learn this was one web search, but it required asking myself the question of whether I was peeling fruit optimally. Same for extracting the seed from an avocado.

Cracking the shell of a hard-boiled egg, making two holes at the ends and blowing air under the membrane before peeling is another trick I wish I had known earlier.

Microwaved food is cooler in the centre, so to avoid scalding one’s mouth, it is helpful to start eating it from the middle. Cooked food left in a covered cooking pot or transferred to a storage container while still mildly hot does not go bad at room temperature for several days – doing this experiment required posing this hypothesis. Drinking without touching the bottle with one’s mouth turns out to be quite easy and is widespread in India.

Only after learning to drive did I start meaningfully using gears on a bicycle, and it took about 15 years more to start shifting approximately correctly (pedalling cadence 60-100 rotations per minute, downshifting before stopping, avoiding cross-geared riding). Similarly for basic bike maintenance like cleaning and oiling the chain, selecting the appropriate front and rear tire pressure given one’s weight and tire widths. Seat height is one thing I figured out early, but not handlebar height.

As a teenager, I would have benefited from asking myself whether I was overtraining, whether my nutrition was reasonable, how soon to return to training after various injuries and whether to seek medical assistance with these. Questioning the competence of coaches and doing a simple web search for sports medicine resources would have prevented following some of their mistaken advice.

Sometimes asking yourself the question reveals that you are already doing the task correctly. On the internet, people claim that they do not use shampoo, just water, and their hair stays clean-smelling and more lush than using detergent. An experiment not to use shampoo was a failure for me, causing greasy hair and lots of dandruff after a few days. The optimality of shampoo may depend on individual scalp and hair characteristics. On the other hand, a single-blade disposable razor and cold water give me a better shave than multi-bladed fancy brands with foam (that get clogged), and the disposable razor stays sharp enough for a month or two of everyday shaving.

When going to teach, it may be worth asking whether the room is the correct one, even if some students show up and the room is free, because once in this situation I was in a room with the right label, but in the wrong building.

On the other hand, constantly doubting oneself is unhealthy and unhelpful. If enough evidence points one way, then it is time to make up one’s mind.

Book-like screen arrangement

Office computer screens are mostly kept in the landscape orientation, but are usually used for documents, which are in the portrait format. Modern screens can be rotated to portrait mode, which makes reading print-view documents easier, or at least allows a larger fraction of the document to be displayed. Taking this one step further, for markup languages (XML, LaTeX) or programming, it is often helpful to see both the code and the compiled output side by side. This may be displayed on one large split screen in landscape orientation or two vertically oriented screens in a book-like arrangement, as in the following image.


Multifunctional layered clothing

Hiking websites recommend wearing layers, because these make adjusting between warm and cold weather or uphill and downhill walking simple. One thick garment would only work for cold, but taking it off when it gets too hot may leave only too thin clothing.

The same principle of layers applies for everyday clothes. My office is 12 degrees in winter mornings, so I wear two pairs of pants, sometimes two vests and a fleece. Instead of one thick pair of pants that would only suit cold temperatures, thin pants can be worn singly in warm weather and doubled up in cold.

For cycling in the cold, shorts can be worn under long athletic slacks. This principle should also work for hats – two thin fleece ski caps instead of one thick, but I have not tested it. Similarly, two pairs of socks. Although, just like with thick socks, if doubled socks make the shoes fit too tightly, then the reduced circulation increases the cold feeling.

Toe warmer making instructions on the internet suggest using the cut-off front parts of old socks. A more multifunctional option is to roll back existing socks halfway, so both the toe and the ankle part of the sock cover the toes, as in the following image.

Cut socks only work as toe warmers, but rolled-back socks can be used year round.

Food calories are not directly related to obesity

It seems that the change in bodyweight should be a strictly increasing function of calories eaten minus calories spent. The first caveat to this claim is that calories in the food eaten do not equal the calories absorbed, which is what matters for weight gain. People differ in the efficiency of their digestion – that is what bariatric surgery relies on. Also, food labels use calories measured by the burn method (dry the food, burn it, measure the heat output), which ignores for example that coarsely chewed food chunks pass through the digestive tract relatively unchanged, thus contribute few nutrients to the organism. An extreme example is wholegrain flax (linseeds) that remain undigested due to a waxy coating. In nature, seed dispersal by birds relies on the indigestibility of the seeds.

Even if calories absorbed could be accurately measured, the type of food eaten would still matter for weight gain due to imperfect willpower. Some foods are more addictive than others, notably those rich in refined carbohydrates – an easy example is drinks that are essentially sugar-water. Consuming a given amount of calories from high-glycaemic-load sucrose makes people eat more sooner on average than ingesting the same calories from slowly digested whole grains or unsaturated fat. Similarly, ignoring willpower limitations is why abstinence-based programs to prevent sexually transmitted infections, which naively might be expected to be 100% effective, are in fact ineffective (Underhill et al 2007, doi:10.1136/bmj.39245.446586.BE).

There are various tricks to circumvent limited willpower to win the game against one’s future tempted self. To reduce temptation, food should be out of sight outside mealtimes (in cupboards, drawers, fridge) and unhealthy snacks should not be bought at all. Even seeing dishes and cutlery may trigger cravings, in which case these too should be placed out of sight when not in use.

Avoiding grocery shopping while hungry is an old piece of advice, which may be taken further by having someone else buy your food. Two people can even agree to grocery-shop for each other according to shopping lists exchanged beforehand. Online ordering may be a solution, but of course the merchants want customers to buy more, so advertise tempting foods with photos on their website. These ads can be blocked with some effort. A more sophisticated solution is to have one’s own user interface (front end) interact with the merchant’s website – scrape the data on inventory and prices, send commands to buy.

Chair material should be breathable

Strangely enough, fancy office chairs are often upholstered in leather or other non-breathable material. After an hour or so, sitting in them gets uncomfortable because the moisture does not evaporate from the skin that is separated from the chair only by some cloth. However, people usually sit in office chairs for hours at a time, and I doubt that the chairs are designed to deliberately provide some discomfort to encourage users to occasionally stand up for health reasons. Especially in a hot climate when the air conditioning may break down or just be too weak, a breathable chair would make much more sense. Making a mesh chair is simple: stretch a breathable fabric on the chair frame. The small holes in the fabric let moisture evaporate from the surface. A mesh chair is probably cheaper to manufacture than a leather-upholstered one.

A reason for using leather may be to signal wealth by using a material associated with expensiveness.

Modern synthetic meshes are as durable as leather for practical purposes, because sitting in a chair is not a high-wear use.

Eggs boiled in an oatmeal cooker

In addition to rice cookers, multi-cookers and egg boilers, there are devices specifically for cooking oatmeal, even though a rice cooker would do the job just fine. Perhaps the reason is that the minimal cooking time is shorter for oatmeal than for rice, so an oatmeal cooker speeds up the process compared to a non-programmable rice cooker. A programmable one could of course be set for the shorter cooking time.

The normal cycle length of rice cookers (30-45 min) and oatmeal cookers (20 min) is longer than the 12-15 minutes it takes to hard-boil eggs. However, overcooking a hard-boiled egg does not worsen its taste or texture significantly in my opinion, unlike for meat or vegetables. It turns out that oatmeal does not stick to eggshells that much, so eggs boiled in a cooker together with the oatmeal can be rinsed off quite easily.

Boiling the eggs and oatmeal together saves either time (if there is only one device available for cooking) or the labour of washing one more cooker (when using separate ones for eggs and oatmeal). Even with a dishwasher, disassembling a cooker, putting it in and taking it out of the washer and reassembling takes a few minutes. Rinsing the eggs is quicker.

Protecting a wound or burn that needs frequent access

If it is necessary to put cream on a burn frequently, then a band-aid is inconvenient, because it must be pulled off every time. Also, a band-aid may stick to an oozing wound and reopen it every time it is pulled off. If the damaged skin needs covering, for example because the weather requires thick clothes, then one solution is to stick or tie a small cup-shaped object on top of the wound. Tying is preferable, because removing a stuck object again irritates the damaged area. The edges of the cup should be soft, because these press on the skin (so a plastic bottle cap is a bad idea). One soft-edged approximately cup-shaped object is the eyepiece of swimming goggles.

Swimming goggles protecting wound

The eyepiece is nicely attached to adjustable straps for tying it on with neither too much nor too little pressure. The eyepiece may be flipped over to the side to get access to the damaged skin.

Of course, the location of the wound may cause difficulties in tying swimming goggles on top of it, e.g. on the torso. Even on the arm or the leg, the lengthwise movement of the sleeve or pant leg may push the goggles off, because the strap running around the limb does not resist lengthwise movement well. Then adding some bandages may be necessary.
Overnight, the area under the goggles gets sweaty. To avoid this, small air holes may be drilled in the eyepieces, which of course makes the goggles useless for swimming.

Improvements for hotels

Commonly in hotels the room keycard has to be inserted into a slot for the lights in the room to turn on. An annoyance occurs when the lights are reset each time the card is removed and re-inserted, such as when leaving and re-entering the room (this problem and most of the subsequently mentioned ones are based on Courtyard by Marriott Chennai, but some are based on other hotels). Typically all the lights turn on and the unnecessary ones have to be turned off one by one. A simple and cheap microcomputer could remember the on-off settings of the lights and keep these until reset. Another similar problem is that the temperature of the AC or heating, as well as the fan speed, gets reset when the keycard is removed from the slot. Thus the AC has to be readjusted after each re-entry.

The keycard should work consistently, not require several attempts to operate the lift or open the room door.

It is a nice touch for a hotel to have a steam room, sauna or jacuzzi next to the fitness centre, but it would be even better if these were in working order and clean. Another nice touch is to provide slippers in the room, but if these are child-sized, then they are not very useful for an adult male. If there are two pairs of slippers in a room, then different-sized pairs would be reasonable and almost as cheap to provide as same-sized ones.

If (free) wifi is advertised, then it would be nice if it was working. Wifi problems can be detected automatically (by wifi-enabled devices placed in the corners of the hotel remotest from the routers) without waiting for annoyed guests to contact the front desk.

An electric kettle in the room is good for making tea, but placing glasses next to the kettle invites an absent-minded person to pour hot water into these, which cracks them.

The carpet should not shed hair that sticks to socks and anything else it comes into contact with (by floating in the air for example).

The fitness centres in hotels are typically less than 25 square metres. It is possible to choose machines and weights for a small room in such a way that cardio and all major muscle groups can be trained, but hotels seem to choose the machines randomly, e.g. three ellipticals and a stair stepper, but no rowing machine. Or two quadriceps training machines (leg extension and leg press), but no hamstring training machine (prone leg curl). This is despite the fact that quads are easy to train without a machine (do squats with or without weights), but hamstrings difficult.

A common problem in hotels is street noise in the room, which may be expensive to fix if the hotel construction quality is bad. One hotel in which the room was quiet despite a busy street outside was Sheraton New Delhi. A possible reason for its quietness was that the windows had two layers of packet glass, consisting of two or three layers each.

Hotel breakfasts should have a list of ingredients next to each dish, not just the name of the dish, especially when the name is unfamiliar to most visitors, e.g. the name is in the local language for a traditional ethnic dish. The list of ingredients would be especially helpful to people with food allergies, but the non-allergic would also benefit – it is easier to choose with more info. The ingredients in the list should be ordered, starting with the ones that constitute the largest percentage of the dish.

The arrangement of dishes at buffet meals should make it logistically convenient to get food, i.e. movement to and from the dishes should be unrestricted (no closely placed tables blocking the way) and similar foods should be located together. Sometimes hotels make strange food placement choices, for example I have seen soups and meat dishes alternate. Rydges on Swanston in Melbourne placed all the dishes in a small recess off the dining area, so there was a traffic jam of people trying to get into and out of that nook with their plates.

Made-to-order (live cooking) dishes at buffet meals could be prepared and distributed faster if their order system was computerised and the eaters could order the dishes from their smartphones. Peak demand time can be predicted and the cooking started in advance to speed up the delivery of the dishes. Such just-in-time production has economies of scale, so is especially easy for larger buffets.

The hotel room logistics are often strange, e.g. a narrow corridor leading from the door to the room, with wardrobes built into the side of the corridor. The doors of said wardrobes open outward, blocking the corridor. On the other hand, in the Chennai Marriott bathroom the shower stall and the the toilet were behind the same sliding door. To access the toilet, the door had to slide in front of the shower, and to access the shower, the door closed off the toilet. This would be annoying if two or more people stayed in that suite and tried to use the shower and toilet simultaneously, because both could not be behind a closed door at the same time.

Another logistical problem in both hotels and apartments is a toilet door that opens inward. When the toilet is small, the door almost hits the pot, making it difficult to maneuver around the door for entry and exit. Some toilets are so tiny that when sitting on the pot, the knees touch the opposite wall. In this case, it would be better to place the pot diagonally so the knees fit in a corner.

Two doors at the ends of a short corridor that both open into the corridor are impossible to open at the same time, which lengthens the time of passing through both doors.

Some hotels want to show how modern they are by replacing light switches with small touchscreens with LED backlighting. The little LED lights are numerous enough to somewhat light up the room when the ceiling and other lights are turned off. For sleeping, it would be good to be able to turn off the LED lights of the touchscreens.

If a motion detector turns on the light, then being able to switch off the motion detector and the light would be preferable. Sometimes the light is unnecessary, such as during the day with curtains open. The sudden bright light may also be annoying, for example when visiting the bathroom at night.

Hotel beds are usually short, so people over 180cm have their feet over the edge, unless they lie diagonally. Luckily hotel beds are usually wide, so their diagonal is significantly longer than the long side.

Saving ventilation cost by using the wind

Most large modern buildings have active ventilation built in, meaning that electric fans drive the air through the building. The airflow direction is usually fixed at construction time. However, if the wind happens to blow from the opposite direction to the ventilation flow, then the fans require extra energy to counter the wind. On the other hand, if the wind agrees with the airflow in the building, then the fans may not need to be run at all. To save electricity, a building could have a wind direction sensor (a weather vane) on the roof connected to a switch that reverses the ventilation fans, so that the fans always pump air in approximately the same direction as the wind. If the wind is strong enough, a wind speed sensor (a small windmill or windsock) on the roof could stop the ventilation fans altogether.
The tradeoff for this adaptive ventilation system is the initial fixed construction cost and the ongoing maintenance of the weather vane, windsock and controller of the fans. All the extra components of the system (relative to the current unidirectional ventilation) are cheap and robust, so the both the fixed cost and the maintenance should be negligible.
Current ventilation systems have differently shaped air inlets and outlets in the rooms, which suggests that the system requires a particular airflow direction. In this case, adaptive ventilation may be much more expensive than the current ones, because the ventilation shafts and air vents need to be doubled. To avoid the need to build twice as many shafts and vents, have just the air inlets and outlets of the whole building switch roles with the wind direction. The rest of the system can remain unidirectional when the valves from the building’s inlet and outlet to the rest of the system switch appropriately. The air inside the building can then move in the opposite direction of the wind some of the time. In this case, the electricity saving is only realised if the building is sufficiently airtight, which is the case for modern highrises that have unopenable windows. If the air is allowed to move through the building independently of the ventilation and the wind is opposite the airflow in the system, then the fans have to overcome the air pressure difference like in the current systems. This wastes electricity.